question about the BitmapData draw() method

[SquirtGun]

Example code:


var bitmap:BitmapData = new BitmapData(100, 100, true, 0x00ffffff)
bitmap.draw(sprite);

Is there a way to define the starting x,y point when drawing a sprites contents to a BitmapData object. I want to only copy a small section of the sprite, that is not the top left most corner.

Thanks for any help.

~squirt

[Templarian]

Theres no way to do it... you have to use the graphics object.

if i could delete this post i would have, i answered your question then notice i read it wrong.

[Reider]

After you created a bitmapdata fom your sprite you can copy the selected content with copyPixels to another bitmapdata on the x,y specified by the destPoint parameter.

[Dazzer]

...

Sorry what are you guys talking about?

http://livedocs.adobe.com/flex/2/langref/flash/display/BitmapData.html#draw()

Use the matrixTransform and clipRect properties.

Those properties are applied to the Sprite you are drawing FIRST, before it draws. Those are not permanent, so you don't have to worry.

[joshchernoff]

I think I all most have it, but it wont work.

I use the corlib JPGEncoder class with this as well to make a jpg of a sprite.

But the problem is that the image inside the sprite has been centered to make it's index of x:0, y:0, it's center.

What happens with the draw it that the center of the sprite becomes the topLeft of the new bitmap and it clips off every thing -x, -y, of the center.

here's what I got now. I'm trying to use a Rectangle to get the proper index of the bitmap so that the draw method sees all of the image.




import com.adobe.images.JPGEncoder;

var test:Loader = new Loader();
var myPreviewLoader:Loader = new Loader();

test.load(new URLRequest("thumbair.jpg"));
test.contentLoaderInfo.addEventListener(Event.COMP LETE, onCom);

function onCom(e:Event):void {
var sprite:Sprite = new Sprite();
sprite.y = (stage.stageHeight >> 1);
sprite.x = (stage.stageWidth >> 1);
addChild(sprite);

test.x -= test.width >> 1;
test.y -= test.height >> 1;
sprite.addChild(test);

var rect:Rectangle = Rectangle(sprite.getBounds(test));

rect.topLeft = new Point(-40, -30);
var myBitmapSource:BitmapData = new BitmapData (test.width, test.height, false, 0xFF0000);

myBitmapSource.draw(sprite, null, null, null, rect);
var myEncoder:JPGEncoder = new JPGEncoder(100);
var myCapStream:ByteArray = myEncoder.encode ( myBitmapSource );
myPreviewLoader.loadBytes( myCapStream );
addChild(myPreviewLoader);

}

[Rezmason]

Try this out, Josh.

import com.adobe.images.JPGEncoder;

var test:Loader = new Loader;
var myPreviewLoader:Loader = new Loader;
var matrix:Matrix = new Matrix;
var myBitmapSource:BitmapData;
var rect:Rectangle;

test.load(new URLRequest("thumbair.jpg"));
test.contentLoaderInfo.addEventListener(Event.COMP LETE, onCom);

function onCom(e:Event):void
{
rect = Rectangle(test.getBounds(test));
matrix.tx = -rect.x;
matrix.ty = -rect.y;
myBitmapSource = new BitmapData (test.width, test.height, false, 0xFF0000);

myBitmapSource.draw(testbed, matrix);
var myEncoder:JPGEncoder = new JPGEncoder(100);
var myCapStream:ByteArray = myEncoder.encode ( myBitmapSource );
myPreviewLoader.loadBytes( myCapStream );
addChild(myPreviewLoader);
}