putty/unix/unifont.c

/*
 * Unified font management for GTK.
 *
 * PuTTY is willing to use both old-style X server-side bitmap
 * fonts _and_ GTK2/Pango client-side fonts. This requires us to
 * do a bit of work to wrap the two wildly different APIs into
 * forms the rest of the code can switch between seamlessly, and
 * also requires a custom font selector capable of handling both
 * types of font.
 */

#include <assert.h>
#include <stdlib.h>
#include <string.h>

#include <gtk/gtk.h>
#if !GTK_CHECK_VERSION(3,0,0)
#include <gdk/gdkkeysyms.h>
#endif

#define MAY_REFER_TO_GTK_IN_HEADERS

#include "putty.h"
#include "unifont.h"
#include "gtkcompat.h"
#include "gtkmisc.h"
#include "tree234.h"

#ifndef NOT_X_WINDOWS
#ifdef DRAW_TEXT_CAIRO
#include <cairo-xlib.h>
#include <cairo-xlib-xrender.h>
#include <X11/extensions/Xrender.h>
#endif
#include <gdk/gdkx.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xatom.h>
#include "x11misc.h"
#endif

/*
 * Future work:
 *
 *  - it would be nice to have a display of the current font name,
 *    and in particular whether it's client- or server-side,
 *    during the progress of the font selector.
 */

#if !GLIB_CHECK_VERSION(1,3,7)
#define g_ascii_strcasecmp g_strcasecmp
#define g_ascii_strncasecmp g_strncasecmp
#endif

/*
 * Ad-hoc vtable mechanism to allow font structures to be
 * polymorphic.
 *
 * Any instance of `unifont' used in the vtable functions will
 * actually be an element of a larger structure containing data
 * specific to the subtype.
 */

#define FONTFLAG_CLIENTSIDE    0x0001
#define FONTFLAG_SERVERSIDE    0x0002
#define FONTFLAG_SERVERALIAS   0x0004
#define FONTFLAG_NONMONOSPACED 0x0008

#define FONTFLAG_SORT_MASK     0x0007 /* used to disambiguate font families */

typedef void (*fontsel_add_entry)(void *ctx, const char *realfontname,
                                  const char *family, const char *charset,
                                  const char *style, const char *stylekey,
                                  int size, int flags,
                                  const struct UnifontVtable *fontclass);

struct UnifontVtable {
    /*
     * `Methods' of the `class'.
     */
    unifont *(*create)(GtkWidget *widget, const char *name, bool wide,
                       bool bold, int shadowoffset, bool shadowalways);
    unifont *(*create_fallback)(GtkWidget *widget, int height, bool wide,
                                bool bold, int shadowoffset,
                                bool shadowalways);
    void (*destroy)(unifont *font);
    bool (*has_glyph)(unifont *font, wchar_t glyph);
    void (*draw_text)(unifont_drawctx *ctx, unifont *font,
                      int x, int y, const wchar_t *string, int len,
                      bool wide, bool bold, int cellwidth);
    void (*draw_combining)(unifont_drawctx *ctx, unifont *font,
                           int x, int y, const wchar_t *string, int len,
                           bool wide, bool bold, int cellwidth);
    void (*enum_fonts)(GtkWidget *widget,
                       fontsel_add_entry callback, void *callback_ctx);
    char *(*canonify_fontname)(GtkWidget *widget, const char *name, int *size,
                               int *flags, bool resolve_aliases);
    char *(*scale_fontname)(GtkWidget *widget, const char *name, int size);
    char *(*size_increment)(unifont *font, int increment);

    /*
     * `Static data members' of the `class'.
     */
    const char *prefix;
};

#ifndef NOT_X_WINDOWS

/* ----------------------------------------------------------------------
 * X11 font implementation, directly using Xlib calls. Conditioned out
 * if X11 fonts aren't available at all (e.g. building with GTK3 for a
 * back end other than X).
 */

static bool x11font_has_glyph(unifont *font, wchar_t glyph);
static void x11font_draw_text(unifont_drawctx *ctx, unifont *font,
                              int x, int y, const wchar_t *string, int len,
                              bool wide, bool bold, int cellwidth);
static void x11font_draw_combining(unifont_drawctx *ctx, unifont *font,
                                   int x, int y, const wchar_t *string,
                                   int len, bool wide, bool bold,
                                   int cellwidth);
static unifont *x11font_create(GtkWidget *widget, const char *name,
                               bool wide, bool bold,
                               int shadowoffset, bool shadowalways);
static void x11font_destroy(unifont *font);
static void x11font_enum_fonts(GtkWidget *widget,
                               fontsel_add_entry callback, void *callback_ctx);
static char *x11font_canonify_fontname(GtkWidget *widget, const char *name,
                                       int *size, int *flags,
                                       bool resolve_aliases);
static char *x11font_scale_fontname(GtkWidget *widget, const char *name,
                                    int size);
static char *x11font_size_increment(unifont *font, int increment);

#ifdef DRAW_TEXT_CAIRO
struct cairo_cached_glyph {
    cairo_surface_t *surface;
};
#endif

/*
 * Structure storing a single physical XFontStruct, plus associated
 * data.
 */
typedef struct x11font_individual {
    /* The XFontStruct itself. */
    XFontStruct *xfs;

    /*
     * The `allocated' flag indicates whether we've tried to fetch
     * this subfont already (thus distinguishing xfs==NULL because we
     * haven't tried yet from xfs==NULL because we tried and failed,
     * so that we don't keep trying and failing subsequently).
     */
    bool allocated;

#ifdef DRAW_TEXT_CAIRO
    /* Cached pixmap etc for drawing into. */
    Pixmap pixmap;
    int pixwidth, pixheight, pixdepth;
    cairo_surface_t *surface;
    cairo_pattern_t *pattern;
    GC gc;
#endif

} x11font_individual;

struct x11font {
    /*
     * Copy of the X display handle, so we don't have to keep
     * extracting it from GDK.
     */
    Display *disp;
    /*
     * Individual physical X fonts. We store a number of these, for
     * automatically guessed bold and wide variants.
     */
    x11font_individual fonts[4];
    /*
     * `sixteen_bit' is true iff the font object is indexed by
     * values larger than a byte. That is, this flag tells us
     * whether the font is encoded in Unicode. If not, we need
     * to translate text into the font character set.
     */
    bool sixteen_bit;
    /*
     * `variable' is true iff the font is non-fixed-pitch. This
     * enables some code which takes greater care over character
     * positioning during text drawing.
     */
    bool variable;
    /*
     * real_charset is the charset used when translating text into the
     * font's internal encoding inside draw_text(). This need not be
     * the same as the public_charset provided to the client; for
     * example, public_charset might be CS_ISO8859_1 while
     * real_charset is CS_ISO8859_1_X11.
     */
    int real_charset;
    /*
     * Data passed in to unifont_create().
     */
    int shadowoffset;
    bool wide, bold, shadowalways;

    unifont u;
};

static const UnifontVtable x11font_vtable = {
    .create = x11font_create,
    .create_fallback = NULL, /* no fallback fonts in X11 */
    .destroy = x11font_destroy,
    .has_glyph = x11font_has_glyph,
    .draw_text = x11font_draw_text,
    .draw_combining = x11font_draw_combining,
    .enum_fonts = x11font_enum_fonts,
    .canonify_fontname = x11font_canonify_fontname,
    .scale_fontname = x11font_scale_fontname,
    .size_increment = x11font_size_increment,
    .prefix = "server",
};

#define XLFD_STRING_PARTS_LIST(S,I)             \
    S(foundry)                                  \
    S(family_name)                              \
    S(weight_name)                              \
    S(slant)                                    \
    S(setwidth_name)                            \
    S(add_style_name)                           \
    I(pixel_size)                               \
    I(point_size)                               \
    I(resolution_x)                             \
    I(resolution_y)                             \
    S(spacing)                                  \
    I(average_width)                            \
    S(charset_registry)                         \
    S(charset_encoding)                         \
    /* end of list */

/* Special value for int fields that xlfd_recompose will render as "*" */
#define XLFD_INT_WILDCARD INT_MIN

struct xlfd_decomposed {
#define STR_FIELD(f) const char *f;
#define INT_FIELD(f) int f;
    XLFD_STRING_PARTS_LIST(STR_FIELD, INT_FIELD)
#undef STR_FIELD
#undef INT_FIELD
};

static struct xlfd_decomposed *xlfd_decompose(const char *xlfd)
{
    char *p, *components[14];
    struct xlfd_decomposed *dec;
    int i;

    if (!xlfd)
        return NULL;

    dec = snew_plus(struct xlfd_decomposed, strlen(xlfd) + 1);
    p = snew_plus_get_aux(dec);
    strcpy(p, xlfd);

    for (i = 0; i < 14; i++) {
        if (*p != '-') {
            /* Malformed XLFD: not enough '-' */
            sfree(dec);
            return NULL;
        }
        *p++ = '\0';
        components[i] = p;
        p += strcspn(p, "-");
    }
    if (*p) {
        /* Malformed XLFD: too many '-' */
        sfree(dec);
        return NULL;
    }

    i = 0;
#define STORE_STR(f) dec->f = components[i++];
#define STORE_INT(f) dec->f = atoi(components[i++]);
    XLFD_STRING_PARTS_LIST(STORE_STR, STORE_INT)
#undef STORE_STR
#undef STORE_INT

    return dec;
}

static char *xlfd_recompose(const struct xlfd_decomposed *dec)
{
#define FMT_STR(f) "-%s"
#define ARG_STR(f) , dec->f
#define FMT_INT(f) "%s%.*d"
#define ARG_INT(f)                                      \
        , dec->f == XLFD_INT_WILDCARD ? "-*" : "-"      \
        , dec->f == XLFD_INT_WILDCARD ? 0 : 1           \
        , dec->f == XLFD_INT_WILDCARD ? 0 : dec->f
    return dupprintf(XLFD_STRING_PARTS_LIST(FMT_STR, FMT_INT)
                     XLFD_STRING_PARTS_LIST(ARG_STR, ARG_INT));
#undef FMT_STR
#undef ARG_STR
#undef FMT_INT
#undef ARG_INT
}

static char *x11_guess_derived_font_name(Display *disp, XFontStruct *xfs,
                                         bool bold, bool wide)
{
    Atom fontprop = XInternAtom(disp, "FONT", False);
    unsigned long ret;
    if (XGetFontProperty(xfs, fontprop, &ret)) {
        char *name = XGetAtomName(disp, (Atom)ret);
        struct xlfd_decomposed *xlfd = xlfd_decompose(name);
        if (!xlfd)
            return NULL;

        if (bold)
            xlfd->weight_name = "bold";

        if (wide) {
            /* Width name obviously may have changed. */
            /* Additional style may now become e.g. `ja' or `ko'. */
            xlfd->setwidth_name = xlfd->add_style_name = "*";

            /* Expect to double the average width. */
            xlfd->average_width *= 2;
        }

        {
            char *ret = xlfd_recompose(xlfd);
            sfree(xlfd);
            return ret;
        }
    }
    return NULL;
}

static int x11_font_width(XFontStruct *xfs)
{
    XChar2b space = { 0, '0' };
    return XTextWidth16(xfs, &space, 1);
}

static const XCharStruct *x11_char_struct(
    XFontStruct *xfs, unsigned char byte1, unsigned char byte2)
{
    int index;

    /*
     * The man page for XQueryFont is rather confusing about how the
     * per_char array in the XFontStruct is laid out, because it gives
     * formulae for determining the two-byte X character code _from_
     * an index into the per_char array. Going the other way, it's
     * rather simpler:
     *
     * The valid character codes have byte1 between min_byte1 and
     * max_byte1 inclusive, and byte2 between min_char_or_byte2 and
     * max_char_or_byte2 inclusive. This gives a rectangle of size
     * (max_byte2-min_byte1+1) by
     * (max_char_or_byte2-min_char_or_byte2+1), which is precisely the
     * rectangle encoded in the per_char array. Hence, given a
     * character code which is valid in the sense that it falls
     * somewhere in that rectangle, its index in per_char is given by
     * setting
     *
     *   x = byte2 - min_char_or_byte2
     *   y = byte1 - min_byte1
     *   index = y * (max_char_or_byte2-min_char_or_byte2+1) + x
     *
     * If min_byte1 and min_byte2 are both zero, that's a special case
     * which can be treated as if min_byte2 was 1 instead, i.e. the
     * per_char array just runs from min_char_or_byte2 to
     * max_char_or_byte2 inclusive, and byte1 should always be zero.
     */

    if (byte2 < xfs->min_char_or_byte2 || byte2 > xfs->max_char_or_byte2)
        return NULL;

    if (xfs->min_byte1 == 0 && xfs->max_byte1 == 0) {
        index = byte2 - xfs->min_char_or_byte2;
    } else {
        if (byte1 < xfs->min_byte1 || byte1 > xfs->max_byte1)
            return NULL;
        index = ((byte2 - xfs->min_char_or_byte2) +
                 ((byte1 - xfs->min_byte1) *
                  (xfs->max_char_or_byte2 - xfs->min_char_or_byte2 + 1)));
    }

    if (!xfs->per_char)   /* per_char NULL => everything in range exists */
        return &xfs->max_bounds;

    return &xfs->per_char[index];
}

static bool x11_font_has_glyph(
    XFontStruct *xfs, unsigned char byte1, unsigned char byte2)
{
    /*
     * Not to be confused with x11font_has_glyph, which is a method of
     * the x11font 'class' and hence takes a unifont as argument. This
     * is the low-level function which grubs about in an actual
     * XFontStruct to see if a given glyph exists.
     *
     * We must do this ourselves rather than letting Xlib's
     * XTextExtents16 do the job, because XTextExtents will helpfully
     * substitute the font's default_char for any missing glyph and
     * not tell us it did so, which precisely won't help us find out
     * which glyphs _are_ missing.
     */
    const XCharStruct *xcs = x11_char_struct(xfs, byte1, byte2);
    return xcs && (xcs->ascent + xcs->descent > 0 || xcs->width > 0);
}

static unifont *x11font_create(GtkWidget *widget, const char *name,
                               bool wide, bool bold,
                               int shadowoffset, bool shadowalways)
{
    struct x11font *xfont;
    XFontStruct *xfs;
    Display *disp;
    Atom charset_registry, charset_encoding, spacing;
    unsigned long registry_ret, encoding_ret, spacing_ret;
    int pubcs, realcs;
    bool sixteen_bit, variable;
    int i;

    if ((disp = get_x11_display()) == NULL)
        return NULL;

    xfs = XLoadQueryFont(disp, name);
    if (!xfs)
        return NULL;

    charset_registry = XInternAtom(disp, "CHARSET_REGISTRY", False);
    charset_encoding = XInternAtom(disp, "CHARSET_ENCODING", False);

    pubcs = realcs = CS_NONE;
    sixteen_bit = false;
    variable = true;

    if (XGetFontProperty(xfs, charset_registry, &registry_ret) &&
        XGetFontProperty(xfs, charset_encoding, &encoding_ret)) {
        char *reg, *enc;
        reg = XGetAtomName(disp, (Atom)registry_ret);
        enc = XGetAtomName(disp, (Atom)encoding_ret);
        if (reg && enc) {
            char *encoding = dupcat(reg, "-", enc);
            pubcs = realcs = charset_from_xenc(encoding);

            /*
             * iso10646-1 is the only wide font encoding we
             * support. In this case, we expect clients to give us
             * UTF-8, which this module must internally convert
             * into 16-bit Unicode.
             */
            if (!strcasecmp(encoding, "iso10646-1")) {
                sixteen_bit = true;
                pubcs = realcs = CS_UTF8;
            }

