[gthumb] restore the correct image size when unding a change

[Paolo Bacchilega <paobac src gnome org>]

commit 3cf16698a573a1aa6ae825f5b4c2a3ea52badb78
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sun Sep 22 10:37:11 2013 +0200

    restore the correct image size when unding a change

 extensions/image_viewer/gth-image-viewer-page.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/extensions/image_viewer/gth-image-viewer-page.c b/extensions/image_viewer/gth-image-viewer-page.c
index 5761ae8..d43092d 100644
--- a/extensions/image_viewer/gth-image-viewer-page.c
+++ b/extensions/image_viewer/gth-image-viewer-page.c
@@ -1403,8 +1403,10 @@ _gth_image_viewer_page_set_image (GthImageViewerPage *self,
        self->priv->image_changed = modified;
        g_file_info_set_attribute_boolean (file_data->info, "gth::file::is-modified", modified);
 
-       width = cairo_image_surface_get_width (image);
-       height = cairo_image_surface_get_height (image);
+       if (! _cairo_image_surface_get_original_size (image, &width, &height)) {
+               width = cairo_image_surface_get_width (image);
+               height = cairo_image_surface_get_height (image);
+       }
        g_file_info_set_attribute_int32 (file_data->info, "image::width", width);
        g_file_info_set_attribute_int32 (file_data->info, "image::height", height);