Mega Code Archive
Bezier Path Animation
<![CDATA[
http://dynapi.sourceforge.net/
GNU LESSER GENERAL PUBLIC LICENSE
Version 2.1, February 1999
<html>
<head>
<title>DynAPI Examples - Bezier Path Animation</title>
<script language="JavaScript" src="./dynapisrc/dynapi.js"></script>
<script language="Javascript">
dynapi.library.setPath('./dynapisrc/');
dynapi.library.include('dynapi.api');
dynapi.library.include('dynapi.debug');
dynapi.library.include('dynapi.fx.Thread');
dynapi.library.include('dynapi.fx.Bezier');
</script>
<script language="Javascript">
var path;
var dots = [];
var cps = [];
function drawBezier() {
clearPage();
var controlPoints = eval(document.b.cp.value);
var steps = parseInt(document.b.steps.value);
// the path includes starting and ending points
// results in total of steps+1 points along path
path = Bezier(controlPoints, steps);
for (var i=0;i<controlPoints.length/2;i++) {
var x = controlPoints[i*2];
var y = controlPoints[i*2+1];
var color = 'red';
if (i==0 || i==controlPoints.length/2-1) color = 'yellow'
if (!cps[i]) cps[i] = dynapi.document.addChild(new DynLayer('',x-2,y-2,5,5,color));
else {
cps[i].setLocation(x-2,y-2);
cps[i].setBgColor(color);
}
cps[i].setVisible(true);
}
for (var i=0;i<path.length/2;i++) {
var x = path[i*2];
var y = path[i*2+1];
if (!dots[i]) dots[i] = dynapi.document.addChild(new DynLayer('',x,y,2,2,'black'));
else {
dots[i].setLocation(x-2,y-2);
}
dots[i].setVisible(true);
}
}
var playblock = dynapi.document.addChild(new DynLayer('',0,0,15,15,'red'));
playblock.setVisible(false);
var pathanim = new Thread(playblock);
pathanim.loop = true;
function startAnim() {
if (path) {
playblock.setVisible(true);
var speed = parseInt(document.b.speed.value);
pathanim.sleep(speed);
pathanim.play(path);
}
}
function stopAnim() {
playblock.setVisible(false);
pathanim.stop();
}
function clearPage() {
for (var i=0;i<dynapi.document.children.length;i++) {
var c = dynapi.document.children[i];
if (c!=playblock) c.setVisible(false);
}
}
function setCP(cp) {
document.b.cp.value = cp;
drawBezier();
startAnim();
}
var t="drawBezier();\nstartAnim();\nthis.watch('playblock.getX()');\n"
+"this.watch('playblock.getY()');\n"
+"this.switchMode('watch');";
dynapi.debug.setEvaluate(t);
</script>
</head>
<body bgcolor="#999999">
<form name=b>
Control Points: <input type=text name="cp" value="[200,150, 200,400, 250,100, 500,300]" size=50>
try these <input type=button value="1" onclick="setCP('[200,150, 200,150, 200,150, 400,150, 400,150, 400,150]');">
<input type=button value="2" onclick="setCP('[200,150, 200,150, 400,300]');">
<input type=button value="3" onclick="setCP('[200,200, 400,200, 400,400, 200,400, 200,200]');">
<input type=button value="4" onclick="setCP('[200,200, 200,300, 300,100, 500,200, 300,400, 500,300]');">
<br>
Steps: <input type=text name="steps" value="25" size=4><br>
Speed: <input type=text name="speed" value="40" size=4>ms<br>
<input type=button value="Draw" onclick="drawBezier()"><br>
<input type=button value="Clear Page" onclick="clearPage()"><br>
<input type=button value="Start Animation" onclick="startAnim()"><br>
<input type=button value="Stop Animation" onclick="stopAnim()"><br>
</form>
</body>
</html>
dynapi.zip( 791 k)
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