            /*
             * Hack for X line-drawing characters: if the primary font
             * is encoded as ISO-8859-1, and has valid glyphs in the
             * low character positions, it is assumed that those
             * glyphs are the VT100 line-drawing character set.
             */
            if (pubcs == CS_ISO8859_1) {
                int ch;
                for (ch = 1; ch < 32; ch++)
                    if (!x11_font_has_glyph(xfs, 0, ch))
                        break;
                if (ch == 32)
                    realcs = CS_ISO8859_1_X11;
            }

            sfree(encoding);
        }
    }

    spacing = XInternAtom(disp, "SPACING", False);
    if (XGetFontProperty(xfs, spacing, &spacing_ret)) {
        char *spc;
        spc = XGetAtomName(disp, (Atom)spacing_ret);

        if (spc && strchr("CcMm", spc[0]))
            variable = false;
    }

    xfont = snew(struct x11font);
    xfont->u.vt = &x11font_vtable;
    xfont->u.width = x11_font_width(xfs);
    xfont->u.ascent = xfs->ascent;
    xfont->u.descent = xfs->descent;
    xfont->u.height = xfont->u.ascent + xfont->u.descent;
    xfont->u.public_charset = pubcs;
    xfont->u.want_fallback = true;
    xfont->u.strikethrough_y = xfont->u.ascent - (xfont->u.ascent * 3 / 8);
#ifdef DRAW_TEXT_GDK
    xfont->u.preferred_drawtype = DRAWTYPE_GDK;
#elif defined DRAW_TEXT_CAIRO
    xfont->u.preferred_drawtype = DRAWTYPE_CAIRO;
#else
#error No drawtype available at all
#endif
    xfont->disp = disp;
    xfont->real_charset = realcs;
    xfont->sixteen_bit = sixteen_bit;
    xfont->variable = variable;
    xfont->wide = wide;
    xfont->bold = bold;
    xfont->shadowoffset = shadowoffset;
    xfont->shadowalways = shadowalways;

    for (i = 0; i < lenof(xfont->fonts); i++) {
        xfont->fonts[i].xfs = NULL;
        xfont->fonts[i].allocated = false;
#ifdef DRAW_TEXT_CAIRO
        xfont->fonts[i].pixmap = None;
        xfont->fonts[i].pixwidth = xfont->fonts[i].pixheight = 0;
        xfont->fonts[i].pixdepth = 0;
        xfont->fonts[i].surface = NULL;
        xfont->fonts[i].pattern = NULL;
        xfont->fonts[i].gc = None;
#endif
    }
    xfont->fonts[0].xfs = xfs;
    xfont->fonts[0].allocated = true;

    return &xfont->u;
}

static void x11font_destroy(unifont *font)
{
    struct x11font *xfont = container_of(font, struct x11font, u);
    Display *disp = xfont->disp;
    int i;

    for (i = 0; i < lenof(xfont->fonts); i++) {
        if (xfont->fonts[i].xfs)
            XFreeFont(disp, xfont->fonts[i].xfs);
#ifdef DRAW_TEXT_CAIRO
        if (xfont->fonts[i].gc != None)
            XFreeGC(disp, xfont->fonts[i].gc);
        if (xfont->fonts[i].pattern != NULL)
            cairo_pattern_destroy(xfont->fonts[i].pattern);
        if (xfont->fonts[i].surface != NULL)
            cairo_surface_destroy(xfont->fonts[i].surface);
        if (xfont->fonts[i].pixmap != None)
            XFreePixmap(disp, xfont->fonts[i].pixmap);
#endif
    }
    sfree(xfont);
}

static void x11_alloc_subfont(struct x11font *xfont, int sfid)
{
    Display *disp = xfont->disp;
    char *derived_name = x11_guess_derived_font_name(
        disp, xfont->fonts[0].xfs, sfid & 1, !!(sfid & 2));
    xfont->fonts[sfid].xfs = XLoadQueryFont(disp, derived_name);
    xfont->fonts[sfid].allocated = true;
    sfree(derived_name);
    /* Note that xfont->fonts[sfid].xfs may still be NULL, if XLQF failed. */
}

static bool x11font_has_glyph(unifont *font, wchar_t glyph)
{
    struct x11font *xfont = container_of(font, struct x11font, u);

    if (xfont->sixteen_bit) {
        /*
         * This X font has 16-bit character indices, which means
         * we can directly use our Unicode input value as long as
         * it's in the BMP.
         */
        return glyph < 0x10000 &&
            x11_font_has_glyph(xfont->fonts[0].xfs, glyph >> 8, glyph & 0xFF);
    } else {
        /*
         * This X font has 8-bit indices, so we must convert to the
         * appropriate character set.
         */
        char c = '\0';
        buffer_sink bs[1];
        buffer_sink_init(bs, &c, 1);
        put_wc_to_mb(bs, xfont->real_charset, &glyph, 1, "");
        if (!c)
            return false;              /* not even in the charset */

        return x11_font_has_glyph(xfont->fonts[0].xfs, 0, (unsigned char)c);
    }
}

#if !GTK_CHECK_VERSION(2,0,0)
#define GDK_DRAWABLE_XID(d) GDK_WINDOW_XWINDOW(d) /* GTK1's name for this */
#elif GTK_CHECK_VERSION(3,0,0)
#define GDK_DRAWABLE_XID(d) GDK_WINDOW_XID(d) /* GTK3's name for this */
#endif

static int x11font_width(unifont_drawctx *ctx, x11font_individual *xfi,
                         const XChar2b *string, int start, int length)
{
    return XTextWidth16(xfi->xfs, string+start, length);
}

#ifdef DRAW_TEXT_GDK
static void x11font_gdk_setup(unifont_drawctx *ctx, x11font_individual *xfi,
                              Display *disp)
{
    XSetFont(disp, GDK_GC_XGC(ctx->u.gdk.gc), xfi->xfs->fid);
}

static void x11font_gdk_draw(unifont_drawctx *ctx, x11font_individual *xfi,
                             Display *disp, int x, int y,
                             const XChar2b *string, int start, int length)
{
    XDrawString16(disp, GDK_DRAWABLE_XID(ctx->u.gdk.target),
                  GDK_GC_XGC(ctx->u.gdk.gc), x, y, string+start, length);
}
#endif

#ifdef DRAW_TEXT_CAIRO
static void x11font_cairo_setup(
    unifont_drawctx *ctx, x11font_individual *xfi, Display *disp)
{

}

static void x11font_cairo_ensure_pixmap(
    unifont_drawctx *ctx, x11font_individual *xfi, Display *disp,
    int width, int height)
{
    Pixmap newpixmap;
    XRenderPictFormat *pictformat = NULL;

    if (xfi->pixmap != None
        && xfi->pixwidth >= width && xfi->pixheight >= height) return;
    if (xfi->pixmap == None) {
        /*
         * To render X fonts under Cairo, we use the usual X font
         * rendering requests to draw text into a pixmap that's also a
         * Cairo surface and then use that as a mask to paint the
         * current colour into the terminal surface.  This means that
         * colours are entirely in the hands of Cairo and we don't
         * have to think about X colourmaps.  But we do need to be
         * able to create that pixmap.
         *
         * All X servers are required to support 1bpp pixmaps, and
         * Cairo can always use one of them as a mask.  But on 2025's
         * X servers, 1bpp font rendering is unaccelerated and hence
         * much slower than on deeper drawables.  So we find out if we
         * can make an 8-bit alpha-only surface, and only fall back to
         * a 1bpp pixmap if that fails.
         *
         * XRenderFindStandardFormat() will return NULL if the X
         * Rendering Extension is missing or unusable, so we don't
         * need to check that in advance.
         */
        pictformat = XRenderFindStandardFormat(disp, PictStandardA8);
        if (pictformat != NULL)
            xfi->pixdepth = 8;
        else
            xfi->pixdepth = 1;
    }
    if (width < xfi->pixwidth) width = xfi->pixwidth;
    if (height < xfi->pixheight) height = xfi->pixheight;
    newpixmap = XCreatePixmap(
        disp, GDK_DRAWABLE_XID(gtk_widget_get_window(ctx->u.cairo.widget)),
        width, height, xfi->pixdepth);
    if (xfi->pixmap != None) {
        assert(xfi->surface != NULL);
        cairo_xlib_surface_set_drawable(xfi->surface, newpixmap,
                                        width, height);
        XFreePixmap(disp, xfi->pixmap);
    } else {
        Screen *widgetscr =
            GDK_SCREEN_XSCREEN(gtk_widget_get_screen(ctx->u.cairo.widget));
        if (pictformat != NULL)
            xfi->surface = cairo_xlib_surface_create_with_xrender_format(
                disp, newpixmap, widgetscr, pictformat, width, height);
        else
            xfi->surface = cairo_xlib_surface_create_for_bitmap(
                disp, newpixmap, widgetscr, width, height);
        xfi->pattern = cairo_pattern_create_for_surface(xfi->surface);
        /* We really don't want bilinear interpolation of bitmap fonts. */
        cairo_pattern_set_filter(xfi->pattern, CAIRO_FILTER_NEAREST);
        XGCValues gcvals = { .font = xfi->xfs->fid };
        xfi->gc = XCreateGC(disp, newpixmap, GCFont, &gcvals);
    }
    XSetFunction(disp, xfi->gc, GXclear);
    XFillRectangle(disp, newpixmap, xfi->gc, 0, 0, width, height);
    xfi->pixmap = newpixmap;
    xfi->pixwidth = width;
    xfi->pixheight = height;
}

static void x11font_cairo_draw(
    unifont_drawctx *ctx, x11font_individual *xfi, Display *disp,
    int x, int y, const XChar2b *string, int start, int length)
{
    XCharStruct bounds;
    int pixwidth, pixheight, direction, font_ascent, font_descent;

    XTextExtents16(xfi->xfs, string + start, length,
                   &direction, &font_ascent, &font_descent, &bounds);
    pixwidth = bounds.rbearing - bounds.lbearing;
    pixheight = bounds.ascent + bounds.descent;
    if (pixwidth > 0 && pixheight > 0) {
        x11font_cairo_ensure_pixmap(ctx, xfi, disp, pixwidth, pixheight);
        XSetFunction(disp, xfi->gc, GXset);
        XDrawString16(disp, xfi->pixmap, xfi->gc,
                           -bounds.lbearing, bounds.ascent,
                           string+start, length);
        cairo_surface_mark_dirty(xfi->surface);
        cairo_matrix_t xfrm;
        cairo_matrix_init_translate(&xfrm,
                                    -x - bounds.lbearing, -y + bounds.ascent);
        cairo_pattern_set_matrix(xfi->pattern, &xfrm);
        cairo_mask(ctx->u.cairo.cr, xfi->pattern);
        /* Clear the part of the pixmap that we used. */
        XSetFunction(disp, xfi->gc, GXclear);
        XFillRectangle(disp, xfi->pixmap, xfi->gc, 0, 0, pixwidth, pixheight);
    }
}
#endif /* DRAW_TEXT_CAIRO */

struct x11font_drawfuncs {
    int (*width)(unifont_drawctx *ctx, x11font_individual *xfi,
                 const XChar2b *string, int start, int length);
    void (*setup)(unifont_drawctx *ctx, x11font_individual *xfi,
                  Display *disp);
    void (*draw)(unifont_drawctx *ctx, x11font_individual *xfi, Display *disp,
                 int x, int y, const XChar2b *string, int start, int length);
};

/*
 * This array has one entry per compiled-in drawtype.
 */
static const struct x11font_drawfuncs x11font_drawfuncs[DRAWTYPE_NTYPES] = {
#ifdef DRAW_TEXT_GDK
    /* gdk */
    {
        x11font_width,
        x11font_gdk_setup,
        x11font_gdk_draw,
    },
#endif
#ifdef DRAW_TEXT_CAIRO
    /* cairo */
    {
        x11font_width,
        x11font_cairo_setup,
        x11font_cairo_draw,
    },
#endif
};

static void x11font_really_draw_text(
    const struct x11font_drawfuncs *dfns, unifont_drawctx *ctx,
    x11font_individual *xfi, Display *disp,
    int x, int y, const void *string, int nchars,
    int shadowoffset, bool fontvariable, int cellwidth)
{
    int start = 0, step, nsteps;
    bool centre;

    if (fontvariable) {
        /*
         * In a variable-pitch font, we draw one character at a
         * time, and centre it in the character cell.
         */
        step = 1;
        nsteps = nchars;
        centre = true;
    } else {
        /*
         * In a fixed-pitch font, we can draw the whole lot in one go.
         */
        step = nchars;
        nsteps = 1;
        centre = false;
    }

    dfns->setup(ctx, xfi, disp);

    while (nsteps-- > 0) {
        int X = x;
        if (centre)
            X += (cellwidth - dfns->width(ctx, xfi, string, start, step)) / 2;

        dfns->draw(ctx, xfi, disp, X, y, string, start, step);
        if (shadowoffset)
            dfns->draw(ctx, xfi, disp, X + shadowoffset, y,
                       string, start, step);

        x += cellwidth;
        start += step;
    }
}

static void x11font_draw_text(unifont_drawctx *ctx, unifont *font,
                              int x, int y, const wchar_t *string, int len,
                              bool wide, bool bold, int cellwidth)
{
    struct x11font *xfont = container_of(font, struct x11font, u);
    int sfid;
    int shadowoffset = 0;
    int mult = (wide ? 2 : 1);
    int index = (int)ctx->type;

    wide = wide && !xfont->wide;
    bold = bold && !xfont->bold;

    /*
     * Decide which subfont we're using, and whether we have to
     * use shadow bold.
     */
    if (xfont->shadowalways && bold) {
        shadowoffset = xfont->shadowoffset;
        bold = false;
    }
    sfid = 2 * wide + bold;
    if (!xfont->fonts[sfid].allocated)
        x11_alloc_subfont(xfont, sfid);
    if (bold && !xfont->fonts[sfid].xfs) {
        bold = false;
        shadowoffset = xfont->shadowoffset;
        sfid = 2 * wide + bold;
        if (!xfont->fonts[sfid].allocated)
            x11_alloc_subfont(xfont, sfid);
    }

    if (!xfont->fonts[sfid].xfs)
        return;                        /* we've tried our best, but no luck */

    XChar2b *xcs;
    int i, xcslen;
    if (xfont->sixteen_bit) {
        /*
         * This X font has 16-bit character indices, which means
         * we can directly use our Unicode input string.
         */
        xcslen = len;
        xcs = snewn(xcslen, XChar2b);
        for (i = 0; i < xcslen; i++) {
            /* We shouldn't see any character not in the font. */
            assert(string[i] < 0x10000);
            xcs[i].byte1 = string[i] >> 8;
            xcs[i].byte2 = string[i];
        }
    } else {
        /*
         * This X font has 8-bit indices, so we must convert to the
         * appropriate character set.
         */
        strbuf *sb = strbuf_new();
        put_wc_to_mb(sb, xfont->real_charset, string, len, ".");
        xcslen = sb->len;
        xcs = snewn(xcslen, XChar2b);
        for (i = 0; i < xcslen; i++) {
            xcs[i].byte1 = 0;
            xcs[i].byte2 = sb->s[i];
        }
        strbuf_free(sb);
    }
    x11font_really_draw_text(x11font_drawfuncs + index, ctx,
                             &xfont->fonts[sfid], xfont->disp, x, y,
                             xcs, xcslen, shadowoffset,
                             xfont->variable, cellwidth * mult);
    sfree(xcs);
}

static void x11font_draw_combining(unifont_drawctx *ctx, unifont *font,
                                   int x, int y, const wchar_t *string,
                                   int len, bool wide, bool bold,
                                   int cellwidth)
{
    /*
     * For server-side fonts, there's no sophisticated system for
     * combining characters intelligently, so the best we can do is to
     * overprint them on each other in the obvious way.
     */
    int i;
    for (i = 0; i < len; i++)
        x11font_draw_text(ctx, font, x, y, string+i, 1, wide, bold, cellwidth);
}

static void x11font_enum_fonts(GtkWidget *widget,
                               fontsel_add_entry callback, void *callback_ctx)
{
    Display *disp;
    char **fontnames;
    char *tmp = NULL;
    int nnames, i, max, tmpsize;

    if ((disp = get_x11_display()) == NULL)
        return;

    max = 32768;
    while (1) {
        fontnames = XListFonts(disp, "*", max, &nnames);
        if (nnames >= max) {
            XFreeFontNames(fontnames);
            max *= 2;
        } else
            break;
    }

    tmpsize = 0;

    for (i = 0; i < nnames; i++) {
        struct xlfd_decomposed *xlfd = xlfd_decompose(fontnames[i]);
        if (xlfd) {
            char *p, *font, *style, *stylekey, *charset;
            int weightkey, slantkey, setwidthkey;
            int thistmpsize;

