Introduction to Logo Turtle

LogoTurtle is currently the FIRST and only one Chrome Extension for Turtle Graphics. I have also written a PHP version of Logo Interpreter in 2006 but that runs only on the server.

Previous Contributions

• v0.0.8: Turtle Programming v0.0.8: /* */ comments, dotxy, and javascript!
• v0.0.7: Turtle Programming v0.0.7: Functions with Parameters + Recursion!
• v0.0.6: Turtle Programming v0.0.6: Adding Circle, MoveTo, Turn and Screen!
• v0.0.5: Turtle Programming v0.0.5: Adding IF/ELSE and STOP!
• v0.0.4: LogoTurtle: Make Variables and Comments
• v0.0.3: Turtle Graphics Programming Update: Adding text, jump, dot, fontsize, download as png
• v0.0.2: LogoTurtle v0.0.2: ShowTurtle, HideTurtle, Color, Width and Help.
• Teach Your Kids Programming - The First Logo Interpreter (Turtle Graphics) in Chrome Extension!
  v0.0.1

v0.0.9 New Features

Along with bug fixes and code tweaks, This Commit has added the support of the following features/functions:

1. Add SetX, SetY that allows turtle to move in only 1 directions. (one parameter)
2. Set Square to draw a filled square. (one parameter)
3. Add Rect to draw a filled rectangle. (two parameters)

Screenshots

Drawing a curve

ht cs make "x 1 make "y 1
repeat 100 [
  setx :x
  sety :y
  make "x :x+1 make "y :y*1.05
]

SetX and SetY in Javascript

case "setx":
    word_next = this.evalVars(word_next);
    if ((word_next == '') || (!isNumeric(word_next))) {
        this.pushErr(word, LOGO_ERR_MISSING_NUMBERS, word_next);
        return false;
    }
    this.logo.moveToX(parseFloat(word_next));
    i = y.next;
    break;      
case "sety":
    word_next = this.evalVars(word_next);
    if ((word_next == '') || (!isNumeric(word_next))) {
        this.pushErr(word, LOGO_ERR_MISSING_NUMBERS, word_next);
        return false;
    }
    this.logo.moveToY(-parseFloat(word_next));
    i = y.next;
    break;  

The Y coordinate mapping to canvas need to be inverted as the positive Y in Logo Coordinate system have a smaller Y value in Canvas.

Roadmap of Chrome Extension: Logo Turtle

1. Add Functions
2. Add IF/THEN/ELSE
3. Add Variables
4. Add Colors
5. Add MoveTo
6. Add PrintText
7. Add Circle
8. Add Arc
9. Add Eraser
10. Add Fill
11. Save As Picture
12. Save As Program
13. Comments
14. Add Recursion Support
15. Add Global/Local Scopes
16. Sleep
17. etc. etc.

Technology Stack

If an App can be written in Javascript, eventually it will be written in Javascript.

Chrome Webstore

Install the Turtle Programming for Kids Now!

Contribution Welcome

Github: https://github.com/DoctorLai/LogoTurtle

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request.

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Posted on Utopian.io - Rewarding Open Source Contributors

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