[gimp] app: fix selection display on right/bottom borders when rulers are…

[Jehan <jehanp src gnome org>]

commit e8a531e51e12b66d664c3c7b7eb7317fe3eeb4d5
Author: Jehan <jehan girinstud io>
Date:   Sun May 9 15:32:49 2021 +0200

    app: fix selection display on right/bottom borders when rulers are…
    
    … displayed.
    
    We should use the dimensions from the GimpDisplayShell not the the
    GimpCanvas. Indeed the canvas is shorter when rulers are visible, hence
    the selection next to the extreme sides (bottom and right sides of the
    canvas) was not drawn.

 app/display/gimpdisplayshell-selection.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/app/display/gimpdisplayshell-selection.c b/app/display/gimpdisplayshell-selection.c
index c872da0daa..8f87ea2c1f 100644
--- a/app/display/gimpdisplayshell-selection.c
+++ b/app/display/gimpdisplayshell-selection.c
@@ -309,7 +309,7 @@ selection_render_mask (Selection *selection)
   cairo_surface_t *surface;
   cairo_t         *cr;
 
-  window = gtk_widget_get_window (selection->shell->canvas);
+  window = gtk_widget_get_window (GTK_WIDGET (selection->shell));
   surface = gdk_window_create_similar_surface (window, CAIRO_CONTENT_ALPHA,
                                                gdk_window_get_width  (window),
                                                gdk_window_get_height (window));
@@ -451,7 +451,7 @@ selection_start_timeout (Selection *selection)
       cairo_rectangle_int_t  rect;
       cairo_region_t        *region;
 
-      window = gtk_widget_get_window (selection->shell->canvas);
+      window = gtk_widget_get_window (GTK_WIDGET (selection->shell));
 
       rect.x      = 0;
       rect.y      = 0;