broken backwards compatibility

[JL VT]

On Thu, Apr 28, 2011 at 2:43 PM, Silvio Heinrich <plassy at web.de> wrote:

> On 04/28/2011 07:46 PM, Boudewijn Rempt wrote:
> > Well, consistency with the way other apps work is important too,
> especially since our users will likely use a range of applications. I'm not
> sure I understand all implications, though.
>
> Ok... I try to explain it better.
> I think we can only maintain compatibility with other applications but
> not UI-consistency (or consistency in usability, or whatever).
>

In the following paragraphs we can see how this idea is explained with
crystal clarity.


> Right now we are trying to maintain compatibility with Gimp and
> Photoshop but this two applications really behave different when it
> comes down
> to compositing. For compositing Photoshop uses some kind of wighted
> average (or whatever) to mix the source color into the resulting color and
> recalculates the alpha value accordingly when the destination color is
> semi transparent but Photoshop does this only for compositing while
> painting.
> And you can disable this by locking the alpha channel in Photoshop. Gimp
> doesn't use this at all (besides the "Normal" blending mode").
> Gimp behaves for all blending modes expect "Normal" like if the alpha
> channel is locked.
>
> And now we are here with Krita.
> Krita doesn't distinguish internally between compositing the brush
> strokes and layer composition (it uses the same code).
> To make it compatible to Photoshop I implemented the blending mode
> computations after the specs of Adobe.
> And since Krita doesn't distinguish between the two compositing types I
> only could bring this all together by adding the "disable alpha" button
> so that the user can choose what he/she prefers.
>
> This explanation maybe wasn't so clear, too... hmm... I'm not good at this.
> Maybe short:
> - Inverting the alpha channel will alter the default behavior of the
> "Normal" blending mode (leads to incompatibility to both Gimp and
> Photoshop)
> - making it completely consistent to Gimp will destroy Photoshop
> consistency (and vice versa)
>
> I thought I found a good way in the middle of both applications.
> But I'm of course open for suggestions on how I can get rid of this
> inconsistencies without introducing other inconsistencies :D
>
> Thx for listening :D
>

Basically you found a way to make Krita consistent to both programs at the
cost of adding the extra UI overhead. Your explanation was very clear.

I think just a good entry in the manual and an introduction to that in the
"using Krita for the 1st time" splash screen would be enough to dispel the
user's doubts.
Maybe giving this explanation in summary mode in krita.org (the blog) would
help gather user feedback on alternative solutions to this problem, but I
already think your solution is very good.

Cheers!,
Pentalis.
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