[mutter] clutter/stage: Fix capturing scaled views

[Jonas Ådahl <jadahl src gnome org>]

commit fef81cd628e2f8ca01893eff80138135cbe2a790
Author: Jonas Ådahl <jadahl gmail com>
Date:   Wed Jun 7 14:49:08 2017 +0800

    clutter/stage: Fix capturing scaled views
    
    Make clutter_stage_capture() work if views are scaled. This needs
    adaptations on the using side to deal with the cairo surface device
    scale that is used to communicate the scale used when capturing.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=765011

 clutter/clutter/clutter-stage.c |   13 +++++++++----
 1 files changed, 9 insertions(+), 4 deletions(-)
---
diff --git a/clutter/clutter/clutter-stage.c b/clutter/clutter/clutter-stage.c
index b7e7cd3..43bcb8b 100644
--- a/clutter/clutter/clutter-stage.c
+++ b/clutter/clutter/clutter-stage.c
@@ -4720,6 +4720,7 @@ capture_view (ClutterStage          *stage,
   int stride;
   CoglBitmap *bitmap;
   cairo_rectangle_int_t view_layout;
+  float view_scale;
 
   framebuffer = clutter_stage_view_get_framebuffer (view);
 
@@ -4730,8 +4731,11 @@ capture_view (ClutterStage          *stage,
       clutter_stage_do_paint_view (stage, view, rect);
     }
 
+  view_scale = clutter_stage_view_get_scale (view);
   image = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
-                                      rect->width, rect->height);
+                                      rect->width * view_scale,
+                                      rect->height * view_scale);
+  cairo_surface_set_device_scale (image, view_scale, view_scale);
 
   data = cairo_image_surface_get_data (image);
   stride = cairo_image_surface_get_stride (image);
@@ -4739,7 +4743,8 @@ capture_view (ClutterStage          *stage,
   backend = clutter_get_default_backend ();
   context = clutter_backend_get_cogl_context (backend);
   bitmap = cogl_bitmap_new_for_data (context,
-                                     rect->width, rect->height,
+                                     rect->width * view_scale,
+                                     rect->height * view_scale,
                                      CLUTTER_CAIRO_FORMAT_ARGB32,
                                      stride,
                                      data);
@@ -4747,8 +4752,8 @@ capture_view (ClutterStage          *stage,
   clutter_stage_view_get_layout (view, &view_layout);
 
   cogl_framebuffer_read_pixels_into_bitmap (framebuffer,
-                                            rect->x - view_layout.x,
-                                            rect->y - view_layout.y,
+                                            (rect->x - view_layout.x) * view_scale,
+                                            (rect->y - view_layout.y) * view_scale,
                                             COGL_READ_PIXELS_COLOR_BUFFER,
                                             bitmap);