SWF It Good

How to use Bitmap and BitmapData in ActionScript 3 – v1

April 21st, 2008

So the last couple of weeks I have been jacking around w/ Bitmaps and BitmapData. I’ve always wanted to try it but never had the courage. Now that I have, I wish I’d have done it sooner.

In this first example I’m just copying each pixel throwing it to the wind and using Tweener to animate it to a spot. I don’t think Tweener is the best option course as you can see it runs slow. I’m also using Grant Skinner’s Memory Gauge to illustrate how slow it is. This is just a proof of concept anyway.

Here is the Bitmap and BitmapData src v1

Here is the code
[as]
// code written by Josh Weatherspoon of http://swfitgood.com

import flash.display.*;
import caurina.transitions.Tweener;
//holds all the “pixels”
var pixHolder:Sprite = new Sprite();
//image of me in the library thru linkage
var img:Img = new Img();
//pixHolder.opaqueBackground = true;

addChild(pixHolder);

//array that will hold info of each pixel
var coords_array:Array = [];

//bitmapdata of the img
var bmd:BitmapData = new BitmapData(img.width, img.height, false);
//put the img bitmapdata in the new bitmapdata object
bmd.draw(img, new Matrix());
//I heard this helps performance
bmd.lock();
//loop thru each pixel
//i.e. i= 0; j = 0 then i=1; j = 0 then i = 2; j = 0 you get it right?
for (var i:int = 0; i < img.width; i++)
{
for (var j:int = 0; j < img.height; j++)
{
//create an obj to hold each pixels info
var coords:Object = {};

//var pixData:BitmapData = new BitmapData(1, 1, false, bmd.getPixel(i, j));

//var pixBit:Bitmap = new Bitmap(pixData, PixelSnapping.ALWAYS, true);
//in this example I decided to use a circlular graphic instead of a single bitmap
//for fun
var pixSprite:Sprite = new Sprite();
//make a pixSprite for each pixel
pixSprite.graphics.beginFill(bmd.getPixel(i, j), 1);
pixSprite.graphics.drawCircle(0, 0, 1);
//set the pixel to a random location on the stage
pixSprite.x = Math.random() * stage.stageWidth;
pixSprite.y = Math.random() * stage.stageHeight;
//pixSprite.filters = [new BlurFilter(5, 5, 3)];
//pixSprite.addChild(pixBit);

pixHolder.addChild(pixSprite);
//gather info to access each pixel individually
coords.sprite = pixSprite;
coords.x = i;
coords.y = j;
coords_array.push(coords);
}
}
bmd.unlock();
// on mouse over start animating
stage.addEventListener(MouseEvent.MOUSE_OVER, updating, false, 0, true);

function updating(evt:MouseEvent):void
{
// loop thru each pixel and move it to the original location
stage.removeEventListener(MouseEvent.MOUSE_OVER, updating);
for(var k:int = 0; k < coords_array.length; k++)
{
Tweener.addTween(coords_array[k].sprite, {x:coords_array[k].x, scaleX:1, scaleY:1, delay: .3, y:coords_array[k].y, transition:”linear”, time:10});
}
}

[/as]

Entry Filed under: Bitmap/BitmapData, actionscript, as3, flash