[mutter/wip/texture-purge-on-nvidia: 6/17] boxes: Add helper to scale rectangles by a double

[Ray Strode <halfline src gnome org>]

commit b78ab01edab03888cea21464ea555322dd1cfd48
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Dec 20 16:58:03 2018 +0100

    boxes: Add helper to scale rectangles by a double
    
    And change the similar region scaling helper to use this one.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/362

 src/core/boxes-private.h | 10 ++++++++++
 src/core/boxes.c         | 22 ++++++++++++++++++++++
 2 files changed, 32 insertions(+)
---
diff --git a/src/core/boxes-private.h b/src/core/boxes-private.h
index bf019b4d6..793f39527 100644
--- a/src/core/boxes-private.h
+++ b/src/core/boxes-private.h
@@ -38,6 +38,12 @@ typedef enum
   FIXED_DIRECTION_Y    = 1 << 1,
 } FixedDirections;
 
+typedef enum _MetaRoundingStrategy
+{
+  META_ROUNDING_STRATEGY_SHRINK,
+  META_ROUNDING_STRATEGY_GROW,
+} MetaRoundingStrategy;
+
 /* Output functions -- note that the output buffer had better be big enough:
  *   rect_to_string:   RECT_LENGTH
  *   region_to_string: (RECT_LENGTH+strlen(separator_string)) *
@@ -218,6 +224,10 @@ GList* meta_rectangle_find_nonintersected_monitor_edges (
 gboolean meta_rectangle_is_adjecent_to (MetaRectangle *rect,
                                         MetaRectangle *other);
 
+void meta_rectangle_scale_double (MetaRectangle        *rect,
+                                  double                scale,
+                                  MetaRoundingStrategy  rounding_strategy);
+
 static inline ClutterRect
 meta_rectangle_to_clutter_rect (MetaRectangle *rect)
 {
diff --git a/src/core/boxes.c b/src/core/boxes.c
index 35e9ac3cd..0854ecf94 100644
--- a/src/core/boxes.c
+++ b/src/core/boxes.c
@@ -2036,3 +2036,25 @@ meta_rectangle_is_adjecent_to (MetaRectangle *rect,
   else
     return FALSE;
 }
+
+void
+meta_rectangle_scale_double (MetaRectangle        *rect,
+                             double                scale,
+                             MetaRoundingStrategy  rounding_strategy)
+{
+  switch (rounding_strategy)
+    {
+    case META_ROUNDING_STRATEGY_SHRINK:
+      rect->x = (int) ceil (rect->x * scale);
+      rect->y = (int) ceil (rect->y * scale);
+      rect->width = (int) floor (rect->width * scale);
+      rect->height = (int) floor (rect->height * scale);
+      break;
+    case META_ROUNDING_STRATEGY_GROW:
+      rect->x = (int) floor (rect->x * scale);
+      rect->y = (int) floor (rect->y * scale);
+      rect->width = (int) ceil (rect->width * scale);
+      rect->height = (int) ceil (rect->height * scale);
+      break;
+    }
+}