media-libs/libpng/files/libpng-1.2.51-pnm2png-pbm.patch

Make PBM actually work.  Before it obviously did not since it
did not take width or height values.  libpng takes bitmaps in
a packed format (I added a call to png_set_packing() but this
is actually the default), which does not require any special
processing apart from inverting the image white-to-black.

While here, initialize dimension values so if sscanf fails
at least we have known invalid values.


--- libpng-1.2.49/contrib/pngminus/pnm2png.c.orig	2013-05-07 13:01:10.385847623 -0700
+++ libpng-1.2.49/contrib/pngminus/pnm2png.c	2013-05-07 18:39:30.821466525 -0700
@@ -197,15 +197,16 @@
   char          height_token[16];
   char          maxval_token[16];
   int           color_type;
-  png_uint_32   width, alpha_width;
-  png_uint_32   height, alpha_height;
-  png_uint_32   maxval;
+  png_uint_32   width = 0, alpha_width = 0;
+  png_uint_32   height = 0, alpha_height = 0;
+  png_uint_32   maxval = 0;
   int           bit_depth = 0;
   int           channels;
   int           alpha_depth = 0;
   int           alpha_present;
   int           row, col;
   BOOL          raw, alpha_raw = FALSE;
+  BOOL          packed_bitmap = FALSE;
   png_uint_32   tmp16;
   int           i;
 
@@ -220,7 +221,12 @@
   {
     raw = (type_token[1] == '4');
     color_type = PNG_COLOR_TYPE_GRAY;
+    get_token(pnm_file, width_token);
+    sscanf (width_token, "%lu", &width);
+    get_token(pnm_file, height_token);
+    sscanf (height_token, "%lu", &height);
     bit_depth = 1;
+    packed_bitmap = TRUE;
   }
   else if ((type_token[1] == '2') || (type_token[1] == '5'))
   {
@@ -329,8 +335,12 @@
 
   alpha_present = (channels - 1) % 2;
 
-  /* row_bytes is the width x number of channels x (bit-depth / 8) */
-  row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);
+  if (packed_bitmap)
+    /* row data is as many bytes as can fit width x channels x bit_depth */
+    row_bytes = (width * channels * bit_depth + 7) / 8;
+  else
+    /* row_bytes is the width x number of channels x (bit-depth / 8) */
+    row_bytes = width * channels * ((bit_depth <= 8) ? 1 : 2);
 
   if ((png_pixels = (png_byte *) malloc (row_bytes * height * sizeof (png_byte))) == NULL)
     return FALSE;
@@ -340,40 +350,45 @@
 
   for (row = 0; row < height; row++)
   {
-    for (col = 0; col < width; col++)
-    {
-      for (i = 0; i < (channels - alpha_present); i++)
+    if (packed_bitmap) {
+      for (i = 0; i < row_bytes; i++)
+        /* png supports this format natively so no conversion is needed */
+        *pix_ptr++ = get_data (pnm_file, 8);
+    } else {
+      for (col = 0; col < width; col++)
       {
-        if (raw)
-          *pix_ptr++ = get_data (pnm_file, bit_depth);
-        else
-          if (bit_depth <= 8)
-            *pix_ptr++ = get_value (pnm_file, bit_depth);
+        for (i = 0; i < (channels - alpha_present); i++)
+        {
+          if (raw)
+            *pix_ptr++ = get_data (pnm_file, bit_depth);
           else
-          {
-            tmp16 = get_value (pnm_file, bit_depth);
-            *pix_ptr = (png_byte) ((tmp16 >> 8) & 0xFF);
-            pix_ptr++;
-            *pix_ptr = (png_byte) (tmp16 & 0xFF);
-            pix_ptr++;
-          }
-      }
-
-      if (alpha) /* read alpha-channel from pgm file */
-      {
-        if (alpha_raw)
-          *pix_ptr++ = get_data (alpha_file, alpha_depth);
-        else
-          if (alpha_depth <= 8)
-            *pix_ptr++ = get_value (alpha_file, bit_depth);
+            if (bit_depth <= 8)
+              *pix_ptr++ = get_value (pnm_file, bit_depth);
+            else
+            {
+              tmp16 = get_value (pnm_file, bit_depth);
+              *pix_ptr = (png_byte) ((tmp16 >> 8) & 0xFF);
+              pix_ptr++;
+              *pix_ptr = (png_byte) (tmp16 & 0xFF);
+              pix_ptr++;
+            }
+        }
+
+        if (alpha) /* read alpha-channel from pgm file */
+        {
+          if (alpha_raw)
+            *pix_ptr++ = get_data (alpha_file, alpha_depth);
           else
-          {
-            tmp16 = get_value (alpha_file, bit_depth);
-            *pix_ptr++ = (png_byte) ((tmp16 >> 8) & 0xFF);
-            *pix_ptr++ = (png_byte) (tmp16 & 0xFF);
-          }
-      } /* if alpha */
-
+            if (alpha_depth <= 8)
+              *pix_ptr++ = get_value (alpha_file, bit_depth);
+            else
+            {
+              tmp16 = get_value (alpha_file, bit_depth);
+              *pix_ptr++ = (png_byte) ((tmp16 >> 8) & 0xFF);
+              *pix_ptr++ = (png_byte) (tmp16 & 0xFF);
+            }
+        } /* if alpha */
+      } /* if packed_bitmap */
     } /* end for col */
   } /* end for row */
 
@@ -390,6 +405,12 @@
     return FALSE;
   }
 
+  if (packed_bitmap == TRUE)
+  {
+    png_set_packing (png_ptr);
+    png_set_invert_mono (png_ptr);
+  }
+
   /* setjmp() must be called in every function that calls a PNG-reading libpng function */
   if (setjmp (png_jmpbuf(png_ptr)))
   {