From 8b0128e8b295fc97bfa3bc5fb4b5e64856d4e3cb Mon Sep 17 00:00:00 2001
From: Aleksandrs Stier <aleks.stier@icloud.com>
Date: Sat, 4 Jun 2022 01:24:07 +0200
Subject: [PATCH] Set _NET_WM_ICON with a png-image

---
 Makefile  |  3 +++
 config.mk |  6 ++++--
 st.h      |  2 ++
 x.c       | 37 ++++++++++++++++++++++++++++++++++++-
 4 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index 470ac86..96e27e3 100644
--- a/Makefile
+++ b/Makefile
@@ -49,9 +49,12 @@ install: st
 	chmod 644 $(DESTDIR)$(MANPREFIX)/man1/st.1
 	tic -sx st.info
 	@echo Please see the README file regarding the terminfo entry of st.
+	mkdir -p $(DESTDIR)$(ICONPREFIX)
+	[ -f $(ICONNAME) ] && cp -f $(ICONNAME) $(DESTDIR)$(ICONPREFIX) || :
 
 uninstall:
 	rm -f $(DESTDIR)$(PREFIX)/bin/st
 	rm -f $(DESTDIR)$(MANPREFIX)/man1/st.1
+	rm -f $(DESTDIR)$(ICONPREFIX)/$(ICONNAME)
 
 .PHONY: all options clean dist install uninstall
diff --git a/config.mk b/config.mk
index 4c4c5d5..f8fc780 100644
--- a/config.mk
+++ b/config.mk
@@ -6,6 +6,8 @@ VERSION = 0.8.5
 # paths
 PREFIX = /usr/local
 MANPREFIX = $(PREFIX)/share/man
+ICONPREFIX = $(PREFIX)/share/pixmaps
+ICONNAME = st.png
 
 X11INC = /usr/X11R6/include
 X11LIB = /usr/X11R6/lib
@@ -16,12 +18,12 @@ PKG_CONFIG = pkg-config
 INCS = -I$(X11INC) \
        `$(PKG_CONFIG) --cflags fontconfig` \
        `$(PKG_CONFIG) --cflags freetype2`
-LIBS = -L$(X11LIB) -lm -lrt -lX11 -lutil -lXft \
+LIBS = -L$(X11LIB) -lm -lrt -lX11 -lutil -lXft -lgd \
        `$(PKG_CONFIG) --libs fontconfig` \
        `$(PKG_CONFIG) --libs freetype2`
 
 # flags
-STCPPFLAGS = -DVERSION=\"$(VERSION)\" -D_XOPEN_SOURCE=600
+STCPPFLAGS = -DVERSION=\"$(VERSION)\" -DICON=\"$(ICONPREFIX)/$(ICONNAME)\" -D_XOPEN_SOURCE=600
 STCFLAGS = $(INCS) $(STCPPFLAGS) $(CPPFLAGS) $(CFLAGS)
 STLDFLAGS = $(LIBS) $(LDFLAGS)
 
diff --git a/st.h b/st.h
index 519b9bd..c10af86 100644
--- a/st.h
+++ b/st.h
@@ -3,6 +3,8 @@
 #include <stdint.h>
 #include <sys/types.h>
 
+#include <gd.h>
+
 /* macros */
 #define MIN(a, b)		((a) < (b) ? (a) : (b))
 #define MAX(a, b)		((a) < (b) ? (b) : (a))
diff --git a/x.c b/x.c
index 8a16faa..169e833 100644
--- a/x.c
+++ b/x.c
@@ -93,7 +93,7 @@ typedef struct {
 	Window win;
 	Drawable buf;
 	GlyphFontSpec *specbuf; /* font spec buffer used for rendering */
-	Atom xembed, wmdeletewin, netwmname, netwmiconname, netwmpid;
+	Atom xembed, wmdeletewin, netwmname, netwmicon, netwmiconname, netwmpid;
 	struct {
 		XIM xim;
 		XIC xic;
@@ -1204,6 +1204,41 @@ xinit(int cols, int rows)
 	xw.netwmiconname = XInternAtom(xw.dpy, "_NET_WM_ICON_NAME", False);
 	XSetWMProtocols(xw.dpy, xw.win, &xw.wmdeletewin, 1);
 
+	/* use a png-image to set _NET_WM_ICON */
+	FILE* file = fopen(ICON, "r");
+	if (file) {
+		/* load image in rgba-format */
+		const gdImagePtr icon_rgba = gdImageCreateFromPng(file);
+		fclose(file);
+		/* declare icon-variable which will store the image in argb-format */
+		const int width  = gdImageSX(icon_rgba);
+		const int height = gdImageSY(icon_rgba);
+		const int icon_n = width * height + 2;
+		long icon_argb[icon_n];
+		/* set width and height of the icon */
+		int i = 0;
+		icon_argb[i++] = width;
+		icon_argb[i++] = height;
+		/* rgba -> argb */
+		for (int y = 0; y < height; y++) {
+			for (int x = 0; x < width; x++) {
+				const int pixel_rgba = gdImageGetPixel(icon_rgba, x, y);
+				unsigned char *pixel_argb = (unsigned char *) &icon_argb[i++];
+				pixel_argb[0] = gdImageBlue(icon_rgba, pixel_rgba);
+				pixel_argb[1] = gdImageGreen(icon_rgba, pixel_rgba);
+				pixel_argb[2] = gdImageRed(icon_rgba, pixel_rgba);
+				/* scale alpha from 0-127 to 0-255 */
+				const unsigned char alpha = 127 - gdImageAlpha(icon_rgba, pixel_rgba);
+				pixel_argb[3] = alpha == 127 ? 255 : alpha * 2;
+			}
+		}
+		gdImageDestroy(icon_rgba);
+		/* set _NET_WM_ICON */
+		xw.netwmicon = XInternAtom(xw.dpy, "_NET_WM_ICON", False);
+		XChangeProperty(xw.dpy, xw.win, xw.netwmicon, XA_CARDINAL, 32,
+				PropModeReplace, (uchar *) icon_argb, icon_n);
+	}
+
 	xw.netwmpid = XInternAtom(xw.dpy, "_NET_WM_PID", False);
 	XChangeProperty(xw.dpy, xw.win, xw.netwmpid, XA_CARDINAL, 32,
 			PropModeReplace, (uchar *)&thispid, 1);
-- 
2.36.1

