[vte] app: Default to the right operator when showing a background image

[Christian Persch <chpe src gnome org>]

commit 69a264904b80b4685e4350157396900c01e3e66a
Author: Christian Persch <chpe src gnome org>
Date:   Tue Oct 24 20:37:27 2017 +0200

    app: Default to the right operator when showing a background image

 src/app/app.cc |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/src/app/app.cc b/src/app/app.cc
index ad4e5bf..8d88ecf 100644
--- a/src/app/app.cc
+++ b/src/app/app.cc
@@ -179,6 +179,11 @@ private:
                 Options* that = static_cast<Options*>(data);
                 g_clear_object(&that->background_pixbuf);
                 that->background_pixbuf = gdk_pixbuf_new_from_file(value, error);
+                if (that->background_pixbuf != nullptr) {
+                        /* Default to actually showing the image */
+                        that->background_operator = CAIRO_OPERATOR_OVER;
+                        that->background_operator_set = true;
+                }
                 return that->background_pixbuf != nullptr;
         }