Altering color and brightness effects with code -- Flash CS3

Suppose you have a display object with multiple colors (for example, a digital photo) and you don't want to completely recolor the object; you just want to adjust the color of a display object based on the existing colors. In this scenario, the ColorTransform class includes a series of multiplier and offset properties that you can use to make this type of adjustment. The multiplier properties, named redMultiplier, greenMultiplier, blueMultiplier, and alphaMultiplier, work like colored photographic filters (or colored sunglasses), amplifying or diminishing certain colors in the display object. The offset properties (redOffset, greenOffset, blueOffset, and alphaOffset) can be used to add extra amounts of a certain color to the object, or to specify the minimum value that a particular color can have.

These multiplier and offset properties are identical to the advanced color settings that are available for movie clip symbols in the Flash authoring tool when you choose Advanced from the Color pop-up menu on the Property inspector.

The following code loads a JPEG image and applies a color transformation to it, which adjusts the red and green channels as the mouse pointer moves along the x axis and y axis. In this case, because no offset values are specified, the color value of each color channel displayed on screen will be a percentage of the original color value in the image--meaning that the most red or green displayed in any given pixel will be the original amount of red or green in that pixel.

import flash.display.Loader;
import flash.events.MouseEvent;
import flash.geom.Transform;
import flash.geom.ColorTransform;
import flash.net.URLRequest;

// Load an image onto the Stage.
var loader:Loader = new Loader();
var url:URLRequest = new URLRequest("http://www.helpexamples.com/flash/images/image1.jpg");
loader.load(url);
this.addChild(loader);

// This function is called when the mouse moves over the loaded image.
function adjustColor(event:MouseEvent):void
{
    // Access the ColorTransform object for the Loader (containing the image)
    var colorTransformer:ColorTransform = loader.transform.colorTransform;
    
    // Set the red and green multipliers according to the mouse position.
    // The red value ranges from 0% (no red) when the cursor is at the left
    // to 100% red (normal image appearance) when the cursor is at the right.
    // The same applies to the green channel, except it's controlled by the
    // position of the mouse in the y axis.
    colorTransformer.redMultiplier = (loader.mouseX / loader.width) * 1;
    colorTransformer.greenMultiplier = (loader.mouseY / loader.height) * 1;
    
    // Apply the changes to the display object.
    loader.transform.colorTransform = colorTransformer;
}

loader.addEventListener(MouseEvent.MOUSE_MOVE, adjustColor);