W3C home > Mailing lists > Public > www-svg@w3.org > July 2012

Re: Compositing math in SVG

From: Calculemus <calculemus1988@gmail.com>
Date: Sat, 14 Jul 2012 13:51:52 +0200
Message-ID: <CAOn8Oo96V4MC8jRZkDpeOMnvFQT6BjbZnwdy5uY37-w1+e4BCQ@mail.gmail.com>
To: Kai-Uwe Behrmann <ku.b@gmx.de>
Cc: Rik Cabanier <cabanier@gmail.com>, www-svg@w3.org
Kai-Uwe Behrmann,

1. "Clamping should always be the last step to preserve the HDR information
as long as possible during processing. HDR highlights behave other than
flat LDR white while compositing."

Should clamping also be the last step for non-HDR too?
For example, I have this code for color burn:

1 - min (1.0f, (1-a)/b)

should it be instead:

clamp (1 - 1.0f, (1-a)/b, 0, 1)

2. "You can of course us a logarythmic function or a tone mapping op, which
looks much better than per channel clipping. The later one easily causes
not so nice colour casts."

Hmm I would like to hear more about this, can you point me to
some other sources that talk about this in more detail?

3. A question I have is, do you think I should have separate
functions for each blend mode, for HDR and non-HDR?
Or can HDR and non-HDR both be handled by one
function for a blend mode?

Thanks a lot !
Received on Saturday, 14 July 2012 11:52:20 GMT

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