[gtk/wip/baedert/for-master] main: Translate coordinates from surface to native before picking

[Timm Bäder <baedert src gnome org>]

commit 3dd4d515ee9cfc0518773d640ac61e487c6dfa62
Author: Timm Bäder <mail baedert org>
Date:   Fri May 15 08:22:04 2020 +0200

    main: Translate coordinates from surface to native before picking
    
    gtk_widget_pick() needs them to be in @self coordinates.

 gtk/gtkmain.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkmain.c b/gtk/gtkmain.c
index 787abd4b23..28e6a4384c 100644
--- a/gtk/gtkmain.c
+++ b/gtk/gtkmain.c
@@ -96,6 +96,7 @@
 #include "gsk/gskprivate.h"
 #include "gsk/gskrendernodeprivate.h"
 #include "gtkarrayimplprivate.h"
+#include "gtknativeprivate.h"
 
 #include <locale.h>
 
@@ -1504,6 +1505,18 @@ set_widget_active_state (GtkWidget       *target,
     }
 }
 
+static GtkWidget *
+native_pick (GtkNative *native,
+             double     x,
+             double     y)
+{
+  int transform_x, transform_y;
+
+  gtk_native_get_surface_transform (native, &transform_x, &transform_y);
+
+  return gtk_widget_pick (GTK_WIDGET (native), x - transform_x, y - transform_y, GTK_PICK_DEFAULT);
+}
+
 static GtkWidget *
 handle_pointing_event (GdkEvent *event)
 {
@@ -1555,7 +1568,7 @@ handle_pointing_event (GdkEvent *event)
       target = gtk_window_lookup_pointer_focus_implicit_grab (toplevel, device, sequence);
 
       if (!target)
-       target = gtk_widget_pick (native, x, y, GTK_PICK_DEFAULT);
+       target = native_pick (GTK_NATIVE (native), x, y);
 
       if (!target)
         target = GTK_WIDGET (native);
@@ -1602,7 +1615,7 @@ handle_pointing_event (GdkEvent *event)
       if (type == GDK_BUTTON_RELEASE)
         {
           GtkWidget *new_target;
-          new_target = gtk_widget_pick (GTK_WIDGET (native), x, y, GTK_PICK_DEFAULT);
+          new_target = native_pick (GTK_NATIVE (native), x, y);
           if (new_target == NULL)
             new_target = GTK_WIDGET (toplevel);
           gtk_synthesize_crossing_events (GTK_ROOT (toplevel), GTK_CROSSING_POINTER, target, new_target,