[Drawkit] Transforms / ScaleBy

[Graham Cox]

On 08/04/2009, at 10:35 AM, Michael Caron wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Hm. Seems like doing it that way yields the same second bounding  
> box. Doesn't matter if I'm using the origin or not:
>
> 	NSRect boundingBox = [currentLayer unionOfAllObjectBounds];
> 	// x=16.0239811, y=15.9680157
>        // h=18.1520519, w=18.1520519
>
> 	
> 	// Get the identity transform
> 	NSAffineTransform* txfm = [NSAffineTransform transform];
> 	
> 	// translate to origin
> 	[txfm translateXBy:-(boundingBox.origin.x) yBy:- 
> (boundingBox.origin.y)];
> 	
> 	// scale by 1000
> 	[txfm scaleBy: [[self metadataObjectForKey:@"scaleFactor"]  
> doubleValue]];
> 	
> 	[currentLayer applyTransformToObjects:txfm];
>
> 	NSRect boundingBox2 = [currentLayer unionOfAllObjectBounds];
> 	// x=25086.7695, y=25030.8047
> 	// h=26.4765625, w=26.4765625
>
> Any thoughts?


Hmm, well I'm not sure.

It might turn out that the method is buggy - it hasn't been used very  
much. That said, the width/height results you're getting really don't  
make much sense.  You could try tracing through the loop within - 
applyTransformToObjects: in the debugger and just verifying that each  
individual value is doing the expected thing.

--Graham