st/patches/st-background-image-0.8.4.diff

From fdf9692358326993f0dc6a6896cc0a7194ba6152 Mon Sep 17 00:00:00 2001
From: Matthias Schoth <mschoth@gmail.com>
Date: Sun, 4 Jul 2021 19:18:20 +0200
Subject: [PATCH] Implements background image and pseudo transparancy support.

---
 config.def.h |  8 +++++
 x.c          | 91 ++++++++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 93 insertions(+), 6 deletions(-)

diff --git a/config.def.h b/config.def.h
index 6f05dce..3d352db 100644
--- a/config.def.h
+++ b/config.def.h
@@ -8,6 +8,14 @@
 static char *font = "Liberation Mono:pixelsize=12:antialias=true:autohint=true";
 static int borderpx = 2;
 
+/*
+ * background image
+ * expects farbfeld format
+ * pseudo transparency fixes coordinates to the screen origin
+ */
+static const char *bgfile = "/path/to/image.ff";
+static const int pseudotransparency = 0;
+
 /*
  * What program is execed by st depends of these precedence rules:
  * 1: program passed with -e
diff --git a/x.c b/x.c
index 210f184..22653ea 100644
--- a/x.c
+++ b/x.c
@@ -14,6 +14,7 @@
 #include <X11/keysym.h>
 #include <X11/Xft/Xft.h>
 #include <X11/XKBlib.h>
+#include <arpa/inet.h>
 
 char *argv0;
 #include "arg.h"
@@ -81,6 +82,7 @@ typedef XftGlyphFontSpec GlyphFontSpec;
 typedef struct {
 	int tw, th; /* tty width and height */
 	int w, h; /* window width and height */
+	int x, y; /* window location */
 	int ch; /* char height */
 	int cw; /* char width  */
 	int mode; /* window state/mode flags */
@@ -101,6 +103,8 @@ typedef struct {
 		XVaNestedList spotlist;
 	} ime;
 	Draw draw;
+	Drawable bgimg;   /* background image */
+	GC bggc;          /* Graphics Context for background */
 	Visual *vis;
 	XSetWindowAttributes attrs;
 	int scr;
@@ -151,6 +155,7 @@ static void ximinstantiate(Display *, XPointer, XPointer);
 static void ximdestroy(XIM, XPointer, XPointer);
 static int xicdestroy(XIC, XPointer, XPointer);
 static void xinit(int, int);
+static void bginit();
 static void cresize(int, int);
 static void xresize(int, int);
 static void xhints(void);
@@ -820,9 +825,9 @@ xsetcolorname(int x, const char *name)
 void
 xclear(int x1, int y1, int x2, int y2)
 {
-	XftDrawRect(xw.draw,
-			&dc.col[IS_SET(MODE_REVERSE)? defaultfg : defaultbg],
-			x1, y1, x2-x1, y2-y1);
+	if (pseudotransparency)
+		XSetTSOrigin(xw.dpy, xw.bggc, -win.x, -win.y);
+	XFillRectangle(xw.dpy, xw.buf, xw.bggc, x1, y1, x2-x1, y2-y1);
 }
 
 void
@@ -1207,6 +1212,65 @@ xinit(int cols, int rows)
 		xsel.xtarget = XA_STRING;
 }
 
+/*
+ * initialize background image
+ */
+void
+bginit()
+{
+	uint32_t hdr[4], bgw, bgh, i = 0;
+	char buf[8], *image32;
+	FILE *bgf = fopen(bgfile, "rb");
+	XGCValues gcvalues;
+	XImage *bgxi;
+
+	if (bgf == NULL) die("could not load background image.\n");
+
+	if (fread(hdr, sizeof(*hdr), LEN(hdr), bgf) != LEN(hdr))
+		if (ferror(bgf))
+			die("fread:");
+		else
+			die("fread: Unexpected end of file\n");
+
+	if (memcmp("farbfeld", hdr, sizeof("farbfeld") - 1))
+		die("Invalid magic value");
+
+	bgw = ntohl(hdr[2]);
+	bgh = ntohl(hdr[3]);
+	image32 = (char *)malloc(bgw * bgh * 4 * sizeof(char));
+
+	while (i < bgh * bgw * 4) {
+		if (fread(buf, sizeof(*buf), LEN(buf), bgf) != LEN(buf))
+			if (ferror(bgf))
+				die("fread:");
+			else
+				die("fread: Unexpected end of file");
+
+		image32[i++] = buf[4]; /* convert 16 bit RGBA to 8 bit BGRA */
+		image32[i++] = buf[2];
+		image32[i++] = buf[0];
+		image32[i++] = buf[6];
+        }
+
+	fclose(bgf);
+	bgxi = XCreateImage(xw.dpy, DefaultVisual(xw.dpy, xw.scr),
+		24, ZPixmap, 0, image32, bgw, bgh, 32, 0);
+	xw.bgimg = XCreatePixmap(xw.dpy, xw.win, bgw, bgh,
+                        DefaultDepth(xw.dpy, xw.scr));
+	XPutImage(xw.dpy, xw.bgimg, dc.gc, bgxi, 0, 0, 0, 0, bgw, bgh);
+	XDestroyImage(bgxi);
+	memset(&gcvalues, 0, sizeof(gcvalues));
+	xw.bggc = XCreateGC(xw.dpy, xw.win, 0, &gcvalues);
+	XSetTile(xw.dpy, xw.bggc, xw.bgimg);
+	XSetFillStyle(xw.dpy, xw.bggc, FillTiled);
+	if (pseudotransparency) {
+		XWindowAttributes xwa;
+		XGetWindowAttributes(xw.dpy, xw.win, &xwa);
+		win.x = xwa.x;
+		win.y = xwa.y;
+	}
+}
+
 int
 xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x, int y)
 {
@@ -1447,7 +1511,10 @@ xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, i
 		xclear(winx, winy + win.ch, winx + width, win.h);
 
 	/* Clean up the region we want to draw to. */
-	XftDrawRect(xw.draw, bg, winx, winy, width, win.ch);
+	if (bg == &dc.col[defaultbg])
+		xclear(winx, winy, winx + width, winy + win.ch);
+	else
+		XftDrawRect(xw.draw, bg, winx, winy, width, win.ch);
 
 	/* Set the clip region because Xft is sometimes dirty. */
 	r.x = 0;
@@ -1855,8 +1922,19 @@ cmessage(XEvent *e)
 void
 resize(XEvent *e)
 {
-	if (e->xconfigure.width == win.w && e->xconfigure.height == win.h)
-		return;
+	if (pseudotransparency) {
+		if (e->xconfigure.width == win.w &&
+			e->xconfigure.height == win.h &&
+			e->xconfigure.x == win.x && e->xconfigure.y == win.y)
+			return;
+
+		win.x = e->xconfigure.x;
+		win.y = e->xconfigure.y;
+	} else {
+		if (e->xconfigure.width == win.w &&
+			e->xconfigure.height == win.h)
+			return;
+	}
 
 	cresize(e->xconfigure.width, e->xconfigure.height);
 }
@@ -2041,6 +2119,7 @@ run:
 	rows = MAX(rows, 1);
 	tnew(cols, rows);
 	xinit(cols, rows);
+	bginit();
 	xsetenv();
 	selinit();
 	run();
-- 
2.32.0