gtk2_ardour/cairo_widget.cc

   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 #include "cairo_widget.h"
  21 #include "gui_thread.h"
  22
  23 CairoWidget::CairoWidget ()
  24         : _width (1),
  25           _height (1),
  26           _dirty (true),
  27           _pixmap (0)
  28 {
  29
  30 }
  31
  32 CairoWidget::~CairoWidget ()
  33 {
  34         if (_pixmap) {
  35                 g_object_unref (_pixmap);
  36         }
  37 }
  38
  39 bool
  40 CairoWidget::on_expose_event (GdkEventExpose *event)
  41 {
  42         Gdk::Rectangle const exposure (
  43                 event->area.x, event->area.y, event->area.width, event->area.height
  44                 );
  45
  46         Gdk::Rectangle r = exposure;
  47         Gdk::Rectangle content (0, 0, _width, _height);
  48         bool intersects;
  49         r.intersect (content, intersects);
  50
  51         if (intersects) {
  52
  53                 GdkDrawable* drawable = get_window()->gobj ();
  54
  55                 if (_dirty) {
  56
  57                         if (_pixmap) {
  58                                 g_object_unref (_pixmap);
  59                         }
  60
  61                         _pixmap = gdk_pixmap_new (drawable, _width, _height, -1);
  62
  63                         cairo_t* cr = gdk_cairo_create (_pixmap);
  64                         render (cr);
  65                         cairo_destroy (cr);
  66
  67                         _dirty = false;
  68                 }
  69
  70                 gdk_draw_drawable (
  71                         drawable,
  72                         get_style()->get_fg_gc (Gtk::STATE_NORMAL)->gobj(),
  73                         _pixmap,
  74                         r.get_x(),
  75                         r.get_y(),
  76                         r.get_x(),
  77                         r.get_y(),
  78                         r.get_width(),
  79                         r.get_height()
  80                         );
  81         }
  82
  83         return true;
  84 }
  85
  86 /** Marks the widget as dirty, so that render () will be called on
  87  *  the next GTK expose event.
  88  */
  89
  90 void
  91 CairoWidget::set_dirty ()
  92 {
  93         ENSURE_GUI_THREAD (*this, &CairoWidget::set_dirty)
  94
  95         _dirty = true;
  96         queue_draw ();
  97 }
  98
  99 /** Handle a size allocation.
 100  *  @param alloc GTK allocation.
 101  */
 102 void
 103 CairoWidget::on_size_allocate (Gtk::Allocation& alloc)
 104 {
 105         Gtk::EventBox::on_size_allocate (alloc);
 106
 107         _width = alloc.get_width ();
 108         _height = alloc.get_height ();
 109
 110         set_dirty ();
 111 }