You are looking at historical revision 26857 of this page. It may differ significantly from its current revision.


An interface to the ploticus library.


(require-extension ploticus)


ploticus is software package for producing plots, charts, and graphics from data, which can generate PNG, GIF, JPEG, PostScript, EPS, SVG and SWF output formats.

The Chicken ploticus library provides a Scheme interface to the ploticus procedures. This interface follows closely the ploticus API, so the main reference is the ploticus manual.


[procedure] procdebug:: [BOOL] => VOID

If this parameter is set to #t, every line of a ploticus procedure will be printed as it is executed.


[procedure] init:: SYMBOL * STRING => INTEGER

Initializes ploticus. The first argument is the output device, which is a symbol that can be one of 'png, 'gif, 'x11, 'svg, 'jpeg, 'eps, or 'swf. (Not all devices may be available, depending on the build.) The second argument is a string pathname of the file where the result will be written.

[procedure] arg:: STRING [* STRING] => INTEGER

Specifies a ploticus command line argument. The first argument specifies the argument name and the second is the argument value. If there is no argument value, the value is passed as empty string. Arguments -f, -prefab, and -ver are not supported. If needed, this procedure should be called after init but before any other ploticus procedure.

[procedure] execline:: STRING => INTEGER

Executes one ploticus script line.

Script lines can contain only these directives: #proc, #procdef, #endproc, #clone and #saveas. They cannot contain flow-of-control directives and do not undergo a variable-evaluation pass, so variables cannot be referenced, and select statements (etc.) that reference data field names should use one at sign (@) instead of two (@@).

ploticus variables can be accessed by getvar, described below.

An alternative is to use execscript (described below) to execute an entire script file. execline and execscript cannot be used in the same application.

[procedure] execscript:: STRING => INTEGER

Executes an entire ploticus script file. The argument is the name of a ploticus script file.

execscript and execline cannot be used in the same application.

[procedure] execprefab:: STRING => INTEGER

Executes a ploticus prefab.

The argument is the name of the prefab.

execprefab and execline cannot be used in the same application.

[procedure] end:: VOID => INTEGER

Finishes up the plot, writes it to the output file, and frees up allocated memory.

[procedure] getvar:: STRING => STRING

Returns the contents of the given ploticus variable name or #f.

[procedure] setvar:: STRING * STRING => INTEGER

Sets the contents of the given ploticus variable name to the given value.

[procedure] proc:: STRING * FIELD-LIST => INTEGER

A convenience procedure for #proc directives (ploticus procedures).

The first arguments is the name of the procedure, the second argument is a list of elements of the form (NAME . VALUE), where NAME is a field name, and VALUE is the corresponding field value.


Text annotation

(use ploticus)

(init "svg" "chicken.svg" )
(arg "-scale" "0.8")
(for-each execline
	  '("#proc annotate" 
	    "location: 2 2" 
	    "text: Chicken" 

Horizontal bars

  (use ploticus)
  (init "svg" "hbars.svg")
  (define data '((X . 1) (Y . 2) (Z . 3)))
  (proc "getdata"
`(("data" . ,@(map (lambda (x) (sprintf "~S\t~A" (car x) (cdr x))) data))))
  (proc "bars"
	`(("horizontalbars" . "yes")
	  ("color"          . "rgb(0,0.5,0.8)")
	  ("lenfield"       . "2")
	  ("barwidth"       . "0.3")
	  ("labeldetails"   . "adjust=0,-0.03 color=rgb(0,0.5,0.8)")
	  ("showvalues"     . "yes")

About this egg


Ivan Raikov

Version history

Added procdebug parameter
Added proc
Initial release


Copyright 2011-2012 Ivan Raikov.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
General Public License for more details.

A full copy of the GPL license can be found at