PostScript File Format

Overview

PostScript is a page description language developed by Adobe Systems in 1982. It revolutionized desktop publishing by providing a device-independent way to describe printed pages with text, graphics, and images. PostScript became the foundation for PDF and remains important in professional printing, graphics applications, and document processing workflows.

Technical Details

• MIME Type: application/postscript
• File Extension: .ps
• Category: Document
• Created by: Adobe Systems (John Warnock, Chuck Geschke)
• First Appeared: 1982
• Current Version: PostScript Level 3 (1997)

Structure and Syntax

PostScript is a stack-based programming language with commands that manipulate a graphics state and render content to pages.

Basic PostScript Structure

%!PS-Adobe-3.0
%%Creator: Example Application
%%Title: Basic PostScript Document
%%Pages: 1
%%BoundingBox: 0 0 612 792
%%EndComments

%%BeginProlog
%%EndProlog

%%BeginSetup
%%EndSetup

%%Page: 1 1
%%BeginPageSetup
%%EndPageSetup

% Begin page content
72 720 moveto
/Helvetica findfont 24 scalefont setfont
(Hello, PostScript World!) show

%%PageTrailer
showpage
%%Trailer
%%EOF

Basic Drawing Commands

%!PS-Adobe-3.0
%%BoundingBox: 0 0 400 400

% Set line width and color
2 setlinewidth
0 0 1 setrgbcolor  % Blue color

% Draw a rectangle
100 100 moveto
200 0 rlineto      % Relative line to right
0 150 rlineto      % Relative line up
-200 0 rlineto     % Relative line to left
closepath
stroke

% Draw a filled circle
1 0 0 setrgbcolor  % Red color
200 200 50 0 360 arc
fill

% Draw text
0 0 0 setrgbcolor  % Black color
/Times-Roman findfont 16 scalefont setfont
150 50 moveto
(PostScript Graphics) show

showpage

Coordinate System and Transformations

%!PS-Adobe-3.0
%%BoundingBox: 0 0 500 500

% Save initial graphics state
gsave

% Translate origin to center
250 250 translate

% Draw coordinate axes
1 setlinewidth
0.5 setgray

% X-axis
-200 0 moveto 200 0 lineto stroke
% Y-axis
0 -200 moveto 0 200 lineto stroke

% Draw rotated squares
0 1 0 setrgbcolor  % Green
0 15 360 {
    gsave
    rotate
    -25 -25 50 50 rectstroke
    grestore
} for

% Restore graphics state
grestore

showpage

Text and Font Handling

Font Management

%!PS-Adobe-3.0
%%BoundingBox: 0 0 612 792

% Define and use different fonts
/showtext {
    gsave
    0 0 moveto
    show
    grestore
    0 -30 rmoveto
} def

100 700 moveto

/Helvetica findfont 18 scalefont setfont
(Helvetica Regular) showtext

/Helvetica-Bold findfont 18 scalefont setfont
(Helvetica Bold) showtext

/Times-Roman findfont 18 scalefont setfont
(Times Roman) showtext

/Times-Italic findfont 18 scalefont setfont
(Times Italic) showtext

/Courier findfont 18 scalefont setfont
(Courier Monospace) showtext

% Custom font scaling and rotation
gsave
300 600 translate
45 rotate
/Times-Bold findfont 24 scalefont setfont
0 0 moveto
(Rotated Text) show
grestore

showpage

Advanced Text Layout

%!PS-Adobe-3.0
%%BoundingBox: 0 0 612 792

% Text justification and formatting
/justify {
    /linewidth exch def
    /text exch def
    
    % Calculate text width
    text stringwidth pop
    linewidth exch sub
    
    % Count spaces in text
    text length 1 sub
    dup 0 eq { pop 1 } if
    div
    
    % Set word spacing
    0 exch 0 exch ashow
} def

/Times-Roman findfont 12 scalefont setfont

50 700 moveto
(This is a sample paragraph that demonstrates text justification in PostScript. The text will be spread across the specified line width with appropriate spacing.)
400 justify

