[EMAIL PROTECTED] (2006-04-19 at 1158.08 +0200):
> > How is this fairly straightforward with the current architecture? I
> > would rather say that it is currently almost impossible to implement
> > sanely.
> Ah, but I'm insane.
> Add a layer type for effect layers, and define 3 operations that you can
> associate with the layer (to start): curves, levels and colour balance.
> All the operations are pixel-by-pixel, which should make things easier.
> Then hack the projection code to add a special case for an effect layer.
Internally I would say they are blend modes. Make them special so
content is fixed and flat (better compression), so only layer mask
matters. Then make the formula for the blend mode be curves, levels,
colour balance... whatever you can find that is pix to pix (and
probably LUT based in many cases, if not all) and make it work in BG
while the FG is unused. The settings would be stored in a parasite.
PS allows the following types:
Except gradient and pattern, all the rest are pixel in, pixel out,
without caring about the position.
> We'd need to evolve the xcf version number, and it probably wouldn't be
> possible to do anything useful with the effects layers in earlier
> versions of the GIMP (ignore seems about the best option).
It would load a flat colour in normal mode and keep the layer mask, if
implemented as above, I think, and maybe lose the parasite? It was
time ago when I ported some modes and thus looked at XCF load/save.
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