[mutter] boxes: Add API to transform a MetaRectangle

[Jonas Ådahl <jadahl src gnome org>]

commit 686b7f8baa467faf855f413350c0c407d2a306af
Author: Robert Mader <robert mader posteo de>
Date:   Fri Dec 21 17:12:49 2018 +0100

    boxes: Add API to transform a MetaRectangle
    
    To be used if not a whole region needs to get transformed.
    It also has an argument for reverse-transforms.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/366

 src/compositor/region-utils.c | 49 ++++-----------------------
 src/core/boxes-private.h      |  7 ++++
 src/core/boxes.c              | 77 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 90 insertions(+), 43 deletions(-)
---
diff --git a/src/compositor/region-utils.c b/src/compositor/region-utils.c
index 1719a4500..3a5839695 100644
--- a/src/compositor/region-utils.c
+++ b/src/compositor/region-utils.c
@@ -22,6 +22,7 @@
 
 #include "backends/meta-monitor-transform.h"
 #include "compositor/region-utils.h"
+#include "core/boxes-private.h"
 
 #include <math.h>
 
@@ -392,51 +393,13 @@ meta_region_transform (cairo_region_t       *region,
   rects = g_new0 (cairo_rectangle_int_t, n_rects);
   for (i = 0; i < n_rects; i++)
     {
-      cairo_rectangle_int_t rect;
-
       cairo_region_get_rectangle (region, i, &rects[i]);
 
-      rect = rects[i];
-
-      switch (transform)
-        {
-        case META_MONITOR_TRANSFORM_90:
-          rects[i].x = width - (rect.y + rect.height);
-          rects[i].y = rect.x;
-          rects[i].width = rect.height;
-          rects[i].height = rect.width;
-          break;
-        case META_MONITOR_TRANSFORM_180:
-          rects[i].x = width - (rect.x + rect.width);
-          rects[i].y = height - (rect.y + rect.height);
-          break;
-        case META_MONITOR_TRANSFORM_270:
-          rects[i].x = rect.y;
-          rects[i].y = height - (rect.x + rect.width);
-          rects[i].width = rect.height;
-          rects[i].height = rect.width;
-          break;
-        case META_MONITOR_TRANSFORM_FLIPPED:
-          rects[i].x = width - (rect.x + rect.width);
-          break;
-        case META_MONITOR_TRANSFORM_FLIPPED_90:
-          rects[i].x = width - (rect.y + rect.height);
-          rects[i].y = height - (rect.x + rect.width);
-          rects[i].width = rect.height;
-          rects[i].height = rect.width;
-          break;
-        case META_MONITOR_TRANSFORM_FLIPPED_180:
-          rects[i].y = height - (rect.y + rect.height);
-          break;
-        case META_MONITOR_TRANSFORM_FLIPPED_270:
-          rects[i].x = rect.y;
-          rects[i].y = rect.x;
-          rects[i].width = rect.height;
-          rects[i].height = rect.width;
-          break;
-        case META_MONITOR_TRANSFORM_NORMAL:
-          g_assert_not_reached ();
-        }
+      meta_rectangle_transform (&rects[i],
+                                transform,
+                                width,
+                                height,
+                                &rects[i]);
     }
 
   transformed_region = cairo_region_create_rectangles (rects, n_rects);
diff --git a/src/core/boxes-private.h b/src/core/boxes-private.h
index 4c6fd08ab..fba9021c9 100644
--- a/src/core/boxes-private.h
+++ b/src/core/boxes-private.h
@@ -24,6 +24,7 @@
 
 #include <glib-object.h>
 
+#include "backends/meta-backend-types.h"
 #include "meta/boxes.h"
 #include "meta/common.h"
 
@@ -245,4 +246,10 @@ meta_rectangle_to_clutter_rect (MetaRectangle *rect)
   };
 }
 
+void meta_rectangle_transform (const MetaRectangle  *rect,
+                               MetaMonitorTransform  transform,
+                               int                   width,
+                               int                   height,
+                               MetaRectangle        *dest);
+
 #endif /* META_BOXES_PRIVATE_H */
diff --git a/src/core/boxes.c b/src/core/boxes.c
index 98a8d3586..471258f40 100644
--- a/src/core/boxes.c
+++ b/src/core/boxes.c
@@ -30,6 +30,7 @@
 
 #include "config.h"
 
+#include "backends/meta-monitor-transform.h"
 #include "core/boxes-private.h"
 
 #include <X11/Xutil.h>
@@ -2071,3 +2072,79 @@ meta_rectangle_scale_double (const MetaRectangle  *rect,
       break;
     }
 }
+
+void
+meta_rectangle_transform (const MetaRectangle  *rect,
+                          MetaMonitorTransform  transform,
+                          int                   width,
+                          int                   height,
+                          MetaRectangle        *dest)
+{
+  switch (transform)
+    {
+    case META_MONITOR_TRANSFORM_NORMAL:
+      *dest = (MetaRectangle) {
+        .x = rect->x,
+        .y = rect->y,
+        .width = rect->width,
+        .height = rect->height,
+      };
+      break;
+    case META_MONITOR_TRANSFORM_90:
+      *dest = (MetaRectangle) {
+        .x = width - (rect->y + rect->height),
+        .y = rect->x,
+        .width = rect->height,
+        .height = rect->width,
+      };
+      break;
+    case META_MONITOR_TRANSFORM_180:
+      *dest = (MetaRectangle) {
+        .x = width - (rect->x + rect->width),
+        .y = height - (rect->y + rect->height),
+        .width = rect->width,
+        .height = rect->height,
+      };
+      break;
+    case META_MONITOR_TRANSFORM_270:
+      *dest = (MetaRectangle) {
+        .x = rect->y,
+        .y = height - (rect->x + rect->width),
+        .width = rect->height,
+        .height = rect->width,
+      };
+      break;
+    case META_MONITOR_TRANSFORM_FLIPPED:
+      *dest = (MetaRectangle) {
+        .x = width - (rect->x + rect->width),
+        .y = rect->y,
+        .width = rect->width,
+        .height = rect->height,
+      };
+      break;
+    case META_MONITOR_TRANSFORM_FLIPPED_90:
+      *dest = (MetaRectangle) {
+        .x = width - (rect->y + rect->height),
+        .y = height - (rect->x + rect->width),
+        .width = rect->height,
+        .height = rect->width,
+      };
+      break;
+    case META_MONITOR_TRANSFORM_FLIPPED_180:
+      *dest = (MetaRectangle) {
+        .x = rect->x,
+        .y = height - (rect->y + rect->height),
+        .width = rect->width,
+        .height = rect->height,
+      };
+      break;
+    case META_MONITOR_TRANSFORM_FLIPPED_270:
+      *dest = (MetaRectangle) {
+        .x = rect->y,
+        .y = rect->x,
+        .width = rect->height,
+        .height = rect->width,
+      };
+      break;
+    }
+}