Files
ladybird/Libraries/LibWeb/SVG/SVGPatternElement.cpp
Aliaksandr Kalenik 568b7ce7ea LibWeb: Make Paintable tree ref-counted
The Paintable tree and its supplemental painting data structures were
GC allocated because that was the easiest way to manage it and avoid
leaks introduced by ref cycles. This included the Paintable subclasses
themselves plus StackingContext, ChromeWidget, Scrollbar, ResizeHandle,
and scroll-frame state.

We are now trying to reduce GC allocation churn on layout and painting
updates, so keeping this short-lived rendering tree outside the JS heap
is a better fit. Move Paintable to RefCountedTreeNode, make painting
helpers ref-counted or weakly reference Paintables, and update the
layout and event-handler call sites to use RefPtr/WeakPtr ownership.
2026-05-07 15:03:44 +02:00

381 lines
16 KiB
C++

/*
* Copyright (c) 2026, Tim Ledbetter <tim.ledbetter@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibGfx/Matrix4x4.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/Bindings/SVGPatternElement.h>
#include <LibWeb/CSS/ComputedProperties.h>
#include <LibWeb/DOM/Document.h>
#include <LibWeb/Layout/SVGPatternBox.h>
#include <LibWeb/Layout/SVGSVGBox.h>
#include <LibWeb/Painting/DisplayList.h>
#include <LibWeb/Painting/DisplayListRecorder.h>
#include <LibWeb/Painting/DisplayListRecordingContext.h>
#include <LibWeb/Painting/PaintStyle.h>
#include <LibWeb/Painting/SVGGraphicsPaintable.h>
#include <LibWeb/Painting/StackingContext.h>
#include <LibWeb/SVG/AttributeNames.h>
#include <LibWeb/SVG/AttributeParser.h>
#include <LibWeb/SVG/SVGGraphicsElement.h>
#include <LibWeb/SVG/SVGPatternElement.h>
namespace Web::SVG {
GC_DEFINE_ALLOCATOR(SVGPatternElement);
SVGPatternElement::SVGPatternElement(DOM::Document& document, DOM::QualifiedName qualified_name)
: SVGElement(document, move(qualified_name))
{
}
void SVGPatternElement::initialize(JS::Realm& realm)
{
WEB_SET_PROTOTYPE_FOR_INTERFACE(SVGPatternElement);
Base::initialize(realm);
SVGFitToViewBox::initialize(realm);
}
void SVGPatternElement::visit_edges(Cell::Visitor& visitor)
{
Base::visit_edges(visitor);
SVGURIReferenceMixin::visit_edges(visitor);
SVGFitToViewBox::visit_edges(visitor);
}
void SVGPatternElement::attribute_changed(FlyString const& name, Optional<String> const& old_value, Optional<String> const& value, Optional<FlyString> const& namespace_)
{
Base::attribute_changed(name, old_value, value, namespace_);
SVGFitToViewBox::attribute_changed(*this, name, value);
if (name == AttributeNames::patternUnits) {
m_pattern_units = AttributeParser::parse_units(value.value_or(String {}));
} else if (name == AttributeNames::patternContentUnits) {
m_pattern_content_units = AttributeParser::parse_units(value.value_or(String {}));
} else if (name == AttributeNames::patternTransform) {
if (auto transform_list = AttributeParser::parse_transform(value.value_or(String {})); transform_list.has_value()) {
m_pattern_transform = transform_from_transform_list(*transform_list);
} else {
m_pattern_transform = {};
}
} else if (name == AttributeNames::x) {
m_x = AttributeParser::parse_number_percentage(value.value_or(String {}));
} else if (name == AttributeNames::y) {
m_y = AttributeParser::parse_number_percentage(value.value_or(String {}));
} else if (name == AttributeNames::width) {
m_width = AttributeParser::parse_number_percentage(value.value_or(String {}));
} else if (name == AttributeNames::height) {
m_height = AttributeParser::parse_number_percentage(value.value_or(String {}));
}
}
GC::Ptr<SVGPatternElement const> SVGPatternElement::linked_pattern(HashTable<SVGPatternElement const*>& seen_patterns) const
{
// FIXME: This can only resolve same-document references. The spec allows cross-document references.
