+PositionImage
+merge (list<PositionImage> images)
+{
+ if (images.empty ()) {
+ return PositionImage ();
+ }
+
+ dcpomatic::Rect<int> all (images.front().position, images.front().image->size().width, images.front().image->size().height);
+ for (list<PositionImage>::const_iterator i = images.begin(); i != images.end(); ++i) {
+ all.extend (dcpomatic::Rect<int> (i->position, i->image->size().width, i->image->size().height));
+ }
+
+ shared_ptr<Image> merged (new Image (images.front().image->pixel_format (), dcp::Size (all.width, all.height), true));
+ merged->make_transparent ();
+ for (list<PositionImage>::const_iterator i = images.begin(); i != images.end(); ++i) {
+ merged->alpha_blend (i->image, i->position);
+ }
+
+ return PositionImage (merged, all.position ());
+}
+