Manipulating pixels with BitmapData.setPixel() and BitmapData.setVector() methods

F-site「BitmapData.setPixel()とBitmapData.setVector()メソッドでピクセルを塗る」に簡単な解説を加えた。
http://f-site.org/articles/2011/10/02000000.html

by Fumio 26 Sep 2011

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/**
 * Copyright Fumio ( http://wonderfl.net/user/Fumio )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/jo6R
 */

package {
	import flash.display.Sprite;
	import flash.display.BitmapData;
	import flash.display.Bitmap;
	import flash.utils.getTimer;
	import flash.text.TextField;
	import flash.text.TextFieldAutoSize;
	import flash.text.TextFormat;
	import flash.text.TextFormatAlign;
	public class ManipulatingPixels extends Sprite {
		private var nWidth:int = stage.stageWidth;
		private var nHeight:int = stage.stageHeight;
		private var myBitmapData:BitmapData;
		private var myBitmap:Bitmap;
		private var my_txt:TextField = new TextField();
		private var label_txt:TextField = new TextField();
		private var my_fmt:TextFormat = new TextFormat();
		public function ManipulatingPixels() {
			// Creating a TextField for display
			initialize();
			createTextField();
			// Starting Test
			test_setPixel();
			test_setPixel2();
			test_setVector();
		}
		private function initialize():void {
			myBitmapData = new BitmapData(nWidth, nHeight, false);
			myBitmap = new Bitmap(myBitmapData);
			addChild(myBitmap);
		}
		private function test_setPixel():void {
			resetBitmap();
			var started:int = getTimer();
			for (var i:uint  = 0; i < nHeight; i++) {
			var pixelY:uint = i / nHeight * 256 + 0.5;
				for (var j:uint = 0; j < nWidth; j++) {
					var pixelX:uint = j / nWidth * 256 + 0.5;
					var color:uint = pixelY << 16 | pixelX
					myBitmapData.setPixel(j, i, color);
				}
			}
			xTrace("setPixel()", getTimer() - started);
		}
		private function test_setPixel2():void {
			resetBitmap();
			var started:int = getTimer();
			myBitmapData.lock();
			for (var i:uint  = 0; i < nHeight; i++) {
			var pixelY:uint = i / nHeight * 256 + 0.5;
				for (var j:uint = 0; j < nWidth; j++) {
					var pixelX:uint = j / nWidth * 256 + 0.5;
					var color:uint = pixelY << 16 | pixelX
					myBitmapData.setPixel(j, i, color);
				}
			}
			myBitmapData.unlock();
			xTrace("setPixel() with lock() and unlock()", getTimer() - started);
		}
		private function test_setVector():void {
			resetBitmap();
			var size:uint = nWidth * nHeight;
			var started:int = getTimer();
			var pixels:Vector.<uint> = new Vector.<uint>(size);
			for (var i:uint  = 0; i < size; i++) {
				var pixelX:uint = (i / nWidth * 256 + 0.5) % 256;
				var pixelY:uint = int(i / nWidth) / nHeight * 256 + 0.5;
				pixels[i] = pixelY << 16 | pixelX;
			}
			myBitmapData.setVector(myBitmapData.rect, pixels);
			xTrace("setVector()", getTimer() - started);
		}
		private function resetBitmap():void {
			myBitmapData.dispose();
			myBitmap.bitmapData = null;
			myBitmapData = new BitmapData(nWidth, nHeight, false);
			myBitmap.bitmapData = myBitmapData;
		}
		private function createTextField():void {
			addChild(my_txt);
			addChild(label_txt);
			my_fmt.align = TextFormatAlign.RIGHT;
			my_txt.x += 100;
			my_txt.defaultTextFormat = my_fmt;
			my_txt.autoSize = TextFieldAutoSize.RIGHT;
			my_txt.background = true;
			my_txt.backgroundColor = 0xFFFFFF;
			label_txt.autoSize = TextFieldAutoSize.LEFT;
			label_txt.background = true;
			label_txt.backgroundColor = 0xFFFFFF;
		}
		private function xTrace(_str:String,n:int):void {
			my_txt.appendText(String(n) + "\n");
			label_txt.appendText(_str + ":" + "\n");
		}
	}
}