Hi Graeme,
> in theory the RGBA case could be handled as a normal color lookup
using a 4D color tabl
Yes, you are right. That could be possible (even if this is beyond my
skills as it would mean digging deeper into LittleCMS optimization
engine) but as you pointed it out, in practice, it may not
Sebastien Leon wrote:
> Back again :-) This WE, I implemented some basic premultiplied alpha
> support.
Something that occurred to me rather a long time ago while
reading one of Jim Blinn's articles in CG&A, is that
(at least in principle), the multi-dimensional nature of
color lookups could be u
Hi,
Back again :-) This WE, I implemented some basic premultiplied alpha
support.
I agree with Bob and John that Premultiplied alpha doesn't "make a lot
of sense with a color management system since color perception varies
with intensity and the colorspace may not be linear across the color
chann
Hi John,
Hi Bob,
Thanks a lot for your advises & feed-back.
Bob:
> Assuming that the input images are not in a consistent color space,
then they should
> be color managed before the compositing step or else the result is
indeterminate.
They are. Input images are in the Working Color Space. The e
On Tue, 11 Dec 2012, jcup...@gmail.com wrote:
> My 2p would be that pre-multiplied alpha is a very useful optimisation for
> compositing, but a hindrance for everything else.
>
> Perhaps you could move your colour management after the compositing step?
Assuming that the input images are not in
On Tue, 11 Dec 2012, Sebastien Leon wrote:
> Hi Bob,
>
> Thank you for your reply !
> I agree with you regarding the fact that PNG and others are not using
> premultiplied alpha and I think it is a very good thing. Using this
> "runtime" format to store data is a bad idea as you loose color accura
My 2p would be that pre-multiplied alpha is a very useful optimisation for
compositing, but a hindrance for everything else.
Perhaps you could move your colour management after the compositing step?
So have RGBA with pre-multipled alpha as your working space, composite down
to a single plain RGB l
Hi Bob,
Thank you for your reply !
I agree with you regarding the fact that PNG and others are not using
premultiplied alpha and I think it is a very good thing. Using this
"runtime" format to store data is a bad idea as you loose color accuracy
(if not using floating color channels).
However, whe
On Tue, 11 Dec 2012, Sebastien Leon wrote:
>
> In my graphic pipeline, it appears that the image that I would like to
> process are in premultiplied RGBA, which is much faster to blend that
> regular RGBA.
> LittleCMS, for now, left unchanged the alpha channel and does not care
> about it.
> Obvio
Hi Marti,
Hi everyone,
I'm using LittleCMS (and reading the ML) for one year and half now and
my first message would be to thank you for this great piece of software !
(BTW, regarding the recent discussion, I'm using multi-thread
QtConcurrent code and it works like a charm... being ~3 times faster
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