Jaroslav Kysela <perex@perex.cz>

   volume.c:  added by Takashi Iwai <tiwai@suse.de>

   (2003/03/22) Changed to hbox/vbox layout.
   Copyright (C) 2003 by Søren Wedel Nielsen
   
   (16.12.2005)  Re-worked user interface -digital mixer display permanently
   visible; pcms split to another page; controls re-arranged and all pages
   scrollable for min window size and greater flexibility; pop-up menu enabled.
   Changes to levelmeters.c to prevent invalid redraws.
   New options added: 'w' to set initial window pixel width and 't' for tall equal mixer height style.
   Copyright (C) 2005 by Alan Horstmann

   (Summer 2010) NPM: (1) Implemented "Peak Hold" functionality in meters;
   reimplemented meters to do away with inefficient "faux LED" peak-meter
   display, which causes thousands of rectangles per-second to be drawn,
   individually, for no good reason other than increasing the load. (2)
   Significantly reduced the number of timer interrupts generated by this
   program by slowing down all updates to 10 per second -- previously
   meters updated 25x/second! (3) All volumes are represented as decibels,
   including the 0 to -48dB range of the hardware peak-meters, the 0 -to-
   -48dB&off attenuation for all inputs to the digital mixer, the 0 -to-
   -63dB attenuation of the analog DAC, and the +18 -to- -63dB
   attenuation/amplification of the analog ADC. (4) All gtk "scale" widgets
   have dB legends; the "PageUp" "PageDown" keys allow rapid movement
   between the marked levels, and "UpArrow" and "DownArrow" allow
   fine-adjustment.  (5) Added command-line options --no_scale_mark,
   --channel_group_modulus, --lights_color and --bg_color options; fixed
   --card and --device to allow valid ALSA card and CTL device names (
   https://bugzilla.redhat.com/show_bug.cgi?id=602900 ).  (6) Add display
   of "Delta IEC958 Input Status" under "Hardware Settings."

   Copyright (C) 2010 Niels Mayer ( http://nielsmayer.com )
   Copyright (C) 2010 Tim E. Real
