subprojects/gst-python/old_examples/fvumeter.py

   1 # -*- Mode: Python -*-
   2 # vi:si:et:sw=4:sts=4:ts=4
   3
   4 # gst-python
   5 # Copyright (C) 2005 Fluendo S.L.
   6 # Originally from the Flumotion streaming server.
   7 #
   8 # This library is free software; you can redistribute it and/or
   9 # modify it under the terms of the GNU Library General Public
  10 # License as published by the Free Software Foundation; either
  11 # version 2 of the License, or (at your option) any later version.
  12 #
  13 # This library is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16 # Library General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU Library General Public
  19 # License along with this library; if not, write to the
  20 # Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21 # Boston, MA 02110-1301, USA.
  22 #
  23 # Author: Zaheer Merali <zaheermerali at gmail dot com>
  24
  25 import gtk
  26 from gtk import gdk
  27 import gobject
  28
  29
  30 # this VUMeter respects IEC standard
  31 # BS 6840-18:1996/IEC-268-18
  32 # and is inspired by JACK's meterbridge dpm_meters.c
  33
  34 class FVUMeter(gtk.DrawingArea):
  35     __gsignals__ = { 'expose-event' : 'override',
  36                      'size-allocate': 'override',
  37                      'size-request': 'override',
  38                      'realize' : 'override'
  39              }
  40     __gproperties__ = {
  41         'peak' : (gobject.TYPE_FLOAT,
  42                   'peak volume level',
  43                   'peak volume level in dB',
  44                   -90.0,
  45                   0,
  46                   -90.0,
  47                   gobject.PARAM_READWRITE),
  48         'decay' : (gobject.TYPE_FLOAT,
  49                    'decay volume level',
  50                    'decay volume level in dB',
  51                    -90.0,
  52                    0,
  53                    -90.0,
  54                    gobject.PARAM_READWRITE),
  55         'orange-threshold': (gobject.TYPE_FLOAT,
  56                             'threshold for orange',
  57                             'threshold for orange use in dB',
  58                             -90.0,
  59                             0,
  60                             -10.0,
  61                             gobject.PARAM_READWRITE),
  62         'red-threshold': (gobject.TYPE_FLOAT,
  63                          'threshold for red',
  64                          'threshold for red use in dB',
  65                          -90.0,
  66                          0,
  67                          -1.0,
  68                          gobject.PARAM_READWRITE)
  69
  70     }
  71     green_gc = None
  72     orange_gc = None
  73     red_gc = None
  74     yellow_gc = None
  75
  76     topborder = 7
  77     peaklevel = -90.0
  78     decaylevel = -90.0
  79     orange_threshold = -10.0
  80     red_threshold = -1.0
  81     bottomborder = 25
  82     leftborder = 15
  83     rightborder = 65
  84
  85     # Returns the meter deflection percentage given a db value
  86     def iec_scale(self, db):
  87         pct = 0.0
  88
  89         if db < -70.0:
  90             pct = 0.0
  91         elif db < -60.0:
  92             pct = (db + 70.0) * 0.25
  93         elif db < -50.0:
  94             pct = (db + 60.0) * 0.5 + 2.5
  95         elif db < -40.0:
  96             pct = (db + 50.0) * 0.75 + 7.5
  97         elif db < -30.0:
  98             pct = (db + 40.0) * 1.5 + 15.0
  99         elif db < -20.0:
 100             pct = (db + 30.0) * 2.0 + 30.0
 101         elif db < 0.0:
 102             pct = (db + 20.0) * 2.5 + 50.0
 103         else:
 104             pct = 100.0
 105
 106         return pct
 107
 108     def do_get_property(self, property):
 109         if property.name == 'peak':
 110             return self.peaklevel
 111         elif property.name == 'decay':
 112             return self.decaylevel
 113         elif property.name == 'orange-threshold':
 114             return self.orange_threshold
 115         elif property.name == 'red-threshold':
 116             return self.red_threshold
 117         else:
 118             raise AttributeError, 'unknown property %s' % property.name
 119
 120     def do_set_property(self, property, value):
 121         if property.name == 'peak':
 122             self.peaklevel = value
 123         elif property.name == 'decay':
 124             self.decaylevel = value
 125         elif property.name == 'orange-threshold':
 126             self.orange_threshold = value
 127         elif property.name == 'red-threshold':
 128             self.red_threshold = value
 129         else:
 130             raise AttributeError, 'unknown property %s' % property.name
 131
 132         self.queue_draw()
 133
 134     def do_size_request(self, requisition):
 135         requisition.width = 250
 136         requisition.height = 50
