rest of bbuf printf

[libucw.git] / images / io-libpng.c

diff --git a/images/io-libpng.c b/images/io-libpng.c
index 638427da8f3950647eb6b0a3558783dc732092f6..f15955a64cf83c045bd953cb1afa33fd96908b96 100644 (file)
--- a/images/io-libpng.c
+++ b/images/io-libpng.c
@@ -197,22 +197,20 @@ libpng_read_data(struct image_io *io)
         return 0;
     }
 
-  /* Prepare the image */
   struct image_io_read_data_internals rdi;
-  if (unlikely(!image_io_read_data_prepare(&rdi, io, rd->cols, rd->rows)))
-    {
-      png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, &rd->end_ptr);
-      return 0;
-    }
+  rdi.image = NULL;
 
   if (setjmp(png_jmpbuf(rd->png_ptr)))
     {
       DBG("Libpng failed to read the image, longjump saved us");
       png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, &rd->end_ptr);
-      image_io_read_data_break(&rdi, io);
+      if (rdi.image)
+        image_io_read_data_break(&rdi, io);
       return 0;
     }
 
+  uns read_flags = io->flags;
+  
   /* Apply transformations */
   if (rd->bit_depth == 16)
     png_set_strip_16(rd->png_ptr);
@@ -226,10 +224,20 @@ libpng_read_data(struct image_io *io)
          }
        else
          png_set_palette_to_rgb(rd->png_ptr);
-       if ((io->flags & IMAGE_ALPHA) || (io->flags & IMAGE_PIXEL_FORMAT) == (COLOR_SPACE_RGB | IMAGE_PIXELS_ALIGNED))
-          png_set_add_alpha(rd->png_ptr, 255, PNG_FILLER_AFTER);
+       if (!(io->flags & IMAGE_ALPHA))
+         {
+           if (io->flags & IMAGE_IO_USE_BACKGROUND)
+             {
+                png_set_add_alpha(rd->png_ptr, 255, PNG_FILLER_AFTER);
+               read_flags = (read_flags | IMAGE_ALPHA) & IMAGE_CHANNELS_FORMAT;
+             }
+           else if ((io->flags & IMAGE_PIXEL_FORMAT) == (COLOR_SPACE_RGB | IMAGE_PIXELS_ALIGNED))
+              png_set_add_alpha(rd->png_ptr, 255, PNG_FILLER_AFTER);
+            else
+             png_set_strip_alpha(rd->png_ptr);
+         }
        else
-         png_set_strip_alpha(rd->png_ptr);
+          png_set_add_alpha(rd->png_ptr, 255, PNG_FILLER_AFTER);
        break;
       case PNG_COLOR_TYPE_GRAY:
        if ((io->flags & IMAGE_COLOR_SPACE) == COLOR_SPACE_RGB)
@@ -241,7 +249,12 @@ libpng_read_data(struct image_io *io)
        if ((io->flags & IMAGE_COLOR_SPACE) == COLOR_SPACE_RGB)
           png_set_gray_to_rgb(rd->png_ptr);
        if (!(io->flags & IMAGE_ALPHA))
-          png_set_strip_alpha(rd->png_ptr);
+         {
+           if (io->flags & IMAGE_IO_USE_BACKGROUND)
+             read_flags = (read_flags | IMAGE_ALPHA) & IMAGE_CHANNELS_FORMAT;
+           else
+              png_set_strip_alpha(rd->png_ptr);
+         }  
        break;
       case PNG_COLOR_TYPE_RGB:
        if ((io->flags & IMAGE_COLOR_SPACE) == COLOR_SPACE_GRAYSCALE)
@@ -252,14 +265,23 @@ libpng_read_data(struct image_io *io)
       case PNG_COLOR_TYPE_RGB_ALPHA:
        if ((io->flags & IMAGE_COLOR_SPACE) == COLOR_SPACE_GRAYSCALE)
          png_set_rgb_to_gray_fixed(rd->png_ptr, 1, 21267, 71514);
-       if (!(io->flags & IMAGE_ALPHA) && (io->flags & IMAGE_PIXEL_FORMAT) != (COLOR_SPACE_RGB | IMAGE_PIXELS_ALIGNED))
-          png_set_strip_alpha(rd->png_ptr);
+       if (!(io->flags & IMAGE_ALPHA))
+         if (io->flags & IMAGE_IO_USE_BACKGROUND)
+           read_flags = (read_flags | IMAGE_ALPHA) & IMAGE_CHANNELS_FORMAT;
+         else if ((io->flags & IMAGE_PIXEL_FORMAT) != (COLOR_SPACE_RGB | IMAGE_PIXELS_ALIGNED))
+            png_set_strip_alpha(rd->png_ptr);
        break;
       default:
        ASSERT(0);
     }
   png_read_update_info(rd->png_ptr, rd->info_ptr);
 
+  /* Prepare the image */
+  if (unlikely(!image_io_read_data_prepare(&rdi, io, rd->cols, rd->rows, read_flags)))
+    {
+      png_destroy_read_struct(&rd->png_ptr, &rd->info_ptr, &rd->end_ptr);
+      return 0;
+    }
   /* Read image data */
   DBG("Reading image data");
   struct image *img = rdi.image;