On Tue, 19 Dec 2000, Henrik Gedenryd wrote:

> It seems the Morphic strategy is this: bottom-up [...]
> A more optimal technique is: top-down [...]
> Any thoughts from the graphics mavens?

I don't even know what a maven is ;)

Okay, I looked it up. I'm not sure I fit this category. But anyway, here
goes:

Morphic actually uses a top-down redraw strategy. It's soemwhat hidden,
though. Check out WorldState>>drawWorld:submorphs:invalidAreasOn: (it used
to be PasteUpMorph>>drawInvalidAreasOn: but Bob shuffles methods around
faster than you can look ;^)

This is the reason why every partly transparent morph should correctly
implement #areasRemainingToFill: .

-- Bert