Files
serenity/Userland/Libraries/LibWeb/CSS/StyleValues/CSSRGB.cpp
Sam Atkins b65ccb4dc6 LibWeb: Introduce color-function-specific style values
Instead of CSSColorValue holding a Gfx::Color, make it an abstract class
with subclasses for each different color function, to match the Typed-OM
spec. This means moving the color calculations from the parsing code to
the `to_color()` method on the style value.

This lets us have calc() inside a color function, instead of having to
fully resolve the color at parse time. The canvas fillStyle tests have
been updated to reflect this.

The other test change is Screenshot/css-color-functions.html: previously
we produced slightly different colors for an alpha of 0.5 and one of
50%, and this incorrect behavior was baked into the test. So now it's
more correct. :^)

(cherry picked from commit 3af6a69f1e13803c64466a9b24b7bd7d75d459df;
amended to:
* resolve a minor conflict in Parser.cpp due to upstream not having
  https://github.com/LadybirdBrowser/ladybird/pull/385#issuecomment-2227130015
* rebaseline canvas-fillstyle-rgb.png since the diff didn't apply due to
  us not having https://github.com/LadybirdBrowser/ladybird/pull/999
* remove css-color-functions-ref.png and instead update
  css-color-functions-ref.html since that file is still a reftest due to us
  not having https://github.com/LadybirdBrowser/ladybird/pull/736
  Makes it much easier to see what actually changed.
)
2024-10-11 10:12:33 -04:00

78 lines
2.6 KiB
C++

/*
* Copyright (c) 2024, Sam Atkins <sam@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include "CSSRGB.h"
#include <AK/TypeCasts.h>
#include <LibWeb/CSS/Serialize.h>
#include <LibWeb/CSS/StyleValues/CalculatedStyleValue.h>
#include <LibWeb/CSS/StyleValues/NumberStyleValue.h>
#include <LibWeb/CSS/StyleValues/PercentageStyleValue.h>
namespace Web::CSS {
Color CSSRGB::to_color(Optional<Layout::NodeWithStyle const&>) const
{
auto resolve_rgb_to_u8 = [](CSSStyleValue const& style_value) -> Optional<u8> {
// <number> | <percentage> | none
auto normalized = [](double number) {
return llround(clamp(number, 0.0, 255.0));
};
if (style_value.is_number())
return normalized(style_value.as_number().number());
if (style_value.is_percentage())
return normalized(style_value.as_percentage().value() * 2.55);
if (style_value.is_calculated()) {
auto const& calculated = style_value.as_calculated();
if (calculated.resolves_to_number())
return normalized(calculated.resolve_number().value());
if (calculated.resolves_to_percentage())
return normalized(calculated.resolve_percentage().value().value() * 2.55);
}
if (style_value.is_keyword() && style_value.to_keyword() == Keyword::None)
return 0;
return {};
};
auto resolve_alpha_to_u8 = [](CSSStyleValue const& style_value) -> Optional<u8> {
auto alpha_0_1 = resolve_alpha(style_value);
if (alpha_0_1.has_value())
return llround(clamp(alpha_0_1.value() * 255.0f, 0.0f, 255.0f));
return {};
};
u8 const r_val = resolve_rgb_to_u8(m_properties.r).value_or(0);
u8 const g_val = resolve_rgb_to_u8(m_properties.g).value_or(0);
u8 const b_val = resolve_rgb_to_u8(m_properties.b).value_or(0);
u8 const alpha_val = resolve_alpha_to_u8(m_properties.alpha).value_or(255);
return Color(r_val, g_val, b_val, alpha_val);
}
bool CSSRGB::equals(CSSStyleValue const& other) const
{
if (type() != other.type())
return false;
auto const& other_color = other.as_color();
if (color_type() != other_color.color_type())
return false;
auto const& other_rgb = verify_cast<CSSRGB>(other_color);
return m_properties == other_rgb.m_properties;
}
// https://www.w3.org/TR/css-color-4/#serializing-sRGB-values
String CSSRGB::to_string() const
{
// FIXME: Do this properly, taking unresolved calculated values into account.
return serialize_a_srgb_value(to_color({}));
}
}