Logo to PostScript: Equivalent Drawing Commands
Introduction
Logo and PostScript are both programming languages that handle vector-based drawing, but they take different approaches. Logo is procedural, often used in education, whereas PostScript is stack-based and designed for printing and high-quality graphics.
In this article, we’ll convert Logo turtle graphics code into PostScript, demonstrating how common Logo commands translate into PostScript equivalents.
1. Draw a Square
Logo Code:
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| REPEAT 4 [ FORWARD 100 RIGHT 90 ]
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PostScript Equivalent:
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| newpath
100 100 moveto % Move to starting point
100 0 rlineto % Draw right
0 100 rlineto % Draw up
-100 0 rlineto % Draw left
closepath
stroke
|
2. Draw a Triangle
Logo Code:
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| REPEAT 3 [ FORWARD 100 RIGHT 120 ]
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PostScript Equivalent:
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| newpath
100 100 moveto % Move to starting point
100 0 rlineto % First side
-50 86.6 rlineto % Second side (Height of equilateral triangle)
closepath
stroke
|
3. Draw a Circle
Logo Code:
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| REPEAT 360 [ FORWARD 1 RIGHT 1 ]
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PostScript Equivalent:
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| newpath
200 200 50 0 360 arc % Draw a circle centered at (200,200) with radius 50
stroke
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4. Create a Custom Procedure (Draw a Star)
Logo Code:
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| TO STAR
REPEAT 5 [ FORWARD 100 RIGHT 144 ]
END
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PostScript Equivalent:
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| newpath
100 100 moveto % Move to starting point
5 {
100 0 rlineto % Move forward
144 rotate % Rotate right 144 degrees
} repeat
closepath
stroke
|
5. Draw a Spiral
Logo Code:
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| REPEAT 100 [ FORWARD REPCOUNT RIGHT 20 ]
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PostScript Equivalent:
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| newpath
100 100 moveto % Move to starting point
0 0 translate
1 100 {
dup % Duplicate loop counter on stack
0 rlineto % Move forward by counter value
20 rotate % Rotate right 20 degrees
} for
stroke
|
Key Differences Between Logo and PostScript
| Feature | Logo | PostScript |
|---|
| Design Purpose | Education, Turtle Graphics | Professional vector graphics & printing |
| Syntax Style | Procedural, command-driven | Stack-based, postfix notation |
| Graphics Model | Relative movement (Turtle) | Absolute Cartesian coordinates |
| Looping Mechanism | REPEAT keyword | repeat or for loops |
| Circle Drawing | Approximate using FORWARD and RIGHT | arc function for precise circles |
| Output Use Case | Interactive learning | High-quality printing and PDFs |
Conclusion
Both Logo and PostScript offer powerful ways to generate vector-based graphics, but they serve different audiences. While Logo excels in teaching programming concepts, PostScript is used in professional printing and graphic design.
If you want to experiment with Logo, check out online interpreters like:
For PostScript programming, consider trying:
Let me know if you have any questions or need more examples! 🚀