% Paragraph with line breaks
50 650 moveto
(Line 1: PostScript provides powerful text handling capabilities.) show
50 630 moveto
(Line 2: Including font selection, sizing, and positioning.) show
50 610 moveto
(Line 3: Complex layouts are possible with proper programming.) show

% Text in a box
gsave
1 setlinewidth
100 500 200 100 rectstroke

/Helvetica findfont 10 scalefont setfont
110 570 moveto
(Text can be positioned) show
110 555 moveto
(precisely within shapes) show
110 540 moveto
(and bounded areas.) show
grestore

showpage

Graphics and Paths

Complex Path Construction

%!PS-Adobe-3.0
%%BoundingBox: 0 0 500 500

% Define reusable path procedures
/star {
    % Draw a 5-pointed star
    newpath
    0 50 moveto
    15 15 lineto
    50 15 lineto
    25 -10 lineto
    35 -45 lineto
    0 -25 lineto
    -35 -45 lineto
    -25 -10 lineto
    -50 15 lineto
    -15 15 lineto
    closepath
} def

/flower {
    % Draw a simple flower
    5 {
        gsave
        72 rotate
        0 0 20 0 180 arc
        fill
        grestore
    } repeat
} def

% Use the defined shapes
gsave
150 400 translate
1 0 0 setrgbcolor
star fill
grestore

gsave
350 400 translate
0 0 1 setrgbcolor
flower
grestore

% Bezier curves
0 1 0 setrgbcolor
2 setlinewidth
100 200 moveto
150 250 200 150 250 200 curveto
stroke

% Clipping path example
gsave
300 200 50 0 360 arc
clip
newpath

% Draw pattern inside clipping area
0 0.5 0.8 setrgbcolor
280 180 moveto
320 220 lineto
320 180 moveto
280 220 lineto
stroke
grestore

showpage

Gradients and Patterns

%!PS-Adobe-3.0
%%BoundingBox: 0 0 400 400

% Define a simple gradient function
/gradient {
    /y2 exch def /x2 exch def
    /y1 exch def /x1 exch def
    
    y2 y1 sub 10 div cvi {
        gsave
        y1 y2 y1 sub 10 div mul add dup
        400 div 1 exch sub 0 0 setrgbcolor
        x1 exch x2 x1 sub 10 div add 10 rectfill
        grestore
    } repeat
} def

% Apply gradient
50 50 350 350 gradient

% Pattern with repeated elements
/checkerboard {
    /size exch def
    gsave
    0 size 400 {
        /y exch def
        0 size 400 {
            /x exch def
            x size div y size div add 2 mod 0 eq {
                0 setgray
            } {
                1 setgray
            } ifelse
            x y size size rectfill
        } for
    } for
    grestore
} def

% Create checkerboard pattern in corner
gsave
200 200 translate
20 checkerboard
grestore

showpage

Programming Constructs

Variables and Procedures

%!PS-Adobe-3.0
%%BoundingBox: 0 0 500 500

% Define variables
/pagewidth 500 def
/pageheight 500 def
/margin 50 def

% Define procedures
/drawborder {
    1 setlinewidth
    0 setgray
    margin margin moveto
    pagewidth margin sub margin lineto
    pagewidth margin sub pageheight margin sub lineto
    margin pageheight margin sub lineto
    closepath
    stroke
} def

/drawtitle {
    /titletext exch def
    /Helvetica-Bold findfont 24 scalefont setfont
    pagewidth 2 div pageheight 50 sub moveto
    titletext stringwidth pop 2 div neg 0 rmoveto
    titletext show
} def

/drawgrid {
    /spacing exch def
    0.8 setgray
    0.5 setlinewidth
    
    spacing spacing pagewidth spacing sub {
        dup margin exch moveto
        pageheight margin sub lineto stroke
    } for
    
    spacing spacing pageheight spacing sub {
        margin exch moveto
        pagewidth margin sub exch lineto stroke
    } for
} def

% Use the procedures
drawborder
(PostScript Programming Example) drawtitle
25 drawgrid

