Adding background image patch

README.md

@@ -15,6 +15,8 @@ Refer to [https://st.suckless.org/](https://st.suckless.org/) for details on the
 
 ### Changelog:
 
+2022-03-10 - Added the background image patch
+
 2022-02-24 - Upgraded to st 0.8.5 e823e23, 2022-02-17 - removing osc_10_11_12_2 patch as no longer relevant
 
 2021-08-18 - Added the CSI 22 & 23 patch
@@ -95,6 +97,10 @@ Refer to [https://st.suckless.org/](https://st.suckless.org/) for details on the
       - a patch that aims to prevent black bars being drawn on the edges of st terminals using the
         anysize patch
 
+   - [background-image](https://st.suckless.org/patches/background_image/)
+      - draws a background image in farbfeld format in place of the defaultbg color allowing for
+        pseudo transparency
+
    - [blinking-cursor](https://st.suckless.org/patches/blinking_cursor/)
       - allows the use of a blinking cursor
 

config.def.h

@@ -14,6 +14,16 @@ static char *font2[] = {
 };
 #endif // FONT2_PATCH
 
+#if BACKGROUND_IMAGE_PATCH
+/*
+ * 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;
+#endif // BACKGROUND_IMAGE_PATCH
+
 #if RELATIVEBORDER_PATCH
 /* borderperc: percentage of cell width to use as a border
  *             0 = no border, 100 = border width is same as cell width */

patch/background_image_x.c

@@ -0,0 +1,104 @@
+void
+updatexy()
+{
+	Window child;
+	XTranslateCoordinates(xw.dpy, xw.win, DefaultRootWindow(xw.dpy), 0, 0, &win.x, &win.y, &child);
+}
+
+/*
+ * load farbfeld file to XImage
+ */
+XImage*
+loadff(const char *filename)
+{
+	uint32_t i, hdr[4], w, h, size;
+	uint64_t *data;
+	FILE *f = fopen(filename, "rb");
+
+	if (f == NULL) {
+		 fprintf(stderr, "could not load background image.\n");
+		 return NULL;
+	}
+
+	if (fread(hdr, sizeof(*hdr), LEN(hdr), f) != LEN(hdr))
+		 if (ferror(f)) {
+			  fprintf(stderr, "fread:");
+			  return NULL;
+		 }
+		 else {
+			  fprintf(stderr, "fread: Unexpected end of file\n");
+			  return NULL;
+		 }
+
+	if (memcmp("farbfeld", hdr, sizeof("farbfeld") - 1)) {
+		 fprintf(stderr, "Invalid magic value");
+		 return NULL;
+	}
+
+	w = ntohl(hdr[2]);
+	h = ntohl(hdr[3]);
+	size = w * h;
+	data = malloc(size * sizeof(uint64_t));
+
+	if (fread(data, sizeof(uint64_t), size, f) != size)
+		 if (ferror(f)) {
+			  fprintf(stderr, "fread:");
+			  return NULL;
+		 }
+		 else {
+			  fprintf(stderr, "fread: Unexpected end of file");
+			  return NULL;
+		 }
+
+	fclose(f);
+
+	for (i = 0; i < size; i++)
+		 data[i] = (data[i] & 0x00000000000000FF) << 16 |
+		           (data[i] & 0x0000000000FF0000) >> 8  |
+		           (data[i] & 0x000000FF00000000) >> 32 |
+		           (data[i] & 0x00FF000000000000) >> 24;
+
+	#if ALPHA_PATCH
+	XImage *xi = XCreateImage(xw.dpy, xw.vis, xw.depth, ZPixmap, 0,
+		(char *)data, w, h, 32, w * 8);
+	#else
+	XImage *xi = XCreateImage(xw.dpy, DefaultVisual(xw.dpy, xw.scr),
+		DefaultDepth(xw.dpy, xw.scr), ZPixmap, 0,
+		(char *)data, w, h, 32, w * 8);
+	#endif // ALPHA_PATCH
+	xi->bits_per_pixel = 64;
+	return xi;
+}
+
+/*
+ * initialize background image
+ */
+void
+bginit()
+{
+	XGCValues gcvalues;
+	Drawable bgimg;
+	XImage *bgxi = loadff(bgfile);
+
+	memset(&gcvalues, 0, sizeof(gcvalues));
+	xw.bggc = XCreateGC(xw.dpy, xw.win, 0, &gcvalues);
+	if (!bgxi)
+		return;
+	#if ALPHA_PATCH
+	bgimg = XCreatePixmap(xw.dpy, xw.win, bgxi->width, bgxi->height,
+		xw.depth);
+	#else
+	bgimg = XCreatePixmap(xw.dpy, xw.win, bgxi->width, bgxi->height,
+		DefaultDepth(xw.dpy, xw.scr));
+	#endif // ALPHA_PATCH
+	XPutImage(xw.dpy, bgimg, dc.gc, bgxi, 0, 0, 0, 0, bgxi->width,
+				 bgxi->height);
+	XDestroyImage(bgxi);
+	XSetTile(xw.dpy, xw.bggc, bgimg);
+	XSetFillStyle(xw.dpy, xw.bggc, FillTiled);
+	if (pseudotransparency) {
+		updatexy();
+		MODBIT(xw.attrs.event_mask, 1, PropertyChangeMask);
+		XChangeWindowAttributes(xw.dpy, xw.win, CWEventMask, &xw.attrs);
+	}
+}

