[mutter] clutter/rect: Clamp to pixel taking care of subpixel values

[Marco Trevisan <marcotrevi src gnome org>]

commit 8bc8dc66f234c223e1fb3ab545a540cb6ccc73d1
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Fri Mar 1 02:49:19 2019 +0100

    clutter/rect: Clamp to pixel taking care of subpixel values
    
    The clamped rectangle currently could not fully contain the original fractional
    rectangle because it doesn't take care of the fact that the new width should
    consider the fact that flooring we'd translate the rectangle, and thus to cover
    the same area we need to take care of it.
    
    So, to properly compute the width and height, calculate x2 and y2 first and then
    use this ceiled value to compute the actual width using the floored x1 and y1.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/3

 clutter/clutter/clutter-base-types.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
---
diff --git a/clutter/clutter/clutter-base-types.c b/clutter/clutter/clutter-base-types.c
index ba38d7e34..f7ad5261e 100644
--- a/clutter/clutter/clutter-base-types.c
+++ b/clutter/clutter/clutter-base-types.c
@@ -1160,15 +1160,20 @@ clutter_rect_inset (ClutterRect *rect,
 void
 clutter_rect_clamp_to_pixel (ClutterRect *rect)
 {
+  float x2, y2;
+
   g_return_if_fail (rect != NULL);
 
   clutter_rect_normalize_internal (rect);
 
+  x2 = rect->origin.x + rect->size.width;
+  y2 = rect->origin.y + rect->size.height;
+
   rect->origin.x = floorf (rect->origin.x);
   rect->origin.y = floorf (rect->origin.y);
 
-  rect->size.width = ceilf (rect->size.width);
-  rect->size.height = ceilf (rect->size.height);
+  rect->size.width = ceilf (x2) - rect->origin.x;
+  rect->size.height = ceilf (y2) - rect->origin.y;
 }
 
 /**