Mercurial > hg > octave-image

changeset 359:262afafd9d88

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Better support for alpha channels (from Eugeniy Mikhailov)
author hauberg
date Fri, 13 Mar 2009 09:33:49 +0000
parents d2cc787481bf
children 99f847fb0cc3
files src/pngread.cc
diffstat 1 files changed, 10 insertions(+), 2 deletions(-) [+]
line wrap: on
line diff
--- a/src/pngread.cc
+++ b/src/pngread.cc
@@ -87,6 +87,10 @@
   if (pic->bit_depth > 1 && pic->bit_depth < 8)
       pic->bit_depth = 8;
 
+  int isAlfaChannelPresent = 0;
+  if ( pic->color_type & PNG_COLOR_MASK_ALPHA) 
+ 	isAlfaChannelPresent=1; 
+
   NDArray out(dim);
   
   dim.resize(2);
@@ -94,6 +98,7 @@
    
   Array<int> coord = Array<int> (3);
   
+  int ElementsPerPixel=out.dims()(2)+isAlfaChannelPresent;
   for (unsigned long j=0; j < pic->height; j++) {
       coord(0) = j;
       for (unsigned long i=0; i < pic->width; i++) {
@@ -101,9 +106,12 @@
 
 	  for (int c = 0; c < out.dims()(2); c++) {
 	      coord(2) = c;
-	      out(coord) = pic->row_pointers[j][i*4+c];
+	      out(coord) = pic->row_pointers[j][i*ElementsPerPixel+c];
 	  }
-	  alpha(j,i) = pic->row_pointers[j][i*4+3];
+	  if (isAlfaChannelPresent)
+	      alpha(j,i) = pic->row_pointers[j][i*ElementsPerPixel+(ElementsPerPixel-1)];
+	  else
+	      alpha(j,i) = 1;
       }
   }
   out = out.squeeze();