            /*
             * Convert a dismembered XLFD into the format we'll be
             * using in the font selector.
             */

            thistmpsize = 4 * strlen(fontnames[i]) + 256;
            if (tmpsize < thistmpsize) {
                tmpsize = thistmpsize;
                tmp = sresize(tmp, tmpsize, char);
            }
            p = tmp;

            /*
             * Font name is in the form "family (foundry)". (This is
             * what the GTK 1.2 X font selector does, and it seems to
             * come out looking reasonably sensible.)
             */
            font = p;
            p += 1 + sprintf(p, "%s (%s)", xlfd->family_name, xlfd->foundry);

            /*
             * Character set.
             */
            charset = p;
            p += 1 + sprintf(p, "%s-%s", xlfd->charset_registry,
                             xlfd->charset_encoding);

            /*
             * Style is a mixture of quite a lot of the fields,
             * with some strange formatting.
             */
            style = p;
            p += sprintf(p, "%s", xlfd->weight_name[0] ? xlfd->weight_name :
                         "regular");
            if (!g_ascii_strcasecmp(xlfd->slant, "i"))
                p += sprintf(p, " italic");
            else if (!g_ascii_strcasecmp(xlfd->slant, "o"))
                p += sprintf(p, " oblique");
            else if (!g_ascii_strcasecmp(xlfd->slant, "ri"))
                p += sprintf(p, " reverse italic");
            else if (!g_ascii_strcasecmp(xlfd->slant, "ro"))
                p += sprintf(p, " reverse oblique");
            else if (!g_ascii_strcasecmp(xlfd->slant, "ot"))
                p += sprintf(p, " other-slant");
            if (xlfd->setwidth_name[0] &&
                g_ascii_strcasecmp(xlfd->setwidth_name, "normal"))
                p += sprintf(p, " %s", xlfd->setwidth_name);
            if (!g_ascii_strcasecmp(xlfd->spacing, "m"))
                p += sprintf(p, " [M]");
            if (!g_ascii_strcasecmp(xlfd->spacing, "c"))
                p += sprintf(p, " [C]");
            if (xlfd->add_style_name[0])
                p += sprintf(p, " %s", xlfd->add_style_name);

            /*
             * Style key is the same stuff as above, but with a
             * couple of transformations done on it to make it
             * sort more sensibly.
             */
            p++;
            stylekey = p;
            if (!g_ascii_strcasecmp(xlfd->weight_name, "medium") ||
                !g_ascii_strcasecmp(xlfd->weight_name, "regular") ||
                !g_ascii_strcasecmp(xlfd->weight_name, "normal") ||
                !g_ascii_strcasecmp(xlfd->weight_name, "book"))
                weightkey = 0;
            else if (!g_ascii_strncasecmp(xlfd->weight_name, "demi", 4) ||
                     !g_ascii_strncasecmp(xlfd->weight_name, "semi", 4))
                weightkey = 1;
            else
                weightkey = 2;
            if (!g_ascii_strcasecmp(xlfd->slant, "r"))
                slantkey = 0;
            else if (!g_ascii_strncasecmp(xlfd->slant, "r", 1))
                slantkey = 2;
            else
                slantkey = 1;
            if (!g_ascii_strcasecmp(xlfd->setwidth_name, "normal"))
                setwidthkey = 0;
            else
                setwidthkey = 1;

            p += sprintf(
                p, "%04d%04d%s%04d%04d%s%04d%04d%s%04d%s%04d%s",
                weightkey, (int)strlen(xlfd->weight_name), xlfd->weight_name,
                slantkey, (int)strlen(xlfd->slant), xlfd->slant,
                setwidthkey,
                (int)strlen(xlfd->setwidth_name), xlfd->setwidth_name,
                (int)strlen(xlfd->spacing), xlfd->spacing,
                (int)strlen(xlfd->add_style_name), xlfd->add_style_name);

            assert(p - tmp < thistmpsize);

            /*
             * Flags: we need to know whether this is a monospaced
             * font, which we do by examining the spacing field
             * again.
             */
            int flags = FONTFLAG_SERVERSIDE;
            if (!strchr("CcMm", xlfd->spacing[0]))
                flags |= FONTFLAG_NONMONOSPACED;

            /*
             * Some fonts have a pixel size of zero, meaning they're
             * treated as scalable. For these purposes, we only want
             * fonts whose pixel size we actually know, so filter
             * those out.
             */
            if (xlfd->pixel_size)
                callback(callback_ctx, fontnames[i], font, charset,
                         style, stylekey, xlfd->pixel_size, flags,
                         &x11font_vtable);

            sfree(xlfd);
        } else {
            /*
             * This isn't an XLFD, so it must be an alias.
             * Transmit it with mostly null data.
             *
             * It would be nice to work out if it's monospaced
             * here, but at the moment I can't see that being
             * anything but computationally hideous. Ah well.
             */
            callback(callback_ctx, fontnames[i], fontnames[i], NULL,
                     NULL, NULL, 0, FONTFLAG_SERVERALIAS, &x11font_vtable);

            sfree(xlfd);
        }
    }
    XFreeFontNames(fontnames);
    sfree(tmp);
}

static char *x11font_canonify_fontname(GtkWidget *widget, const char *name,
                                       int *size, int *flags,
                                       bool resolve_aliases)
{
    /*
     * When given an X11 font name to try to make sense of for a
     * font selector, we must attempt to load it (to see if it
     * exists), and then canonify it by extracting its FONT
     * property, which should give its full XLFD even if what we
     * originally had was a wildcard.
     *
     * However, we must carefully avoid canonifying font
     * _aliases_, unless specifically asked to, because the font
     * selector treats them as worthwhile in their own right.
     */
    XFontStruct *xfs;
    Display *disp;
    Atom fontprop, fontprop2;
    unsigned long ret;

    if ((disp = get_x11_display()) == NULL)
        return NULL;

    xfs = XLoadQueryFont(disp, name);

    if (!xfs)
        return NULL;                   /* didn't make sense to us, sorry */

    fontprop = XInternAtom(disp, "FONT", False);

    if (XGetFontProperty(xfs, fontprop, &ret)) {
        char *newname = XGetAtomName(disp, (Atom)ret);
        if (newname) {
            unsigned long fsize = 12;

            fontprop2 = XInternAtom(disp, "PIXEL_SIZE", False);
            if (XGetFontProperty(xfs, fontprop2, &fsize) && fsize > 0) {
                *size = fsize;
                XFreeFont(disp, xfs);
                if (flags) {
                    if (name[0] == '-' || resolve_aliases)
                        *flags = FONTFLAG_SERVERSIDE;
                    else
                        *flags = FONTFLAG_SERVERALIAS;
                }
                return dupstr(name[0] == '-' || resolve_aliases ?
                              newname : name);
            }
        }
    }

    XFreeFont(disp, xfs);

    return NULL;                       /* something went wrong */
}

static char *x11font_scale_fontname(GtkWidget *widget, const char *name,
                                    int size)
{
    return NULL;                       /* shan't */
}

static char *x11font_size_increment(unifont *font, int increment)
{
    struct x11font *xfont = container_of(font, struct x11font, u);
    Display *disp = xfont->disp;
    Atom fontprop = XInternAtom(disp, "FONT", False);
    char *returned_name = NULL;
    unsigned long ret;
    if (XGetFontProperty(xfont->fonts[0].xfs, fontprop, &ret)) {
        struct xlfd_decomposed *xlfd;
        struct xlfd_decomposed *xlfd_best;
        char *wc;
        char **fontnames;
        int nnames, i, max;

        xlfd = xlfd_decompose(XGetAtomName(disp, (Atom)ret));
        if (!xlfd)
            return NULL;

        /*
         * Form a wildcard consisting of everything in the
         * original XLFD except for the size-related fields.
         */
        {
            struct xlfd_decomposed xlfd_wc = *xlfd; /* structure copy */
            xlfd_wc.pixel_size = XLFD_INT_WILDCARD;
            xlfd_wc.point_size = XLFD_INT_WILDCARD;
            xlfd_wc.average_width = XLFD_INT_WILDCARD;
            wc = xlfd_recompose(&xlfd_wc);
        }

        /*
         * Fetch all the font names matching that wildcard.
         */
        max = 32768;
        while (1) {
            fontnames = XListFonts(disp, wc, max, &nnames);
            if (nnames >= max) {
                XFreeFontNames(fontnames);
                max *= 2;
            } else
                break;
        }

        sfree(wc);

        /*
         * Iterate over those to find the one closest in size to the
         * original font, in the correct direction.
         */

#define FLIPPED_SIZE(xlfd) \
        (((xlfd)->pixel_size + (xlfd)->point_size) * \
         (increment < 0 ? -1 : +1))

        xlfd_best = NULL;
        for (i = 0; i < nnames; i++) {
            struct xlfd_decomposed *xlfd2 = xlfd_decompose(fontnames[i]);
            if (!xlfd2)
                continue;

            if (xlfd2->pixel_size != 0 &&
                FLIPPED_SIZE(xlfd2) > FLIPPED_SIZE(xlfd) &&
                (!xlfd_best || FLIPPED_SIZE(xlfd2)<FLIPPED_SIZE(xlfd_best))) {
                sfree(xlfd_best);
                xlfd_best = xlfd2;
                xlfd2 = NULL;
            }

            sfree(xlfd2);
        }

#undef FLIPPED_SIZE

        if (xlfd_best) {
            char *bare_returned_name = xlfd_recompose(xlfd_best);
            returned_name = dupcat(
                xfont->u.vt->prefix, ":", bare_returned_name);
            sfree(bare_returned_name);
        }

        XFreeFontNames(fontnames);
        sfree(xlfd);
        sfree(xlfd_best);
    }
    return returned_name;
}

#endif /* NOT_X_WINDOWS */

#if GTK_CHECK_VERSION(2,0,0)

/* ----------------------------------------------------------------------
 * Pango font implementation (for GTK 2+ only).
 */

#if defined PANGO_PRE_1POINT4 && !defined PANGO_PRE_1POINT6
#define PANGO_PRE_1POINT6              /* make life easier for pre-1.4 folk */
#endif

static bool pangofont_has_glyph(unifont *font, wchar_t glyph);
static void pangofont_draw_text(unifont_drawctx *ctx, unifont *font,
                                int x, int y, const wchar_t *string, int len,
                                bool wide, bool bold, int cellwidth);
static void pangofont_draw_combining(unifont_drawctx *ctx, unifont *font,
                                     int x, int y, const wchar_t *string,
                                     int len, bool wide, bool bold,
                                     int cellwidth);
static unifont *pangofont_create(GtkWidget *widget, const char *name,
                                 bool wide, bool bold,
                                 int shadowoffset, bool shadowalways);
static unifont *pangofont_create_fallback(GtkWidget *widget, int height,
                                          bool wide, bool bold,
                                          int shadowoffset, bool shadowalways);
static void pangofont_destroy(unifont *font);
static void pangofont_enum_fonts(GtkWidget *widget, fontsel_add_entry callback,
                                 void *callback_ctx);
static char *pangofont_canonify_fontname(GtkWidget *widget, const char *name,
                                         int *size, int *flags,
                                         bool resolve_aliases);
static char *pangofont_scale_fontname(GtkWidget *widget, const char *name,
                                      int size);
static char *pangofont_size_increment(unifont *font, int increment);

struct pangofont {
    /*
     * Pango objects.
     */
    PangoFontDescription *desc;
    PangoFontset *fset;
    /*
     * The containing widget.
     */
    GtkWidget *widget;
    /*
     * Data passed in to unifont_create().
     */
    int shadowoffset;
    bool bold, shadowalways;
    /*
     * Cache of character widths, indexed by Unicode code point. In
     * pixels; -1 means we haven't asked Pango about this character
     * before.
     */
    int *widthcache;
    unsigned nwidthcache;

    struct unifont u;
};

static const UnifontVtable pangofont_vtable = {
    .create = pangofont_create,
    .create_fallback = pangofont_create_fallback,
    .destroy = pangofont_destroy,
    .has_glyph = pangofont_has_glyph,
    .draw_text = pangofont_draw_text,
    .draw_combining = pangofont_draw_combining,
    .enum_fonts = pangofont_enum_fonts,
    .canonify_fontname = pangofont_canonify_fontname,
    .scale_fontname = pangofont_scale_fontname,
    .size_increment = pangofont_size_increment,
    .prefix = "client",
};

/*
 * This function is used to rigorously validate a
 * PangoFontDescription. Later versions of Pango have a nasty
 * habit of accepting _any_ old string as input to
 * pango_font_description_from_string and returning a font
 * description which can actually be used to display text, even if
 * they have to do it by falling back to their most default font.
 * This is doubtless helpful in some situations, but not here,
 * because we need to know if a Pango font string actually _makes
 * sense_ in order to fall back to treating it as an X font name
 * if it doesn't. So we check that the font family is actually one
 * supported by Pango.
 */
static bool pangofont_check_desc_makes_sense(PangoContext *ctx,
                                             PangoFontDescription *desc)
{
#ifndef PANGO_PRE_1POINT6
    PangoFontMap *map;
#endif
    PangoFontFamily **families;
    int i, nfamilies;
    bool matched;

    /*
     * Ask Pango for a list of font families, and iterate through
     * them to see if one of them matches the family in the
     * PangoFontDescription.
     */
#ifndef PANGO_PRE_1POINT6
    map = pango_context_get_font_map(ctx);
    if (!map)
        return false;
    pango_font_map_list_families(map, &families, &nfamilies);
#else
    pango_context_list_families(ctx, &families, &nfamilies);
#endif

    matched = false;
    for (i = 0; i < nfamilies; i++) {
        if (!g_ascii_strcasecmp(pango_font_family_get_name(families[i]),
                                pango_font_description_get_family(desc))) {
            matched = true;
            break;
        }
    }
    g_free(families);

    return matched;
}

static unifont *pangofont_create_internal(GtkWidget *widget,
                                          PangoContext *ctx,
                                          PangoFontDescription *desc,
                                          bool wide, bool bold,
                                          int shadowoffset, bool shadowalways)
{
    struct pangofont *pfont;
#ifndef PANGO_PRE_1POINT6
    PangoFontMap *map;
#endif
    PangoFontset *fset;
    PangoFontMetrics *metrics;