auto link = has_attribute(AttributeNames::href) ? get_attribute(AttributeNames::href) : get_attribute("xlink:href"_fly_string);
if (!link.has_value() || link->is_empty())
return {};
auto url = document().encoding_parse_url(*link);
if (!url.has_value())
return {};
auto id = url->fragment();
if (!id.has_value() || id->is_empty())
return {};
auto element = document().get_element_by_id(id.value());
if (!element)
return {};
if (element == this)
return {};
auto* pattern = as_if<SVGPatternElement>(*element);
if (!pattern)
return {};
// Detect circular references in the template chain.
if (seen_patterns.set(pattern) != AK::HashSetResult::InsertedNewEntry)
return {};
return pattern;
}
GC::Ptr<SVGPatternElement const> SVGPatternElement::pattern_content_element() const
{
HashTable<SVGPatternElement const*> seen_patterns;
return pattern_content_element_impl(seen_patterns);
}
GC::Ptr<SVGPatternElement const> SVGPatternElement::pattern_content_element_impl(HashTable<SVGPatternElement const*>& seen_patterns) const
{
if (child_element_count() > 0)
return this;
if (auto pattern = linked_pattern(seen_patterns))
return pattern->pattern_content_element_impl(seen_patterns);
return {};
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementPatternUnitsAttribute
SVGUnits SVGPatternElement::pattern_units() const
{
HashTable<SVGPatternElement const*> seen_patterns;
return pattern_units_impl(seen_patterns);
}
SVGUnits SVGPatternElement::pattern_units_impl(HashTable<SVGPatternElement const*>& seen_patterns) const
{
if (m_pattern_units.has_value())
return *m_pattern_units;
if (auto pattern = linked_pattern(seen_patterns))
return pattern->pattern_units_impl(seen_patterns);
// Initial value: objectBoundingBox
return SVGUnits::ObjectBoundingBox;
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementPatternContentUnitsAttribute
SVGUnits SVGPatternElement::pattern_content_units() const
{
HashTable<SVGPatternElement const*> seen_patterns;
return pattern_content_units_impl(seen_patterns);
}
SVGUnits SVGPatternElement::pattern_content_units_impl(HashTable<SVGPatternElement const*>& seen_patterns) const
{
if (m_pattern_content_units.has_value())
return *m_pattern_content_units;
if (auto pattern = linked_pattern(seen_patterns))
return pattern->pattern_content_units_impl(seen_patterns);
// Initial value: userSpaceOnUse
return SVGUnits::UserSpaceOnUse;
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementPatternTransformAttribute
Optional<Gfx::AffineTransform> SVGPatternElement::pattern_transform() const
{
HashTable<SVGPatternElement const*> seen_patterns;
return pattern_transform_impl(seen_patterns);
}
Optional<Gfx::AffineTransform> SVGPatternElement::pattern_transform_impl(HashTable<SVGPatternElement const*>& seen_patterns) const
{
if (m_pattern_transform.has_value())
return m_pattern_transform;
if (auto pattern = linked_pattern(seen_patterns))
return pattern->pattern_transform_impl(seen_patterns);
return {};
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementXAttribute
NumberPercentage SVGPatternElement::pattern_x() const
{
HashTable<SVGPatternElement const*> seen_patterns;
return pattern_x_impl(seen_patterns);
}
NumberPercentage SVGPatternElement::pattern_x_impl(HashTable<SVGPatternElement const*>& seen_patterns) const
{
if (m_x.has_value())
return *m_x;
if (auto pattern = linked_pattern(seen_patterns))
return pattern->pattern_x_impl(seen_patterns);
return NumberPercentage::create_number(0);
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementYAttribute
NumberPercentage SVGPatternElement::pattern_y() const
{
HashTable<SVGPatternElement const*> seen_patterns;
return pattern_y_impl(seen_patterns);
}
NumberPercentage SVGPatternElement::pattern_y_impl(HashTable<SVGPatternElement const*>& seen_patterns) const
{
if (m_y.has_value())
return *m_y;
if (auto pattern = linked_pattern(seen_patterns))
return pattern->pattern_y_impl(seen_patterns);
return NumberPercentage::create_number(0);
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementWidthAttribute
NumberPercentage SVGPatternElement::pattern_width() const
{
HashTable<SVGPatternElement const*> seen_patterns;
return pattern_width_impl(seen_patterns);
}
NumberPercentage SVGPatternElement::pattern_width_impl(HashTable<SVGPatternElement const*>& seen_patterns) const
{
if (m_width.has_value())
return *m_width;
if (auto pattern = linked_pattern(seen_patterns))
return pattern->pattern_width_impl(seen_patterns);
return NumberPercentage::create_number(0);
