Monday, June 23, 2008
Monday, June 23, 2008    
I've found a situation using BitmapData that I'm sure many have run into. I have a sprite whose registration point is smack dab in the middle of it.

If I'd like to copy that Sprite and use it somewhere else too as a copy, I have to nest the Sprite in another Sprite so the registration point of the outer DisplayObject is 0, 0 and thus when I take a scrape of it using BitmapData, I don't just end up with the lower right quadrant of it.

I looked at the clipRect property of the draw method, and I tried negative x & y for it... which work GREAT for me here to avoid nesting... but it doesn't seem to work correctly at all.

var bmp:BitmapData = new BitmapData( 100, 100, true, 0xFFFFFF );
bmp.draw( someDispObj, null, null, "normal",
new Rectangle(-100,-100,200,200),true);

mySprite.addChild( bmp );

Hrmm. Well, for now it seems like I am shackled with nesting which is okay I guess. Just wish I didn't need to do that. Any solution in avoiding nesting to get something like this rolling?

Update:
Quasimondo (Mario Klingemann) posted a response to this posting here. I haven't tried the solution yet for scaling and rotation:

function snapClip( clip:DisplayObject ):BitmapData
{
var bounds:Rectangle = clip.getBounds( clip.parent );

var bitmap:BitmapData = new BitmapData( int( bounds.width + 0.5 ),

int( bounds.height + 0.5 ), true, 0 );

bitmap.draw( clip.parent, new Matrix(1,0,0,1,-bounds.x,-bounds.y) );
return bitmap;
}



2 Comments:

 


“ClipRect is not your friend here, it's the matrix that you'll have to use: http://www.quasimondo.com/archives/000670.php”
 
Blogger phreed said...
 


“Sure the transform matrix is great and all but what does the clipRect actually do?
It appears to clip the target bitmapData rather than the source.”
 
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