From: ellson <devnull@localhost>
Date: Fri, 7 Jan 2011 16:13:21 +0000 (+0000)
Subject: fix for bug #2102
X-Git-Tag: LAST_LIBGRAPH~32^2~1117
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3c9db39e23b43b1bc9622866f7761a3ea0d376e1;p=graphviz

fix for bug #2102
Apparently cairo doesn't leave a valid surface if nothing was ever written to it.
---

diff --git a/plugin/gd/gvdevice_gd.c b/plugin/gd/gvdevice_gd.c
index e22bc8943..a973786cd 100644
--- a/plugin/gd/gvdevice_gd.c
+++ b/plugin/gd/gvdevice_gd.c
@@ -85,15 +85,17 @@ static void gd_format(GVJ_t * job)
     switch (job->device.id) {
 #ifdef HAVE_GD_PNG
     case FORMAT_PNG:
-        for (y = 0; y < height; y++) {
-            for (x = 0; x < width; x++) {
-                color = *data++;
-	        /* gd's max alpha is 127 */
-	        /*   so right-shift 25 to lose lsb of alpha */
-	        alpha = (color >> 25) & 0x7f;
-	        im->tpixels[y][x] = (color & 0xffffff) | ((0x7f - alpha) << 24);
-	    }
-        }
+	if (data) {
+            for (y = 0; y < height; y++) {
+                for (x = 0; x < width; x++) {
+                    color = *data++;
+	            /* gd's max alpha is 127 */
+	            /*   so right-shift 25 to lose lsb of alpha */
+	            alpha = (color >> 25) & 0x7f;
+	            im->tpixels[y][x] = (color & 0xffffff) | ((0x7f - alpha) << 24);
+	        }
+            }
+	}
         break;
 #endif
     default:
@@ -102,18 +104,20 @@ static void gd_format(GVJ_t * job)
 
         gdImageColorTransparent(im, TRANSPARENT);
         gdImageAlphaBlending(im, FALSE);
-        for (y = 0; y < height; y++) {
-            for (x = 0; x < width; x++) {
-                color = *data++;
-	        /* gd's max alpha is 127 */
-	        /*   so right-shift 25 to lose lsb of alpha */
-	        if ((alpha = (color >> 25) & 0x7f) >= 0x20)
-		    /* if not > 75% transparent */
-		    im->tpixels[y][x] = (color & 0xffffff) | ((0x7f - alpha) << 24);
-	        else
-		    im->tpixels[y][x] = TRANSPARENT;
-	    }
-        }
+	if (data) {
+            for (y = 0; y < height; y++) {
+                for (x = 0; x < width; x++) {
+                    color = *data++;
+	            /* gd's max alpha is 127 */
+	            /*   so right-shift 25 to lose lsb of alpha */
+	            if ((alpha = (color >> 25) & 0x7f) >= 0x20)
+		        /* if not > 75% transparent */
+		        im->tpixels[y][x] = (color & 0xffffff) | ((0x7f - alpha) << 24);
+	            else
+		        im->tpixels[y][x] = TRANSPARENT;
+	        }
+            }
+	}
         break;
     }