[gthumb] Transparent webp images are rendered incorrectly

[Paolo Bacchilega <paobac src gnome org>]

commit b0e99414b94d9fea2207892b9c33bd9ffd0bcc6d
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sun Mar 20 12:48:05 2022 +0100

    Transparent webp images are rendered incorrectly
    
    Use RGB-premultiplied transparent modes.
    
    Fixes #199

 extensions/cairo_io/cairo-image-surface-webp.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/extensions/cairo_io/cairo-image-surface-webp.c b/extensions/cairo_io/cairo-image-surface-webp.c
index 4c0c22c7..4f5e12ae 100644
--- a/extensions/cairo_io/cairo-image-surface-webp.c
+++ b/extensions/cairo_io/cairo-image-surface-webp.c
@@ -99,9 +99,9 @@ _cairo_image_surface_create_from_webp (GInputStream  *istream,
 #endif
 
 #if G_BYTE_ORDER == G_LITTLE_ENDIAN
-       config.output.colorspace = MODE_BGRA;
+       config.output.colorspace = MODE_bgrA;
 #elif G_BYTE_ORDER == G_BIG_ENDIAN
-       config.output.colorspace = MODE_ARGB;
+       config.output.colorspace = MODE_Argb;
 #endif
        config.output.u.RGBA.rgba = (uint8_t *) _cairo_image_surface_flush_and_get_data (surface);
        config.output.u.RGBA.stride = cairo_image_surface_get_stride (surface);