% Draw some content
1 0 0 setrgbcolor
3 setlinewidth
100 100 moveto
150 200 lineto
200 150 lineto
250 250 lineto
stroke

showpage

Control Flow and Loops

%!PS-Adobe-3.0
%%BoundingBox: 0 0 400 400

% Conditional drawing
/drawshape {
    /shapetype exch def
    
    shapetype 1 eq {
        % Draw circle
        20 0 360 arc
        fill
    } {
        shapetype 2 eq {
            % Draw square
            -15 -15 30 30 rectfill
        } {
            % Draw triangle
            newpath
            0 20 moveto
            -17 -10 lineto
            17 -10 lineto
            closepath
            fill
        } ifelse
    } ifelse
} def

% Loop to create pattern
1 1 10 {
    /row exch def
    1 1 10 {
        /col exch def
        
        gsave
        col 35 mul row 35 mul translate
        
        % Choose shape based on position
        row col add 3 mod 1 add drawshape
        
        % Set color based on position
        row 10 div col 10 div 0.5 setrgbcolor
        
        grestore
    } for
} for

% Recursive procedure example
/spiral {
    /angle exch def
    /radius exch def
    
    radius 1 gt {
        0 radius moveto
        radius 0 360 arc stroke
        
        gsave
        angle rotate
        radius 0.9 mul angle 5 add spiral
        grestore
    } if
} def

gsave
300 300 translate
0.1 setlinewidth
0 0 1 setrgbcolor
50 0 spiral
grestore

showpage

Advanced Features

Image Handling

%!PS-Adobe-3.0
%%BoundingBox: 0 0 400 400

% Simple bitmap image
/drawbitmap {
    gsave
    100 100 translate
    100 100 scale
    
    % 8x8 bitmap data (1 bit per pixel)
    8 8 1 [8 0 0 -8 0 8] {
        <FF818181818181FF>  % Bitmap data as hex string
    } image
    
    grestore
} def

% Grayscale image
/drawgrayimage {
    gsave
    200 200 translate
    80 80 scale
    
    % 4x4 grayscale image (8 bits per pixel)
    4 4 8 [4 0 0 -4 0 4] {
        <00FF0000FF00FF00FF0000FF00000000>
    } image
    
    grestore
} def

drawbitmap
drawgrayimage

% Image with color
gsave
50 250 translate
100 50 scale
3 2 8 [3 0 0 -2 0 2] {
    <FF0000 00FF00 0000FF 
     FFFF00 FF00FF 00FFFF>
} false 3 colorimage
grestore

showpage

Print Production Features

%!PS-Adobe-3.0
%%BoundingBox: 0 0 612 792
%%DocumentSuppliedResources: procset Adobe_level2_AI5 1.2 0
%%+ procset Adobe_ColorImage_AI6 1.1 0

% Color separations
/CMYK {
    setcmykcolor
} def

% Spot color definition
/PantoneBlue {
    /Separation (PANTONE 286 C)
    /DeviceCMYK
    {1 0.43 0 0.06}
    setcolorspace
    setcolor
} def

% Overprint and knockout controls
/overprint {
    true setoverprint
} def

/knockout {
    false setoverprint
} def

% Registration marks
/regmarks {
    gsave
    0 setgray
    0.5 setlinewidth
    
    % Corner registration marks
    18 18 moveto 36 18 lineto 36 36 lineto stroke
    576 18 moveto 594 18 lineto 594 36 lineto stroke
    18 756 moveto 36 756 lineto 36 774 lineto stroke
    576 756 moveto 594 756 lineto 594 774 lineto stroke
    
    grestore
} def

% Crop marks
/cropmarks {
    gsave
    0 setgray
    0.25 setlinewidth
    
    % Top crop marks
    306 782 moveto 306 792 lineto stroke
    % Bottom crop marks  
    306 0 moveto 306 10 lineto stroke
    % Left crop marks
    0 396 moveto 10 396 lineto stroke
    % Right crop marks
    602 396 moveto 612 396 lineto stroke
    
    grestore
} def

% Main content
306 396 translate
0 0 200 200 rectfill

% Print production elements
regmarks
cropmarks

showpage

Document Structure and Comments

Document Structure Convention

%!PS-Adobe-3.0
%%Creator: Professional Application v2.1
%%Title: Annual Report 2025
%%CreationDate: (D:20250614120000+00'00')
%%For: (Corporate Communications)
%%Pages: 24
%%BoundingBox: 0 0 612 792
%%HiResBoundingBox: 0.0 0.0 612.0 792.0
%%DocumentSuppliedResources: font Helvetica-Custom
%%+ font TimesNewRoman-Corporate
%%DocumentNeededResources: font Arial
%%PageOrder: Ascend
%%Orientation: Portrait
%%EndComments