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementHeightAttribute
NumberPercentage SVGPatternElement::pattern_height() const
{
HashTable<SVGPatternElement const*> seen_patterns;
return pattern_height_impl(seen_patterns);
}
NumberPercentage SVGPatternElement::pattern_height_impl(HashTable<SVGPatternElement const*>& seen_patterns) const
{
if (m_height.has_value())
return *m_height;
if (auto pattern = linked_pattern(seen_patterns))
return pattern->pattern_height_impl(seen_patterns);
return NumberPercentage::create_number(0);
}
Optional<Painting::PaintStyle> SVGPatternElement::to_gfx_paint_style(SVGPaintContext const& paint_context, DisplayListRecordingContext& recording_context, Layout::Node const& target_layout_node) const
{
auto content_element = pattern_content_element();
if (!content_element)
return {};
Layout::SVGPatternBox const* pattern_box = nullptr;
target_layout_node.for_each_child_of_type<Layout::SVGPatternBox>([&](auto const& candidate) {
if (&candidate.dom_node() == content_element.ptr()) {
pattern_box = &candidate;
return IterationDecision::Break;
}
return IterationDecision::Continue;
});
if (!pattern_box)
return {};
auto pattern_paintable = pattern_box->paintable_box();
if (!pattern_paintable)
return {};
float tile_x = 0;
float tile_y = 0;
float tile_width = 0;
float tile_height = 0;
if (pattern_units() == SVGUnits::ObjectBoundingBox) {
// For objectBoundingBox, values are fractions of the bounding box.
// NumberPercentage::value() already normalizes percentages to 0-1 range.
auto const& bbox = paint_context.path_bounding_box;
tile_x = pattern_x().value() * bbox.width() + bbox.x();
tile_y = pattern_y().value() * bbox.height() + bbox.y();
tile_width = pattern_width().value() * bbox.width();
tile_height = pattern_height().value() * bbox.height();
} else {
// For userSpaceOnUse, resolve percentages relative to the viewport.
auto const& viewport = paint_context.viewport;
tile_x = pattern_x().resolve_relative_to(viewport.width());
tile_y = pattern_y().resolve_relative_to(viewport.height());
tile_width = pattern_width().resolve_relative_to(viewport.width());
tile_height = pattern_height().resolve_relative_to(viewport.height());
}
if (tile_width <= 0 || tile_height <= 0)
return {};
auto tile_rect = paint_context.paint_transform.map(Gfx::FloatRect { tile_x, tile_y, tile_width, tile_height });
if (tile_rect.is_empty())
return {};
auto const* svg_node = target_layout_node.first_ancestor_of_type<Layout::SVGSVGBox>();
if (!svg_node || !svg_node->paintable_box())
return {};
auto svg_element_rect = svg_node->paintable_box()->absolute_rect();
auto svg_offset = recording_context.rounded_device_point(svg_element_rect.location()).to_type<int>().to_type<float>();
tile_rect.translate_by(svg_offset);
auto display_list = Painting::DisplayList::create(Painting::AccumulatedVisualContextTree::create());
Painting::DisplayListRecorder display_list_recorder(*display_list);
auto content_origin = paint_context.paint_transform.map(Gfx::FloatPoint { 0, 0 }) + svg_offset;
display_list_recorder.translate(-Gfx::IntPoint(content_origin.to_type<int>()));
auto paint_context_copy = recording_context.clone(display_list_recorder);
Gfx::AffineTransform target_svg_transform;
auto first_paintable = target_layout_node.first_paintable();
if (auto const* svg_graphics_paintable = as_if<Painting::SVGGraphicsPaintable>(first_paintable.ptr()))
target_svg_transform = svg_graphics_paintable->computed_transforms().svg_transform();
paint_context_copy.set_svg_transform(target_svg_transform);
Painting::StackingContext::paint_svg(paint_context_copy, *pattern_paintable, Painting::PaintPhase::Foreground);
Optional<Gfx::AffineTransform> user_space_pattern_transform;
auto css_transformations = computed_properties()->transformations();
if (!css_transformations.is_empty()) {
auto matrix = Gfx::FloatMatrix4x4::identity();
bool transform_valid = true;
for (auto const& css_transform : css_transformations) {
auto result = css_transform->to_matrix(*pattern_paintable);
if (result.is_error()) {
transform_valid = false;
break;
}
matrix = matrix * result.release_value();
}
if (transform_valid)
user_space_pattern_transform = extract_2d_affine_transform(matrix);
} else {
user_space_pattern_transform = pattern_transform();
}
Optional<Gfx::AffineTransform> device_pattern_transform;
if (user_space_pattern_transform.has_value()) {
if (!user_space_pattern_transform->inverse().has_value())
return {};
// patternTransform is defined in user space, but the tile rect and shader operate in device pixel space.
