[clutter/clutter-1.18] canvas: Use the window-scaling-factor setting

[Emmanuele Bassi <ebassi src gnome org>]

commit c1d6194d24ba04ebb8fe15aacea5017f8b49ce37
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Thu Jan 16 12:24:57 2014 +0000

    canvas: Use the window-scaling-factor setting
    
    ClutterCanvas is a ClutterContent interface implementation; this means
    that it can be created and modified regardless of whether it is
    associated to a specific actor or a stage. For this reason, we cannot
    walk the hierarchy and get the window scaling factor for high DPI
    density displays out of the ClutterStage when we create the Cairo
    surface that we will use to draw the canvas contents on.
    
    We can use ClutterSettings:window-scaling-factor instead, since it's
    what each ClutterStage will use anyway.
    
    This will get slightly more complicated when we support per-output
    window scaling factors (like on Wayland), but that will require changes
    in the entire settings architecture anyway.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=705915

 clutter/clutter-canvas.c |   32 ++++++++++++++++++++++++++------
 1 files changed, 26 insertions(+), 6 deletions(-)
---
diff --git a/clutter/clutter-canvas.c b/clutter/clutter-canvas.c
index 482bdd1..071d1d8 100644
--- a/clutter/clutter-canvas.c
+++ b/clutter/clutter-canvas.c
@@ -62,10 +62,12 @@
 #include "clutter-cairo.h"
 #include "clutter-color.h"
 #include "clutter-content-private.h"
+#include "clutter-debug.h"
 #include "clutter-marshal.h"
 #include "clutter-paint-node.h"
 #include "clutter-paint-nodes.h"
 #include "clutter-private.h"
+#include "clutter-settings.h"
 
 struct _ClutterCanvasPrivate
 {
@@ -353,23 +355,37 @@ static void
 clutter_canvas_emit_draw (ClutterCanvas *self)
 {
   ClutterCanvasPrivate *priv = self->priv;
+  int real_width, real_height;
   cairo_surface_t *surface;
   gboolean mapped_buffer;
   unsigned char *data;
   CoglBuffer *buffer;
+  int window_scale = 1;
   gboolean res;
   cairo_t *cr;
 
   g_assert (priv->width > 0 && priv->width > 0);
 
+  g_object_get (clutter_settings_get_default (),
+                "window-scaling-factor", &window_scale,
+                NULL);
+
+  real_width = priv->width * window_scale;
+  real_height = priv->height * window_scale;
+
+  CLUTTER_NOTE (MISC, "Creating Cairo surface with size %d x %d (real: %d x %d, scale: %d)",
+                priv->width, priv->height,
+                real_width, real_height,
+                window_scale);
+
   if (priv->buffer == NULL)
     {
       CoglContext *ctx;
 
       ctx = clutter_backend_get_cogl_context (clutter_get_default_backend ());
       priv->buffer = cogl_bitmap_new_with_size (ctx,
-                                                priv->width,
-                                                priv->height,
+                                                real_width,
+                                                real_height,
                                                 CLUTTER_CAIRO_FORMAT_ARGB32);
     }
 
@@ -389,20 +405,24 @@ clutter_canvas_emit_draw (ClutterCanvas *self)
 
       surface = cairo_image_surface_create_for_data (data,
                                                      CAIRO_FORMAT_ARGB32,
-                                                     priv->width,
-                                                     priv->height,
+                                                     real_width,
+                                                     real_height,
                                                      bitmap_stride);
       mapped_buffer = TRUE;
     }
   else
     {
       surface = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
-                                            priv->width,
-                                            priv->height);
+                                            real_width,
+                                            real_height);
 
       mapped_buffer = FALSE;
     }
 
+#ifdef HAVE_CAIRO_SURFACE_SET_DEVICE_SCALE
+  cairo_surface_set_device_scale (surface, window_scale, window_scale);
+#endif
+
   self->priv->cr = cr = cairo_create (surface);
 
   g_signal_emit (self, canvas_signals[DRAW], 0,