#ifndef PANGO_PRE_1POINT6
    map = pango_context_get_font_map(ctx);
    if (!map) {
        pango_font_description_free(desc);
        return NULL;
    }
    fset = pango_font_map_load_fontset(map, ctx, desc,
                                       pango_context_get_language(ctx));
#else
    fset = pango_context_load_fontset(ctx, desc,
                                      pango_context_get_language(ctx));
#endif
    if (!fset) {
        pango_font_description_free(desc);
        return NULL;
    }
    metrics = pango_fontset_get_metrics(fset);
    if (!metrics ||
        pango_font_metrics_get_approximate_digit_width(metrics) == 0) {
        pango_font_description_free(desc);
        g_object_unref(fset);
        return NULL;
    }

    pfont = snew(struct pangofont);
    pfont->u.vt = &pangofont_vtable;
    pfont->u.width =
        PANGO_PIXELS(pango_font_metrics_get_approximate_digit_width(metrics));
    pfont->u.ascent =
        PANGO_PIXELS_CEIL(pango_font_metrics_get_ascent(metrics));
    pfont->u.descent =
        PANGO_PIXELS_CEIL(pango_font_metrics_get_descent(metrics));
    pfont->u.height = pfont->u.ascent + pfont->u.descent;
    pfont->u.strikethrough_y =
        PANGO_PIXELS(pango_font_metrics_get_ascent(metrics) -
                     pango_font_metrics_get_strikethrough_position(metrics));
    pfont->u.want_fallback = false;
#ifdef DRAW_TEXT_CAIRO
    pfont->u.preferred_drawtype = DRAWTYPE_CAIRO;
#elif defined DRAW_TEXT_GDK
    pfont->u.preferred_drawtype = DRAWTYPE_GDK;
#else
#error No drawtype available at all
#endif
    /* The Pango API is hardwired to UTF-8 */
    pfont->u.public_charset = CS_UTF8;
    pfont->desc = desc;
    pfont->fset = fset;
    pfont->widget = widget;
    pfont->bold = bold;
    pfont->shadowoffset = shadowoffset;
    pfont->shadowalways = shadowalways;
    pfont->widthcache = NULL;
    pfont->nwidthcache = 0;

    pango_font_metrics_unref(metrics);

    return &pfont->u;
}

static unifont *pangofont_create(GtkWidget *widget, const char *name,
                                 bool wide, bool bold,
                                 int shadowoffset, bool shadowalways)
{
    PangoContext *ctx;
    PangoFontDescription *desc;

    desc = pango_font_description_from_string(name);
    if (!desc)
        return NULL;
    ctx = gtk_widget_get_pango_context(widget);
    if (!ctx) {
        pango_font_description_free(desc);
        return NULL;
    }
    if (!pangofont_check_desc_makes_sense(ctx, desc)) {
        pango_font_description_free(desc);
        return NULL;
    }
    return pangofont_create_internal(widget, ctx, desc, wide, bold,
                                     shadowoffset, shadowalways);
}

static unifont *pangofont_create_fallback(GtkWidget *widget, int height,
                                          bool wide, bool bold,
                                          int shadowoffset, bool shadowalways)
{
    PangoContext *ctx;
    PangoFontDescription *desc;

    desc = pango_font_description_from_string("Monospace");
    if (!desc)
        return NULL;
    ctx = gtk_widget_get_pango_context(widget);
    if (!ctx) {
        pango_font_description_free(desc);
        return NULL;
    }
    pango_font_description_set_absolute_size(desc, height * PANGO_SCALE);
    return pangofont_create_internal(widget, ctx, desc, wide, bold,
                                     shadowoffset, shadowalways);
}

static void pangofont_destroy(unifont *font)
{
    struct pangofont *pfont = container_of(font, struct pangofont, u);
    pango_font_description_free(pfont->desc);
    sfree(pfont->widthcache);
    g_object_unref(pfont->fset);
    sfree(pfont);
}

static int pangofont_char_width(PangoLayout *layout, struct pangofont *pfont,
                                wchar_t uchr, const char *utfchr, int utflen)
{
    /*
     * Here we check whether a character has the same width as the
     * character cell it'll be drawn in. Because profiling showed that
     * asking Pango for text sizes was a huge bottleneck when we were
     * calling it every time we needed to know this, we instead call
     * it only on characters we don't already know about, and cache
     * the results.
     */

    if ((unsigned)uchr >= pfont->nwidthcache) {
        unsigned newsize = ((int)uchr + 0x100) & ~0xFF;
        pfont->widthcache = sresize(pfont->widthcache, newsize, int);
        while (pfont->nwidthcache < newsize)
            pfont->widthcache[pfont->nwidthcache++] = -1;
    }

    if (pfont->widthcache[uchr] < 0) {
        PangoRectangle rect;
        pango_layout_set_text(layout, utfchr, utflen);
        pango_layout_get_extents(layout, NULL, &rect);
        pfont->widthcache[uchr] = rect.width;
    }

    return pfont->widthcache[uchr];
}

static bool pangofont_has_glyph(unifont *font, wchar_t glyph)
{
    /* Pango implements font fallback, so assume it has everything */
    return true;
}

#ifdef DRAW_TEXT_GDK
static void pango_gdk_draw_layout(unifont_drawctx *ctx,
                                  gint x, gint y, PangoLayout *layout)
{
    gdk_draw_layout(ctx->u.gdk.target, ctx->u.gdk.gc, x, y, layout);
}
#endif

#ifdef DRAW_TEXT_CAIRO
static void pango_cairo_draw_layout(unifont_drawctx *ctx,
                                    gint x, gint y, PangoLayout *layout)
{
    cairo_move_to(ctx->u.cairo.cr, x, y);
    pango_cairo_show_layout(ctx->u.cairo.cr, layout);
}
#endif

static void pangofont_draw_internal(unifont_drawctx *ctx, unifont *font,
                                    int x, int y, const wchar_t *string,
                                    int len, bool wide, bool bold,
                                    int cellwidth, bool combining)
{
    struct pangofont *pfont = container_of(font, struct pangofont, u);
    PangoLayout *layout;
    PangoRectangle rect;
    char *utfstring, *utfptr;
    size_t utflen;
    bool shadowbold = false;
    void (*draw_layout)(unifont_drawctx *ctx,
                        gint x, gint y, PangoLayout *layout) = NULL;

#ifdef DRAW_TEXT_GDK
    if (ctx->type == DRAWTYPE_GDK) {
        draw_layout = pango_gdk_draw_layout;
    }
#endif
#ifdef DRAW_TEXT_CAIRO
    if (ctx->type == DRAWTYPE_CAIRO) {
        draw_layout = pango_cairo_draw_layout;
    }
#endif
    assert(draw_layout);

    if (wide)
        cellwidth *= 2;

    y -= pfont->u.ascent;

    layout = pango_layout_new(gtk_widget_get_pango_context(pfont->widget));
    pango_layout_set_font_description(layout, pfont->desc);
    if (bold && !pfont->bold) {
        if (pfont->shadowalways)
            shadowbold = true;
        else {
            PangoFontDescription *desc2 =
                pango_font_description_copy_static(pfont->desc);
            pango_font_description_set_weight(desc2, PANGO_WEIGHT_BOLD);
            pango_layout_set_font_description(layout, desc2);
        }
    }

    /*
     * Pango always expects UTF-8, so convert the input wide character
     * string to UTF-8.
     */
    utfstring = dup_wc_to_mb_c(CS_UTF8, string, len, "", &utflen);

    utfptr = utfstring;
    while (utflen > 0) {
        size_t clen, n;
        int desired = cellwidth * PANGO_SCALE;

        /*
         * We want to display every character from this string in
         * the centre of its own character cell. In the worst case,
         * this requires a separate text-drawing call for each
         * character; but in the common case where the font is
         * properly fixed-width, we can draw many characters in one
         * go which is much faster.
         *
         * This still isn't really ideal. If you look at what
         * happens in the X protocol as a result of all of this, you
         * find - naturally enough - that each call to
         * gdk_draw_layout() generates a separate set of X RENDER
         * operations involving creating a picture, setting a clip
         * rectangle, doing some drawing and undoing the whole lot.
         * In an ideal world, we should _always_ be able to turn the
         * contents of this loop into a single RenderCompositeGlyphs
         * operation which internally specifies inter-character
         * deltas to get the spacing right, which would give us full
         * speed _even_ in the worst case of a non-fixed-width font.
         * However, Pango's architecture and documentation are so
         * unhelpful that I have no idea how if at all to persuade
         * them to do that.
         */

        if (combining) {
            /*
             * For a character with combining stuff, we just dump the
             * whole lot in one go, and expect it to take up just one
             * character cell.
             */
            clen = utflen;
            n = 1;
        } else {
            /*
             * Start by extracting a single UTF-8 character from the
             * string.
             */
            clen = 1;
            while (clen < utflen &&
                   (unsigned char)utfptr[clen] >= 0x80 &&
                   (unsigned char)utfptr[clen] < 0xC0)
                clen++;
            n = 1;

            if (is_rtl(string[0]) ||
                pangofont_char_width(layout, pfont, string[n-1],
                                     utfptr, clen) != desired) {
                /*
                 * If this character is a right-to-left one, or has an
                 * unusual width, then we must display it on its own.
                 */
            } else {
                /*
                 * Try to amalgamate a contiguous string of characters
                 * with the expected sensible width, for the common case
                 * in which we're using a monospaced font and everything
                 * works as expected.
                 */
                while (clen < utflen) {
                    int oldclen = clen;
                    clen++;                    /* skip UTF-8 introducer byte */
                    while (clen < utflen &&
                           (unsigned char)utfptr[clen] >= 0x80 &&
                           (unsigned char)utfptr[clen] < 0xC0)
                        clen++;
                    n++;
                    if (is_rtl(string[n-1]) ||
                        pangofont_char_width(layout, pfont,
                                             string[n-1], utfptr + oldclen,
                                             clen - oldclen) != desired) {
                        clen = oldclen;
                        n--;
                        break;
                    }
                }
            }
        }

        pango_layout_set_text(layout, utfptr, clen);
        pango_layout_get_pixel_extents(layout, NULL, &rect);

        draw_layout(ctx,
                    x + (n*cellwidth - rect.width)/2,
                    y + (pfont->u.height - rect.height)/2, layout);
        if (shadowbold)
            draw_layout(ctx,
                        x + (n*cellwidth - rect.width)/2 + pfont->shadowoffset,
                        y + (pfont->u.height - rect.height)/2, layout);

        utflen -= clen;
        utfptr += clen;
        string += n;
        x += n * cellwidth;
    }

    sfree(utfstring);

    g_object_unref(layout);
}

static void pangofont_draw_text(unifont_drawctx *ctx, unifont *font,
                                int x, int y, const wchar_t *string, int len,
                                bool wide, bool bold, int cellwidth)
{
    pangofont_draw_internal(ctx, font, x, y, string, len, wide, bold,
                            cellwidth, false);
}

static void pangofont_draw_combining(unifont_drawctx *ctx, unifont *font,
                                     int x, int y, const wchar_t *string,
                                     int len, bool wide, bool bold,
                                     int cellwidth)
{
    wchar_t *tmpstring = NULL;
    if (mk_wcwidth(string[0]) == 0) {
        /*
         * If we've been told to draw a sequence of _only_ combining
         * characters, prefix a space so that they have something to
         * combine with.
         */
        tmpstring = snewn(len+1, wchar_t);
        memcpy(tmpstring+1, string, len * sizeof(wchar_t));
        tmpstring[0] = L' ';
        string = tmpstring;
        len++;
    }
    pangofont_draw_internal(ctx, font, x, y, string, len, wide, bold,
                            cellwidth, true);
    sfree(tmpstring);
}

/*
 * Dummy size value to be used when converting a
 * PangoFontDescription of a scalable font to a string for
 * internal use.
 */
#define PANGO_DUMMY_SIZE 12

static void pangofont_enum_fonts(GtkWidget *widget, fontsel_add_entry callback,
                                 void *callback_ctx)
{
    PangoContext *ctx;
#ifndef PANGO_PRE_1POINT6
    PangoFontMap *map;
#endif
    PangoFontFamily **families;
    int i, nfamilies;

    ctx = gtk_widget_get_pango_context(widget);
    if (!ctx)
        return;

    /*
     * Ask Pango for a list of font families, and iterate through
     * them.
     */
#ifndef PANGO_PRE_1POINT6
    map = pango_context_get_font_map(ctx);
    if (!map)
        return;
    pango_font_map_list_families(map, &families, &nfamilies);
#else
    pango_context_list_families(ctx, &families, &nfamilies);
#endif
    for (i = 0; i < nfamilies; i++) {
        PangoFontFamily *family = families[i];
        const char *familyname;
        int flags;
        PangoFontFace **faces;
        int j, nfaces;

        /*
         * Set up our flags for this font family, and get the name
         * string.
         */
        flags = FONTFLAG_CLIENTSIDE;
#ifndef PANGO_PRE_1POINT4
        /*
         * In very early versions of Pango, we can't tell
         * monospaced fonts from non-monospaced.
         */
        if (!pango_font_family_is_monospace(family))
            flags |= FONTFLAG_NONMONOSPACED;
#endif
        familyname = pango_font_family_get_name(family);

        /*
         * Go through the available font faces in this family.
         */
        pango_font_family_list_faces(family, &faces, &nfaces);
        for (j = 0; j < nfaces; j++) {
            PangoFontFace *face = faces[j];
            PangoFontDescription *desc;
            const char *facename;
            int *sizes;
            int k, nsizes, dummysize;

            /*
             * Get the face name string.
             */
            facename = pango_font_face_get_face_name(face);

            /*
             * Set up a font description with what we've got so
             * far. We'll fill in the size field manually and then
             * call pango_font_description_to_string() to give the
             * full real name of the specific font.
             */
            desc = pango_font_face_describe(face);

            /*
             * See if this font has a list of specific sizes.
             */
#ifndef PANGO_PRE_1POINT4
            pango_font_face_list_sizes(face, &sizes, &nsizes);
#else
            /*
             * In early versions of Pango, that call wasn't
             * supported; we just have to assume everything is
             * scalable.
             */
            sizes = NULL;
#endif
            if (!sizes) {
                /*
                 * Write a single entry with a dummy size.
                 */
                dummysize = PANGO_DUMMY_SIZE * PANGO_SCALE;
                sizes = &dummysize;
                nsizes = 1;
            }

            /*
             * If so, go through them one by one.
             */
            for (k = 0; k < nsizes; k++) {
                char *fullname, *stylekey;

                pango_font_description_set_size(desc, sizes[k]);

                fullname = pango_font_description_to_string(desc);

                /*
                 * Construct the sorting key for font styles.
                 */
                {
                    strbuf *buf = strbuf_new();

                    int weight = pango_font_description_get_weight(desc);
                    /* Weight: normal, then lighter, then bolder */
                    if (weight <= PANGO_WEIGHT_NORMAL)
                        weight = PANGO_WEIGHT_NORMAL - weight;
                    put_fmt(buf, "%4d", weight);

                    put_fmt(buf, " %2d",
                            pango_font_description_get_style(desc));

                    int stretch = pango_font_description_get_stretch(desc);
                    /* Stretch: closer to normal sorts earlier */
                    stretch = 2 * abs(PANGO_STRETCH_NORMAL - stretch) +
                        (stretch < PANGO_STRETCH_NORMAL);
                    put_fmt(buf, " %2d", stretch);

                    put_fmt(buf, " %2d",
                            pango_font_description_get_variant(desc));

                    stylekey = strbuf_to_str(buf);
                }

                /*
                 * Got everything. Hand off to the callback.
                 * (The charset string is NULL, because only
                 * server-side X fonts use it.)
                 */
                callback(callback_ctx, fullname, familyname, NULL, facename,
                         stylekey,
                         (sizes == &dummysize ? 0 : PANGO_PIXELS(sizes[k])),
                         flags, &pangofont_vtable);

                sfree(stylekey);
                g_free(fullname);
            }
            if (sizes != &dummysize)
                g_free(sizes);

            pango_font_description_free(desc);
        }
        g_free(faces);
    }
    g_free(families);
}

static char *pangofont_canonify_fontname(GtkWidget *widget, const char *name,
                                         int *size, int *flags,
                                         bool resolve_aliases)
{
    /*
     * When given a Pango font name to try to make sense of for a
     * font selector, we must normalise it to PANGO_DUMMY_SIZE and
     * extract its original size (in pixels) into the `size' field.
     */
    PangoContext *ctx;
#ifndef PANGO_PRE_1POINT6
    PangoFontMap *map;
#endif
    PangoFontDescription *desc;
    PangoFontset *fset;
    PangoFontMetrics *metrics;
    char *newname, *retname;

    desc = pango_font_description_from_string(name);
    if (!desc)
        return NULL;
    ctx = gtk_widget_get_pango_context(widget);
    if (!ctx) {
        pango_font_description_free(desc);
        return NULL;
    }
    if (!pangofont_check_desc_makes_sense(ctx, desc)) {
        pango_font_description_free(desc);
        return NULL;
    }
#ifndef PANGO_PRE_1POINT6
    map = pango_context_get_font_map(ctx);
    if (!map) {
        pango_font_description_free(desc);
        return NULL;
    }
    fset = pango_font_map_load_fontset(map, ctx, desc,
                                       pango_context_get_language(ctx));
#else
    fset = pango_context_load_fontset(ctx, desc,
                                      pango_context_get_language(ctx));
#endif
    if (!fset) {
        pango_font_description_free(desc);
        return NULL;
    }
    metrics = pango_fontset_get_metrics(fset);
    if (!metrics ||
        pango_font_metrics_get_approximate_digit_width(metrics) == 0) {
        pango_font_description_free(desc);
        g_object_unref(fset);
        return NULL;
    }