 137
 138     def do_size_allocate(self, allocation):
 139         self.allocation = allocation
 140         if self.flags() & gtk.REALIZED:
 141             self.window.move_resize(*allocation)
 142
 143     def do_realize(self):
 144         self.set_flags(self.flags() | gtk.REALIZED)
 145
 146         self.window = gdk.Window(self.get_parent_window(),
 147                                  width=self.allocation.width,
 148                                  height=self.allocation.height,
 149                                  window_type=gdk.WINDOW_CHILD,
 150                                  wclass=gdk.INPUT_OUTPUT,
 151                                  event_mask=self.get_events() | gdk.EXPOSURE_MASK)
 152
 153         colormap = gtk.gdk.colormap_get_system()
 154         green = colormap.alloc_color(0, 65535, 0)
 155         orange = colormap.alloc_color(65535, 32768, 0)
 156         red = colormap.alloc_color(65535, 0, 0)
 157         yellow = colormap.alloc_color(65535, 65535, 0)
 158         self.green_gc = gdk.GC(self.window, foreground=green)
 159         self.orange_gc = gdk.GC(self.window, foreground=orange)
 160         self.red_gc = gdk.GC(self.window, foreground=red)
 161         self.yellow_gc = gdk.GC(self.window, foreground=yellow)
 162
 163         self.window.set_user_data(self)
 164         self.style.attach(self.window)
 165         self.style.set_background(self.window, gtk.STATE_NORMAL)
 166
 167     def do_expose_event(self, event):
 168         self.chain(event)
 169
 170         x, y, w, h = self.allocation
 171         vumeter_width = w - (self.leftborder + self.rightborder)
 172         vumeter_height = h - (self.topborder + self.bottomborder)
 173         self.window.draw_rectangle(self.style.black_gc, True,
 174                                    self.leftborder, self.topborder,
 175                                    vumeter_width,
 176                                    vumeter_height)
 177         # draw peak level
 178         # 0 maps to width of 0, full scale maps to total width
 179         peaklevelpct = self.iec_scale(self.peaklevel)
 180         peakwidth = int(vumeter_width * (peaklevelpct / 100))
 181         draw_gc = self.green_gc
 182         if self.peaklevel >= self.orange_threshold:
 183             draw_gc = self.orange_gc
 184         if self.peaklevel >= self.red_threshold:
 185             draw_gc = self.red_gc
 186         if peakwidth > 0:
 187             self.window.draw_rectangle(draw_gc, True,
 188                     self.leftborder, self.topborder,
 189                     peakwidth, vumeter_height)
 190
 191         # draw yellow decay level
 192         if self.decaylevel > -90.0:
 193             decaylevelpct = self.iec_scale(self.decaylevel)
 194             decaywidth = int(vumeter_width * (decaylevelpct / 100))
 195             # cheat the geometry by drawing 0% level at pixel 0,
 196             # which is same position as just above 0%
 197             if decaywidth == 0:
 198                 decaywidth = 1
 199             self.window.draw_line(self.yellow_gc,
 200                 self.leftborder + decaywidth - 1,
 201                 self.topborder,
 202                 self.leftborder + decaywidth - 1,
 203                 self.topborder + vumeter_height - 1)
 204
 205         # draw tick marks
 206         scalers = [
 207             ('-90', 0.0),
 208             ('-40', 0.15),
 209             ('-30', 0.30),
 210             ('-20', 0.50),
 211             ('-10', 0.75),
 212             ( '-5', 0.875),
 213             (  '0', 1.0),
 214         ]
 215         for level, scale in scalers:
 216             # tick mark, 6 pixels high
 217             # we cheat again here by putting the 0 at the first pixel
 218             self.window.draw_line(self.style.black_gc,
 219                 self.leftborder + int(scale * (vumeter_width - 1)),
 220                 h - self.bottomborder,
 221                 self.leftborder + int(scale * (vumeter_width - 1)),
 222                 h - self.bottomborder + 5)
 223             # tick label
 224             layout = self.create_pango_layout(level)
 225             layout_width, layout_height = layout.get_pixel_size()
 226             self.window.draw_layout(self.style.black_gc,
 227                 self.leftborder + int(scale * vumeter_width)
 228                     - int(layout_width / 2),
 229                 h - self.bottomborder + 7, layout)
 230
 231         # draw the peak level to the right
 232         layout = self.create_pango_layout("%.2fdB" % self.peaklevel)
 233         layout_width, layout_height = layout.get_pixel_size()
 234         self.window.draw_layout(self.style.black_gc,
 235             self.leftborder + vumeter_width + 5,
 236             self.topborder + int(vumeter_height / 2 - layout_height / 2),
 237             layout)
 238
 239 gobject.type_register(FVUMeter)