From: ellson <devnull@localhost>
Date: Fri, 7 Jan 2011 18:43:06 +0000 (+0000)
Subject: Better fix for bug #2102
X-Git-Tag: LAST_LIBGRAPH~32^2~1116
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=592f0b815bb03243cc29f57046ff3d7173682dc5;p=graphviz

Better fix for bug #2102

Root cause was zero-divides from rendering of degenerate ellipse
---

diff --git a/plugin/gd/gvdevice_gd.c b/plugin/gd/gvdevice_gd.c
index a973786cd..e22bc8943 100644
--- a/plugin/gd/gvdevice_gd.c
+++ b/plugin/gd/gvdevice_gd.c
@@ -85,17 +85,15 @@ static void gd_format(GVJ_t * job)
     switch (job->device.id) {
 #ifdef HAVE_GD_PNG
     case FORMAT_PNG:
-	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);
-	        }
-            }
-	}
+        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:
@@ -104,20 +102,18 @@ static void gd_format(GVJ_t * job)
 
         gdImageColorTransparent(im, TRANSPARENT);
         gdImageAlphaBlending(im, FALSE);
-	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;
-	        }
-            }
-	}
+        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;
     }
 
diff --git a/plugin/pango/gvrender_pango.c b/plugin/pango/gvrender_pango.c
index af6aa7241..41d835611 100644
--- a/plugin/pango/gvrender_pango.c
+++ b/plugin/pango/gvrender_pango.c
@@ -200,6 +200,10 @@ static void cairogen_end_page(GVJ_t * job)
     case FORMAT_CAIRO:
     default:
         surface = cairo_get_target(cr);
+        if (cairo_image_surface_get_width(surface) == 0 || cairo_image_surface_get_height(surface) == 0) {
+	    /* apparently cairo never allocates a surface if nothing was ever written to it */
+	    fprintf(stderr, "ERROR: cairo surface has zero area, this may indicate some problem during rendering shapes.\n");
+	}
 	job->imagedata = (char *)(cairo_image_surface_get_data(surface));	
 	break;
        	/* formatting will be done by gvdevice_format() */
@@ -260,14 +264,17 @@ static void cairogen_ellipse(GVJ_t * job, pointf * A, int filled)
     cairogen_set_penstyle(job, cr);
 
     cairo_get_matrix(cr, &matrix);
-    cairo_translate(cr, A[0].x, -A[0].y);
 
     rx = A[1].x - A[0].x;
     ry = A[1].y - A[0].y;
-    cairo_scale(cr, 1, ry / rx);
-    cairo_move_to(cr, rx, 0);
-    cairo_arc(cr, 0, 0, rx, 0, 2 * M_PI);
-    cairo_close_path(cr);
+
+#define RMIN 0.01
+if (rx < RMIN) rx = RMIN;
+if (ry < RMIN) ry = RMIN;
+
+    cairo_translate(cr, A[0].x, -A[0].y);
+    cairo_scale(cr, rx, ry);
+    cairo_arc(cr, 0., 0., 1., 0., 2 * M_PI);
 
     cairo_set_matrix(cr, &matrix);