    *size = PANGO_PIXELS(pango_font_description_get_size(desc));
    *flags = FONTFLAG_CLIENTSIDE;
    pango_font_description_set_size(desc, PANGO_DUMMY_SIZE * PANGO_SCALE);
    newname = pango_font_description_to_string(desc);
    retname = dupstr(newname);
    g_free(newname);

    pango_font_metrics_unref(metrics);
    pango_font_description_free(desc);
    g_object_unref(fset);

    return retname;
}

static char *pangofont_scale_fontname(GtkWidget *widget, const char *name,
                                      int size)
{
    PangoFontDescription *desc;
    char *newname, *retname;

    desc = pango_font_description_from_string(name);
    if (!desc)
        return NULL;
    pango_font_description_set_size(desc, size * PANGO_SCALE);
    newname = pango_font_description_to_string(desc);
    retname = dupstr(newname);
    g_free(newname);
    pango_font_description_free(desc);

    return retname;
}

static char *pangofont_size_increment(unifont *font, int increment)
{
    struct pangofont *pfont = container_of(font, struct pangofont, u);
    PangoFontDescription *desc;
    int size;
    char *newname, *retname;

    desc = pango_font_description_copy_static(pfont->desc);

    size = pango_font_description_get_size(desc);
    size += PANGO_SCALE * increment;

    if (size <= 0) {
        retname = NULL;
    } else {
        pango_font_description_set_size(desc, size);
        newname = pango_font_description_to_string(desc);
        retname = dupcat(pfont->u.vt->prefix, ":", newname);
        g_free(newname);
    }

    pango_font_description_free(desc);
    return retname;
}

#endif /* GTK_CHECK_VERSION(2,0,0) */

/* ----------------------------------------------------------------------
 * Outermost functions which do the vtable dispatch.
 */

/*
 * Complete list of font-type subclasses. Listed in preference
 * order for unifont_create(). (That is, in the extremely unlikely
 * event that the same font name is valid as both a Pango and an
 * X11 font, it will be interpreted as the former in the absence
 * of an explicit type-disambiguating prefix.)
 *
 * The 'multifont' subclass is omitted here, as discussed above.
 */
static const struct UnifontVtable *unifont_types[] = {
#if GTK_CHECK_VERSION(2,0,0)
    &pangofont_vtable,
#endif
#ifndef NOT_X_WINDOWS
    &x11font_vtable,
#endif
};

/*
 * Function which takes a font name and processes the optional
 * scheme prefix. Returns the tail of the font name suitable for
 * passing to individual font scheme functions, and also provides
 * a subrange of the unifont_types[] array above.
 *
 * The return values `start' and `end' denote a half-open interval
 * in unifont_types[]; that is, the correct way to iterate over
 * them is
 *
 *   for (i = start; i < end; i++) {...}
 */
static const char *unifont_do_prefix(const char *name, int *start, int *end)
{
    int colonpos = strcspn(name, ":");
    int i;

    if (name[colonpos]) {
        /*
         * There's a colon prefix on the font name. Use it to work
         * out which subclass to use.
         */
        for (i = 0; i < lenof(unifont_types); i++) {
            if (strlen(unifont_types[i]->prefix) == colonpos &&
                !strncmp(unifont_types[i]->prefix, name, colonpos)) {
                *start = i;
                *end = i+1;
                return name + colonpos + 1;
            }
        }
        /*
         * None matched, so return an empty scheme list to prevent
         * any scheme from being called at all.
         */
        *start = *end = 0;
        return name + colonpos + 1;
    } else {
        /*
         * No colon prefix, so just use all the subclasses.
         */
        *start = 0;
        *end = lenof(unifont_types);
        return name;
    }
}

unifont *unifont_create(GtkWidget *widget, const char *name, bool wide,
                        bool bold, int shadowoffset, bool shadowalways)
{
    int i, start, end;

    name = unifont_do_prefix(name, &start, &end);

    for (i = start; i < end; i++) {
        unifont *ret = unifont_types[i]->create(widget, name, wide, bold,
                                                shadowoffset, shadowalways);
        if (ret)
            return ret;
    }
    return NULL;                       /* font not found in any scheme */
}

void unifont_destroy(unifont *font)
{
    font->vt->destroy(font);
}

void unifont_draw_text(unifont_drawctx *ctx, unifont *font,
                       int x, int y, const wchar_t *string, int len,
                       bool wide, bool bold, int cellwidth)
{
    font->vt->draw_text(ctx, font, x, y, string, len, wide, bold, cellwidth);
}

void unifont_draw_combining(unifont_drawctx *ctx, unifont *font,
                            int x, int y, const wchar_t *string, int len,
                            bool wide, bool bold, int cellwidth)
{
    font->vt->draw_combining(ctx, font, x, y, string, len, wide, bold,
                             cellwidth);
}

char *unifont_size_increment(unifont *font, int increment)
{
    return font->vt->size_increment(font, increment);
}

/* ----------------------------------------------------------------------
 * Multiple-font wrapper. This is a type of unifont which encapsulates
 * up to two other unifonts, permitting missing glyphs in the main
 * font to be filled in by a fallback font.
 *
 * This is a type of unifont just like the previous two, but it has a
 * separate constructor which is manually called by the client, so it
 * doesn't appear in the list of available font types enumerated by
 * unifont_create. This means it's not used by unifontsel either, so
 * it doesn't need to support any methods except draw_text and
 * destroy.
 */

static void multifont_draw_text(unifont_drawctx *ctx, unifont *font,
                                int x, int y, const wchar_t *string, int len,
                                bool wide, bool bold, int cellwidth);
static void multifont_draw_combining(unifont_drawctx *ctx, unifont *font,
                                     int x, int y, const wchar_t *string,
                                     int len, bool wide, bool bold,
                                     int cellwidth);
static void multifont_destroy(unifont *font);
static char *multifont_size_increment(unifont *font, int increment);

struct multifont {
    unifont *main;
    unifont *fallback;

    struct unifont u;
};

static const UnifontVtable multifont_vtable = {
    .create = NULL, /* creation is done specially */
    .create_fallback = NULL,
    .destroy = multifont_destroy,
    .has_glyph = NULL,
    .draw_text = multifont_draw_text,
    .draw_combining = multifont_draw_combining,
    .enum_fonts = NULL,
    .canonify_fontname = NULL,
    .scale_fontname = NULL,
    .size_increment = multifont_size_increment,
    .prefix = "client",
};

unifont *multifont_create(GtkWidget *widget, const char *name,
                          bool wide, bool bold,
                          int shadowoffset, bool shadowalways)
{
    int i;
    unifont *font, *fallback;
    struct multifont *mfont;

    font = unifont_create(widget, name, wide, bold,
                          shadowoffset, shadowalways);
    if (!font)
        return NULL;

    fallback = NULL;
    if (font->want_fallback) {
        for (i = 0; i < lenof(unifont_types); i++) {
            if (unifont_types[i]->create_fallback) {
                fallback = unifont_types[i]->create_fallback(
                    widget, font->height, wide, bold,
                    shadowoffset, shadowalways);
                if (fallback)
                    break;
            }
        }
    }

    /*
     * Construct our multifont. Public members are all copied from the
     * primary font we're wrapping.
     */
    mfont = snew(struct multifont);
    mfont->u.vt = &multifont_vtable;
    mfont->u.width = font->width;
    mfont->u.ascent = font->ascent;
    mfont->u.descent = font->descent;
    mfont->u.height = font->height;
    mfont->u.strikethrough_y = font->strikethrough_y;
    mfont->u.public_charset = font->public_charset;
    mfont->u.want_fallback = false; /* shouldn't be needed, but just in case */
    mfont->u.preferred_drawtype = font->preferred_drawtype;
    mfont->main = font;
    mfont->fallback = fallback;

    return &mfont->u;
}

static void multifont_destroy(unifont *font)
{
    struct multifont *mfont = container_of(font, struct multifont, u);
    unifont_destroy(mfont->main);
    if (mfont->fallback)
        unifont_destroy(mfont->fallback);
    sfree(mfont);
}

typedef void (*unifont_draw_func_t)(unifont_drawctx *ctx, unifont *font,
                                    int x, int y, const wchar_t *string,
                                    int len, bool wide, bool bold,
                                    int cellwidth);

static void multifont_draw_main(unifont_drawctx *ctx, unifont *font, int x,
                                int y, const wchar_t *string, int len,
                                bool wide, bool bold, int cellwidth,
                                int cellinc, unifont_draw_func_t draw)
{
    struct multifont *mfont = container_of(font, struct multifont, u);
    unifont *f;
    bool ok;
    int i;

    while (len > 0) {
        /*
         * Find a maximal sequence of characters which are, or are
         * not, supported by our main font.
         */
        ok = mfont->main->vt->has_glyph(mfont->main, string[0]);
        for (i = 1;
             i < len &&
             !mfont->main->vt->has_glyph(mfont->main, string[i]) == !ok;
             i++);

        /*
         * Now display it.
         */
        f = ok ? mfont->main : mfont->fallback;
        if (f)
            draw(ctx, f, x, y, string, i, wide, bold, cellwidth);
        string += i;
        len -= i;
        x += i * cellinc;
    }
}

static void multifont_draw_text(unifont_drawctx *ctx, unifont *font, int x,
                                int y, const wchar_t *string, int len,
                                bool wide, bool bold, int cellwidth)
{
    multifont_draw_main(ctx, font, x, y, string, len, wide, bold,
                        cellwidth, cellwidth, unifont_draw_text);
}

static void multifont_draw_combining(unifont_drawctx *ctx, unifont *font,
                                     int x, int y, const wchar_t *string,
                                     int len, bool wide, bool bold,
                                     int cellwidth)
{
    multifont_draw_main(ctx, font, x, y, string, len, wide, bold,
                        cellwidth, 0, unifont_draw_combining);
}

static char *multifont_size_increment(unifont *font, int increment)
{
    struct multifont *mfont = container_of(font, struct multifont, u);
    return unifont_size_increment(mfont->main, increment);
}

#if GTK_CHECK_VERSION(2,0,0)

/* ----------------------------------------------------------------------
 * Implementation of a unified font selector. Used on GTK 2+ only;
 * for GTK 1 we still use the standard font selector.
 */

typedef struct fontinfo fontinfo;

typedef struct unifontsel_internal {
    GtkListStore *family_model, *style_model, *size_model;
    GtkWidget *family_list, *style_list, *size_entry, *size_list;
    GtkWidget *filter_buttons[4];
    int n_filter_buttons;
    GtkWidget *preview_area;
#ifndef NO_BACKING_PIXMAPS
    GdkPixmap *preview_pixmap;
#endif
    int preview_width, preview_height;
    GdkColor preview_fg, preview_bg;
    int filter_flags;
    tree234 *fonts_by_realname, *fonts_by_selorder;
    fontinfo *selected;
    int selsize, intendedsize;
    bool inhibit_response;  /* inhibit callbacks when we change GUI controls */

    unifontsel u;
} unifontsel_internal;

/*
 * The structure held in the tree234s. All the string members are
 * part of the same allocated area, so don't need freeing
 * separately.
 */
struct fontinfo {
    char *realname;
    char *family, *charset, *style, *stylekey;
    int size, flags;
    /*
     * Fallback sorting key, to permit multiple identical entries
     * to exist in the selorder tree.
     */
    int index;
    /*
     * Indices mapping fontinfo structures to indices in the list
     * boxes. sizeindex is irrelevant if the font is scalable
     * (size==0).
     */
    int familyindex, styleindex, sizeindex;
    /*
     * The class of font.
     */
    const struct UnifontVtable *fontclass;
};

struct fontinfo_realname_find {
    const char *realname;
    int flags;
};

static int strnullcasecmp(const char *a, const char *b)
{
    int i;

    /*
     * If exactly one of the inputs is NULL, it compares before
     * the other one.
     */
    if ((i = (!b) - (!a)) != 0)
        return i;

    /*
     * NULL compares equal.
     */
    if (!a)
        return 0;

    /*
     * Otherwise, ordinary strcasecmp.
     */
    return g_ascii_strcasecmp(a, b);
}

static int fontinfo_realname_compare(void *av, void *bv)
{
    fontinfo *a = (fontinfo *)av;
    fontinfo *b = (fontinfo *)bv;
    int i;

    if ((i = strnullcasecmp(a->realname, b->realname)) != 0)
        return i;
    if ((a->flags & FONTFLAG_SORT_MASK) != (b->flags & FONTFLAG_SORT_MASK))
        return ((a->flags & FONTFLAG_SORT_MASK) <
                (b->flags & FONTFLAG_SORT_MASK) ? -1 : +1);
    return 0;
}

static int fontinfo_realname_find(void *av, void *bv)
{
    struct fontinfo_realname_find *a = (struct fontinfo_realname_find *)av;
    fontinfo *b = (fontinfo *)bv;
    int i;

    if ((i = strnullcasecmp(a->realname, b->realname)) != 0)
        return i;
    if ((a->flags & FONTFLAG_SORT_MASK) != (b->flags & FONTFLAG_SORT_MASK))
        return ((a->flags & FONTFLAG_SORT_MASK) <
                (b->flags & FONTFLAG_SORT_MASK) ? -1 : +1);
    return 0;
}

static int fontinfo_selorder_compare(void *av, void *bv)
{
    fontinfo *a = (fontinfo *)av;
    fontinfo *b = (fontinfo *)bv;
    int i;
    if ((i = strnullcasecmp(a->family, b->family)) != 0)
        return i;
    /*
     * Font class comes immediately after family, so that fonts
     * from different classes with the same family
     */
    if ((a->flags & FONTFLAG_SORT_MASK) != (b->flags & FONTFLAG_SORT_MASK))
        return ((a->flags & FONTFLAG_SORT_MASK) <
                (b->flags & FONTFLAG_SORT_MASK) ? -1 : +1);
    if ((i = strnullcasecmp(a->charset, b->charset)) != 0)
        return i;
    if ((i = strnullcasecmp(a->stylekey, b->stylekey)) != 0)
        return i;
    if ((i = strnullcasecmp(a->style, b->style)) != 0)
        return i;
    if (a->size != b->size)
        return (a->size < b->size ? -1 : +1);
    if (a->index != b->index)
        return (a->index < b->index ? -1 : +1);
    return 0;
}

static void unifontsel_draw_preview_text(unifontsel_internal *fs);

static void unifontsel_deselect(unifontsel_internal *fs)
{
    fs->selected = NULL;
    gtk_list_store_clear(fs->style_model);
    gtk_list_store_clear(fs->size_model);
    gtk_widget_set_sensitive(fs->u.ok_button, false);
    gtk_widget_set_sensitive(fs->size_entry, false);
    unifontsel_draw_preview_text(fs);
}

static void unifontsel_setup_familylist(unifontsel_internal *fs)
{
    GtkTreeIter iter;
    int i, listindex, minpos = -1, maxpos = -1;
    char *currfamily = NULL;
    int currflags = -1;
    fontinfo *info;

    fs->inhibit_response = true;

    gtk_list_store_clear(fs->family_model);
    listindex = 0;

