[CSS Color 4] Add support for oklab() and oklch() colors

Reviewed by Cameron McCormack.


Add new tests for oklab() and oklch() based on the existing lab()
and lch() tests.

* web-platform-tests/css/css-color/oklab-001-expected.html: Added.
* web-platform-tests/css/css-color/oklab-001.html: Added.
* web-platform-tests/css/css-color/oklab-002-expected.html: Added.
* web-platform-tests/css/css-color/oklab-002.html: Added.
* web-platform-tests/css/css-color/oklab-003-expected.html: Added.
* web-platform-tests/css/css-color/oklab-003.html: Added.
* web-platform-tests/css/css-color/oklab-004-expected.html: Added.
* web-platform-tests/css/css-color/oklab-004.html: Added.
* web-platform-tests/css/css-color/oklab-005-expected.html: Added.
* web-platform-tests/css/css-color/oklab-005.html: Added.
* web-platform-tests/css/css-color/oklab-006-expected.html: Added.
* web-platform-tests/css/css-color/oklab-006.html: Added.
* web-platform-tests/css/css-color/oklab-007-expected.html: Added.
* web-platform-tests/css/css-color/oklab-007.html: Added.
* web-platform-tests/css/css-color/oklab-008-expected.html: Added.
* web-platform-tests/css/css-color/oklab-008.html: Added.
* web-platform-tests/css/css-color/oklch-001-expected.html: Added.
* web-platform-tests/css/css-color/oklch-001.html: Added.
* web-platform-tests/css/css-color/oklch-002-expected.html: Added.
* web-platform-tests/css/css-color/oklch-002.html: Added.
* web-platform-tests/css/css-color/oklch-003-expected.html: Added.
* web-platform-tests/css/css-color/oklch-003.html: Added.
* web-platform-tests/css/css-color/oklch-004-expected.html: Added.
* web-platform-tests/css/css-color/oklch-004.html: Added.
* web-platform-tests/css/css-color/oklch-005-expected.html: Added.
* web-platform-tests/css/css-color/oklch-005.html: Added.
* web-platform-tests/css/css-color/oklch-006-expected.html: Added.
* web-platform-tests/css/css-color/oklch-006.html: Added.
* web-platform-tests/css/css-color/oklch-007-expected.html: Added.
* web-platform-tests/css/css-color/oklch-007.html: Added.
* web-platform-tests/css/css-color/oklch-008-expected.html: Added.
* web-platform-tests/css/css-color/oklch-008.html: Added.


Tests: imported/w3c/web-platform-tests/css/css-color/oklab-001.html

Adds support for oklab() and oklch() CSS colors and as interpolation
parameters for color-mix().

OKLab (and its polar form OKLCH) is a relatively new Lab-like colorspace that aims
to be an improved (improved hue linearity, hue uniformity, and chroma uniformity)
Lab. It was create by Björn Ottosson and is documented at https://bottosson.github.io/posts/oklab/.

* css/CSSValueKeywords.in:
Add 'oklab' and 'oklch' to the keyword list so they can be used as function
identifiers. Remove old mention of 'lab' in the color() function section,
since 'lab' is no longer a valid colorspace to use in the color() function
(rather, only lab() is supported).

* css/parser/CSSPropertyParserHelpers.cpp:
Generalize lab and lch function parsing to also support the oklab and
oklch variants (they have the same parsing rules).

Add support for using oklab and oklch as the interpolation space of a color-mix().
This was already generalized so all it meant doing was adding mappings of the
new identifiers to enums and mixColorComponentsInColorSpace calls.

* platform/graphics/ColorComponents.h:
(WebCore::ColorComponents::subset const):
Fix compile error (no one had used subset yet it seems). 'std::remove_const_t<decltype(T::Size)>'
was likely copied from mapColorComponents() where it is templatized and needs to deduce the loop
variable, but that is not needed here.

* platform/graphics/ColorConversion.cpp:
Move conversion to/from polar/rectangular forms from the LCHA conversion
code here, so that it can be reused for OKLCHA.

Add support for converting OKLab to/from XYZ D65. Matrix values come from https://bottosson.github.io/posts/oklab/
with updates from https://github.com/w3c/csswg-drafts/issues/6642#issuecomment-943521484

Add support for converting OKLCHA. This is identical to the LCHA code above.

Add cases for new colorspaces.

* platform/graphics/ColorConversion.h:
Add converters for new colorspaces. Update diagram with them as well.

* platform/graphics/ColorMatrix.h:
(WebCore::ColorMatrix::transformedColorComponents const):
Generalize transformedColorComponents to work with any size ColorComponents object. This allows
the OKLab conversion code to be a bit simpler as it can operate on just the non-alpha components
in a more systematic way.

* platform/graphics/ColorModels.h:
Add new predicate template variables to help when needing to check what model a particular
color type uses.

* platform/graphics/ColorSerialization.cpp:
Add serialization support for new colorspaces. Also removes unused support for serializing lab
colors using the color(lab ...) syntax which has not been supported for some time.

* platform/graphics/ColorSpace.cpp:
* platform/graphics/ColorSpace.h:
* platform/graphics/cg/ColorSpaceCG.h:
Add OKLab and OKLCH to the list of enumerated colorspaces and add mappings to their
newly defined types OKLab<T> and OKLCHA<T>.

* platform/graphics/ColorTypes.h:
Add new types OKLab<T> and OKLCHA<T> (it looks like at some point an earlier version of this
must have partially landed as there were existing forward declarations). Like Lab<T> and LCHA<T>,
these new types use the LabModel<T> and LCHModel<T> models, but unlike them they use a whitepoint
of D65.

* platform/graphics/ColorUtilities.h:
Generalize isBlack and isWhite to have a variant that works with Lab, LCH, OKLab and OKLCH (as they
all are identical) using SFINAE, use the new model predicates to make this more clear.


Update existing tests for lab() and lch() to also test oklab() and oklch().
As they have the same parsing rules, this is mostly done by templatizing
the tests and running them in a loop.

* fast/css/parsing-color-mix-expected.txt:
* fast/css/parsing-color-mix.html:
* fast/css/parsing-lab-colors-expected.txt:
* fast/css/parsing-lab-colors.html:
* fast/css/parsing-relative-color-syntax-expected.txt:
* fast/css/parsing-relative-color-syntax.html:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@286191 268f45cc-cd09-0410-ab3c-d52691b4dbfc
54 files changed
tree: 72448e8910b4d62a13d12f2066b1c9fff4de5269
  1. JSTests/
  2. LayoutTests/
  3. ManualTests/
  4. PerformanceTests/
  5. Source/
  6. Tools/
  7. WebDriverTests/
  8. WebKit.xcworkspace/
  9. WebKitLibraries/
  10. Websites/
  11. metadata/
  12. resources/
  13. .ccls
  14. .clang-format
  15. .dir-locals.el
  16. .editorconfig
  17. .gitattributes
  18. .gitignore
  19. CMakeLists.txt
  20. ChangeLog
  21. ChangeLog-2012-05-22
  22. ChangeLog-2018-01-01
  23. Introduction.md
  24. Makefile
  25. Makefile.shared
  26. ReadMe.md


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