Looping with canvas: Difference between revisions
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The condition should be some kind of "boolean" expression that is "true" for a while, and eventually "false" when the loop should stop running. | The condition should be some kind of "boolean" expression that is "true" for a while, and eventually "false" when the loop should stop running. | ||
<canvas id="c1" showsrc> | <canvas id="c1" showsrc> |
Revision as of 16:01, 25 September 2012
See also Canvas.
A basic coding control structure is the loop which takes it's simplest form as:
while CONDITION { LOOP LOOP LOOP... }
The condition should be some kind of "boolean" expression that is "true" for a while, and eventually "false" when the loop should stop running.
<canvas id="c1" showsrc> 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 edge it breaks the line. It redefines the "x" value to the beginning 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>