diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2008-11-04 11:18:22 +0000 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2008-11-04 13:03:23 +0000 |
| commit | aa616abc9ab02e333cf0cad4f524b15c710bf449 (patch) | |
| tree | 3d0afb0ab0942a4175bede1fac6c67fdc0c52315 | |
| parent | 30976635d7072c06d00e39b106e41be7b08c6c49 (diff) | |
[png] Use RGB for opaque images.
If the ARGB32 is opaque, discard the alpha channel - so we should generate
byte identical output to the reference images.
| -rw-r--r-- | src/cairo-png.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/src/cairo-png.c b/src/cairo-png.c index 06e7cb55..4721825e 100644 --- a/src/cairo-png.c +++ b/src/cairo-png.c @@ -190,7 +190,10 @@ write_png (cairo_surface_t *surface, switch (image->format) { case CAIRO_FORMAT_ARGB32: depth = 8; - png_color_type = PNG_COLOR_TYPE_RGB_ALPHA; + if (_cairo_image_analyze_transparency (image) == CAIRO_IMAGE_IS_OPAQUE) + png_color_type = PNG_COLOR_TYPE_RGB; + else + png_color_type = PNG_COLOR_TYPE_RGB_ALPHA; break; case CAIRO_FORMAT_RGB24: depth = 8; @@ -237,12 +240,12 @@ write_png (cairo_surface_t *surface, */ png_write_info (png, info); - if (image->format == CAIRO_FORMAT_ARGB32) + if (png_color_type == PNG_COLOR_TYPE_RGB_ALPHA) { png_set_write_user_transform_fn (png, unpremultiply_data); - else if (image->format == CAIRO_FORMAT_RGB24) + } else if (png_color_type == PNG_COLOR_TYPE_RGB) { png_set_write_user_transform_fn (png, convert_data_to_bytes); - if (image->format == CAIRO_FORMAT_RGB24) png_set_filler (png, 0, PNG_FILLER_AFTER); + } png_write_image (png, rows); png_write_end (png, info); |