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 //
   6
   7 //
   8 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System;
  31 using System.Reflection;
  32 using System.Runtime.InteropServices;
  33 using Cairo;
  34 using Gtk;
  35
  36 class GtkCairo
  37 {
  38         static DrawingArea a,b;
  39
  40         static void Main ()
  41         {
  42                 Application.Init ();
  43                 Gtk.Window w = new Gtk.Window ("Mono.Cairo Circles demo");
  44
  45                 a = new CairoGraphic ();
  46
  47                 Box box = new HBox (true, 0);
  48                 box.Add (a);
  49                 w.Add (box);
  50                 w.Resize (500,500);
  51                 w.ShowAll ();
  52
  53                 Application.Run ();
  54         }
  55
  56
  57 }
  58
  59 class CairoGraphic : DrawingArea
  60 {
  61         static readonly double  M_PI = 3.14159265358979323846;
  62
  63         static void oval_path (Cairo.Graphics gr, double xc, double yc, double xr, double yr)
  64         {
  65                 Matrix matrix  = gr.Matrix;
  66
  67                 gr.Translate (xc, yc);
  68                 gr.Scale (1.0, yr / xr);
  69                 gr.MoveTo (xr, 0.0);
  70                 gr.Arc (0, 0, xr, 0, 2 * M_PI);
  71                 gr.ClosePath ();
  72
  73                 gr.Matrix = matrix;
  74                 matrix.Destroy();
  75         }
  76
  77         /*
  78         * Draw a red, green, and blue circle equally spaced inside
  79         * the larger circle of radius r at (xc, yc)
  80         */
  81         static void draw_3circles (Cairo.Graphics gr, double xc, double yc, double radius)
  82         {
  83                 double subradius = radius * (2 / 3.0 - 0.1);
  84
  85                 gr.SetRGBColor (1, 0, 0);
  86
  87                 oval_path (gr,
  88                         xc + radius / 3 * Math.Cos (M_PI * (0.5)),
  89                         yc - radius / 3 * Math.Sin (M_PI * (0.5)),
  90                         subradius, subradius);
  91
  92                 gr.Fill ();
  93
  94                 gr.SetRGBColor (0, 1, 0);
  95                 oval_path (gr,
  96                         xc + radius / 3 * Math.Cos (M_PI * (0.5 + 2/.3)),
  97                         yc - radius / 3 * Math.Sin (M_PI * (0.5 + 2/.3)),
  98                         subradius, subradius);
  99
 100                 gr.Fill ();
 101
 102                 gr.SetRGBColor (0, 0, 1);
 103
 104                 oval_path (gr,
 105                         xc + radius / 3 * Math.Cos (M_PI * (0.5 + 4/.3)),
 106                         yc - radius / 3 * Math.Sin (M_PI * (0.5 + 4/.3)),
 107                         subradius, subradius);
 108
 109                 gr.Fill ();
 110         }
 111
 112         static void draw (Cairo.Graphics gr, int width, int height)
 113         {
 114                 Surface overlay, punch, circles;
 115
 116                 /* Fill the background */
 117                 double radius = 0.5 * (width < height ? width : height) - 10;
 118                 double xc = width / 2;
 119                 double yc = height / 2;
 120
 121                 overlay = Surface.CreateSimilar (gr.TargetSurface, Format.ARGB32, width, height);
 122                 punch = Surface.CreateSimilar (gr.TargetSurface, Format.A8, width, height);
 123                 circles = Surface.CreateSimilar (gr.TargetSurface, Format.ARGB32, width, height);
 124
 125                 gr.Save ();
 126                 gr.TargetSurface = overlay;
 127
 128                 /* Draw a black circle on the overlay
 129                 */
 130
 131                 gr.SetRGBColor (0, 0, 0);
 132
 133                 oval_path (gr, xc, yc, radius, radius);
 134                 gr.Fill ();
 135                 gr.Save ();
 136                 gr.TargetSurface =  punch;
 137
 138
 139                 /* Draw 3 circles to the punch surface, then cut
 140                 * that out of the main circle in the overlay
 141                 */
 142                 draw_3circles (gr, xc, yc, radius);
 143
 144                 gr.Restore ();
 145
 146                 gr.Operator = Operator.OutReverse;
 147                 punch.Show (gr, width, height);
 148
 149
 150                 /* Now draw the 3 circles in a subgroup again
 151                 * at half intensity, and use OperatorAdd to join up
 152                 * without seams.
 153                 */
 154                 gr.Save ();
 155                 gr.TargetSurface =  circles;
 156
 157                 gr.Alpha = 0.5;
 158                 gr.Operator = Operator.Over;
 159                 draw_3circles (gr, xc, yc, radius);
 160
 161                 gr.Restore ();
 162
 163                 gr.Operator = Operator.Add;
 164                 circles.Show (gr, width, height);
 165
 166
 167                 gr.Restore ();
 168
 169                 overlay.Show (gr, width, height);
 170
 171                 /*
 172                 cairo_surface_destroy (overlay);
 173                 cairo_surface_destroy (punch);
 174                 cairo_surface_destroy (circles);
 175                 */
 176
 177         }
 178
 179         protected override bool OnExposeEvent (Gdk.EventExpose args)
 180         {
 181                 Gdk.Window win = args.Window;
 182                 Gdk.Rectangle area = args.Area;
 183
 184                 Cairo.Graphics g = new Cairo.Graphics ();
 185                 Gdk.Graphics.CreateDrawable (win,  g);
 186
 187                 draw (g, 500, 500);
 188
 189                 return true;
 190         }
 191 }
 192