Looping with canvas: Difference between revisions

Revision as of 16:57, 25 September 2012

while CONDITION {
   LOOP
   LOOP
   LOOP...
}

Examples

<canvas id="c1"> function draw(){

 c = document.getElementById("c1")
 //console.log("c is",c)
 p = c.getContext("2d")
 x = 10
 while (x<250) {
   p.strokeRect(x,100,20,40)
   x+=60
 }

} </canvas>

Variation: When the loop reaches the end of page it breaks the line. It redefines the "x" value to the begin of the line and adds 40px to "y".

<canvas id="c2" width="300" height="300" showsrc> function draw() {

   c = document.getElementById("c2");
   p = c.getContext("2d");
   hands = 1;
   x = 20;
   y = 20;
   while (hands < 100) {
       //console.log(hands);
       p.strokeRect(x,y,20,20);
       x = x + 50;
       hands++;
       if (x > 600) {
           x = 20;
           y = y + 40;
       }
   }

} </canvas>

@@ Line 8: / Line 8: @@
 == Examples ==
-Here is a complete HTML page with a working canvas:
-<source lang="javascript"><!DOCTYPE html>
-<html>
-<head>
-<meta charset="utf-8" />
-<script>
-function draw(){
-  c = document.getElementById("canvas")
-  //console.log("c is",c)
-  p = c.getContext("2d")
-  x = 10
-  while (x<300) {
-    p.strokeRect(x,100,20,40)
-    x+=60
-  }
-}
-</script>
-</head>
-<body onload="draw()">
-<h1>Hello canvas</h1>
-<canvas id="canvas" width="640" height="640" style="border: 3px dotted red"></canvas>
-</body>
-</html>
-</source>
-Here's the output:
 <canvas id="c1">
@@ Line 53: / Line 25: @@
 It redefines the "x" value to the begin of the line and adds 40px to "y".
-<canvas id="c2" width="300" height="300" showsrc="true">
+<canvas id="c2" width="300" height="300" showsrc>
 function draw() {
      c = document.getElementById("c2");