Custom WPS Display
File Format Specifications

Description / General Info
--------------------------
* The Custom WPS Display is used on both the Rockbox Player and Recorder, 
  as a means to customize the WPS to the user's likings.
* After editing the .wps file, "play" it to make it take effect.
* The file may be 2 lines long for the Player, and 10 lines for the Recorder.
* The line that has the time displayed on it MUST NOT be the line that
  is scrolled, or the time will not be updated.
* All characters not preceded by % are displayed as typed.

File Location
-------------
Custom WPS files may be located anywhere on the drive. The only restriction is
that they must end in .wps. When you PLAY a .wps file, it'll be used for the
future WPS screens. If the "played" wps file is located in the /.rockbox
folder, it'll be remembered and used for subsequent restarts.

Tags
----
ID3 Info Tags:
  %ia : ID3 Artist
  %id : ID3 Album Name
  %ig : ID3 Genre Name
  %in : ID3 Track Number
  %it : ID3 Track Title
  %iy : ID3 Year


Battery Info:
  %bl : Show numeric battery level
  %bt : Show estimated battery time left

File Info Tags:
  %fb : File Bitrate (in kbps)
  %ff : File Frequency (in Hz)
  %fm : File Name
  %fn : File Name (without extension)
  %fp : File Path
  %fs : File Size (In Kilobytes)
  %fv : "(vbr)" if variable bit rate or "" if constant bit rate
  %d1 : First directory from end of file path.
  %d2 : Second directory from end of file path.
  %d3 : Third directory from end of file path.

Example for the the %dN commands: If the path is "/Rock/Kent/Isola/11 -
747.mp3", %d1 is "Isola", %d2 is "Kent"... You get the picture.

Playlist/Song Info Tags:
  %pb : Progress Bar
        Player: This will display a 1 character "cup" that empties as the
                progresses.
        Recorder: This will replace the entire line with a progress bar.
  %pc : Current Time In Song
  %pe : Total Number of Playlist Entries
  %pm : Peak Meter (Recorder only)
        The entire line is used as volume peak meter.
  %pn : Playlist Name (Without path or extension)
  %pp : Playlist Position
  %pr : Remaining Time In Song
  %ps : Shuffle. Shows 's' if shuffle mode is enabled.
  %pt : Total Track Time

Conditional Tags (If/Else block):
  %?xx<|> : Conditional: if the tag specified by "xx" has a value, the 
            text between the "<" and the "|" is displayed, else the text
            between the "|" and the ">" is displayed. 
            The else part is optional, so the "|" does not have to be
            specified if no else part is desired. The conditionals nest, 
            so the text in the if and else part can contain all % 
            commands, including conditionals.

Other Tags:
  %%  : Display a '%'
  %<  : Display a '<'
  %|  : Display a '|'
  %>  : Display a '>'
  %s  : Indicate that the line should scroll. Can occur anywhere in 
        a line (given that the text is displayed; see conditional 
        below). You can specify up to 10 scrolling lines.
        %s is ignored if combined with %pb, %pc or %pr on the same
        line (the result wouldn't be good anyway).

Example File
------------
%s%?in<%in - >%?it<%it|%fn> %?ia<[%ia%?id<, %id>]>
%pb%pc/%pt

That is, "tracknum - title [artist, album]", where most fields are only
displayed if available. Could also be rendered as "filename" or
"tracknum - title [artist]".

Default
-------
If you haven't selected a .wps file in the .rockbox directory, you get the
hardcoded wps layout. The default WPS screen is for player:

%s%pp/%pe: %?ia<%ia - >%?it<%it|%fm>
%pc%pb%pt

and for recorder:

%s%fp
%it
%id
%ia
%fb kbit %fv
Time: %pc / %pt
%pb
%pm