    /*
     * Search through the font tree for anything matching our
     * current filter criteria. When we find one, add its font
     * name to the list box.
     */
    for (i = 0 ;; i++) {
        info = (fontinfo *)index234(fs->fonts_by_selorder, i);
        /*
         * info may be NULL if we've just run off the end of the
         * tree. We must still do a processing pass in that
         * situation, in case we had an unfinished font record in
         * progress.
         */
        if (info && (info->flags &~ fs->filter_flags)) {
            info->familyindex = -1;
            continue;                  /* we're filtering out this font */
        }
        if (!info || strnullcasecmp(currfamily, info->family) ||
            currflags != (info->flags & FONTFLAG_SORT_MASK)) {
            /*
             * We've either finished a family, or started a new
             * one, or both.
             */
            if (currfamily) {
                gtk_list_store_append(fs->family_model, &iter);
                gtk_list_store_set(fs->family_model, &iter,
                                   0, currfamily, 1, minpos, 2, maxpos+1, -1);
                listindex++;
            }
            if (info) {
                minpos = i;
                currfamily = info->family;
                currflags = info->flags & FONTFLAG_SORT_MASK;
            }
        }
        if (!info)
            break;                     /* now we're done */
        info->familyindex = listindex;
        maxpos = i;
    }

    /*
     * If we've just filtered out the previously selected font,
     * deselect it thoroughly.
     */
    if (fs->selected && fs->selected->familyindex < 0)
        unifontsel_deselect(fs);

    fs->inhibit_response = false;
}

static void unifontsel_setup_stylelist(unifontsel_internal *fs,
                                       int start, int end)
{
    GtkTreeIter iter;
    int i, listindex, minpos = -1, maxpos = -1;
    bool started = false;
    char *currcs = NULL, *currstyle = NULL;
    fontinfo *info;

    gtk_list_store_clear(fs->style_model);
    listindex = 0;
    started = false;

    /*
     * Search through the font tree for anything matching our
     * current filter criteria. When we find one, add its charset
     * and/or style name to the list box.
     */
    for (i = start; i <= end; i++) {
        if (i == end)
            info = NULL;
        else
            info = (fontinfo *)index234(fs->fonts_by_selorder, i);
        /*
         * info may be NULL if we've just run off the end of the
         * relevant data. We must still do a processing pass in
         * that situation, in case we had an unfinished font
         * record in progress.
         */
        if (info && (info->flags &~ fs->filter_flags)) {
            info->styleindex = -1;
            continue;                  /* we're filtering out this font */
        }
        if (!info || !started || strnullcasecmp(currcs, info->charset) ||
            strnullcasecmp(currstyle, info->style)) {
            /*
             * We've either finished a style/charset, or started a
             * new one, or both.
             */
            started = true;
            if (currstyle) {
                gtk_list_store_append(fs->style_model, &iter);
                gtk_list_store_set(fs->style_model, &iter,
                                   0, currstyle, 1, minpos, 2, maxpos+1,
                                   3, true, 4, PANGO_WEIGHT_NORMAL, -1);
                listindex++;
            }
            if (info) {
                minpos = i;
                if (info->charset && strnullcasecmp(currcs, info->charset)) {
                    gtk_list_store_append(fs->style_model, &iter);
                    gtk_list_store_set(fs->style_model, &iter,
                                       0, info->charset, 1, -1, 2, -1,
                                       3, false, 4, PANGO_WEIGHT_BOLD, -1);
                    listindex++;
                }
                currcs = info->charset;
                currstyle = info->style;
            }
        }
        if (!info)
            break;                     /* now we're done */
        info->styleindex = listindex;
        maxpos = i;
    }
}

static const int unifontsel_default_sizes[] = { 10, 12, 14, 16, 20, 24, 32 };

static void unifontsel_setup_sizelist(unifontsel_internal *fs,
                                      int start, int end)
{
    GtkTreeIter iter;
    int i, listindex;
    char sizetext[40];
    fontinfo *info;

    gtk_list_store_clear(fs->size_model);
    listindex = 0;

    /*
     * Search through the font tree for anything matching our
     * current filter criteria. When we find one, add its font
     * name to the list box.
     */
    for (i = start; i < end; i++) {
        info = (fontinfo *)index234(fs->fonts_by_selorder, i);
        if (!info) {
            /* _shouldn't_ happen unless font list is completely funted */
            break;
        }
        if (info->flags &~ fs->filter_flags) {
            info->sizeindex = -1;
            continue;                  /* we're filtering out this font */
        }
        if (info->size) {
            sprintf(sizetext, "%d", info->size);
            info->sizeindex = listindex;
            gtk_list_store_append(fs->size_model, &iter);
            gtk_list_store_set(fs->size_model, &iter,
                               0, sizetext, 1, i, 2, info->size, -1);
            listindex++;
        } else {
            int j;

            assert(i == start);
            assert(i+1 == end);

            for (j = 0; j < lenof(unifontsel_default_sizes); j++) {
                sprintf(sizetext, "%d", unifontsel_default_sizes[j]);
                gtk_list_store_append(fs->size_model, &iter);
                gtk_list_store_set(fs->size_model, &iter, 0, sizetext, 1, i,
                                   2, unifontsel_default_sizes[j], -1);
                listindex++;
            }
        }
    }
}

static void unifontsel_set_filter_buttons(unifontsel_internal *fs)
{
    int i;

    for (i = 0; i < fs->n_filter_buttons; i++) {
        int flagbit = GPOINTER_TO_INT(g_object_get_data(
                                          G_OBJECT(fs->filter_buttons[i]),
                                          "user-data"));
        gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(fs->filter_buttons[i]),
                                     !!(fs->filter_flags & flagbit));
    }
}

static void unifontsel_draw_preview_text_inner(unifont_drawctx *dctx,
                                               unifontsel_internal *fs)
{
    unifont *font;
    char *sizename = NULL;
    fontinfo *info = fs->selected;

    if (info) {
        sizename = info->fontclass->scale_fontname(
            GTK_WIDGET(fs->u.window), info->realname, fs->selsize);
        font = info->fontclass->create(GTK_WIDGET(fs->u.window),
                                       sizename ? sizename : info->realname,
                                       false, false, 0, 0);
    } else
        font = NULL;

#ifdef DRAW_TEXT_GDK
    if (dctx->type == DRAWTYPE_GDK) {
        gdk_gc_set_foreground(dctx->u.gdk.gc, &fs->preview_bg);
        gdk_draw_rectangle(dctx->u.gdk.target, dctx->u.gdk.gc, 1, 0, 0,
                           fs->preview_width, fs->preview_height);
        gdk_gc_set_foreground(dctx->u.gdk.gc, &fs->preview_fg);
    }
#endif
#ifdef DRAW_TEXT_CAIRO
    if (dctx->type == DRAWTYPE_CAIRO) {
        cairo_set_source_rgb(dctx->u.cairo.cr,
                             fs->preview_bg.red / 65535.0,
                             fs->preview_bg.green / 65535.0,
                             fs->preview_bg.blue / 65535.0);
        cairo_paint(dctx->u.cairo.cr);
        cairo_set_source_rgb(dctx->u.cairo.cr,
                             fs->preview_fg.red / 65535.0,
                             fs->preview_fg.green / 65535.0,
                             fs->preview_fg.blue / 65535.0);
    }
#endif

    if (font) {
        /*
         * The pangram used here is rather carefully
         * constructed: it contains a sequence of very narrow
         * letters (`jil') and a pair of adjacent very wide
         * letters (`wm').
         *
         * If the user selects a proportional font, it will be
         * coerced into fixed-width character cells when used
         * in the actual terminal window. We therefore display
         * it the same way in the preview pane, so as to show
         * it the way it will actually be displayed - and we
         * deliberately pick a pangram which will show the
         * resulting miskerning at its worst.
         *
         * We aren't trying to sell people these fonts; we're
         * trying to let them make an informed choice. Better
         * that they find out the problems with using
         * proportional fonts in terminal windows here than
         * that they go to the effort of selecting their font
         * and _then_ realise it was a mistake.
         */
        info->fontclass->draw_text(dctx, font,
                                   0, font->ascent,
                                   L"bankrupt jilted showmen quiz convex fogey",
                                   41, false, false, font->width);
        info->fontclass->draw_text(dctx, font,
                                   0, font->ascent + font->height,
                                   L"BANKRUPT JILTED SHOWMEN QUIZ CONVEX FOGEY",
                                   41, false, false, font->width);
        /*
         * The ordering of punctuation here is also selected
         * with some specific aims in mind. I put ` and '
         * together because some software (and people) still
         * use them as matched quotes no matter what Unicode
         * might say on the matter, so people can quickly
         * check whether they look silly in a candidate font.
         * The sequence #_@ is there to let people judge the
         * suitability of the underscore as an effectively
         * alphabetic character (since that's how it's often
         * used in practice, at least by programmers).
         */
        info->fontclass->draw_text(dctx, font,
                                   0, font->ascent + font->height * 2,
                                   L"0123456789!?,.:;<>()[]{}\\/`'\"+*-=~#_@|%&^$",
                                   42, false, false, font->width);

        info->fontclass->destroy(font);
    }

    sfree(sizename);
}

static void unifontsel_draw_preview_text(unifontsel_internal *fs)
{
    unifont_drawctx dctx;
    GdkWindow *target;

#ifndef NO_BACKING_PIXMAPS
    target = fs->preview_pixmap;
#else
    target = gtk_widget_get_window(fs->preview_area);
#endif
    if (!target) /* we may be called when we haven't created everything yet */
        return;

    dctx.type = DRAWTYPE_DEFAULT;
#ifdef DRAW_TEXT_GDK
    if (dctx.type == DRAWTYPE_GDK) {
        dctx.u.gdk.target = target;
        dctx.u.gdk.gc = gdk_gc_new(target);
    }
#endif
#ifdef DRAW_TEXT_CAIRO
    if (dctx.type == DRAWTYPE_CAIRO) {
#if GTK_CHECK_VERSION(3,22,0)
        cairo_region_t *region;
#endif

        dctx.u.cairo.widget = GTK_WIDGET(fs->preview_area);

#if GTK_CHECK_VERSION(3,22,0)
        dctx.u.cairo.gdkwin = gtk_widget_get_window(dctx.u.cairo.widget);
        region = gdk_window_get_clip_region(dctx.u.cairo.gdkwin);
        dctx.u.cairo.drawctx = gdk_window_begin_draw_frame(
            dctx.u.cairo.gdkwin, region);
        dctx.u.cairo.cr = gdk_drawing_context_get_cairo_context(
            dctx.u.cairo.drawctx);
        cairo_region_destroy(region);
#else
        dctx.u.cairo.cr = gdk_cairo_create(target);
#endif
    }
#endif

    unifontsel_draw_preview_text_inner(&dctx, fs);

#ifdef DRAW_TEXT_GDK
    if (dctx.type == DRAWTYPE_GDK) {
        gdk_gc_unref(dctx.u.gdk.gc);
    }
#endif
#ifdef DRAW_TEXT_CAIRO
    if (dctx.type == DRAWTYPE_CAIRO) {
#if GTK_CHECK_VERSION(3,22,0)
        gdk_window_end_draw_frame(dctx.u.cairo.gdkwin, dctx.u.cairo.drawctx);
#else
        cairo_destroy(dctx.u.cairo.cr);
#endif
    }
#endif

    gdk_window_invalidate_rect(gtk_widget_get_window(fs->preview_area),
                               NULL, false);
}

static void unifontsel_select_font(unifontsel_internal *fs,
                                   fontinfo *info, int size, int leftlist,
                                   bool size_is_explicit)
{
    int index;
    int minval, maxval;
    gboolean success;
    GtkTreePath *treepath;
    GtkTreeIter iter;

    fs->inhibit_response = true;

    fs->selected = info;
    fs->selsize = size;
    if (size_is_explicit)
        fs->intendedsize = size;

    gtk_widget_set_sensitive(fs->u.ok_button, true);

    /*
     * Find the index of this fontinfo in the selorder list.
     */
    index = -1;
    findpos234(fs->fonts_by_selorder, info, NULL, &index);
    assert(index >= 0);

    /*
     * Adjust the font selector flags and redo the font family
     * list box, if necessary.
     */
    if (leftlist <= 0 &&
        (fs->filter_flags | info->flags) != fs->filter_flags) {
        fs->filter_flags |= info->flags;
        unifontsel_set_filter_buttons(fs);
        unifontsel_setup_familylist(fs);
    }

    /*
     * Find the appropriate family name and select it in the list.
     */
    assert(info->familyindex >= 0);
    treepath = gtk_tree_path_new_from_indices(info->familyindex, -1);
    gtk_tree_selection_select_path(
        gtk_tree_view_get_selection(GTK_TREE_VIEW(fs->family_list)),
        treepath);
    gtk_tree_view_scroll_to_cell(GTK_TREE_VIEW(fs->family_list),
                                 treepath, NULL, false, 0.0, 0.0);
    success = gtk_tree_model_get_iter(GTK_TREE_MODEL(fs->family_model),
                                      &iter, treepath);
    assert(success);
    gtk_tree_path_free(treepath);

    /*
     * Now set up the font style list.
     */
    gtk_tree_model_get(GTK_TREE_MODEL(fs->family_model), &iter,
                       1, &minval, 2, &maxval, -1);
    if (leftlist <= 1)
        unifontsel_setup_stylelist(fs, minval, maxval);

    /*
     * Find the appropriate style name and select it in the list.
     */
    if (info->style) {
        assert(info->styleindex >= 0);
        treepath = gtk_tree_path_new_from_indices(info->styleindex, -1);
        gtk_tree_selection_select_path(
            gtk_tree_view_get_selection(GTK_TREE_VIEW(fs->style_list)),
            treepath);
        gtk_tree_view_scroll_to_cell(GTK_TREE_VIEW(fs->style_list),
                                     treepath, NULL, false, 0.0, 0.0);
        gtk_tree_model_get_iter(GTK_TREE_MODEL(fs->style_model),
                                &iter, treepath);
        gtk_tree_path_free(treepath);

        /*
         * And set up the size list.
         */
        gtk_tree_model_get(GTK_TREE_MODEL(fs->style_model), &iter,
                           1, &minval, 2, &maxval, -1);
        if (leftlist <= 2)
            unifontsel_setup_sizelist(fs, minval, maxval);

        /*
         * Find the appropriate size, and select it in the list.
         */
        if (info->size) {
            assert(info->sizeindex >= 0);
            treepath = gtk_tree_path_new_from_indices(info->sizeindex, -1);
            gtk_tree_selection_select_path(
                gtk_tree_view_get_selection(GTK_TREE_VIEW(fs->size_list)),
                treepath);
            gtk_tree_view_scroll_to_cell(GTK_TREE_VIEW(fs->size_list),
                                         treepath, NULL, false, 0.0, 0.0);
            gtk_tree_path_free(treepath);
            size = info->size;
        } else {
            int j;
            for (j = 0; j < lenof(unifontsel_default_sizes); j++)
                if (unifontsel_default_sizes[j] == size) {
                    treepath = gtk_tree_path_new_from_indices(j, -1);
                    gtk_tree_view_set_cursor(GTK_TREE_VIEW(fs->size_list),
                                             treepath, NULL, false);
                    gtk_tree_view_scroll_to_cell(GTK_TREE_VIEW(fs->size_list),
                                                 treepath, NULL, false, 0.0,
                                                 0.0);
                    gtk_tree_path_free(treepath);
                }
        }

        /*
         * And set up the font size text entry box.
         */
        {
            char sizetext[40];
            sprintf(sizetext, "%d", size);
            gtk_entry_set_text(GTK_ENTRY(fs->size_entry), sizetext);
        }
    } else {
        if (leftlist <= 2)
            unifontsel_setup_sizelist(fs, 0, 0);
        gtk_entry_set_text(GTK_ENTRY(fs->size_entry), "");
    }

