gtk: Introduce GtkPointerFocus

These objects (tied to a toplevel) track the focus of a pointer/touchpoint.
The info in these basically consists of current toplevel coordinates and the
current target widget.

gtk/Makefile.am

@@ -513,6 +513,7 @@ gtk_private_h_sources =		\
 	gtkplacessidebarprivate.h	\
 	gtkplacesviewprivate.h	\
 	gtkplacesviewrowprivate.h	\
+	gtkpointerfocusprivate.h	\
 	gtkpopoverprivate.h	\
 	gtkprintoperation-private.h \
 	gtkprintutils.h		\
@@ -832,6 +833,7 @@ gtk_base_c_sources = 		\
 	gtkprivatetypebuiltins.c \
 	gtkprogressbar.c	\
 	gtkprogresstracker.c	\
+	gtkpointerfocus.c	\
 	gtkpopover.c		\
 	gtkpopovermenu.c	\
 	gtkradiobutton.c	\

gtk/gtkpointerfocus.c

@@ -0,0 +1,98 @@
+/* GTK - The GIMP Toolkit
+ * Copyright (C) 2017 - Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "gtkpointerfocusprivate.h"
+#include "gtkprivate.h"
+
+static void
+target_destroyed (gpointer  data,
+                  GObject  *object_location)
+{
+  GtkPointerFocus *focus = data;
+
+  focus->target = NULL;
+  gtk_pointer_focus_repick_target (focus);
+}
+
+GtkPointerFocus *
+gtk_pointer_focus_new (GtkWindow        *toplevel,
+                       GtkWidget        *widget,
+                       GdkDevice        *device,
+                       GdkEventSequence *sequence,
+                       gdouble           x,
+                       gdouble           y)
+{
+  GtkPointerFocus *focus;
+
+  focus = g_new0 (GtkPointerFocus, 1);
+  focus->toplevel = toplevel;
+  focus->device = device;
+  focus->sequence = sequence;
+  gtk_pointer_focus_set_target (focus, widget);
+  gtk_pointer_focus_set_coordinates (focus, x, y);
+
+  return focus;
+}
+
+void
+gtk_pointer_focus_free (GtkPointerFocus *focus)
+{
+  gtk_pointer_focus_set_target (focus, NULL);
+  gtk_pointer_focus_set_implicit_grab (focus, NULL);
+  g_free (focus);
+}
+
+void
+gtk_pointer_focus_set_target (GtkPointerFocus *focus,
+                              GtkWidget       *target)
+{
+  if (focus->target == target)
+    return;
+
+  if (focus->target)
+    g_object_weak_unref (G_OBJECT (focus->target), target_destroyed, focus);
+
+  focus->target = target;
+
+  if (focus->target)
+    g_object_weak_ref (G_OBJECT (focus->target), target_destroyed, focus);
+}
+
+GtkWidget *
+gtk_pointer_focus_get_target (GtkPointerFocus *focus)
+{
+  return focus->target;
+}
+
+void
+gtk_pointer_focus_set_coordinates (GtkPointerFocus *focus,
+                                   gdouble          x,
+                                   gdouble          y)
+{
+  focus->x = x;
+  focus->y = y;
+}
+
+void
+gtk_pointer_focus_repick_target (GtkPointerFocus *focus)
+{
+  GtkWidget *target;
+
+  target = _gtk_toplevel_pick (focus->toplevel, focus->x, focus->y,
+                               NULL, NULL);
+  gtk_pointer_focus_set_target (focus, target);
+}

gtk/gtkpointerfocusprivate.h

@@ -0,0 +1,52 @@
+/* GTK - The GIMP Toolkit
+ * Copyright (C) 2017 - Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _GTK_POINTER_FOCUS_PRIVATE_H_
+#define _GTK_POINTER_FOCUS_PRIVATE_H_
+
+#include <gtk/gtk.h>
+
+typedef struct _GtkPointerFocus GtkPointerFocus;
+
+struct _GtkPointerFocus
+{
+  GdkDevice *device;
+  GdkEventSequence *sequence;
+  GtkWindow *toplevel;
+  GtkWidget *target; /* Unaffected by the implicit grab */
+  GtkWidget *grab_widget;
+  gdouble x, y; /* In toplevel coordinates */
+};
+
+GtkPointerFocus * gtk_pointer_focus_new  (GtkWindow        *toplevel,
+                                          GtkWidget        *widget,
+                                          GdkDevice        *device,
+                                          GdkEventSequence *sequence,
+                                          gdouble           x,
+                                          gdouble           y);
+void              gtk_pointer_focus_free (GtkPointerFocus *focus);
+
+void              gtk_pointer_focus_set_coordinates (GtkPointerFocus *focus,
+                                                     gdouble          x,
+                                                     gdouble          y);
+void              gtk_pointer_focus_set_target      (GtkPointerFocus *focus,
+                                                     GtkWidget       *target);
+GtkWidget *       gtk_pointer_focus_get_target      (GtkPointerFocus *focus);
+
+void              gtk_pointer_focus_repick_target (GtkPointerFocus *focus);
+
+#endif /* _GTK_POINTER_FOCUS_PRIVATE_H_ */