mcs/class/Mono.Cairo/Samples/gtk/circles.cs

   1 //
   2 //
   3 //      Mono.Cairo drawing samples using GTK# as drawing surface
   4 //      Autor: Jordi Mas <jordi@ximian.com>. Based on work from Owen Taylor
   5 //             Hisham Mardam Bey <hisham@hisham.cc>
   6 //
   7
   8 //
   9 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System;
  32 using Cairo;
  33 using Gtk;
  34
  35 public class GtkCairo
  36 {
  37         static DrawingArea a;
  38
  39         static void Main ()
  40         {
  41                 Application.Init ();
  42                 Gtk.Window w = new Gtk.Window ("Mono.Cairo Circles demo");
  43
  44                 a = new CairoGraphic ();
  45
  46                 Box box = new HBox (true, 0);
  47                 box.Add (a);
  48                 w.Add (box);
  49                 w.Resize (500,500);
  50                 w.ShowAll ();
  51
  52                 Application.Run ();
  53         }
  54
  55
  56 }
  57
  58 public class CairoGraphic : DrawingArea
  59 {
  60         static readonly double  M_PI = 3.14159265358979323846;
  61
  62         static void oval_path (Cairo.Context gr, double xc, double yc, double xr, double yr)
  63         {
  64                 gr.Translate (xc, yc);
  65                 gr.Scale (1.0, yr / xr);
  66                 gr.MoveTo (new PointD (xr, 0.0) );
  67                 gr.Arc (0, 0, xr, 0, 2 * M_PI);
  68                 gr.ClosePath ();
  69         }
  70
  71         /*
  72         * Draw a red, green, and blue circle equally spaced inside
  73         * the larger circle of radius r at (xc, yc)
  74         */
  75         static void draw_3circles (Cairo.Context gr, double xc, double yc, double radius)
  76         {
  77                 double subradius = radius * (2 / 3.0 - 0.1);
  78
  79                 gr.Color =  new Color (1, 0, 0, 0.5);
  80
  81                 oval_path (gr,
  82                         xc + radius / 3 * Math.Cos (M_PI * (0.5)),
  83                         yc - radius / 3 * Math.Sin (M_PI * (0.5)),
  84                         subradius, subradius);
  85
  86                 gr.Fill ();
  87
  88                 gr.Color  = new Color (0, 1, 0, 0.5);
  89                 oval_path (gr,
  90                         xc + radius / 3 * Math.Cos (M_PI * (0.5 + 2/.3)),
  91                         yc - radius / 3 * Math.Sin (M_PI * (0.5 + 2/.3)),
  92                         subradius, subradius);
  93
  94                 gr.Fill ();
  95
  96                 gr.Color = new Color (0, 0, 1, 0.5);
  97
  98                 oval_path (gr,
  99                         xc + radius / 3 * Math.Cos (M_PI * (0.5 + 4/.3)),
 100                         yc - radius / 3 * Math.Sin (M_PI * (0.5 + 4/.3)),
 101                         subradius, subradius);
 102
 103                 gr.Fill ();
 104         }
 105
 106         static void draw (Cairo.Context gr, int width, int height)
 107         {
 108                 Surface overlay, punch, circles;
 109
 110                 /* Fill the background */
 111                 double radius = 0.5 * (width < height ? width : height) - 10;
 112                 double xc = width / 2;
 113                 double yc = height / 2;
 114
 115                 Surface target = gr.Target;
 116                 overlay = target.CreateSimilar (Content.ColorAlpha, width, height);
 117                 punch = target.CreateSimilar (Content.Alpha, width, height);
 118                 circles = target.CreateSimilar (Content.ColorAlpha, width, height);
 119
 120                 gr.Save ();
 121                 gr.Target = overlay;
 122
 123                 /* Draw a black circle on the overlay
 124                 */
 125
 126                 gr.Color = new Color (0, 0, 0, 1);
 127
 128                 oval_path (gr, xc, yc, radius, radius);
 129                 gr.Fill ();
 130                 gr.Save ();
 131                 gr.Target =  punch;
 132
 133
 134                 /* Draw 3 circles to the punch surface, then cut
 135                 * that out of the main circle in the overlay
 136                 */
 137                 draw_3circles (gr, xc, yc, radius);
 138
 139                 gr.Restore ();
 140
 141                 gr.Operator = Operator.DestOut;
 142                 punch.Show (gr, width, height);
 143
 144
 145                 /* Now draw the 3 circles in a subgroup again
 146                 * at half intensity, and use OperatorAdd to join up
 147                 * without seams.
 148                 */
 149                 gr.Save ();
 150                 gr.Target =  circles;
 151
 152                 //gr.Alpha = 0.5;
 153                 gr.Operator = Operator.Over;
 154                 draw_3circles (gr, xc, yc, radius);
 155
 156                 gr.Restore ();
 157
 158                 gr.Operator = Operator.Add;
 159                 circles.Show (gr, width, height);
 160
 161
 162                 gr.Restore ();
 163
 164                 overlay.Show (gr, width, height);
 165         }
 166
 167         protected override bool OnExposeEvent (Gdk.EventExpose args)
 168         {
 169                 Gdk.Window win = args.Window;
 170                 //Gdk.Rectangle area = args.Area;
 171
 172                 Cairo.Context g = Gdk.Context.CreateDrawable (win);
 173
 174                 int x, y, w, h, d;
 175                 win.GetGeometry(out x, out y, out w, out h, out d);
 176
 177                 draw (g, w, h);
 178                 return true;
 179         }
 180 }
 181