From f4519f34fbdc1eaa2787396f76ce99743d8e2dfb Mon Sep 17 00:00:00 2001
From: Tharre <tharre3@gmail.com>
Date: Mon, 13 Jul 2015 18:32:13 +0200
Subject: [PATCH] Add transparency

---
 config.def.h |  3 +++
 config.mk    |  2 +-
 st.c         | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 3 files changed, 57 insertions(+), 9 deletions(-)

diff --git a/config.def.h b/config.def.h
index e246e3c..1f8c524 100644
--- a/config.def.h
+++ b/config.def.h
@@ -96,6 +96,9 @@ static unsigned int defaultfg = 7;
 static unsigned int defaultbg = 0;
 static unsigned int defaultcs = 256;
 
+/* background opacity */
+static const int alpha = 0xed;
+
 /*
  * Colors used, when the specific fg == defaultfg. So in reverse mode this
  * will reverse too. Another logic would only make the simple feature too
diff --git a/config.mk b/config.mk
index 67844dc..ce5753a 100644
--- a/config.mk
+++ b/config.mk
@@ -14,7 +14,7 @@ X11LIB = /usr/X11R6/lib
 INCS = -I. -I/usr/include -I${X11INC} \
        `pkg-config --cflags fontconfig` \
        `pkg-config --cflags freetype2`
-LIBS = -L/usr/lib -lc -L${X11LIB} -lm -lrt -lX11 -lutil -lXext -lXft \
+LIBS = -L/usr/lib -lc -L${X11LIB} -lm -lrt -lX11 -lutil -lXext -lXft -lXrender \
        `pkg-config --libs fontconfig`  \
        `pkg-config --libs freetype2`
 
diff --git a/st.c b/st.c
index 64e2cec..11025b2 100644
--- a/st.c
+++ b/st.c
@@ -60,6 +60,7 @@ char *argv0;
 #define XK_ANY_MOD    UINT_MAX
 #define XK_NO_MOD     0
 #define XK_SWITCH_MOD (1<<13)
+#define OPAQUE 0xff
 
 /* macros */
 #define MIN(a, b)		((a) < (b) ? (a) : (b))
@@ -84,6 +85,7 @@ char *argv0;
 #define TRUERED(x)		(((x) & 0xff0000) >> 8)
 #define TRUEGREEN(x)		(((x) & 0xff00))
 #define TRUEBLUE(x)		(((x) & 0xff) << 8)
+#define USE_ARGB (alpha != OPAQUE && opt_embed == NULL)
 
 
 enum glyph_attribute {
@@ -266,6 +268,7 @@ typedef struct {
 	int w, h; /* window width and height */
 	int ch; /* char height */
 	int cw; /* char width  */
+	int depth; /* bit depth */
 	char state; /* focus, redraw, visible */
 	int cursor; /* cursor style */
 } XWindow;
@@ -3102,8 +3105,7 @@ xresize(int col, int row)
 	xw.th = MAX(1, row * xw.ch);
 
 	XFreePixmap(xw.dpy, xw.buf);
-	xw.buf = XCreatePixmap(xw.dpy, xw.win, xw.w, xw.h,
-			DefaultDepth(xw.dpy, xw.scr));
+	xw.buf = XCreatePixmap(xw.dpy, xw.win, xw.w, xw.h, xw.depth);
 	XftDrawChange(xw.draw, xw.buf);
 	xclear(0, 0, xw.w, xw.h);
 }
@@ -3157,6 +3159,14 @@ xloadcols(void)
 			else
 				die("Could not allocate color %d\n", i);
 		}
+
+	/* set alpha value of bg color */
+	if (USE_ARGB) {
+		dc.col[defaultbg].color.alpha = (0xffff * alpha) / OPAQUE; //0xcccc;
+		dc.col[defaultbg].pixel &= 0x00111111;
+		dc.col[defaultbg].pixel |= alpha << 24; // 0xcc000000;
+	}
+
 	loaded = 1;
 }
 
@@ -3415,7 +3425,38 @@ xinit(void)
 	if (!(xw.dpy = XOpenDisplay(NULL)))
 		die("Can't open display\n");
 	xw.scr = XDefaultScreen(xw.dpy);
-	xw.vis = XDefaultVisual(xw.dpy, xw.scr);
+	xw.depth = (USE_ARGB)? 32: XDefaultDepth(xw.dpy, xw.scr);
+	if (! USE_ARGB)
+		xw.vis = XDefaultVisual(xw.dpy, xw.scr);
+	else {
+		XVisualInfo *vis;
+		XRenderPictFormat *fmt;
+		int nvi;
+		int i;
+
+		XVisualInfo tpl = {
+			.screen = xw.scr,
+			.depth = 32,
+			.class = TrueColor
+		};
+
+		vis = XGetVisualInfo(xw.dpy, VisualScreenMask | VisualDepthMask | VisualClassMask, &tpl, &nvi);
+		xw.vis = NULL;
+		for(i = 0; i < nvi; i ++) {
+			fmt = XRenderFindVisualFormat(xw.dpy, vis[i].visual);
+			if (fmt->type == PictTypeDirect && fmt->direct.alphaMask) {
+				xw.vis = vis[i].visual;
+				break;
+			}
+		}
+
+		XFree(vis);
+
+		if (! xw.vis) {
+			fprintf(stderr, "Couldn't find ARGB visual.\n");
+			exit(1);
+		}
+	}
 
 	/* font */
 	if (!FcInit())
@@ -3425,7 +3466,10 @@ xinit(void)
 	xloadfonts(usedfont, 0);
 
 	/* colors */
-	xw.cmap = XDefaultColormap(xw.dpy, xw.scr);
+	if (! USE_ARGB)
+		xw.cmap = XDefaultColormap(xw.dpy, xw.scr);
+	else
+		xw.cmap = XCreateColormap(xw.dpy, XRootWindow(xw.dpy, xw.scr), xw.vis, None);
 	xloadcols();
 
 	/* adjust fixed window geometry */
@@ -3448,16 +3492,17 @@ xinit(void)
 	if (!(opt_embed && (parent = strtol(opt_embed, NULL, 0))))
 		parent = XRootWindow(xw.dpy, xw.scr);
 	xw.win = XCreateWindow(xw.dpy, parent, xw.l, xw.t,
-			xw.w, xw.h, 0, XDefaultDepth(xw.dpy, xw.scr), InputOutput,
+			xw.w, xw.h, 0, xw.depth, InputOutput,
 			xw.vis, CWBackPixel | CWBorderPixel | CWBitGravity
 			| CWEventMask | CWColormap, &xw.attrs);
 
 	memset(&gcvalues, 0, sizeof(gcvalues));
 	gcvalues.graphics_exposures = False;
-	dc.gc = XCreateGC(xw.dpy, parent, GCGraphicsExposures,
+	xw.buf = XCreatePixmap(xw.dpy, xw.win, xw.w, xw.h, xw.depth);
+	dc.gc = XCreateGC(xw.dpy,
+			(USE_ARGB)? xw.buf: parent,
+			GCGraphicsExposures,
 			&gcvalues);
-	xw.buf = XCreatePixmap(xw.dpy, xw.win, xw.w, xw.h,
-			DefaultDepth(xw.dpy, xw.scr));
 	XSetForeground(xw.dpy, dc.gc, dc.col[defaultbg].pixel);
 	XFillRectangle(xw.dpy, xw.buf, dc.gc, 0, 0, xw.w, xw.h);
 
-- 
2.4.5