Re: [Gimp-developer] tile row hints (was: caching considerations ingegl)

2003-03-11 Thread David Necas (Yeti)
On Tue, Mar 11, 2003 at 01:07:21PM +0100, Raphaël Quinet wrote:
> On Tue, 11 Mar 2003 09:46:49 +, "Adam D. Moss" <[EMAIL PROTECTED]> wrote:
> > [...]  The idea
> > of rehash-on-dirty would be to catch identical tiles, even
> > accidentally-identical tiles (like great masses of transparent
> > tiles, presuming that you scrub the RGB data of a transparent
> > pixel; the row-hints stuff has been doing this and potentially
> > breaking the ill-advised anti-erase feature for 100 years now
> > and no-one has complained), that the normal COW routes miss.
> 
> Hmmm...  This is interesting.  I didn't know that a side effect of the
> row-hints would be to discard the RGB data from fully transparent
> pixels.  Of course, this makes sense and this is the right thing to do.
> 
> But this also means that some plug-ins such as Noisify should
> definitely never use the invisible RGB data in any operation, because
> the results could be (very) different if some tiles are swapped out.
> See the discussion in: http://bugzilla.gnome.org/show_bug.cgi?id=72853

Hm.  Though I see the posibility to temporarily make some
area transparent just to give some its parts nonzero opacity
later as a useful feature, the rest of world obviously thinks
otherwise ;-(

Yeti
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Re: [Gimp-developer] tile row hints (was: caching considerations ingegl)

2003-03-11 Thread Raphaël Quinet
On Tue, 11 Mar 2003 09:46:49 +, "Adam D. Moss" <[EMAIL PROTECTED]> wrote:
> [...]  The idea
> of rehash-on-dirty would be to catch identical tiles, even
> accidentally-identical tiles (like great masses of transparent
> tiles, presuming that you scrub the RGB data of a transparent
> pixel; the row-hints stuff has been doing this and potentially
> breaking the ill-advised anti-erase feature for 100 years now
> and no-one has complained), that the normal COW routes miss.

Hmmm...  This is interesting.  I didn't know that a side effect of the
row-hints would be to discard the RGB data from fully transparent
pixels.  Of course, this makes sense and this is the right thing to do.

But this also means that some plug-ins such as Noisify should
definitely never use the invisible RGB data in any operation, because
the results could be (very) different if some tiles are swapped out.
See the discussion in: http://bugzilla.gnome.org/show_bug.cgi?id=72853

-Raphaël
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