prolooks/VuMeter.vala

   1 /*
   2     Copyright 2009 by Hans Baier, Krzysztof Foltman
   3     License: LGPLv2+
   4 */
   5
   6 using Gtk;
   7
   8 namespace Prolooks {
   9
  10 public class VuMeter : DrawingArea {
  11
  12     public enum Mode {
  13         STANDARD,
  14         MONOCHROME,
  15         MONOCHROME_REVERSE
  16     }
  17
  18     private Cairo.Surface? cache_surface = null;
  19     private Mode _mode = Mode.STANDARD; private double _value = 0.5;
  20
  21     public double value {
  22         set {
  23             if (Math.fabs(_value - value) >= 0.0001)
  24                 queue_draw();
  25             _value = value;
  26         }
  27         get {
  28             return _value;
  29         }
  30     }
  31
  32     public Mode mode {
  33         set {
  34             if (value != _mode) {
  35                 _mode = value;
  36                 cache_surface = null;
  37                 queue_draw();
  38             }
  39         }
  40         get {
  41             return _mode;
  42         }
  43     }
  44
  45     public VuMeter () {
  46
  47         // Set favored widget size
  48         set_size_request (100, 14);
  49     }
  50
  51     /* Widget is asked to draw itself */
  52     public override bool expose_event (Gdk.EventExpose event) {
  53         int ox = 1, oy = 1;
  54         int sx = allocation.width - 2, sy = allocation.height - 2;
  55
  56         // Create a Cairo context
  57         var cr = Gdk.cairo_create (this.window);
  58
  59         if (cache_surface == null)
  60         {
  61             int x;
  62             // looks like its either first call or the widget has been resized.
  63             // create the cache_surface.
  64             cache_surface = new Cairo.Surface.similar (cr.get_target(),
  65                                                        Cairo.Content.COLOR,
  66                                                        allocation.width,
  67                                                        allocation.height );
  68
  69             // And render the meterstuff again.
  70
  71             Cairo.Context cache_cr = new Cairo.Context ( cache_surface );
  72             cache_cr.set_source_rgba (0, 0, 0, 0);
  73             cache_cr.rectangle (ox, oy, sx, sy);
  74             cache_cr.fill ();
  75             cache_cr.set_line_width (1);
  76
  77             for (x = ox; x <= ox + sx; x += 3)
  78             {
  79                 double ts = (x - ox) * 1.0 / sx;
  80                 double r = 0, g = 0, b = 0;
  81                 switch(mode)
  82                 {
  83                     case Mode.STANDARD:
  84                     default:
  85                         if (ts < 0.75) {
  86                             r = ts / 0.75;
  87                             g = 1;
  88                             b = 0;
  89                         }
  90                         else {
  91                             r = 1;
  92                             g = 1 - (ts - 0.75) / 0.25;
  93                             b = 0;
  94                         }
  95                         break;
  96                     case Mode.MONOCHROME_REVERSE:
  97                         r = 1;
  98                         g = 1;
  99                         b = 0;
 100                         break;
 101                     case Mode.MONOCHROME:
 102                         r = 1;
 103                         g = 1;
 104                         b = 0;
 105                         break;
 106                 }
 107                 cache_cr.set_source_rgb(r, g, b);
 108                 cache_cr.move_to (x, oy);
 109                 cache_cr.line_to (x, oy + sy + 1);
 110                 cache_cr.move_to (x, oy + sy);
 111                 cache_cr.line_to (x, oy );
 112                 cache_cr.stroke  ();
 113             }
 114         }
 115
 116         // Set clipping area in order to avoid unnecessary drawing
 117         cr.rectangle (event.area.x, event.area.y,
 118                       event.area.width, event.area.height);
 119         cr.clip ();
 120
 121         cr.set_source_surface (cache_surface, 0, 0);
 122         cr.paint ();
 123         cr.set_source_rgba (0, 0, 0, 0.5);
 124
 125         if( mode == Mode.MONOCHROME_REVERSE )
 126             cr.rectangle (ox, oy, _value * (sx - ox) + 1, sy - oy + 1);
 127         else
 128             cr.rectangle (ox + _value * (sx - ox), oy, sx - ox + 1, sy - oy + 1);
 129
 130         cr.fill ();
 131
 132         return false;
 133     }
 134 }
 135
 136 } // namespace Prolooks