[webkit-help] Canvas rendering should be done in linear color space (gamma 1) and the result displayed in sRGB color space (approximately gamma 2.2)

[Hugues De Keyzer]

Hi all,

For the moment, it seems that drawing on canvas is done without
accounting for gamma, actually making wrong assumptions, like a^x +
b^x = (a + b)^x. This gives incorrect results, although they are not
always obvious to perceive. For example, all shapes and font
antialiasing is incorrect, as are gradients. I propose to address this
issue by ensuring that all drawing operations are done in linear
space.

I wrote a thorough explanation in a W3C bug report, so please see
http://www.w3.org/Bugs/Public/show_bug.cgi?id=12444 for more
information. As a picture is often more expressive than text, please
take a look at the example picture:
http://www.w3.org/Bugs/Public/attachment.cgi?id=975 (has to be
displayed unscaled).

I don’t know whether this is the appropriate mailing list to present
this problem. The actual drawing is probably done through
platform-specific libraries, so maybe this issue concerns those? If it
is the case, could someone give me a list of these platform-specific
libraries?

Kind regards,

Hugues De Keyzer

La sola konstanto en la vivo estas la ŝanĝo.
The only constant in life is change.
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