livetrax/gtk2_ardour/cairo_widget.h

/*
    Copyright (C) 2009 Paul Davis

    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., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#ifndef __gtk2_ardour_cairo_widget_h__
#define __gtk2_ardour_cairo_widget_h__

#include <gtkmm/eventbox.h>

/** A parent class for widgets that are made up of a pixmap rendered using Cairo.
 *  The pixmap is painted to screen on GTK expose events, but the rendering
 *  is only done after set_dirty() has been called.
 */

class CairoWidget : public Gtk::EventBox
{
public:
	CairoWidget ();
	virtual ~CairoWidget ();

	void set_dirty ();

protected:
	/** Render the widget to the given Cairo context */
	virtual void render (cairo_t *) = 0;
	virtual bool on_expose_event (GdkEventExpose *);
	void on_size_allocate (Gtk::Allocation &);

	int _width; ///< pixmap width
	int _height; ///< pixmap height

private:
	bool _dirty; ///< true if the pixmap requires re-rendering
	GdkPixmap* _pixmap; ///< our pixmap
};

#endif