vendredi 29 mai 2015

Merge two images and retain its transparency

It was a while since I programmed AS3. Now I have a problem where I need to merge the two images where the upper image is a png that must retain its transparency. The upper image is an area that must pass through the lower image. A bit like a masked layer.

The result of this merge should result in a a display object. This object will later be sent to a method with the following signature:

public function addImage (
    display_object:DisplayObject,
    x:Number = 0,
    y:Number = 0,
    width:Number = 0,
    height:Number = 0,
    image_format:String = "PNG",
    quality:Number = 100,
    alpha:Number = 1,
    resizeMode:String = "None",
    blendMode:String = "Normal",
    keep_transformation:Boolean = true,
    link:String = ''
):void

Any advice is of the utmost interest. Thanks!

UPDATE;

After some struggling I've come up with this:

var bitmapDataBuffer:BitmapData = new BitmapData ( front.loader.width, front.loader.height, true );     
bitmapDataBuffer.draw ( front.loader );

var bitmapOverlay:BitmapData = new BitmapData ( front.loader.width, front.loader.height, true );
bitmapOverlay.draw ( frontBanner.loader );

var rect:Rectangle = new Rectangle(0, 0, front.loader.width, front.loader.height);
var pt:Point = new Point(0, 0);
var mult:uint = 0x00;
bitmapOverlay.merge(bitmapDataBuffer, rect, pt, mult, mult, mult, mult);

var bmp:Bitmap = new Bitmap(bitmapOverlay);

pdf.addImage(bmp,0,0,0,0,ImageFormat.PNG,100,1,ResizeMode.FIT_TO_PAGE); 

The problem is that my background image (represented by bitmapDataBuffer) will be totally overwritten by my upper image (the one I call overlay).

The overlay image is a png image. This image has a part of it that is transparent. Through this transparency I want to see my background image.

Any more suggestions?

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