mirror of
https://github.com/LadybirdBrowser/ladybird.git
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263 lines
11 KiB
C++
263 lines
11 KiB
C++
/*
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* Copyright (c) 2020-2024, Andreas Kling <andreas@ladybird.org>
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* Copyright (c) 2021, Tobias Christiansen <tobyase@serenityos.org>
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* Copyright (c) 2022-2025, Sam Atkins <sam@ladybird.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/NonnullOwnPtr.h>
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#include <AK/Variant.h>
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#include <LibGfx/Font/Font.h>
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#include <LibGfx/Rect.h>
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#include <LibWeb/CSS/Length.h>
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#include <LibWeb/CSS/Percentage.h>
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#include <LibWeb/CSS/StyleComputer.h>
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#include <LibWeb/DOM/Document.h>
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#include <LibWeb/HTML/BrowsingContext.h>
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#include <LibWeb/HTML/Navigable.h>
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#include <LibWeb/HTML/Window.h>
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#include <LibWeb/Layout/Node.h>
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namespace Web::CSS {
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Length::FontMetrics::FontMetrics(CSSPixels font_size, Gfx::FontPixelMetrics const& pixel_metrics, CSSPixels line_height)
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: font_size(font_size)
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, x_height(pixel_metrics.x_height)
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// FIXME: This is only approximately the cap height. The spec suggests measuring the "O" glyph:
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// https://www.w3.org/TR/css-values-4/#cap
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, cap_height(pixel_metrics.ascent)
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, zero_advance(pixel_metrics.advance_of_ascii_zero)
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, line_height(line_height)
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{
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}
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Length Length::percentage_of(Percentage const& percentage) const
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{
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return Length { percentage.as_fraction() * raw_value(), m_unit };
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}
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CSSPixels Length::font_relative_length_to_px(Length::FontMetrics const& font_metrics, Length::FontMetrics const& root_font_metrics) const
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{
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switch (m_unit) {
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case LengthUnit::Em:
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return CSSPixels::nearest_value_for(m_value * font_metrics.font_size.to_double());
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case LengthUnit::Rem:
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return CSSPixels::nearest_value_for(m_value * root_font_metrics.font_size.to_double());
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case LengthUnit::Ex:
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return CSSPixels::nearest_value_for(m_value * font_metrics.x_height.to_double());
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case LengthUnit::Rex:
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return CSSPixels::nearest_value_for(m_value * root_font_metrics.x_height.to_double());
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case LengthUnit::Cap:
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return CSSPixels::nearest_value_for(m_value * font_metrics.cap_height.to_double());
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case LengthUnit::Rcap:
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return CSSPixels::nearest_value_for(m_value * root_font_metrics.cap_height.to_double());
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case LengthUnit::Ch:
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return CSSPixels::nearest_value_for(m_value * font_metrics.zero_advance.to_double());
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case LengthUnit::Rch:
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return CSSPixels::nearest_value_for(m_value * root_font_metrics.zero_advance.to_double());
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case LengthUnit::Ic:
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// FIXME: Use the "advance measure of the “水” (CJK water ideograph, U+6C34) glyph"
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return CSSPixels::nearest_value_for(m_value * font_metrics.font_size.to_double());
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case LengthUnit::Ric:
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// FIXME: Use the "advance measure of the “水” (CJK water ideograph, U+6C34) glyph"
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return CSSPixels::nearest_value_for(m_value * root_font_metrics.font_size.to_double());
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case LengthUnit::Lh:
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return CSSPixels::nearest_value_for(m_value * font_metrics.line_height.to_double());
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case LengthUnit::Rlh:
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return CSSPixels::nearest_value_for(m_value * root_font_metrics.line_height.to_double());
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default:
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VERIFY_NOT_REACHED();
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}
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}
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CSSPixels Length::viewport_relative_length_to_px(CSSPixelRect const& viewport_rect) const
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{
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switch (m_unit) {
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case LengthUnit::Vw:
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case LengthUnit::Svw:
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case LengthUnit::Lvw:
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case LengthUnit::Dvw:
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return viewport_rect.width() * (CSSPixels::nearest_value_for(m_value) / 100);
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case LengthUnit::Vh:
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case LengthUnit::Svh:
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case LengthUnit::Lvh:
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case LengthUnit::Dvh:
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return viewport_rect.height() * (CSSPixels::nearest_value_for(m_value) / 100);
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case LengthUnit::Vi:
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case LengthUnit::Svi:
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case LengthUnit::Lvi:
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case LengthUnit::Dvi:
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// FIXME: Select the width or height based on which is the inline axis.
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return viewport_rect.width() * (CSSPixels::nearest_value_for(m_value) / 100);
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case LengthUnit::Vb:
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case LengthUnit::Svb:
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case LengthUnit::Lvb:
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case LengthUnit::Dvb:
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// FIXME: Select the width or height based on which is the block axis.