    /*
     * Grey out the font size edit box if we're not using a
     * scalable font.
     */
    gtk_editable_set_editable(GTK_EDITABLE(fs->size_entry),
                              fs->selected->size == 0);
    gtk_widget_set_sensitive(fs->size_entry, fs->selected->size == 0);

    unifontsel_draw_preview_text(fs);

    fs->inhibit_response = false;
}

static void unifontsel_button_toggled(GtkToggleButton *tb, gpointer data)
{
    unifontsel_internal *fs = (unifontsel_internal *)data;
    bool newstate = gtk_toggle_button_get_active(tb);
    int newflags;
    int flagbit = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(tb),
                                                    "user-data"));

    if (newstate)
        newflags = fs->filter_flags | flagbit;
    else
        newflags = fs->filter_flags & ~flagbit;

    if (fs->filter_flags != newflags) {
        fs->filter_flags = newflags;
        unifontsel_setup_familylist(fs);
    }
}

static void unifontsel_add_entry(void *ctx, const char *realfontname,
                                 const char *family, const char *charset,
                                 const char *style, const char *stylekey,
                                 int size, int flags,
                                 const struct UnifontVtable *fontclass)
{
    unifontsel_internal *fs = (unifontsel_internal *)ctx;
    fontinfo *info;
    int totalsize;
    char *p;

    totalsize = sizeof(fontinfo) + strlen(realfontname) +
        (family ? strlen(family) : 0) + (charset ? strlen(charset) : 0) +
        (style ? strlen(style) : 0) + (stylekey ? strlen(stylekey) : 0) + 10;
    info = (fontinfo *)smalloc(totalsize);
    info->fontclass = fontclass;
    p = (char *)info + sizeof(fontinfo);
    info->realname = p;
    strcpy(p, realfontname);
    p += 1+strlen(p);
    if (family) {
        info->family = p;
        strcpy(p, family);
        p += 1+strlen(p);
    } else
        info->family = NULL;
    if (charset) {
        info->charset = p;
        strcpy(p, charset);
        p += 1+strlen(p);
    } else
        info->charset = NULL;
    if (style) {
        info->style = p;
        strcpy(p, style);
        p += 1+strlen(p);
    } else
        info->style = NULL;
    if (stylekey) {
        info->stylekey = p;
        strcpy(p, stylekey);
        p += 1+strlen(p);
    } else
        info->stylekey = NULL;
    assert(p - (char *)info <= totalsize);
    info->size = size;
    info->flags = flags;
    info->index = count234(fs->fonts_by_selorder);

    /*
     * It's just conceivable that a misbehaving font enumerator
     * might tell us about the same font real name more than once,
     * in which case we should silently drop the new one.
     */
    if (add234(fs->fonts_by_realname, info) != info) {
        sfree(info);
        return;
    }
    /*
     * However, we should never get a duplicate key in the
     * selorder tree, because the index field carefully
     * disambiguates otherwise identical records.
     */
    add234(fs->fonts_by_selorder, info);
}

static fontinfo *update_for_intended_size(unifontsel_internal *fs,
                                          fontinfo *info)
{
    fontinfo info2, *below, *above;
    int pos;

    /*
     * Copy the info structure. This doesn't copy its dynamic
     * string fields, but that's unimportant because all we're
     * going to do is to adjust the size field and use it in one
     * tree search.
     */
    info2 = *info;
    info2.size = fs->intendedsize;

    /*
     * Search in the tree to find the fontinfo structure which
     * best approximates the size the user last requested.
     */
    below = findrelpos234(fs->fonts_by_selorder, &info2, NULL,
                          REL234_LE, &pos);
    if (!below)
        pos = -1;
    above = index234(fs->fonts_by_selorder, pos+1);

    /*
     * See if we've found it exactly, which is an easy special
     * case. If we have, it'll be in `below' and not `above',
     * because we did a REL234_LE rather than REL234_LT search.
     */
    if (below && !fontinfo_selorder_compare(&info2, below))
        return below;

    /*
     * Now we've either found two suitable fonts, one smaller and
     * one larger, or we're at one or other extreme end of the
     * scale. Find out which, by NULLing out either of below and
     * above if it differs from this one in any respect but size
     * (and the disambiguating index field). Bear in mind, also,
     * that either one might _already_ be NULL if we're at the
     * extreme ends of the font list.
     */
    if (below) {
        info2.size = below->size;
        info2.index = below->index;
        if (fontinfo_selorder_compare(&info2, below))
            below = NULL;
    }
    if (above) {
        info2.size = above->size;
        info2.index = above->index;
        if (fontinfo_selorder_compare(&info2, above))
            above = NULL;
    }

    /*
     * Now return whichever of above and below is non-NULL, if
     * that's unambiguous.
     */
    if (!above)
        return below;
    if (!below)
        return above;

    /*
     * And now we really do have to make a choice about whether to
     * round up or down. We'll do it by rounding to nearest,
     * breaking ties by rounding up.
     */
    if (above->size - fs->intendedsize <= fs->intendedsize - below->size)
        return above;
    else
        return below;
}

static void family_changed(GtkTreeSelection *treeselection, gpointer data)
{
    unifontsel_internal *fs = (unifontsel_internal *)data;
    GtkTreeModel *treemodel;
    GtkTreeIter treeiter;
    int minval;
    fontinfo *info;

    if (fs->inhibit_response)          /* we made this change ourselves */
        return;

    if (!gtk_tree_selection_get_selected(treeselection, &treemodel, &treeiter))
        return;

    gtk_tree_model_get(treemodel, &treeiter, 1, &minval, -1);
    info = (fontinfo *)index234(fs->fonts_by_selorder, minval);
    if (!info)
        return; /* _shouldn't_ happen unless font list is completely funted */
    info = update_for_intended_size(fs, info);
    if (!info)
        return; /* similarly shouldn't happen */
    if (!info->size)
        fs->selsize = fs->intendedsize;   /* font is scalable */
    unifontsel_select_font(fs, info, info->size ? info->size : fs->selsize,
                           1, false);
}

static void style_changed(GtkTreeSelection *treeselection, gpointer data)
{
    unifontsel_internal *fs = (unifontsel_internal *)data;
    GtkTreeModel *treemodel;
    GtkTreeIter treeiter;
    int minval;
    fontinfo *info;

    if (fs->inhibit_response)          /* we made this change ourselves */
        return;

    if (!gtk_tree_selection_get_selected(treeselection, &treemodel, &treeiter))
        return;

    gtk_tree_model_get(treemodel, &treeiter, 1, &minval, -1);
    if (minval < 0)
        return;                    /* somehow a charset heading got clicked */
    info = (fontinfo *)index234(fs->fonts_by_selorder, minval);
    if (!info)
        return; /* _shouldn't_ happen unless font list is completely funted */
    info = update_for_intended_size(fs, info);
    if (!info)
        return; /* similarly shouldn't happen */
    if (!info->size)
        fs->selsize = fs->intendedsize;   /* font is scalable */
    unifontsel_select_font(fs, info, info->size ? info->size : fs->selsize,
                           2, false);
}

static void size_changed(GtkTreeSelection *treeselection, gpointer data)
{
    unifontsel_internal *fs = (unifontsel_internal *)data;
    GtkTreeModel *treemodel;
    GtkTreeIter treeiter;
    int minval, size;
    fontinfo *info;

    if (fs->inhibit_response)          /* we made this change ourselves */
        return;

    if (!gtk_tree_selection_get_selected(treeselection, &treemodel, &treeiter))
        return;

    gtk_tree_model_get(treemodel, &treeiter, 1, &minval, 2, &size, -1);
    info = (fontinfo *)index234(fs->fonts_by_selorder, minval);
    if (!info)
        return; /* _shouldn't_ happen unless font list is completely funted */
    unifontsel_select_font(fs, info, info->size ? info->size : size, 3, true);
}

static void size_entry_changed(GtkEditable *ed, gpointer data)
{
    unifontsel_internal *fs = (unifontsel_internal *)data;
    const char *text;
    int size;

    if (fs->inhibit_response)          /* we made this change ourselves */
        return;

    text = gtk_entry_get_text(GTK_ENTRY(ed));
    size = atoi(text);

    if (size > 0) {
        assert(fs->selected->size == 0);
        unifontsel_select_font(fs, fs->selected, size, 3, true);
    }
}

static void alias_resolve(GtkTreeView *treeview, GtkTreePath *path,
                          GtkTreeViewColumn *column, gpointer data)
{
    unifontsel_internal *fs = (unifontsel_internal *)data;
    GtkTreeIter iter;
    int minval, newsize;
    fontinfo *info, *newinfo;
    char *newname;

    if (fs->inhibit_response)          /* we made this change ourselves */
        return;

    gtk_tree_model_get_iter(GTK_TREE_MODEL(fs->family_model), &iter, path);
    gtk_tree_model_get(GTK_TREE_MODEL(fs->family_model), &iter, 1,&minval, -1);
    info = (fontinfo *)index234(fs->fonts_by_selorder, minval);
    if (info) {
        int flags;
        struct fontinfo_realname_find f;

        newname = info->fontclass->canonify_fontname(
            GTK_WIDGET(fs->u.window), info->realname, &newsize, &flags, true);

        f.realname = newname;
        f.flags = flags;
        newinfo = find234(fs->fonts_by_realname, &f, fontinfo_realname_find);

        sfree(newname);
        if (!newinfo)
            return;                    /* font name not in our index */
        if (newinfo == info)
            return;   /* didn't change under canonification => not an alias */
        unifontsel_select_font(fs, newinfo,
                               newinfo->size ? newinfo->size : newsize,
                               1, true);
    }
}

#if GTK_CHECK_VERSION(3,0,0)
static gint unifontsel_draw_area(GtkWidget *widget, cairo_t *cr, gpointer data)
{
    unifontsel_internal *fs = (unifontsel_internal *)data;
    unifont_drawctx dctx;

    dctx.type = DRAWTYPE_CAIRO;
    dctx.u.cairo.widget = widget;
    dctx.u.cairo.cr = cr;
    unifontsel_draw_preview_text_inner(&dctx, fs);

    return true;
}
#else
static gint unifontsel_expose_area(GtkWidget *widget, GdkEventExpose *event,
                                   gpointer data)
{
    unifontsel_internal *fs = (unifontsel_internal *)data;

#ifndef NO_BACKING_PIXMAPS
    if (fs->preview_pixmap) {
        gdk_draw_pixmap(gtk_widget_get_window(widget),
                        (gtk_widget_get_style(widget)->fg_gc
                         [gtk_widget_get_state(widget)]),
                        fs->preview_pixmap,
                        event->area.x, event->area.y,
                        event->area.x, event->area.y,
                        event->area.width, event->area.height);
    }
#else
    unifontsel_draw_preview_text(fs);
#endif

    return true;
}
#endif

static gint unifontsel_configure_area(GtkWidget *widget,
                                      GdkEventConfigure *event, gpointer data)
{
#ifndef NO_BACKING_PIXMAPS
    unifontsel_internal *fs = (unifontsel_internal *)data;
    int ox, oy, nx, ny, x, y;

    /*
     * Enlarge the pixmap, but never shrink it.
     */
    ox = fs->preview_width;
    oy = fs->preview_height;
    x = event->width;
    y = event->height;
    if (x > ox || y > oy) {
        if (fs->preview_pixmap)
            gdk_pixmap_unref(fs->preview_pixmap);

        nx = (x > ox ? x : ox);
        ny = (y > oy ? y : oy);
        fs->preview_pixmap = gdk_pixmap_new(gtk_widget_get_window(widget),
                                            nx, ny, -1);
        fs->preview_width = nx;
        fs->preview_height = ny;

        unifontsel_draw_preview_text(fs);
    }
#endif

    gdk_window_invalidate_rect(gtk_widget_get_window(widget), NULL, false);

    return true;
}

unifontsel *unifontsel_new(const char *wintitle)
{
    unifontsel_internal *fs = snew(unifontsel_internal);
    GtkWidget *table, *label, *w, *ww, *scroll;
    GtkListStore *model;
    GtkTreeViewColumn *column;
    int lists_height, preview_height, font_width, style_width, size_width;
    int i;

    fs->inhibit_response = false;
    fs->selected = NULL;

    {
        int width, height;

        /*
         * Invent some magic size constants.
         */
        get_label_text_dimensions("Quite Long Font Name (Foundry)",
                                  &width, &height);
        font_width = width;
        lists_height = 14 * height;
        preview_height = 5 * height;

        get_label_text_dimensions("Italic Extra Condensed", &width, &height);
        style_width = width;

        get_label_text_dimensions("48000", &width, &height);
        size_width = width;
    }

    /*
     * Create the dialog box and initialise the user-visible
     * fields in the returned structure.
     */
    fs->u.user_data = NULL;
    fs->u.window = GTK_WINDOW(gtk_dialog_new());
    gtk_window_set_title(fs->u.window, wintitle);
    fs->u.cancel_button = gtk_dialog_add_button(
        GTK_DIALOG(fs->u.window), STANDARD_CANCEL_LABEL, GTK_RESPONSE_CANCEL);
    fs->u.ok_button = gtk_dialog_add_button(
        GTK_DIALOG(fs->u.window), STANDARD_OK_LABEL, GTK_RESPONSE_OK);
    gtk_widget_grab_default(fs->u.ok_button);

    /*
     * Now set up the internal fields, including in particular all
     * the controls that actually allow the user to select fonts.
     */
#if GTK_CHECK_VERSION(3,0,0)
    table = gtk_grid_new();
    gtk_grid_set_column_spacing(GTK_GRID(table), 8);
#else
    table = gtk_table_new(8, 3, false);
    gtk_table_set_col_spacings(GTK_TABLE(table), 8);
#endif
    gtk_widget_show(table);

#if GTK_CHECK_VERSION(3,0,0)
    /* GtkAlignment has become deprecated and we use the "margin"
     * property */
    w = table;
    g_object_set(G_OBJECT(w), "margin", 8, (const char *)NULL);
#elif GTK_CHECK_VERSION(2,4,0)
    /* GtkAlignment seems to be the simplest way to put padding round things */
    w = gtk_alignment_new(0, 0, 1, 1);
    gtk_alignment_set_padding(GTK_ALIGNMENT(w), 8, 8, 8, 8);
    gtk_container_add(GTK_CONTAINER(w), table);
    gtk_widget_show(w);
#else
    /* In GTK < 2.4, even that isn't available */
    w = table;
#endif

    gtk_box_pack_start(GTK_BOX(gtk_dialog_get_content_area(
                                   GTK_DIALOG(fs->u.window))),
                       w, true, true, 0);

    label = gtk_label_new_with_mnemonic("_Font:");
    gtk_widget_show(label);
    align_label_left(GTK_LABEL(label));
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), label, 0, 0, 1, 1);
    g_object_set(G_OBJECT(label), "hexpand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), label, 0, 1, 0, 1, GTK_FILL, 0, 0, 0);
#endif

