Files
ladybird/Libraries/LibWeb/SVG/SVGCircleElement.cpp
Andreas Kling ed7f4664c2 LibWeb: Split StyleComputer work into two phases with separate outputs
Before this change, StyleComputer would essentially take a DOM element,
find all the CSS rules that apply to it, and resolve the computed value
for each CSS property for that element.

This worked great, but it meant we had to do all the work of selector
matching and cascading every time.

To enable new optimizations, this change introduces a break in the
middle of this process where we've produced a "CascadedProperties".
This object contains the result of the cascade, before we've begun
turning cascaded values into computed values.

The cascaded properties are now stored with each element, which will
later allow us to do partial updates without re-running the full
StyleComputer machine. This will be particularly valuable for
re-implementing CSS inheritance, which is extremely heavy today.

Note that CSS animations and CSS transitions operate entirely on the
computed values, even though the cascade order would have you believe
they happen earlier. I'm not confident we have the right architecture
for this, but that's a separate issue.
2024-12-22 10:12:49 +01:00

104 lines
3.6 KiB
C++

/*
* Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibGfx/Path.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/Bindings/SVGCircleElementPrototype.h>
#include <LibWeb/CSS/Parser/Parser.h>
#include <LibWeb/Layout/Node.h>
#include <LibWeb/SVG/AttributeNames.h>
#include <LibWeb/SVG/AttributeParser.h>
#include <LibWeb/SVG/SVGCircleElement.h>
#include <LibWeb/SVG/SVGViewport.h>
namespace Web::SVG {
GC_DEFINE_ALLOCATOR(SVGCircleElement);
SVGCircleElement::SVGCircleElement(DOM::Document& document, DOM::QualifiedName qualified_name)
: SVGGeometryElement(document, qualified_name)
{
}
void SVGCircleElement::initialize(JS::Realm& realm)
{
Base::initialize(realm);
WEB_SET_PROTOTYPE_FOR_INTERFACE(SVGCircleElement);
}
void SVGCircleElement::apply_presentational_hints(GC::Ref<CSS::CascadedProperties> cascaded_properties) const
{
Base::apply_presentational_hints(cascaded_properties);
auto parsing_context = CSS::Parser::ParsingContext { document(), CSS::Parser::ParsingContext::Mode::SVGPresentationAttribute };
auto cx_attribute = attribute(SVG::AttributeNames::cx);
if (auto cx_value = parse_css_value(parsing_context, cx_attribute.value_or(String {}), CSS::PropertyID::Cx))
cascaded_properties->set_property_from_presentational_hint(CSS::PropertyID::Cx, cx_value.release_nonnull());
auto cy_attribute = attribute(SVG::AttributeNames::cy);
if (auto cy_value = parse_css_value(parsing_context, cy_attribute.value_or(String {}), CSS::PropertyID::Cy))
cascaded_properties->set_property_from_presentational_hint(CSS::PropertyID::Cy, cy_value.release_nonnull());
auto r_attribute = attribute(SVG::AttributeNames::r);
if (auto r_value = parse_css_value(parsing_context, r_attribute.value_or(String {}), CSS::PropertyID::R))
cascaded_properties->set_property_from_presentational_hint(CSS::PropertyID::R, r_value.release_nonnull());
}
Gfx::Path SVGCircleElement::get_path(CSSPixelSize viewport_size)
{
auto node = layout_node();
auto cx = float(node->computed_values().cx().to_px(*node, viewport_size.width()));
auto cy = float(node->computed_values().cy().to_px(*node, viewport_size.height()));
// Percentages refer to the normalized diagonal of the current SVG viewport
// (see Units: https://svgwg.org/svg2-draft/coords.html#Units)
auto r = float(node->computed_values().r().to_px(*node, normalized_diagonal_length(viewport_size)));
// A zero radius disables rendering.
if (r == 0)
return {};
Gfx::Path path;
bool large_arc = false;
bool sweep = true;
// 1. A move-to command to the point cx+r,cy;
path.move_to({ cx + r, cy });
// 2. arc to cx,cy+r;
path.arc_to({ cx, cy + r }, r, large_arc, sweep);
// 3. arc to cx-r,cy;
path.arc_to({ cx - r, cy }, r, large_arc, sweep);
// 4. arc to cx,cy-r;
path.arc_to({ cx, cy - r }, r, large_arc, sweep);
// 5. arc with a segment-completing close path operation.
path.arc_to({ cx + r, cy }, r, large_arc, sweep);
return path;
}
// https://www.w3.org/TR/SVG11/shapes.html#CircleElementCXAttribute
GC::Ref<SVGAnimatedLength> SVGCircleElement::cx() const
{
return svg_animated_length_for_property(CSS::PropertyID::Cx);
}
// https://www.w3.org/TR/SVG11/shapes.html#CircleElementCYAttribute
GC::Ref<SVGAnimatedLength> SVGCircleElement::cy() const
{
return svg_animated_length_for_property(CSS::PropertyID::Cy);
}
// https://www.w3.org/TR/SVG11/shapes.html#CircleElementRAttribute
GC::Ref<SVGAnimatedLength> SVGCircleElement::r() const
{
return svg_animated_length_for_property(CSS::PropertyID::R);
}
}