// Convert by conjugating with paint_transform.
if (auto inv = paint_context.paint_transform.inverse(); inv.has_value()) {
auto transform = paint_context.paint_transform;
device_pattern_transform = transform.multiply(*user_space_pattern_transform).multiply(*inv);
}
}
return Painting::SVGPatternPaintStyle::create(display_list, tile_rect, device_pattern_transform);
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementXAttribute
GC::Ref<SVGAnimatedLength> SVGPatternElement::x() const
{
// FIXME: Populate the unit type when it is parsed (0 here is "unknown").
// FIXME: Create a proper animated value when animations are supported.
auto base_length = SVGLength::create(realm(), 0, m_x.value_or(NumberPercentage::create_number(0)).value(), SVGLength::ReadOnly::No);
auto anim_length = SVGLength::create(realm(), 0, m_x.value_or(NumberPercentage::create_number(0)).value(), SVGLength::ReadOnly::Yes);
return SVGAnimatedLength::create(realm(), base_length, anim_length);
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementYAttribute
GC::Ref<SVGAnimatedLength> SVGPatternElement::y() const
{
// FIXME: Populate the unit type when it is parsed (0 here is "unknown").
// FIXME: Create a proper animated value when animations are supported.
auto base_length = SVGLength::create(realm(), 0, m_y.value_or(NumberPercentage::create_number(0)).value(), SVGLength::ReadOnly::No);
auto anim_length = SVGLength::create(realm(), 0, m_y.value_or(NumberPercentage::create_number(0)).value(), SVGLength::ReadOnly::Yes);
return SVGAnimatedLength::create(realm(), base_length, anim_length);
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementWidthAttribute
GC::Ref<SVGAnimatedLength> SVGPatternElement::width() const
{
// FIXME: Populate the unit type when it is parsed (0 here is "unknown").
// FIXME: Create a proper animated value when animations are supported.
auto base_length = SVGLength::create(realm(), 0, m_width.value_or(NumberPercentage::create_number(0)).value(), SVGLength::ReadOnly::No);
auto anim_length = SVGLength::create(realm(), 0, m_width.value_or(NumberPercentage::create_number(0)).value(), SVGLength::ReadOnly::Yes);
return SVGAnimatedLength::create(realm(), base_length, anim_length);
}
// https://svgwg.org/svg2-draft/pservers.html#PatternElementHeightAttribute
GC::Ref<SVGAnimatedLength> SVGPatternElement::height() const
{
// FIXME: Populate the unit type when it is parsed (0 here is "unknown").
// FIXME: Create a proper animated value when animations are supported.
auto base_length = SVGLength::create(realm(), 0, m_height.value_or(NumberPercentage::create_number(0)).value(), SVGLength::ReadOnly::No);
auto anim_length = SVGLength::create(realm(), 0, m_height.value_or(NumberPercentage::create_number(0)).value(), SVGLength::ReadOnly::Yes);
return SVGAnimatedLength::create(realm(), base_length, anim_length);
}
}