%%BeginProlog
% Custom procedures and definitions
/corporateblue { 0.2 0.4 0.8 setrgbcolor } def
/corporatefont { /Helvetica-Bold findfont 14 scalefont setfont } def
%%EndProlog

%%BeginSetup
% Document-wide setup
<<
  /PageSize [612 792]
  /Orientation 0
>> setpagedevice
%%EndSetup

%%Page: 1 1
%%BeginPageSetup
% Page-specific setup
%%EndPageSetup

% Page content here
corporateblue
corporatefont
72 720 moveto
(Annual Report 2025) show

%%PageTrailer
showpage

%%Page: 2 2
% Next page content...
showpage

%%Trailer
%%Pages: 2
%%EOF

Tools and Applications

PostScript Generators

• Adobe Illustrator: Vector graphics with PostScript export
• LaTeX: Document typesetting with PostScript output
• Ghostscript: PostScript interpreter and converter
• CAD Applications: Technical drawings in PostScript format
• Print Drivers: OS print subsystems generating PostScript

Processing Tools

# Ghostscript commands for PostScript processing

# Convert PostScript to PDF
gs -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sOutputFile=output.pdf input.ps

# Convert to raster image
gs -dNOPAUSE -dBATCH -sDEVICE=png16m -r300 -sOutputFile=output.png input.ps

# Optimize PostScript file
gs -dNOPAUSE -dBATCH -sDEVICE=ps2write -sOutputFile=optimized.ps input.ps

# Extract text from PostScript
gs -dNOPAUSE -dBATCH -sDEVICE=txtwrite -sOutputFile=output.txt input.ps

# Print PostScript file
lpr -o raw input.ps  # Unix/Linux

Validation and Debugging

% Debug procedures
/debug {
    /message exch def
    (DEBUG: ) print message print (\n) print flush
} def

/stackdump {
    (Stack contents:) debug
    count {
        dup ==
    } repeat
} def

% Error handling
/errorhandler {
    $error /newerror get {
        (PostScript Error: ) print
        $error /errorname get ==
        stackdump
    } if
} def

% Use debug features
(Starting document processing) debug
% ... document content ...
(Document processing complete) debug

Best Practices

Performance Optimization

% Efficient path construction
/efficientcircle {
    % Use arc instead of manual curve construction
    0 0 50 0 360 arc
} def

% Font caching
/setupfonts {
    /titlefont /Helvetica-Bold findfont 24 scalefont def
    /bodyfont /Times-Roman findfont 12 scalefont def
    /captionfont /Helvetica findfont 10 scalefont def
} def

% Graphics state management
/drawheader {
    gsave
    % Header drawing code
    grestore
} def

% Memory management
/clearmemory {
    vmreclaim
    save restore
} def

Code Organization

• Use meaningful procedure names
• Comment complex calculations
• Separate setup from content
• Use consistent indentation
• Group related procedures together

Common Use Cases

Professional Printing

• High-end commercial printing
• Color separations and spot colors
• Print production workflows
• Prepress file preparation

Graphics Applications

• Vector graphics export
• Technical illustrations
• Maps and diagrams
• Scientific visualizations

Document Processing

• Automated report generation
• Template-based documents
• Form generation
• Legacy document conversion

Font and Typography

• Custom font implementations
• Advanced typesetting
• Multi-language text layout
• Professional typography

PostScript remains a cornerstone technology in professional printing and graphics, providing precise control over page layout, typography, and graphics rendering that continues to influence modern document formats.