Revert https://github.com/WayfireWM/wf-shell/commit/6e3ac5da8d24
until x11-toolkits/gtkmm30 is updated to 3.24 or later.

../src/background/background.cpp:33:35: error: no member named 'create_surface_from_pixbuf' in namespace 'Gdk::Cairo'
    to_image.source = Gdk::Cairo::create_surface_from_pixbuf(image,
                      ~~~~~~~~~~~~^

--- src/background/background.cpp.orig	2020-03-21 19:18:51 UTC
+++ src/background/background.cpp
@@ -21,19 +21,17 @@ void BackgroundDrawingArea::show_image(Glib::RefPtr<Gd
 {
     if (!image)
     {
-        to_image.source.clear();
-        from_image.source.clear();
+        to_image.pbuf.clear();
+        from_image.pbuf.clear();
         return;
     }
 
     from_image = to_image;
-    to_image.source = Gdk::Cairo::create_surface_from_pixbuf(image,
-        this->get_scale_factor());
+    to_image.pbuf = image;
+    to_image.x = offset_x;
+    to_image.y = offset_y;
+    fade.animate(from_image.pbuf ? 0.0 : 1.0, 1.0);
 
-    to_image.x = offset_x / this->get_scale_factor();
-    to_image.y = offset_y / this->get_scale_factor();
-    fade.animate(from_image.source ? 0.0 : 1.0, 1.0);
-
     Glib::signal_idle().connect_once([=] () {
         this->queue_draw();
     });
@@ -41,19 +39,25 @@ void BackgroundDrawingArea::show_image(Glib::RefPtr<Gd
 
 bool BackgroundDrawingArea::on_draw(const Cairo::RefPtr<Cairo::Context>& cr)
 {
-    if (!to_image.source)
+    if (!to_image.pbuf)
         return false;
 
     if (fade.running())
         queue_draw();
 
-    cr->set_source(to_image.source, to_image.x, to_image.y);
+    Gdk::Cairo::set_source_pixbuf(cr, to_image.pbuf, to_image.x, to_image.y);
+    cr->rectangle(0, 0, to_image.pbuf->get_width(), to_image.pbuf->get_height());
     cr->paint_with_alpha(fade);
-    if (!from_image.source)
+
+    if (!from_image.pbuf)
         return false;
 
-    cr->set_source(from_image.source, from_image.x, from_image.y);
+    Gdk::Cairo::set_source_pixbuf(cr, from_image.pbuf,
+        from_image.x, from_image.y);
+    cr->rectangle(0, 0, from_image.pbuf->get_width(),
+        from_image.pbuf->get_height());
     cr->paint_with_alpha(1.0 - fade);
+
     return false;
 }
 
--- src/background/background.hpp.orig	2020-03-21 19:18:51 UTC
+++ src/background/background.hpp
@@ -11,9 +11,9 @@ class WayfireBackground;
 
 class BackgroundImage
 {
-  public:
+    public:
     double x, y;
-    Cairo::RefPtr<Cairo::Surface> source;
+    Glib::RefPtr<Gdk::Pixbuf> pbuf;
 };
 
 class BackgroundDrawingArea : public Gtk::DrawingArea