patch/background_image_x.h

@@ -0,0 +1,5 @@
+#include <arpa/inet.h>
+
+static void updatexy(void);
+static XImage *loadff(const char *);
+static void bginit();

patch/x_include.c

@@ -1,4 +1,7 @@
 /* Patches */
+#if BACKGROUND_IMAGE_PATCH
+#include "background_image_x.c"
+#endif
 #if BOXDRAW_PATCH
 #include "boxdraw.c"
 #endif

patch/x_include.h

@@ -1,4 +1,7 @@
 /* Patches */
+#if BACKGROUND_IMAGE_PATCH
+#include "background_image_x.h"
+#endif
 #if BOXDRAW_PATCH
 #include "boxdraw.h"
 #endif

patches.def.h

@@ -48,6 +48,12 @@
  */
 #define ANYSIZE_SIMPLE_PATCH 0
 
+/* Draws a background image in farbfeld format in place of the defaultbg color allowing for pseudo
+ * transparency.
+ * https://st.suckless.org/patches/background_image/
+ */
+#define BACKGROUND_IMAGE_PATCH 0
+
 /* This patch allows the use of a blinking cursor.
  * Only cursor styles 0, 1, 3, 5, and 7 blink. Set cursorstyle accordingly.
  * Cursor styles are defined here:

st.h

@@ -181,6 +181,9 @@ typedef union {
 typedef struct {
 	int tw, th; /* tty width and height */
 	int w, h; /* window width and height */
+	#if BACKGROUND_IMAGE_PATCH
+	int x, y; /* window location */
+	#endif // BACKGROUND_IMAGE_PATCH
 	#if ANYSIZE_PATCH
 	int hborderpx, vborderpx;
 	#endif // ANYSIZE_PATCH
@@ -210,6 +213,9 @@ typedef struct {
 		XVaNestedList spotlist;
 	} ime;
 	Draw draw;
+	#if BACKGROUND_IMAGE_PATCH
+	GC bggc;          /* Graphics Context for background */
+	#endif // BACKGROUND_IMAGE_PATCH
 	Visual *vis;
 	XSetWindowAttributes attrs;
 	#if HIDECURSOR_PATCH

x.c

@@ -548,6 +548,14 @@ propnotify(XEvent *e)
 			 xpev->atom == clipboard)) {
 		selnotify(e);
 	}
+
+	#if BACKGROUND_IMAGE_PATCH
+	if (pseudotransparency &&
+		!strncmp(XGetAtomName(xw.dpy, e->xproperty.atom), "_NET_WM_STATE", 13)) {
+		updatexy();
+		redraw();
+	}
+	#endif // BACKGROUND_IMAGE_PATCH
 }
 
