This class was being copied all over the place, however, most of these
cases can be easily prevented with `auto const&` or `NonnullRawPtr<>`.
It also didn't have a move constructor, causing `Vector` to copy on
every resize as well.
Removing all these copies results in an almost 15% increase in
performance for CSS parsing, as measured with callgrind.
This updates the CSS parser to support the keyword 'none' in the CSS4
color functions. The underlying CSSColorValue already supports this
keyword, meaning the parser can instantiate the color directly.
This is an attempt to bring the size of Parser.cpp down. No code
changes, just moves and some explicit template instantiations now that
we're using them from a different file.
Better support for CSS shorthands when setting the style attribute. This
improves some tests in WPT /css/css-align/default-alignment/*shorthand.
When setting the style attribute in JS via element.style = '..' or the
setAttribute method, shorthand properties were not expanded to longhand
properties.
This seems to have vanished from the spec, but in any case, we still
need it. Without this change we erroneously thought that calculations
that match <percentage> did not match <number-percentage>.
This will allow us to remove the use of SafeFunction in it's
implementation. This requires a fair amount of plumbing to wire up the
GC heap to the appropriate places in order to create the timers.
We use the CSSRule::Type enum for identifying the type of a CSSRule, but
the spec requires that only some of these types are exposed via the
`type` attribute. For the rest, we're required to return 0, so let's do
so. :^)
Similar to LadybirdBrowser/ladybird#1714.
We don't implement the linejoin values `miter-clip` and `arcs`, because
according to the SVG 2 spec:
> The values miter-clip and arcs of the stroke-linejoin property are at
> risk. There are no known browser implementations. See issue Github
> issue w3c/svgwg#592.
Nothing uses this yet. The next step is to change
SVGPathPaintable::paint() to read `graphics_element.stroke_linejoin()`
and `graphics_element.stroke_miterlimit()` when painting.
This is really bare bone as we only support the `xyz-d50` color space
for the moment.
It makes us pass the following WPT tests:
- css/css-color/predefined-016.html
- css/css-color/xyz-d50-001.html
- css/css-color/xyz-d50-002.html
All its overrides return constants, and without virtual dispatch the
`qualified_layer_name` and `absolutized_selectors` functions can benefit
from slightly better optimizations.
`CSSRule`s aren't allocated that often, so the memory impact is minimal.
The traversal for these was incorrect and awkward. Now it's less
incorrect but still very awkward. We should find better ways to
implement this, but for now this at least passes many more WPT tests.
The support in LibWeb is quite easy as the previous commits introduced
helpers to support lab-like colors.
Now for the methods in Color:
- The formulas in `from_lab()` are derived from the CIEXYZ to CIELAB
formulas the "Colorimetry" paper published by the CIE.
- The conversion in `from_xyz50()` can be decomposed in multiple steps
XYZ D50 -> XYZ D65 -> Linear sRGB -> sRGB. The two first conversion
are done with a singular matrix operation. This matrix was generated
with a Python script [1].
This commit makes us pass all the `css/css-color/lab-00*.html` WPT
tests (0 to 7 at the time of writing).
[1] Python script used to generate the XYZ D50 -> Linear sRGB
conversion:
```python
import numpy as np
# http://www.brucelindbloom.com/index.html?Eqn_ChromAdapt.html
# First let's convert from D50 to D65 using the Bradford method.
m_a = np.array([
[0.8951000, 0.2664000, -0.1614000],
[-0.7502000, 1.7135000, 0.0367000],
[0.0389000, -0.0685000, 1.0296000]
])
# D50
chromaticities_source = np.array([0.96422, 1, 0.82521])
# D65
chromaticities_destination = np.array([0.9505, 1, 1.0890])
cone_response_source = m_a @ chromaticities_source
cone_response_destination = m_a @ chromaticities_destination
cone_response_ratio = cone_response_destination / cone_response_source
m = np.linalg.inv(m_a) @ np.diagflat(cone_response_ratio) @ m_a
D50_to_D65 = m
# https://en.wikipedia.org/wiki/SRGB#From_CIE_XYZ_to_sRGB
# Then, the matrix to convert to linear sRGB.
xyz_65_to_srgb = np.array([
[3.2406, - 1.5372, - 0.4986],
[-0.9689, + 1.8758, 0.0415],
[0.0557, - 0.2040, 1.0570]
])
# Finally, let's retrieve the final transformation.
xyz_50_to_srgb = xyz_65_to_srgb @ D50_to_D65
print(xyz_50_to_srgb)
```
