New additions to draw package



Hello,

This is a report on the latest changes and additions to package draw.
Since there are some incompatibilities with previous versions, I think
the following lines will help to avoid mistakes and misunderstandings. 


* Now, draw always writes two files: maxout.gnuplot (gnuplot 
  preamble and command) and data.gnuplot (numeric data). In
  non windows systems, Maxima calls gnuplot via pipes, but
  the only command is now 'load maxima.gnuplot'. I reached
  the limits of piping with the new geomap object and this
  trick fixes the problem. This change also lets zooming 
  in windows (I think).

* I have reorganized the documentation on draw. You can ask
  for information on both graphic options and objects:
  ? point_type, ? image, ? geomap, etc.

* 2D points: if you give object 'points a list of numbers,
  abscissas are automatically set to consecutive positive
  integers: points([2,6,2,9]) plots [1,2],[2,6],
  [3,2] and [4,9].

* 2D & 3D label: each string, together with its coordinates,
  must be enclosed between brackets. Now you can write as many
  labels as you want calling 'label only once, as in
  label(["hi",0,0],["you",1,1]). label("hi",0,0) returns an
  error, but label(["hi",0,0]) is correct.

* Package 'picture added. This gives basic support for
  image processing and reads picture files in xpm format.
  This package is (very) unstable and not well suited for 
  rendering large photos. You can build a picture object from a 
  matrix or from an xpm file and pass it to 'image, as in 
  draw2d(image(read_xpm("myfile.xpm"),0,0,10,10)).
  Package 'picture is automatically loaded with 'draw.
  See examples in
  http://www.telefonica.net/web2/biomates/maxima/gpdraw/image

* New 2D graphic object geomap for drawing maps. Examples in
  http://www.telefonica.net/web2/biomates/maxima/gpdraw/geomap
  Notes on geomap:
  - Some boundaries and islands are controversial. I tried to
    define countries according to the borders recognized by
    the United Nations. Please, don't feel offended due to 
    my mistakes and/or ignorance.
  - The WBD (public domain World Boundaries Database) doesn't
    contain borders for Eritrea.
  - I have assigned the antarctic islands to the Antarctica
    variable. Not sure if this is 100% correct.
  - The WBD doesn't separate european and asian Russia,
    that's why I haven't included Russia as an european
    country.
  - The WDB contains some lakes not yet included here.
  - When drawing countries as coloured polygons, don't forget
    that some countries are completely surrounded by other
    countries: San_Marino by Italy and Lesotho by South_Africa.
  - File share/wdb.lisp contains boundary coordinates as lisp
    arrays, and in share/worldmap.map are the country and 
    continent definitions.    

* All the above changes are included in doc/info/draw.texi,
  but the Spanish documentation will be commited before 
  the next release of Maxima, together with some other minor changes.

Happy drawing!

-- 
Mario Rodriguez Riotorto
www.biomates.net