netwmicon: upgrading patch and adding farbfeld variant (#121)

patch/netwmicon_ff.c

@@ -0,0 +1,46 @@
+void
+setnetwmicon(void)
+{
+	/* use a farbfeld image to set _NET_WM_ICON */
+	FILE* file = fopen(ICON, "r");
+	if (file) {
+		unsigned char buf[8] = {0};
+
+		int hasdata = fread(buf,1,16,file);
+		if (memcmp(buf,"farbfeld",8)) {
+			fprintf(stderr,"netwmicon: file %s is not a farbfeld image\n", ICON);
+			fclose(file);
+			return;
+		}
+
+		/* declare icon-variable which will store the image in bgra-format */
+		const int width=(buf[8]<<24)|(buf[9]<<16)|(buf[10]<<8)|buf[11];
+		const int height=(buf[12]<<24)|(buf[13]<<16)|(buf[14]<<8)|buf[15];
+		const int icon_n = width * height + 2;
+		long icon_bgra[icon_n];
+
+		/* set width and height of the icon */
+		int i = 0;
+		icon_bgra[i++] = width;
+		icon_bgra[i++] = height;
+
+		/* rgba -> bgra */
+		for (int y = 0; y < height && hasdata; y++) {
+			for (int x = 0; x < width && hasdata; x++) {
+				unsigned char *pixel_bgra = (unsigned char *) &icon_bgra[i++];
+				hasdata = fread(buf,1,8,file);
+				pixel_bgra[0] = buf[4];
+				pixel_bgra[1] = buf[2];
+				pixel_bgra[2] = buf[0];
+				pixel_bgra[3] = buf[6];
+			}
+		}
+
+		/* 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_bgra, icon_n);
+
+		fclose(file);
+	}
+}