tree e539b3a7be113605093ba142b5e8d0b85b308422
parent fb11acdeefce2fe24e98dc4e4c1d002291604119
author Mike Klein <mtklein@chromium.org> 1493664964 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> 1493667046 +0000

fix t / t2 confusion in hsl_to_rgb

I think the original[1] SkRasterPipeline_opts.h version had a typo that
I faithfully copied over to hsl_to_rgb.  In Hue2RGB[2], the scalar
equivalent of hue_to_rgb, we mutate t to keep it in 0-1 range[3].  In
the SkRasterPipeline_opts.h code we introduced a new value t2 instead,
and then used it everywhere, but accidentally typed 't' in the t < 1/6 case.

The expression "p + (q - p)*6.0f*t" should have been "p + (q - p)*6.0f*t2".

This fixes things by changing t in place, much like Hue2RGB does.

The GM doesn't change anywhere, which is troubling.

[1] https://skia-review.googlesource.com/c/7460/21/src/opts/SkRasterPipeline_opts.h#808
[2] https://skia-review.googlesource.com/c/7460/21/src/effects/SkHighContrastFilter.cpp#26
[3] I think this whole clamp should probably become "t = fract(t)".
    Will follow up.

Change-Id: I3dcc1a79ffae46830178d931844ee3113f8bdfd1
Reviewed-on: https://skia-review.googlesource.com/14910
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>