Re: DPScomposite behaviour, was Coordinate transformations

[Pete French]

> The composite code assumes that the `from rect' is completely
> backed by the device, and this goes wrong.

Question - what is the source for the composition for an NSImage that
has never been drawn into a view ? The behaviour of compositeToPoint
under OpenStep is that it acts like a "draw" method in terms of scaling. i.e.
the image is rendered into the locked view such that it exactly fills
(0,0,width,height).

As I understood it the way NSImage is supposed too work is that it does
a normal scaled dwar, then caches the result. If a composite operation
is sent again and the bitmap size of the desination recatngle is
identical to that of the source then the pixels are copied verbatim, else
the image is redrawn and a new cache of pixels created.

So there should never be a situation in which the source and destination
rectangles do not match up.

Under OpenStep I am pretty sure this is done using an off-screen window
to do the drawing into.

-bat.