[gimp] gimpcursor: cursor hotspots platform specific

[Jehan <jehanp src gnome org>]

commit b0f0f46b1c35d209b08c59f37a99928ab421257c
Author: Lukas Oberhuber <lukaso gmail com>
Date:   Sat Feb 19 14:20:28 2022 +0000

    gimpcursor: cursor hotspots platform specific
    
    MacOS and Wayland need the hotspot in surface coordinates
      * X11 needs the hotspot in pixel coordinates (not scaled)
      * Windows doesn't handle scaled cursors at all
      * Broadway does not appear to support surface cursors at all,
      let alone scaled surface cursors.
    https://gitlab.gnome.org/GNOME/gimp/-/merge_requests/545#note_1388777

 app/widgets/gimpcursor.c | 35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)
---
diff --git a/app/widgets/gimpcursor.c b/app/widgets/gimpcursor.c
index f43bbadb3c..2fcbe8310c 100644
--- a/app/widgets/gimpcursor.c
+++ b/app/widgets/gimpcursor.c
@@ -18,6 +18,12 @@
 #include "config.h"
 
 #include <gtk/gtk.h>
+#ifdef GDK_WINDOWING_QUARTZ
+#include <gdk/gdkquartz.h>
+#endif
+#ifdef GDK_WINDOWING_WAYLAND
+#include <gdk/gdkwayland.h>
+#endif
 
 #include "widgets-types.h"
 
@@ -451,10 +457,37 @@ gimp_cursor_new (GdkWindow          *window,
 
   if (scale_factor > 1)
     {
+      gint hot_x_scaled = hot_x;
+      gint hot_y_scaled = hot_y;
+
       cairo_surface_t *surface =
         gdk_cairo_surface_create_from_pixbuf (pixbuf, scale_factor, NULL);
 
-      cursor = gdk_cursor_new_from_surface (display, surface, hot_x, hot_y);
+      /*
+       * MacOS and Wayland need the hotspot in surface coordinates
+       * X11 needs the hotspot in pixel coordinates (not scaled)
+       * Windows doesn't handle scaled cursors at all
+       * Broadway does not appear to support surface cursors at all,
+       * let alone scaled surface cursors.
+       * https://gitlab.gnome.org/GNOME/gimp/-/merge_requests/545#note_1388777
+       */
+      if (FALSE                            ||
+#ifdef GDK_WINDOWING_WAYLAND
+          GDK_IS_WAYLAND_DISPLAY (display) ||
+#endif
+#ifdef GDK_WINDOWING_QUARTZ
+          GDK_IS_QUARTZ_DISPLAY (display)  ||
+#endif
+          FALSE)
+        {
+          hot_x_scaled *= scale_factor;
+          hot_y_scaled *= scale_factor;
+        }
+
+      cursor = gdk_cursor_new_from_surface (display,
+                                            surface,
+                                            hot_x_scaled,
+                                            hot_y_scaled);
       cairo_surface_destroy (surface);
     }
   else