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LibWeb: Support interpolation of mixed percentage dimension units

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This commit is contained in:
Matthew Olsson
2024-05-25 13:24:18 -07:00
committed by Andreas Kling
parent ef766b0b5f
commit e2cb25e35c
3 changed files with 109 additions and 1 deletions
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75
Userland/Libraries/LibWeb/CSS/StyleComputer.cpp
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@@ -43,6 +43,7 @@
#include <LibWeb/CSS/StyleValues/DisplayStyleValue.h>
#include <LibWeb/CSS/StyleValues/EasingStyleValue.h>
#include <LibWeb/CSS/StyleValues/FilterValueListStyleValue.h>
#include <LibWeb/CSS/StyleValues/FrequencyStyleValue.h>
#include <LibWeb/CSS/StyleValues/GridTrackPlacementStyleValue.h>
#include <LibWeb/CSS/StyleValues/GridTrackSizeListStyleValue.h>
#include <LibWeb/CSS/StyleValues/IdentifierStyleValue.h>
@@ -1234,8 +1235,80 @@ static NonnullRefPtr<StyleValue const> interpolate_box_shadow(DOM::Element& elem
static NonnullRefPtr<StyleValue const> interpolate_value(DOM::Element& element, StyleValue const& from, StyleValue const& to, float delta)
{
if (from.type() != to.type())
if (from.type() != to.type()) {
// Handle mixed percentage and dimension types
// https://www.w3.org/TR/css-values-4/#mixed-percentages
struct NumericBaseTypeAndDefault {
CSSNumericType::BaseType base_type;
ValueComparingNonnullRefPtr<CSS::StyleValue> default_value;
};
static constexpr auto numeric_base_type_and_default = [](StyleValue const& value) -> Optional<NumericBaseTypeAndDefault> {
switch (value.type()) {
case StyleValue::Type::Angle: {
static auto default_angle_value = AngleStyleValue::create(Angle::make_degrees(0));
return NumericBaseTypeAndDefault { CSSNumericType::BaseType::Angle, default_angle_value };
}
case StyleValue::Type::Frequency: {
static auto default_frequency_value = FrequencyStyleValue::create(Frequency::make_hertz(0));
return NumericBaseTypeAndDefault { CSSNumericType::BaseType::Frequency, default_frequency_value };
}
case StyleValue::Type::Length: {
static auto default_length_value = LengthStyleValue::create(Length::make_px(0));
return NumericBaseTypeAndDefault { CSSNumericType::BaseType::Length, default_length_value };
}
case StyleValue::Type::Percentage: {
static auto default_percentage_value = PercentageStyleValue::create(Percentage { 0.0 });
return NumericBaseTypeAndDefault { CSSNumericType::BaseType::Percent, default_percentage_value };
}
case StyleValue::Type::Time: {
static auto default_time_value = TimeStyleValue::create(Time::make_seconds(0));
return NumericBaseTypeAndDefault { CSSNumericType::BaseType::Time, default_time_value };
}
default:
return {};
}
};
static constexpr auto to_calculation_node = [](StyleValue const& value) -> NonnullOwnPtr<CalculationNode> {
switch (value.type()) {
case StyleValue::Type::Angle:
return NumericCalculationNode::create(value.as_angle().angle());
case StyleValue::Type::Frequency:
return NumericCalculationNode::create(value.as_frequency().frequency());
case StyleValue::Type::Length:
return NumericCalculationNode::create(value.as_length().length());
case StyleValue::Type::Percentage:
return NumericCalculationNode::create(value.as_percentage().percentage());
case StyleValue::Type::Time:
return NumericCalculationNode::create(value.as_time().time());
default:
VERIFY_NOT_REACHED();
}
};
auto from_base_type_and_default = numeric_base_type_and_default(from);
auto to_base_type_and_default = numeric_base_type_and_default(to);
if (from_base_type_and_default.has_value() && to_base_type_and_default.has_value() && (from_base_type_and_default->base_type == CSSNumericType::BaseType::Percent || to_base_type_and_default->base_type == CSSNumericType::BaseType::Percent)) {
// This is an interpolation from a numeric unit to a percentage, or vice versa. The trick here is to
// interpolate two separate values. For example, consider an interpolation from 30px to 80%. It's quite
// hard to understand how this interpolation works, but if instead we rewrite the values as "30px + 0%" and
// "0px + 80%", then it is very simple to understand; we just interpolate each component separately.
auto interpolated_from = interpolate_value(element, from, from_base_type_and_default->default_value, delta);
auto interpolated_to = interpolate_value(element, to_base_type_and_default->default_value, to, delta);
Vector<NonnullOwnPtr<CalculationNode>> values;
values.ensure_capacity(2);
values.unchecked_append(to_calculation_node(interpolated_from));
values.unchecked_append(to_calculation_node(interpolated_to));
auto calc_node = SumCalculationNode::create(move(values));
return CalculatedStyleValue::create(move(calc_node), CSSNumericType { to_base_type_and_default->base_type, 1 });
}
return delta >= 0.5f ? to : from;
}
switch (from.type()) {
case StyleValue::Type::Angle: