Overview

• Preliminaries.
  • Admin.
  • Experiences with Processing.
• PostScript basics.
• Important drawing commands.
• Program control.
• Sample procedures.
• Why study PostScript?
• Lab.

Preliminaries

Admin

• I need to leave at 8:35 today for an optometrist's appointment.
• Most of the live examples from today are in the examples/postscript folder.
• Assignment 4: Getting Started with Postscript is not yet available.
  • Skim/read the PostScript Tutorial http://partners.adobe.com/public/developer/ps/sdk/sample/index_psbooks.html
  • Get a copy of the PostScript reference manual http://www.adobe.com/products/postscript/pdfs/PLRM.pdf
  • Write a PostScript procedure to draw a star.
  • Write another interesting PostScript procedure.

What you learned about Processing ...

• It's really cool because ... you can learn about where the mouse pointer is and use that to affect lots of different things: colors, other positions, etc.
  • It an also be a trigger/catalyst
• You can set the frame rate to make things faster/slower.
  • But if your code is slow, the frame rate may screw up
• It's pretty easy to make cool stuff
  • A lot of built in things
  • Straightforward language
• Nice hybrid things available - Square/rectangle vs. four lines
  • Our moral: Primer challenges them to build, but we provide

PostScript basics

• Language for describing documents to printers.
• 1982! Still used today!
• We think of documents as markup - PostScript is a Turing-complete programming language
  • Stack based!
  • operand operand operation
• Vector graphics
• In MathLAN
  • Preview with ghostview
  • Convert to pdf with ps2pdf
• Three books
  • Red Book - Reference manual
  • Green Book - Tutorial and Cookbook
  • Blue Book - Program design

Important drawing commands

Program control

Sample procedures

Sample Code

How Sam Draws Rectangles

% left bottom width height rect
%   Draw the specified rectangle.
/rect {     % l b w h
  4 2 roll  % w h l b
  moveto    % w h
  1 index   % w h w
  0         % w h w 0
  rlineto   % w h
  dup       % w h h
  0 exch    % w h 0 h
  rlineto   % w h
  exch      % h w
  neg 0     % h -w 0
  rlineto   % h
  neg       % -h
  0 exch    % 0 -h
  rlineto   % 
  stroke    % 
} def

Right-justifying text

% string showright
/showright {    % str 
  dup           % str str
  stringwidth   % str str-width str-height
  pop           % str str-width
  neg           % str -str-width
  0             % str -str-width 0
  rmoveto       % str 
  show
} def

Why study PostScript?

Lab

• Set a (simple) goal for your neighbor.
• Achieve the goal your neighbor set for you.

or

• Just play

or

• Read the first few pages of the PostScript tutorial