Re: DPScomposite behaviour, was Coordinate transformations

[Willem Rein Oudshoorn]

Pete French <pete@twisted.org.uk> writes:

> > 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 DPS composite operator works on gState's, not on images

[Explanation of the compositeToPoint method of NSImage deleted]
> 
> So there should never be a situation in which the source and
> destination rectangles do not match up.

Well, that is actually not true.  The mapping from User coordinates
to device space coordinates does not preserve size.  The NSImage
class does not know anything about device space so it has no way
of knowing which size will actually be used.  And this is right,
the gui classes should not know nor care about device space.


Wim Oudshoorn.