static bool encodeImage(cairo_surface_t* surface, const String& mimeType, std::optional<double> quality, GUniqueOutPtr<gchar>& buffer, gsize& bufferSize)
{
// List of supported image encoding types comes from the GdkPixbuf documentation.
// http://developer.gnome.org/gdk-pixbuf/stable/gdk-pixbuf-File-saving.html#gdk-pixbuf-save-to-bufferv
String type = mimeType.substring(sizeof "image");
if (type != "jpeg" && type != "png" && type != "tiff" && type != "ico" && type != "bmp")
return false;
GRefPtr<GdkPixbuf> pixbuf;
if (type == "jpeg") {
// JPEG doesn't support alpha channel. The <canvas> spec states that toDataURL() must encode a Porter-Duff
// composite source-over black for image types that do not support alpha.
RefPtr<cairo_surface_t> newSurface;
if (cairo_surface_get_type(surface) == CAIRO_SURFACE_TYPE_IMAGE) {
newSurface = adoptRef(cairo_image_surface_create_for_data(cairo_image_surface_get_data(surface),
CAIRO_FORMAT_RGB24,
cairo_image_surface_get_width(surface),
cairo_image_surface_get_height(surface),
cairo_image_surface_get_stride(surface)));
} else {
IntSize size = cairoSurfaceSize(surface);
newSurface = adoptRef(cairo_image_surface_create(CAIRO_FORMAT_RGB24, size.width(), size.height()));
RefPtr<cairo_t> cr = adoptRef(cairo_create(newSurface.get()));
cairo_set_source_surface(cr.get(), surface, 0, 0);
cairo_paint(cr.get());
}
pixbuf = adoptGRef(cairoSurfaceToGdkPixbuf(newSurface.get()));
} else
pixbuf = adoptGRef(cairoSurfaceToGdkPixbuf(surface));
if (!pixbuf)
return false;
GUniqueOutPtr<GError> error;
if (type == "jpeg" && quality && *quality >= 0.0 && *quality <= 1.0) {
String qualityString = String::format("%d", static_cast<int>(*quality * 100.0 + 0.5));
gdk_pixbuf_save_to_buffer(pixbuf.get(), &buffer.outPtr(), &bufferSize, type.utf8().data(), &error.outPtr(), "quality", qualityString.utf8().data(), NULL);
} else
gdk_pixbuf_save_to_buffer(pixbuf.get(), &buffer.outPtr(), &bufferSize, type.utf8().data(), &error.outPtr(), NULL);
return !error;
}
GdkPixbuf* BitmapImage::getGdkPixbuf()
{
RefPtr<cairo_surface_t> surface = nativeImageForCurrentFrame();
return surface ? cairoSurfaceToGdkPixbuf(surface.get()) : 0;
}