ladybird/Libraries/LibWeb/CSS/StyleInvalidation.cpp
Andreas Kling c1cad8fa0e LibWeb: Rename CSS::StyleProperties => CSS::ComputedProperties
Now that StyleProperties is only used to hold computed properties, let's
name it ComputedProperties.
2024-12-22 10:12:49 +01:00

61 lines
3 KiB
C++

/*
* Copyright (c) 2024, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibWeb/CSS/ComputedProperties.h>
#include <LibWeb/CSS/StyleInvalidation.h>
namespace Web::CSS {
RequiredInvalidationAfterStyleChange compute_property_invalidation(CSS::PropertyID property_id, RefPtr<CSSStyleValue const> const& old_value, RefPtr<CSSStyleValue const> const& new_value)
{
RequiredInvalidationAfterStyleChange invalidation;
bool const property_value_changed = (!old_value || !new_value) || *old_value != *new_value;
if (!property_value_changed)
return invalidation;
// NOTE: If the computed CSS display, content, or content-visibility property changes, we have to rebuild the entire layout tree.
// In the future, we should figure out ways to rebuild a smaller part of the tree.
if (AK::first_is_one_of(property_id, CSS::PropertyID::Display, CSS::PropertyID::Content, CSS::PropertyID::ContentVisibility)) {
return RequiredInvalidationAfterStyleChange::full();
}
// NOTE: If one of the overflow properties change, we rebuild the entire layout tree.
// This ensures that overflow propagation from root/body to viewport happens correctly.
// In the future, we can make this invalidation narrower.
if (property_id == CSS::PropertyID::OverflowX || property_id == CSS::PropertyID::OverflowY) {
return RequiredInvalidationAfterStyleChange::full();
}
// OPTIMIZATION: Special handling for CSS `visibility`:
if (property_id == CSS::PropertyID::Visibility) {
// We don't need to relayout if the visibility changes from visible to hidden or vice versa. Only collapse requires relayout.
if ((old_value && old_value->to_keyword() == CSS::Keyword::Collapse) != (new_value && new_value->to_keyword() == CSS::Keyword::Collapse))
invalidation.relayout = true;
// Of course, we still have to repaint on any visibility change.
invalidation.repaint = true;
} else if (CSS::property_affects_layout(property_id)) {
invalidation.relayout = true;
}
if (property_id == CSS::PropertyID::Opacity && old_value && new_value) {
// OPTIMIZATION: An element creates a stacking context when its opacity changes from 1 to less than 1
// and stops to create one when opacity returns to 1. So stacking context tree rebuild is
// not required for opacity changes within the range below 1.
auto old_value_opacity = CSS::ComputedProperties::resolve_opacity_value(*old_value);
auto new_value_opacity = CSS::ComputedProperties::resolve_opacity_value(*new_value);
if (old_value_opacity != new_value_opacity && (old_value_opacity == 1 || new_value_opacity == 1)) {
invalidation.rebuild_stacking_context_tree = true;
}
} else if (CSS::property_affects_stacking_context(property_id)) {
invalidation.rebuild_stacking_context_tree = true;
}
invalidation.repaint = true;
return invalidation;
}
}