The Weekly Juan #3: Coordinate Systems in Morphic 3.0

Michael Rueger m.rueger at acm.org
Tue Oct 31 17:15:07 UTC 2006


Hans-Martin Mosner wrote:

> A first implementation using Balloon can probably be done, but some fine
> details might only be doable right with a framework such as Cairo where
> others have already put a lot of work into getting things right. Don't
> get me wrong - I'd prefer to have everything done within Squeak to be
> independent of external libraries as far as possible, but even though
> the Squeak community has a lot of really bright folks, our resources are
> ultimately limited, so doing everything ourselves is not always feasible.

When you look at the Rome package we took care to both support a Squeak 
native, based on Balloon, and a Cairo backend.
The APIs between the old Canvases and Rome are sufficiently different, 
so porting later might not be as easy as you think.

In Sophie we do all our document drawing using Rome. We do actually use 
integer coordinates though, based on cTwips (127th of a Twip). As this 
provides a very high resolution we yet have to see rounding artifacts 
that we wouldn't also see with floats.

Just MTC

Michael



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