    /*
     * The Font list box displays only a string, but additionally
     * stores two integers which give the limits within the
     * tree234 of the font entries covered by this list entry.
     */
    model = gtk_list_store_new(3, G_TYPE_STRING, G_TYPE_INT, G_TYPE_INT);
    w = gtk_tree_view_new_with_model(GTK_TREE_MODEL(model));
    gtk_tree_view_set_headers_visible(GTK_TREE_VIEW(w), false);
    gtk_label_set_mnemonic_widget(GTK_LABEL(label), w);
    gtk_widget_show(w);
    column = gtk_tree_view_column_new_with_attributes(
        "Font", gtk_cell_renderer_text_new(),
        "text", 0, (char *)NULL);
    gtk_tree_view_column_set_sizing(column, GTK_TREE_VIEW_COLUMN_AUTOSIZE);
    gtk_tree_view_append_column(GTK_TREE_VIEW(w), column);
    g_signal_connect(G_OBJECT(gtk_tree_view_get_selection(GTK_TREE_VIEW(w))),
                     "changed", G_CALLBACK(family_changed), fs);
    g_signal_connect(G_OBJECT(w), "row-activated",
                     G_CALLBACK(alias_resolve), fs);

    scroll = gtk_scrolled_window_new(NULL, NULL);
    gtk_scrolled_window_set_shadow_type(GTK_SCROLLED_WINDOW(scroll),
                                        GTK_SHADOW_IN);
    gtk_container_add(GTK_CONTAINER(scroll), w);
    gtk_widget_show(scroll);
    gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(scroll),
                                   GTK_POLICY_AUTOMATIC, GTK_POLICY_ALWAYS);
    gtk_widget_set_size_request(scroll, font_width, lists_height);
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), scroll, 0, 1, 1, 2);
    g_object_set(G_OBJECT(scroll), "expand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), scroll, 0, 1, 1, 3, GTK_FILL,
                     GTK_EXPAND | GTK_FILL, 0, 0);
#endif
    fs->family_model = model;
    fs->family_list = w;

    label = gtk_label_new_with_mnemonic("_Style:");
    gtk_widget_show(label);
    align_label_left(GTK_LABEL(label));
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), label, 1, 0, 1, 1);
    g_object_set(G_OBJECT(label), "hexpand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), label, 1, 2, 0, 1, GTK_FILL, 0, 0, 0);
#endif

    /*
     * The Style list box can contain insensitive elements (character
     * set headings for server-side fonts), so we add an extra column
     * to the list store to hold that information. Also, since GTK3 at
     * least doesn't seem to display insensitive elements differently
     * by default, we add a further column to change their style.
     */
    model = gtk_list_store_new(5, G_TYPE_STRING, G_TYPE_INT, G_TYPE_INT,
                               G_TYPE_BOOLEAN, G_TYPE_INT);
    w = gtk_tree_view_new_with_model(GTK_TREE_MODEL(model));
    gtk_tree_view_set_headers_visible(GTK_TREE_VIEW(w), false);
    gtk_label_set_mnemonic_widget(GTK_LABEL(label), w);
    gtk_widget_show(w);
    column = gtk_tree_view_column_new_with_attributes(
        "Style", gtk_cell_renderer_text_new(),
        "text", 0, "sensitive", 3, "weight", 4, (char *)NULL);
    gtk_tree_view_column_set_sizing(column, GTK_TREE_VIEW_COLUMN_AUTOSIZE);
    gtk_tree_view_append_column(GTK_TREE_VIEW(w), column);
    g_signal_connect(G_OBJECT(gtk_tree_view_get_selection(GTK_TREE_VIEW(w))),
                     "changed", G_CALLBACK(style_changed), fs);

    scroll = gtk_scrolled_window_new(NULL, NULL);
    gtk_scrolled_window_set_shadow_type(GTK_SCROLLED_WINDOW(scroll),
                                        GTK_SHADOW_IN);
    gtk_container_add(GTK_CONTAINER(scroll), w);
    gtk_widget_show(scroll);
    gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(scroll),
                                   GTK_POLICY_AUTOMATIC, GTK_POLICY_ALWAYS);
    gtk_widget_set_size_request(scroll, style_width, lists_height);
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), scroll, 1, 1, 1, 2);
    g_object_set(G_OBJECT(scroll), "expand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), scroll, 1, 2, 1, 3, GTK_FILL,
                     GTK_EXPAND | GTK_FILL, 0, 0);
#endif
    fs->style_model = model;
    fs->style_list = w;

    label = gtk_label_new_with_mnemonic("Si_ze:");
    gtk_widget_show(label);
    align_label_left(GTK_LABEL(label));
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), label, 2, 0, 1, 1);
    g_object_set(G_OBJECT(label), "hexpand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), label, 2, 3, 0, 1, GTK_FILL, 0, 0, 0);
#endif

    /*
     * The Size label attaches primarily to a text input box so
     * that the user can select a size of their choice. The list
     * of available sizes is secondary.
     */
    fs->size_entry = w = gtk_entry_new();
    gtk_label_set_mnemonic_widget(GTK_LABEL(label), w);
    gtk_widget_set_size_request(w, size_width, -1);
    gtk_widget_show(w);
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), w, 2, 1, 1, 1);
    g_object_set(G_OBJECT(w), "hexpand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), w, 2, 3, 1, 2, GTK_FILL, 0, 0, 0);
#endif
    g_signal_connect(G_OBJECT(w), "changed", G_CALLBACK(size_entry_changed),
                     fs);

    model = gtk_list_store_new(3, G_TYPE_STRING, G_TYPE_INT, G_TYPE_INT);
    w = gtk_tree_view_new_with_model(GTK_TREE_MODEL(model));
    gtk_tree_view_set_headers_visible(GTK_TREE_VIEW(w), false);
    gtk_widget_show(w);
    column = gtk_tree_view_column_new_with_attributes(
        "Size", gtk_cell_renderer_text_new(),
        "text", 0, (char *)NULL);
    gtk_tree_view_column_set_sizing(column, GTK_TREE_VIEW_COLUMN_AUTOSIZE);
    gtk_tree_view_append_column(GTK_TREE_VIEW(w), column);
    g_signal_connect(G_OBJECT(gtk_tree_view_get_selection(GTK_TREE_VIEW(w))),
                     "changed", G_CALLBACK(size_changed), fs);

    scroll = gtk_scrolled_window_new(NULL, NULL);
    gtk_scrolled_window_set_shadow_type(GTK_SCROLLED_WINDOW(scroll),
                                        GTK_SHADOW_IN);
    gtk_container_add(GTK_CONTAINER(scroll), w);
    gtk_widget_show(scroll);
    gtk_scrolled_window_set_policy(GTK_SCROLLED_WINDOW(scroll),
                                   GTK_POLICY_AUTOMATIC, GTK_POLICY_ALWAYS);
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), scroll, 2, 2, 1, 1);
    g_object_set(G_OBJECT(scroll), "expand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), scroll, 2, 3, 2, 3, GTK_FILL,
                     GTK_EXPAND | GTK_FILL, 0, 0);
#endif
    fs->size_model = model;
    fs->size_list = w;

    /*
     * Preview widget.
     */
    fs->preview_area = gtk_drawing_area_new();
#ifndef NO_BACKING_PIXMAPS
    fs->preview_pixmap = NULL;
#endif
    fs->preview_width = 0;
    fs->preview_height = 0;
    fs->preview_fg.pixel = fs->preview_bg.pixel = 0;
    fs->preview_fg.red = fs->preview_fg.green = fs->preview_fg.blue = 0x0000;
    fs->preview_bg.red = fs->preview_bg.green = fs->preview_bg.blue = 0xFFFF;
#if !GTK_CHECK_VERSION(3,0,0)
    gdk_colormap_alloc_color(gdk_colormap_get_system(), &fs->preview_fg,
                             false, false);
    gdk_colormap_alloc_color(gdk_colormap_get_system(), &fs->preview_bg,
                             false, false);
#endif
#if GTK_CHECK_VERSION(3,0,0)
    g_signal_connect(G_OBJECT(fs->preview_area), "draw",
                     G_CALLBACK(unifontsel_draw_area), fs);
#else
    g_signal_connect(G_OBJECT(fs->preview_area), "expose_event",
                     G_CALLBACK(unifontsel_expose_area), fs);
#endif
    g_signal_connect(G_OBJECT(fs->preview_area), "configure_event",
                     G_CALLBACK(unifontsel_configure_area), fs);
    gtk_widget_set_size_request(fs->preview_area, 1, preview_height);
    gtk_widget_show(fs->preview_area);
    ww = fs->preview_area;
    w = gtk_frame_new(NULL);
    gtk_container_add(GTK_CONTAINER(w), ww);
    gtk_widget_show(w);

#if GTK_CHECK_VERSION(3,0,0)
    /* GtkAlignment has become deprecated and we use the "margin"
     * property */
    g_object_set(G_OBJECT(w), "margin", 8, (const char *)NULL);
#elif GTK_CHECK_VERSION(2,4,0)
    ww = w;
    /* GtkAlignment seems to be the simplest way to put padding round things */
    w = gtk_alignment_new(0, 0, 1, 1);
    gtk_alignment_set_padding(GTK_ALIGNMENT(w), 8, 8, 8, 8);
    gtk_container_add(GTK_CONTAINER(w), ww);
    gtk_widget_show(w);
#endif

    ww = w;
    w = gtk_frame_new("Preview of font");
    gtk_container_add(GTK_CONTAINER(w), ww);
    gtk_widget_show(w);
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), w, 0, 3, 3, 1);
    g_object_set(G_OBJECT(w), "expand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), w, 0, 3, 3, 4,
                     GTK_EXPAND | GTK_FILL, GTK_EXPAND | GTK_FILL, 0, 8);
#endif

    /*
     * We only provide the checkboxes for client- and server-side
     * fonts if we have the X11 back end available, because that's the
     * only situation in which more than one class of font is
     * available anyway.
     */
    fs->n_filter_buttons = 0;
#ifndef NOT_X_WINDOWS
    w = gtk_check_button_new_with_label("Show client-side fonts");
    g_object_set_data(G_OBJECT(w), "user-data",
                      GINT_TO_POINTER(FONTFLAG_CLIENTSIDE));
    g_signal_connect(G_OBJECT(w), "toggled",
                     G_CALLBACK(unifontsel_button_toggled), fs);
    gtk_widget_show(w);
    fs->filter_buttons[fs->n_filter_buttons++] = w;
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), w, 0, 4, 3, 1);
    g_object_set(G_OBJECT(w), "hexpand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), w, 0, 3, 4, 5, GTK_FILL, 0, 0, 0);
#endif
    w = gtk_check_button_new_with_label("Show server-side fonts");
    g_object_set_data(G_OBJECT(w), "user-data",
                      GINT_TO_POINTER(FONTFLAG_SERVERSIDE));
    g_signal_connect(G_OBJECT(w), "toggled",
                     G_CALLBACK(unifontsel_button_toggled), fs);
    gtk_widget_show(w);
    fs->filter_buttons[fs->n_filter_buttons++] = w;
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), w, 0, 5, 3, 1);
    g_object_set(G_OBJECT(w), "hexpand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), w, 0, 3, 5, 6, GTK_FILL, 0, 0, 0);
#endif
    w = gtk_check_button_new_with_label("Show server-side font aliases");
    g_object_set_data(G_OBJECT(w), "user-data",
                      GINT_TO_POINTER(FONTFLAG_SERVERALIAS));
    g_signal_connect(G_OBJECT(w), "toggled",
                     G_CALLBACK(unifontsel_button_toggled), fs);
    gtk_widget_show(w);
    fs->filter_buttons[fs->n_filter_buttons++] = w;
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), w, 0, 6, 3, 1);
    g_object_set(G_OBJECT(w), "hexpand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), w, 0, 3, 6, 7, GTK_FILL, 0, 0, 0);
#endif
#endif /* NOT_X_WINDOWS */
    w = gtk_check_button_new_with_label("Show non-monospaced fonts");
    g_object_set_data(G_OBJECT(w), "user-data",
                      GINT_TO_POINTER(FONTFLAG_NONMONOSPACED));
    g_signal_connect(G_OBJECT(w), "toggled",
                     G_CALLBACK(unifontsel_button_toggled), fs);
    gtk_widget_show(w);
    fs->filter_buttons[fs->n_filter_buttons++] = w;
#if GTK_CHECK_VERSION(3,0,0)
    gtk_grid_attach(GTK_GRID(table), w, 0, 7, 3, 1);
    g_object_set(G_OBJECT(w), "hexpand", true, (const char *)NULL);
#else
    gtk_table_attach(GTK_TABLE(table), w, 0, 3, 7, 8, GTK_FILL, 0, 0, 0);
#endif

    assert(fs->n_filter_buttons <= lenof(fs->filter_buttons));
    fs->filter_flags = FONTFLAG_CLIENTSIDE | FONTFLAG_SERVERSIDE |
        FONTFLAG_SERVERALIAS;
    unifontsel_set_filter_buttons(fs);

    /*
     * Go and find all the font names, and set up our master font
     * list.
     */
    fs->fonts_by_realname = newtree234(fontinfo_realname_compare);
    fs->fonts_by_selorder = newtree234(fontinfo_selorder_compare);
    for (i = 0; i < lenof(unifont_types); i++)
        unifont_types[i]->enum_fonts(GTK_WIDGET(fs->u.window),
                                     unifontsel_add_entry, fs);

    /*
     * And set up the initial font names list.
     */
    unifontsel_setup_familylist(fs);

    fs->selsize = fs->intendedsize = 13;   /* random default */
    gtk_widget_set_sensitive(fs->u.ok_button, false);

    return &fs->u;
}

void unifontsel_destroy(unifontsel *fontsel)
{
    unifontsel_internal *fs = container_of(fontsel, unifontsel_internal, u);
    fontinfo *info;

#ifndef NO_BACKING_PIXMAPS
    if (fs->preview_pixmap)
        gdk_pixmap_unref(fs->preview_pixmap);
#endif

    freetree234(fs->fonts_by_selorder);
    while ((info = delpos234(fs->fonts_by_realname, 0)) != NULL)
        sfree(info);
    freetree234(fs->fonts_by_realname);

    gtk_widget_destroy(GTK_WIDGET(fs->u.window));
    sfree(fs);
}

void unifontsel_set_name(unifontsel *fontsel, const char *fontname)
{
    unifontsel_internal *fs = container_of(fontsel, unifontsel_internal, u);
    int i, start, end, size, flags;
    const char *fontname2 = NULL;
    fontinfo *info;

    /*
     * Provide a default if given an empty or null font name.
     */
    if (!fontname || !*fontname)
        fontname = DEFAULT_GTK_FONT;

    /*
     * Call the canonify_fontname function.
     */
    fontname = unifont_do_prefix(fontname, &start, &end);
    for (i = start; i < end; i++) {
        fontname2 = unifont_types[i]->canonify_fontname(
            GTK_WIDGET(fs->u.window), fontname, &size, &flags, false);
        if (fontname2)
            break;
    }
    if (i == end)
        return;                        /* font name not recognised */

    /*
     * Now look up the canonified font name in our index.
     */
    {
        struct fontinfo_realname_find f;
        f.realname = fontname2;
        f.flags = flags;
        info = find234(fs->fonts_by_realname, &f, fontinfo_realname_find);
    }

    /*
     * If we've found the font, and its size field is either
     * correct or zero (the latter indicating a scalable font),
     * then we're done. Otherwise, try looking up the original
     * font name instead.
     */
    if (!info || (info->size != size && info->size != 0)) {
        struct fontinfo_realname_find f;
        f.realname = fontname;
        f.flags = flags;

        info = find234(fs->fonts_by_realname, &f, fontinfo_realname_find);
        if (!info || info->size != size)
            return;                    /* font name not in our index */
    }

    /*
     * Now we've got a fontinfo structure and a font size, so we
     * know everything we need to fill in all the fields in the
     * dialog.
     */
    unifontsel_select_font(fs, info, size, 0, true);
}

char *unifontsel_get_name(unifontsel *fontsel)
{
    unifontsel_internal *fs = container_of(fontsel, unifontsel_internal, u);
    char *name;

    if (!fs->selected)
        return NULL;

    if (fs->selected->size == 0) {
        name = fs->selected->fontclass->scale_fontname(
            GTK_WIDGET(fs->u.window), fs->selected->realname, fs->selsize);
        if (name) {
            char *ret = dupcat(fs->selected->fontclass->prefix, ":", name);
            sfree(name);
            return ret;
        }
    }

    return dupcat(fs->selected->fontclass->prefix, ":",
                  fs->selected->realname);
}

#endif /* GTK_CHECK_VERSION(2,0,0) */