Re: cairo built against libpng16
Ingmar Runge <[email protected]>
| Newsgroups | gmane.comp.lib.cairo |
|---|---|
| Message-ID | <CAAUiU8ayMsGsAV1dX4Twe-3BB_=hRAKrJzwPxMujf0iFqDpjHw@mail.gmail.com> |
Sorry, here's the correct version - copy/paste error in the first one. On Sat, Mar 30, 2013 at 9:22 AM, Ingmar Runge <[email protected]> wrote: > Hey everyone, here's a possible patch. It's the least invasive patch I > could think of. > -- cairo mailing list [email protected] http://lists.cairographics.org/mailman/listinfo/cairo
cairo-libpng16-v2.patch
(application/octet-stream, 1.6 KB)
--- cairo-png.c 2012-03-29 12:05:32.000000000 +0200
+++ cairo-png.c 2013-03-30 09:13:50.817181600 +0100
@@ -497,6 +497,20 @@
}
}
+/* branches into premultiply_data or convert_bytes_to_data depending on color type */
+static void read_user_transform_func (png_structp png, png_row_infop row_info, png_bytep data)
+{
+ switch ((cairo_format_t) png_get_user_transform_ptr (png)) {
+ case CAIRO_FORMAT_ARGB32:
+ premultiply_data (png, row_info, data);
+ break;
+
+ case CAIRO_FORMAT_RGB24:
+ convert_bytes_to_data (png, row_info, data);
+ break;
+ }
+}
+
static cairo_status_t
stdio_read_func (void *closure, unsigned char *data, unsigned int size)
{
@@ -623,6 +637,9 @@
png_set_filler (png, 0xff, PNG_FILLER_AFTER);
+ /* this must be stored before calling png_read_update_info */
+ png_set_read_user_transform_fn (png, read_user_transform_func);
+
/* recheck header after setting EXPAND options */
png_read_update_info (png, info);
png_get_IHDR (png, info,
@@ -643,15 +660,15 @@
case PNG_COLOR_TYPE_RGB_ALPHA:
format = CAIRO_FORMAT_ARGB32;
- png_set_read_user_transform_fn (png, premultiply_data);
break;
case PNG_COLOR_TYPE_RGB:
format = CAIRO_FORMAT_RGB24;
- png_set_read_user_transform_fn (png, convert_bytes_to_data);
break;
}
+ png_set_user_transform_info (png, (void*) format, 0, 0);
+
stride = cairo_format_stride_for_width (format, png_width);
if (stride < 0) {
surface = _cairo_surface_create_in_error (_cairo_error (CAIRO_STATUS_INVALID_STRIDE));