PostScript is a page description language (PDL) primarily used in the electronic and desktop publishing areas. PostScript is instrumental for applications that need to send printing instructions to a printer or other output devices. It is especially prevalent with laser printers.
Understanding PostScript and Its Importance
What is PostScript?
PostScript is a dynamically typed, concatenative programming language focusing on producing graphical content. It was developed by Adobe Systems in 1982 and serves as a communication bridge between an application and the printer, providing precise control over layout and graphics.
Applications of PostScript
PostScript finds use in various applications:
- Desktop Publishing: It enables high-quality graphical and textual composition.
- Printing: Ensures that output devices execute high-fidelity rendering from application-generated code.
- Graphics Design: Used to provide intricate design and layout capabilities without reliance on application-specific rendering engines.
Historical Context
The Evolution of PostScript
PostScript played a pivotal role in transforming the printing industry post its inception in 1982. Before PostScript, printing high-quality text and graphics was cumbersome and platform-specific. PostScript abstracted these processes, allowing identical output across different printers without preprocessing.
Milestones
- 1984: Introduction in Apple’s LaserWriter.
- 1985-1990s: Adoption in various desktop publishing tools and printers, becoming the industry standard.
Key Features
Text and Graphics
PostScript commands facilitate rendering of both text and graphical elements, enabling diverse outputs including complex images, intricate font designs, and vector graphics.
Device Independence
One of the core benefits of PostScript is its device-independent nature. When applications send PostScript code to any compliant printer, the output remains consistent, leading to predictable and reproducible results.
Examples and Usage
Basic PostScript Code
A simple example of PostScript code to draw a circle would look like this:
1%!PS
2newpath
350 50 20 0 360 arc
4stroke
5showpage
Here:
%!PSidentifies the file as a PostScript document.newpathstarts a new drawing path.50 50 20 0 360 arcdraws a full circle centered at (50, 50) with a radius of 20.strokeoutlines the path.showpageends the page description and initiates printing.
Special Considerations
Compatibility
To print documents with PostScript code, the printer must be PostScript-compatible. Many modern printers offer PostScript emulation to extend their compatibility with PostScript commands.
Performance
While highly versatile, PostScript can be computationally intensive, making efficient rendering strategies and sufficient processing power crucial, particularly for graphics-heavy documents.
Related Terms
- Printer Control Language (PCL): Another popular page description language developed by Hewlett-Packard, often compared with PostScript.
- PDF: The Portable Document Format, also developed by Adobe, incorporating many of PostScript’s traits but streamlined for electronic document distribution.
FAQs
What are the advantages of using PostScript?
Can all printers handle PostScript?
How does PostScript differ from PDF?
References
- Adobe Systems. PostScript(R) Language Reference Manual.
- Knuth, D.E. (1986). “Digital Typography”.
- Warnock, J., Geschke, C., The Development of PostScript.
Summary
PostScript has been a cornerstone in electronic and desktop publishing, providing a powerful, consistent way to communicate graphical content to output devices. Its precision and device-independent nature make it indispensable for high-quality printing tasks even in today’s digital age.
