[mutter] clutter/stage: Use rounded values to create image surfaces

[Jonas Ådahl <jadahl src gnome org>]

commit 97a3b88f2516efcea868b05903b64797600d2315
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Sat Dec 23 00:57:03 2017 +0100

    clutter/stage: Use rounded values to create image surfaces
    
    This needs to be an integer, and since the assumptions we
    have in Monitor this multiplication should always return
    an integer, however in case of precision loss it could
    return something very close to the next/prev integer, so
    let's be sure this won't happen, by just rounding it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=765011
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/3

 clutter/clutter/clutter-stage.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)
---
diff --git a/clutter/clutter/clutter-stage.c b/clutter/clutter/clutter-stage.c
index 67992d816..d284692c0 100644
--- a/clutter/clutter/clutter-stage.c
+++ b/clutter/clutter/clutter-stage.c
@@ -4769,6 +4769,8 @@ capture_view (ClutterStage          *stage,
   CoglBitmap *bitmap;
   cairo_rectangle_int_t view_layout;
   float view_scale;
+  float texture_width;
+  float texture_height;
 
   framebuffer = clutter_stage_view_get_framebuffer (view);
 
@@ -4780,9 +4782,10 @@ capture_view (ClutterStage          *stage,
     }
 
   view_scale = clutter_stage_view_get_scale (view);
+  texture_width = roundf (rect->width * view_scale);
+  texture_height = roundf (rect->height * view_scale);
   image = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
-                                      rect->width * view_scale,
-                                      rect->height * view_scale);
+                                      texture_width, texture_height);
   cairo_surface_set_device_scale (image, view_scale, view_scale);
 
   data = cairo_image_surface_get_data (image);
@@ -4790,9 +4793,7 @@ 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 * view_scale,
-                                     rect->height * view_scale,
+  bitmap = cogl_bitmap_new_for_data (context, texture_width, texture_height,
                                      CLUTTER_CAIRO_FORMAT_ARGB32,
                                      stride,
                                      data);
@@ -4800,8 +4801,8 @@ capture_view (ClutterStage          *stage,
   clutter_stage_view_get_layout (view, &view_layout);
 
   cogl_framebuffer_read_pixels_into_bitmap (framebuffer,
-                                            (rect->x - view_layout.x) * view_scale,
-                                            (rect->y - view_layout.y) * view_scale,
+                                            roundf ((rect->x - view_layout.x) * view_scale),
+                                            roundf ((rect->y - view_layout.y) * view_scale),
                                             COGL_READ_PIXELS_COLOR_BUFFER,
                                             bitmap);