Temporarily (I hope) disabled reduction of grayscale images to bitdepth < 8

diff --git a/ChangeLog b/ChangeLog
index 84c721e0e6c968bc0db37fb7965be15b29eed724..c93a62cc3c8ea25f96c48053da0c53ad91e371b3 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2011-02-22  6.6.7-9 Glenn Randers-Pehrson <glennrp@image...>
+  * Disabled reduction of grayscale images (color-type 0) to less than 8 bits
+    when writing because this sometimes produced incorrect output (reference
+    http://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=18098).
+
 2011-02-22  6.6.7-9 Cristy  <quetzlzacatenango@image...>
   * New version 6.6.7-9.
 

diff --git a/coders/png.c b/coders/png.c
index e5a9affd711c16ea6a8eac87b6aa5a7071bd6a88..3bf84326f7d9dc244547e98f238d4d2ef4a48e1d 100644 (file)
--- a/coders/png.c
+++ b/coders/png.c
@@ -1979,8 +1979,8 @@ static Image *ReadOnePNGImage(MngInfo *mng_info,
 #if defined(PNG_oFFs_SUPPORTED)
   if (png_get_valid(ping,ping_info,PNG_INFO_oFFs))
     {
-      image->page.x=(int) png_get_x_offset_pixels(ping, ping_info);
-      image->page.y=(int) png_get_y_offset_pixels(ping, ping_info);
+      image->page.x=(ssize_t) png_get_x_offset_pixels(ping, ping_info);
+      image->page.y=(ssize_t) png_get_y_offset_pixels(ping, ping_info);
 
       if (logging != MagickFalse)
         if (image->page.x || image->page.y)
@@ -3693,8 +3693,8 @@ static Image *ReadOneJNGImage(MngInfo *mng_info,
       {
         if (length > 8)
           {
-            image->page.x=(int) mng_get_long(p);
-            image->page.y=(int) mng_get_long(&p[4]);
+            image->page.x=(ssize_t) mng_get_long(p);
+            image->page.y=(ssize_t) mng_get_long(&p[4]);
 
             if ((int) p[8] != 0)
               {
@@ -8024,6 +8024,7 @@ static MagickBooleanType WriteOnePNGImage(MngInfo *mng_info,
                   }
               }
 
+#if 0 /* TO DO: Enable this when low bit-depth grayscale is working */
             else if (ping_color_type ==
                 PNG_COLOR_TYPE_GRAY && image_colors < 17 &&
                 mng_info->IsPalette)
@@ -8061,6 +8062,7 @@ static MagickBooleanType WriteOnePNGImage(MngInfo *mng_info,
                 else if (depth_4_ok && mng_info->write_png_depth <= 4)
                   ping_bit_depth=4;
               }
+#endif /* 0 */
           }
 
           image_depth=ping_bit_depth;
@@ -9009,17 +9011,27 @@ static MagickBooleanType WriteOnePNGImage(MngInfo *mng_info,
                   }
 
                 else
-                  (void) ExportQuantumPixels(image,(const CacheView *) NULL,
-                    quantum_info,IndexQuantum,ping_pixels,&image->exception);
-
-                  if (logging != MagickFalse && y <= 2)
                   {
-                    (void) LogMagickEvent(CoderEvent,GetMagickModule(),
-                        "  Writing row of pixels (4)");
+                    /* TO DO:
+                     *
+                     * This is failing to account for 1, 2, 4-bit depths
+                     * The call to png_set_packing() above is supposed to
+                     * take care of those.
+                     */
+
+                    /* GrayQuantum does not work here */
+                    (void) ExportQuantumPixels(image,(const CacheView *) NULL,
+                      quantum_info,IndexQuantum,ping_pixels,&image->exception);
 
-                    (void) LogMagickEvent(CoderEvent,GetMagickModule(),
-                        "  ping_pixels[0]=%d,ping_pixels[1]=%d",
-                        (int)ping_pixels[0],(int)ping_pixels[1]);
+                    if (logging != MagickFalse && y <= 2)
+                    {
+                      (void) LogMagickEvent(CoderEvent,GetMagickModule(),
+                          "  Writing row of pixels (4)");
+
+                      (void) LogMagickEvent(CoderEvent,GetMagickModule(),
+                          "  ping_pixels[0]=%d,ping_pixels[1]=%d",
+                          (int)ping_pixels[0],(int)ping_pixels[1]);
+                    }
                   }
                 png_write_row(ping,ping_pixels);
               }