1 files changed, 59 insertions, 0 deletions
diff --git a/libs/widgets/widgets/eventboxext.h b/libs/widgets/widgets/eventboxext.h
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+++ b/libs/widgets/widgets/eventboxext.h
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+/*
+ * Copyright (C) 2017 Robin Gareus <robin@gareus.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#ifndef _WIDGETS_EVENTBOX_EXT_H_
+#define _WIDGETS_EVENTBOX_EXT_H_
+
+#include <gtkmm/eventbox.h>
+
+#include "widgets/visibility.h"
+
+namespace ArdourWidgets {
+
+class LIBWIDGETS_API EventBoxExt : public Gtk::EventBox
+{
+public:
+	EventBoxExt ();
+	virtual ~EventBoxExt () {}
+
+protected:
+	/* gtk2's gtk/gtkcontainer.c does not
+	 * unmap child widgets if the container has a window.
+	 *
+	 * (this is for historical reasons and optimization
+	 * because back in the day each GdkWindow was backed by
+	 * an actual windowing system surface).
+	 *
+	 * In Ardour's case an EventBox is used in the Editor's top-level
+	 * and child-widgets (e.g. Canvas::GtkCanvas never receive an unmap.
+	 *
+	 * However, when switching Tabbable pages, we do need to hide overlays
+	 * such as ArdourCanvasOpenGLView
+	 *
+	 */
+	void on_unmap () {
+		Gtk::EventBox::on_unmap();
+		if (get_child ()) {
+			get_child()->unmap();
+		}
+	}
+};
+
+} /* namespace */
+
+#endif