libtdevnc/tightvnc-1.3dev5-vncviewer-alpha-cursor.patch

--- vnc_unixsrc.orig/vncviewer/cursor.c	2003-01-15 04:46:52.000000000 -0500
+++ vnc_unixsrc/vncviewer/cursor.c	2005-02-05 12:28:10.000000000 -0500
@@ -472,6 +472,140 @@
   int offset, bytesPerPixel;
   char *pos;
 
+#define alphahack
+#ifdef alphahack
+  /* hack to have cursor transparency at 32bpp <runge@karlrunge.com> */
+  static int alphablend = -1;
+
+  if (alphablend < 0) {
+	/* you have to set NO_ALPHABLEND=1 in your environment to disable */
+	if (getenv("NO_ALPHABLEND")) {
+		alphablend = 0;
+	} else {
+		alphablend = 1;
+	}
+  }
+
+  bytesPerPixel = myFormat.bitsPerPixel / 8;
+
+  if (alphablend && bytesPerPixel == 4) {
+	unsigned long pixel, put, *upos, *upix;
+	int got_alpha = 0, rsX, rsY, rsW, rsH;
+	static XImage *image = NULL;
+	static int iwidth = 128;
+
+	if (! image) {
+		/* watch out for tiny fb (rare) */
+		if (iwidth > si.framebufferWidth) {
+			iwidth = si.framebufferWidth;
+		}
+		if (iwidth > si.framebufferHeight) {
+			iwidth = si.framebufferHeight;
+		}
+
+		/* initialize an XImage with a chunk of desktopWin */
+		image = XGetImage(dpy, desktopWin, 0, 0, iwidth, iwidth,
+		    AllPlanes, ZPixmap);
+	}
+
+	/* first check if there is any non-zero alpha channel data at all: */
+	for (y = 0; y < rcHeight; y++) {
+		for (x = 0; x < rcWidth; x++) {
+			int alpha;
+
+			offset = y * rcWidth + x;
+			pos = (char *)&rcSource[offset * bytesPerPixel];
+
+			upos = (unsigned long *) pos;
+			alpha = (*upos & 0xff000000) >> 24;
+			if (alpha) {
+				got_alpha = 1;
+				break;
+			}
+		}
+		if (got_alpha) {
+			break;
+		}
+	}
+
+	if (!got_alpha) {
+		/* no alpha channel data, fallback to the old way */
+		goto oldway;
+	}
+
+	/* load the saved fb patch in to image (faster way?) */
+	XGetSubImage(dpy, rcSavedArea, 0, 0, rcWidth, rcHeight,
+	    AllPlanes, ZPixmap, image, 0, 0);
+	upix = (unsigned long *)image->data;
+
+	/* if the richcursor is clipped, the fb patch will be smaller */
+	rsW = rcWidth;
+	rsX = 0;	/* used to denote a shift from the left side */
+	x = rcCursorX - rcHotX;
+	if (x < 0) {
+		rsW += x;
+		rsX = -x;
+	} else if (x + rsW > si.framebufferWidth) {
+		rsW = si.framebufferWidth - x;
+	}
+	rsH = rcHeight;
+	rsY = 0;	/* used to denote a shift from the top side */
+	y = rcCursorY - rcHotY;
+	if (y < 0) {
+		rsH += y;
+		rsY = -y;
+	} else if (y + rsH > si.framebufferHeight) {
+		rsH = si.framebufferHeight - y;
+	}
+
+	/*
+	 * now loop over the cursor data, blend in the fb values,
+	 * and then overwrite the fb (CopyDataToScreen())
+	 */
+	for (y = 0; y < rcHeight; y++) {
+		y0 = rcCursorY - rcHotY + y;
+		if (y0 < 0 || y0 >= si.framebufferHeight) {
+			continue;	/* clipped */
+		}
+		for (x = 0; x < rcWidth; x++) {
+			int alpha, color_curs, color_fb, i;
+
+			x0 = rcCursorX - rcHotX + x;
+			if (x0 < 0 || x0 >= si.framebufferWidth) {
+				continue;	/* clipped */
+			}
+
+			offset = y * rcWidth + x;
+			pos = (char *)&rcSource[offset * bytesPerPixel];
+
+			/* extract secret alpha byte from rich cursor: */
+			upos = (unsigned long *) pos;
+			alpha = (*upos & 0xff000000) >> 24;	/* XXX MSB? */
+
+			/* extract the pixel from the fb: */
+			pixel = *(upix + (y-rsY)*iwidth + (x-rsX));
+
+			put = 0;
+			/* for simplicity, blend all 4 bytes */
+			for (i = 0; i < 4; i++) {
+				int sh = i*8;
+				color_curs = ((0xff << sh) & *upos) >> sh;
+				color_fb   = ((0xff << sh) & pixel) >> sh;
+
+				/* XXX assumes pre-multipled color_curs */
+				color_fb = color_curs
+				    + ((0xff - alpha) * color_fb)/0xff;
+				put |= color_fb << sh;
+			}
+			/* place in the fb: */
+	    		CopyDataToScreen((char *)&put, x0, y0, 1, 1);
+		}
+	}
+	return;
+  }
+oldway:
+#endif
+
   bytesPerPixel = myFormat.bitsPerPixel / 8;
 
   /* FIXME: Speed optimization is possible. */