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    <p>( too slow :) ) so this is the sae as above with a linear loop instead of 2 nested loops.</p> <pre><code>//creates a new BitmapData, with transparency, white 0xFFFFFF var bd:BitmapData = new BitmapData( 100, 100, false, 0xFFFFFF ); //stores the width and height of the image var w:int = bd.width; var h:int = bd.height; var i:int = w * h; var x:int, y:int, col; //decremental loop are said to be faster :) while ( i-- ) { //this is the position of each pixel in x &amp; y x = i % w; y = int( i / w ); //gets the current color of the pixel ( 0xFFFFFF ) col = bd.getPixel( x, y ); //assign the 0xFF0000 ( red ) color to the pixel bd.setPixel( x, y, 0xFF0000 ); } addChild( new Bitmap( bd ) );//a nice red block </code></pre> <p>note that if you're using a bitmapData with an alpha channel (say if you load the image, the alpha will be turned on automatically ) you 'll have to use </p> <pre><code>bd.getPixel32( x, y );// returns a uint : 0xFF000000 //and bd.setPixel32( x, y, UINT );// 0xFF000000 </code></pre> <p>EDIT : I 've done a quick bench :</p> <pre><code>package { import flash.display.BitmapData; import flash.display.Sprite; import flash.utils.getTimer; public class pixels extends Sprite { private var bd:BitmapData = new BitmapData( 100, 100, false, 0xFFFFFF ); public function pixels() { var i:int, total:int = 100, t:int = 0; t = getTimer(); i = total; while( i-- ) { whileLoop( bd ); } trace( 'while:', getTimer() - t ); t = getTimer(); i = total; while( i-- ) { forLoop( bd ); } trace( 'for:', getTimer() - t ); } private function forLoop( bd:BitmapData ):void { var i:int, j:int; var col:int; for ( i = 0; i &lt; bd.width; i++ ) { for ( j = 0; j &lt; bd.height; j++ ) { col = bd.getPixel( i, j ); // +/- 790 ms } } //for ( i = 0; i &lt; bd.width; i++ ) for ( j = 0; j &lt; bd.height; j++ ) col = bd.getPixel( i, j ); // +/-530 ms //var w:int = bd.width; //var h:int = bd.height; //for ( i = 0; i &lt; w; i++ ) for ( j = 0; j &lt; h; j++ ) col = bd.getPixel( i, j ); // +/-250 ms } private function whileLoop( bd:BitmapData ):void { var w:int = bd.width; var h:int = bd.height; var i:int = w * h; var col:int; while ( i-- ) { col = bd.getPixel( i % w, int( i / w ) ); // +/- 580 ms } //while ( i-- ) col = bd.getPixel( i % w, int( i / w ) ); // +/- 330 ms } } } </code></pre> <p>for 100 * ( 100 * 100 ) getPixel, the fastest (on my machine) is the one-line for loop with local variables. ( +/- 250 ms ) then the one-line while( +/- 330 ms ) :)</p> <p>storing local variables w and h for width and height makes the for loops twice faster :) </p> <p>good to know </p>
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    1. POIterating each pixel of a Bitmap image in ActionScript
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    1. COIMHO, storing the width & height is not necessary (those are attributes, not methods). But nice solution :)
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    2. COthanks :) hmmm, I haven't benchmarked this yet. my take is that accessing an object's property through a getter is slower than adressing a local variable. I may be wrong + I'm some kind of local var maniac ^^'
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    3. COGetting x and y with modulo and division, why not two nested cycles? That would be faster.
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