[gtk/wip/chergert/for-macos-1: 1/3] macos: improve monitor detection at display coordinates

[Christian Hergert <chergert src gnome org>]

commit 056e9012d2d01c04899dcb8cd4c14b1933a0b2c8
Author: Christian Hergert <christian hergert me>
Date:   Tue Feb 15 12:11:36 2022 -0800

    macos: improve monitor detection at display coordinates
    
    This needs to handle the boundary case where the value is exactly equal
    to the edge of a rectangle (which gdk_rectangle_contains_point() does not
    consider to be containing). However, if there is a monitor in the list
    that is a better match, we still want to prefer it.

 gdk/macos/gdkmacosdisplay.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)
---
diff --git a/gdk/macos/gdkmacosdisplay.c b/gdk/macos/gdkmacosdisplay.c
index 8d3aa0224e..a76cc1e111 100644
--- a/gdk/macos/gdkmacosdisplay.c
+++ b/gdk/macos/gdkmacosdisplay.c
@@ -815,6 +815,7 @@ _gdk_macos_display_get_monitor_at_coords (GdkMacosDisplay *self,
                                           int              x,
                                           int              y)
 {
+  GdkMacosMonitor *best_match = NULL;
   guint n_monitors;
 
   g_return_val_if_fail (GDK_IS_MACOS_DISPLAY (self), NULL);
@@ -824,12 +825,25 @@ _gdk_macos_display_get_monitor_at_coords (GdkMacosDisplay *self,
   for (guint i = 0; i < n_monitors; i++)
     {
       GdkMacosMonitor *monitor = get_monitor (self, i);
+      const GdkRectangle *geom = &GDK_MONITOR (monitor)->geometry;
 
-      if (gdk_rectangle_contains_point (&GDK_MONITOR (monitor)->geometry, x, y))
-        return GDK_MONITOR (monitor);
+      if (x >= geom->x &&
+          y >= geom->y &&
+          x <= (geom->x + geom->width) &&
+          y <= (geom->y + geom->height))
+        {
+          if (x <= geom->x + geom->width && y < geom->y + geom->height)
+            return GDK_MONITOR (monitor);
+
+          /* Not an exact match as we're on a boundary, but there is
+           * a good chance another monitor doesn't exist there so we
+           * would want to still treat this as the best monitor.
+           */
+          best_match = monitor;
+        }
     }
 
-  return NULL;
+  return GDK_MONITOR (best_match);
 }
 
 GdkMonitor *