From 7f70ef0b19d87fed262093adf9db8dc9b4a3c881 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ian@liberator.relativity.greenend.org.uk>
Date: Sun, 5 Jul 2009 15:14:27 +0100
Subject: [PATCH] Optimised copyout from XImage for 24-deep 32bpp RGB LE
 XImages

---
 pctb/pages.c | 34 +++++++++++++++++++++++++++-------
 pctb/x.gdb   |  4 ++--
 2 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/pctb/pages.c b/pctb/pages.c
index fcee3d5..433ea36 100644
--- a/pctb/pages.c
+++ b/pctb/pages.c
@@ -225,6 +225,8 @@ static void compute_shift_mask(ShMask *sm, unsigned long ximage_mask) {
   }
   assert(sm->lshift < LONG_BIT);
   assert(sm->rshift < LONG_BIT);
+  debugf("SHIFTMASK %p={.lshift=%d, .rshift=%d} image_mask=%lx\n",
+	 sm, sm->lshift, sm->rshift, ximage_mask);
 }
 
 static void rtimestamp(double *t, const char *wh) {
@@ -273,13 +275,31 @@ static void snapshot(Snapshot **output) {
   int x,y,i;
   unsigned char *op= (*output)->data;
   for (y=0; y<wheight; y++) {
-    for (x=0; x<wwidth; x++) {
-      long xrgb= XGetPixel(im_use,x,y);
-      for (i=0; i<3; i++) {
-	unsigned long sample=
-	  ((xrgb << shiftmasks[i].lshift) >> shiftmasks[i].rshift)
-	  & SAMPLEMASK;
-	*op++= sample;
+    if (im_use->xoffset == 0 &&
+	im_use->format == ZPixmap &&
+	im_use->byte_order == LSBFirst &&
+	im_use->depth == 24 &&
+	im_use->bits_per_pixel == 32 &&
+	im_use->red_mask   == 0x0000ffU &&
+	im_use->green_mask == 0x00ff00U &&
+	im_use->blue_mask  == 0xff0000U) {
+      const char *p= im_use->data + y * im_use->bytes_per_line;
+//      debugf("optimised copy y=%d",y);
+      for (x=0; x<wwidth; x++) {
+	*op++ = *p++;
+	*op++ = *p++;
+	*op++ = *p++;
+	p++;
+      }
+    } else {
+      for (x=0; x<wwidth; x++) {
+	long xrgb= XGetPixel(im_use,x,y);
+	for (i=0; i<3; i++) {
+	  unsigned long sample=
+	    ((xrgb << shiftmasks[i].lshift) >> shiftmasks[i].rshift)
+	    & SAMPLEMASK;
+	  *op++= sample;
+	}
       }
     }
   }
diff --git a/pctb/x.gdb b/pctb/x.gdb
index 2088825..9c71346 100644
--- a/pctb/x.gdb
+++ b/pctb/x.gdb
@@ -1,4 +1,4 @@
 file ypp-commodities
-set args --same --test-servers --raw-tsv
-break findchar
+set args --screenshot-only --test-servers --single-page
+break pages.c:277
 run
-- 
2.30.2