gtk2_ardour/cairo_widget.h

   1 /*
   2     Copyright (C) 2009 Paul Davis
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 #ifndef __gtk2_ardour_cairo_widget_h__
  21 #define __gtk2_ardour_cairo_widget_h__
  22
  23 #include <gtkmm/eventbox.h>
  24
  25 /** A parent class for widgets that are made up of a pixmap rendered using Cairo.
  26  *  The pixmap is painted to screen on GTK expose events, but the rendering
  27  *  is only done after set_dirty() has been called.
  28  */
  29
  30 class CairoWidget : public Gtk::EventBox
  31 {
  32 public:
  33         CairoWidget ();
  34         virtual ~CairoWidget ();
  35
  36         void set_dirty ();
  37
  38 protected:
  39         /** Render the widget to the given Cairo context */
  40         virtual void render (cairo_t *) = 0;
  41         virtual bool on_expose_event (GdkEventExpose *);
  42         void on_size_allocate (Gtk::Allocation &);
  43
  44         int _width; ///< pixmap width
  45         int _height; ///< pixmap height
  46
  47 private:
  48         bool _dirty; ///< true if the pixmap requires re-rendering
  49         GdkPixmap* _pixmap; ///< our pixmap
  50 };
  51
  52 #endif