Package: openjpeg-tools Version: 1:1.5.2-3 Tags: patch The TGA file writer used by j2k_to_image writes a wrong field to the header for alpha-less images.
To reproduce: 1. Take any 24-bit j2k image with no alpha. 2. Convert it to TGA with j2k_to_image -i <image>.j2k -o <image>.tga 3. Open <image>.tga with Gimp. When opened, the image will have a wrong alpha channel, because Gimp uses a certain field in the header to determine if the image has alpha. That field is saved wrongly by j2k_to_image for alpha-less images. Per the TGA specification, Gimp is correct in this case. The attached patch fixes this issue.
--- openjpeg-1.5.2/applications/codec/convert.c.orig 2014-03-27 11:58:06.000000000 +0100 +++ openjpeg-1.5.2/applications/codec/convert.c 2015-02-11 00:12:10.000000000 +0100 @@ -243,7 +243,10 @@ if(fwrite(&pixel_depth, 1, 1, fp) != 1) goto fails; - image_desc = 8; /* 8 bits per component. */ + tga.image_desc = // bits 0-3 are # of alpha bits per pixel + bits_per_pixel == 16 ? 1 : + bits_per_pixel == 32 ? 8 : + 0; if (flip_image) image_desc |= 32;