 void
@@ -578,7 +586,12 @@ selnotify(XEvent *e)
 			return;
 		}
 
-		if (e->type == PropertyNotify && nitems == 0 && rem == 0) {
+		#if BACKGROUND_IMAGE_PATCH
+		if (e->type == PropertyNotify && nitems == 0 && rem == 0 && !pseudotransparency)
+		#else
+		if (e->type == PropertyNotify && nitems == 0 && rem == 0)
+		#endif // BACKGROUND_IMAGE_PATCH
+		{
 			/*
 			 * If there is some PropertyNotify with no data, then
 			 * this is the signal of the selection owner that all
@@ -596,9 +609,15 @@ selnotify(XEvent *e)
 			 * when the selection owner does send us the next
 			 * chunk of data.
 			 */
+			#if BACKGROUND_IMAGE_PATCH
+			if (!pseudotransparency) {
+			#endif // BACKGROUND_IMAGE_PATCH
 			MODBIT(xw.attrs.event_mask, 1, PropertyChangeMask);
 			XChangeWindowAttributes(xw.dpy, xw.win, CWEventMask,
 					&xw.attrs);
+			#if BACKGROUND_IMAGE_PATCH
+			}
+			#endif // BACKGROUND_IMAGE_PATCH
 
 			/*
 			 * Deleting the property is the transfer start signal.
@@ -997,7 +1016,11 @@ xsetcolorname(int x, const char *name)
 void
 xclear(int x1, int y1, int x2, int y2)
 {
-	#if INVERT_PATCH
+	#if BACKGROUND_IMAGE_PATCH
+	if (pseudotransparency)
+		XSetTSOrigin(xw.dpy, xw.bggc, -win.x, -win.y);
+	XFillRectangle(xw.dpy, xw.buf, xw.bggc, x1, y1, x2-x1, y2-y1);
+	#elif INVERT_PATCH
 	Color c;
 	c = dc.col[IS_SET(MODE_REVERSE)? defaultfg : defaultbg];
 	if (invertcolors) {
@@ -1911,6 +1934,11 @@ xdrawglyphfontspecs(const XftGlyphFontSpec *specs, Glyph base, int len, int x, i
 	#endif // ANYSIZE_PATCH
 
 	/* Clean up the region we want to draw to. */
+	#if BACKGROUND_IMAGE_PATCH
+	if (bg == &dc.col[defaultbg])
+		xclear(winx, winy, winx + width, winy + win.ch);
+	else
+	#endif // BACKGROUND_IMAGE_PATCH
 	XftDrawRect(xw.draw, bg, winx, winy, width, win.ch);
 	#if WIDE_GLYPHS_PATCH
 	}
@@ -3094,6 +3122,15 @@ resize(XEvent *e)
 	XWindowChanges wc;
 	#endif // ST_EMBEDDER_PATCH
 
+	#if BACKGROUND_IMAGE_PATCH
+	if (pseudotransparency) {
+		if (e->xconfigure.width == win.w &&
+			e->xconfigure.height == win.h &&
+			e->xconfigure.x == win.x && e->xconfigure.y == win.y)
+			return;
+		updatexy();
+	} else
+	#endif // BACKGROUND_IMAGE_PATCH
 	if (e->xconfigure.width == win.w && e->xconfigure.height == win.h)
 		return;
 
@@ -3379,6 +3416,9 @@ run:
 	#endif // ALPHA_FOCUS_HIGHLIGHT_PATCH
 	tnew(cols, rows);
 	xinit(cols, rows);
+	#if BACKGROUND_IMAGE_PATCH
+	bginit();
+	#endif // BACKGROUND_IMAGE_PATCH
 	xsetenv();
 	selinit();
 	#if WORKINGDIR_PATCH