Turtle Graphics: Difference between revisions

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This is a very basic implementation of turtle graphics in JavaScript with [http://jsxgraph.org JSXGraph].
[http://u2d.com/turtle_js/index.html CanvasTurtle] does the same on browsers which support the ''canvas'' element.
* [[List of available commands]]
===Snowflake and Branches Example===
<html>
<html>
<link rel="stylesheet" type="text/css" href="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraph.css" />
<form><textarea id="input1" rows=7 cols=35 wrap="off" style="width:300px; float:left;">
<script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/distrib/prototype.js"></script>
function side(size, level) {
<script type="text/javascript" src="http://jsxgraph.uni-bayreuth.de/distrib/jsxgraphcore.js"></script>
    if (level==0) {
<form><textarea id="input" rows=7 cols=35 wrap="off" >
        t.fd(size);
</textarea> <br>
        return;
<input type="button" value="plot" onClick="doIt()" style='margin-right:1em'>  
    }
<input type="button" value="clear all" onClick="board=clearAll(board)">
    side(size/3, level-1);
<input type='button' value='Zoom In' onclick='board.zoomIn()'>
    t.lt(60);
<input type='button' value='Zoom Out' onclick='board.zoomOut()'>
    side(size/3, level-1);
<input type='button' value='Zoom 100%' onclick='board.zoom100()'>  
    t.rt(120);
    side(size/3, level-1);
    t.lt(60);
    side(size/3, level-1);
}
 
function snowflake(size, level) {
    for (var i=0;i<3;i++) {
        side(size, level);
        t.rt(120);
    };
}
 
t.clearScreen();
t.hideTurtle();
t.setPenSize(1)
t.setPenColor("#000000")
t.lt(30);
t.setPos(0,-100);
snowflake(250, 4);
</textarea>
<textarea id="input2" rows=7 cols=35 wrap="off" style="width:300px">
function branch(length, level)
{
    if(level == 0) return
    t.fd(length)
    t.lt(45)
    branch(length/2, level-1)
    t.rt(90)
    branch(length/2, level-1)
    t.lt(45)
    t.bk(length)
}
 
function lbranch(length, angle, level)
{
    t.fd(2*length)
    node(length, angle, level)
    t.bk(2*length)
}
function rbranch(length, angle, level)
{
    t.fd(length)
    node(length, angle, level)
    t.bk(length)
}
 
function node(length, angle, level)
{
    if (level == 0) return;
    t.lt(angle)
    lbranch(length, angle, level -1)
    t.rt(2*angle)
    rbranch(length, angle, level-1)
    t.lt(angle)
}
 
t.clearScreen()
t.hideTurtle();
//branch(100,6)
 
t.setPenSize(5)
t.setPenColor("#008800")
t.setPos(30, -150)
lbranch(25, 20, 7)
</textarea><br />
<input type="button" value="run example 1" onClick="run(1)">  
<input type="button" value="run example 2" onClick="run(2)">  
</form>
</form>
<div id="box" class="jxgbox" style="width:600px; height:600px;"></div>
<script language="JavaScript">
</script>
</html>
</html>
<jsxgraph width="600" height="600" box="box">
var brd = JXG.JSXGraph.initBoard('box', {boundingbox: [-300, 300, 300, -300]});
var t = brd.create('turtle');
function run(nr) {
  brd.suspendUpdate();
  eval(document.getElementById('input'+nr).value);
  brd.unsuspendUpdate();
}
</jsxgraph>
===References===
* The snowflake and branches example have been adapted from the excellent [http://u2d.com/turtle_js/index.html CanvasTurtle]
===The turtle graphics code===
<source lang="html4strict">
<form><textarea id="input1" rows=7 cols=35 wrap="off" style="width:300px; float:left;">
turtle code...
</textarea>
<input type="button" value="run example 1" onClick="run(1)">
</source>
<source lang="javascript">
var brd = JXG.JSXGraph.initBoard('box', {boundingbox: [-300, 300, 300, -300]});
var t = brd.create('turtle');
function run(nr) {
  brd.suspendUpdate();
  eval($('input'+nr).value);
  brd.unsuspendUpdate();
}
</source>


[[Category:Examples]]
[[Category:Examples]]
[[Category:Turtle Graphics]]
[[Category:Fractals]]

Latest revision as of 07:40, 9 June 2011

This is a very basic implementation of turtle graphics in JavaScript with JSXGraph. CanvasTurtle does the same on browsers which support the canvas element.

Snowflake and Branches Example


References

  • The snowflake and branches example have been adapted from the excellent CanvasTurtle

The turtle graphics code

<form><textarea id="input1" rows=7 cols=35 wrap="off" style="width:300px; float:left;">
turtle code...
</textarea>
<input type="button" value="run example 1" onClick="run(1)">

var brd = JXG.JSXGraph.initBoard('box', {boundingbox: [-300, 300, 300, -300]});
var t = brd.create('turtle');

function run(nr) {
  brd.suspendUpdate();
  eval($('input'+nr).value);
  brd.unsuspendUpdate();
}
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