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return viewport_rect.height() * (CSSPixels::nearest_value_for(m_value) / 100);
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case LengthUnit::Vmin:
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case LengthUnit::Svmin:
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case LengthUnit::Lvmin:
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case LengthUnit::Dvmin:
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return min(viewport_rect.width(), viewport_rect.height()) * (CSSPixels::nearest_value_for(m_value) / 100);
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case LengthUnit::Vmax:
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case LengthUnit::Svmax:
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case LengthUnit::Lvmax:
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case LengthUnit::Dvmax:
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return max(viewport_rect.width(), viewport_rect.height()) * (CSSPixels::nearest_value_for(m_value) / 100);
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default:
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VERIFY_NOT_REACHED();
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}
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}
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Length::ResolutionContext Length::ResolutionContext::for_element(DOM::AbstractElement const& element)
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{
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auto const* root_element = element.element().document().document_element();
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VERIFY(element.computed_properties());
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VERIFY(root_element);
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VERIFY(root_element->computed_properties());
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return Length::ResolutionContext {
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.viewport_rect = element.element().navigable()->viewport_rect(),
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.font_metrics = { element.computed_properties()->font_size(), element.computed_properties()->first_available_computed_font().pixel_metrics(), element.computed_properties()->line_height() },
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.root_font_metrics = { root_element->computed_properties()->font_size(), root_element->computed_properties()->first_available_computed_font().pixel_metrics(), element.computed_properties()->line_height() }
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};
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}
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Length::ResolutionContext Length::ResolutionContext::for_window(HTML::Window const& window)
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{
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auto const& initial_font = window.associated_document().style_computer().initial_font();
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Gfx::FontPixelMetrics const& initial_font_metrics = initial_font.pixel_metrics();
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Length::FontMetrics font_metrics { CSSPixels { initial_font.pixel_size() }, initial_font_metrics, InitialValues::line_height() };
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return Length::ResolutionContext {
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.viewport_rect = window.page().web_exposed_screen_area(),
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.font_metrics = font_metrics,
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.root_font_metrics = font_metrics,
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};
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}
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Length::ResolutionContext Length::ResolutionContext::for_document(DOM::Document const& document)
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{
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auto const& initial_font = document.style_computer().initial_font();
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Gfx::FontPixelMetrics const& initial_font_metrics = initial_font.pixel_metrics();
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Length::FontMetrics font_metrics { CSSPixels { initial_font.pixel_size() }, initial_font_metrics, InitialValues::line_height() };
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CSSPixelRect viewport_rect;
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if (document.navigable())
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viewport_rect = document.navigable()->viewport_rect();
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return Length::ResolutionContext {
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.viewport_rect = viewport_rect,
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.font_metrics = font_metrics,
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.root_font_metrics = font_metrics,
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};
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}
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Length::ResolutionContext Length::ResolutionContext::for_layout_node(Layout::Node const& node)
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{
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Layout::Node const* root_layout_node;
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if (is<DOM::Document>(node.dom_node())) {
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root_layout_node = &node;
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} else {
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auto const* root_element = node.document().document_element();
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VERIFY(root_element);
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VERIFY(root_element->layout_node());
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root_layout_node = root_element->layout_node();
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}
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return Length::ResolutionContext {
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.viewport_rect = node.navigable()->viewport_rect(),
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.font_metrics = { node.computed_values().font_size(), node.first_available_font().pixel_metrics(), node.computed_values().line_height() },
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.root_font_metrics = { root_layout_node->computed_values().font_size(), root_layout_node->first_available_font().pixel_metrics(), node.computed_values().line_height() },
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};
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}
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CSSPixels Length::to_px(ResolutionContext const& context) const
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{
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return to_px(context.viewport_rect, context.font_metrics, context.root_font_metrics);
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}
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CSSPixels Length::to_px_slow_case(Layout::Node const& layout_node) const
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{
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if (!layout_node.document().browsing_context())
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return 0;
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if (is_font_relative()) {
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auto* root_element = layout_node.document().document_element();
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if (!root_element || !root_element->layout_node())
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return 0;
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FontMetrics font_metrics {
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layout_node.computed_values().font_size(),
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layout_node.first_available_font().pixel_metrics(),
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layout_node.computed_values().line_height()
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};
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FontMetrics root_font_metrics {
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root_element->layout_node()->computed_values().font_size(),
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root_element->layout_node()->first_available_font().pixel_metrics(),
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layout_node.computed_values().line_height()
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};
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return font_relative_length_to_px(font_metrics, root_font_metrics);
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}
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VERIFY(is_viewport_relative());
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auto const& viewport_rect = layout_node.document().viewport_rect();
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return viewport_relative_length_to_px(viewport_rect);
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}
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String Length::to_string(SerializationMode serialization_mode) const
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{
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// https://drafts.csswg.org/cssom/#serialize-a-css-value
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// -> <length>
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// The <number> component serialized as per <number> followed by the unit in its canonical form as defined in its
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// respective specification.
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// FIXME: Manually skip this for px so we avoid rounding errors in absolute_length_to_px.
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// Maybe provide alternative functions that don't produce CSSPixels?
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if (serialization_mode == SerializationMode::ResolvedValue && is_absolute() && m_unit != LengthUnit::Px) {
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StringBuilder builder;
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serialize_a_number(builder, absolute_length_to_px().to_double());
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builder.append("px"sv);
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return builder.to_string_without_validation();
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}
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StringBuilder builder;
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serialize_a_number(builder, m_value);
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builder.append(unit_name());
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return builder.to_string_without_validation();
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}
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Optional<Length> Length::absolutize(CSSPixelRect const& viewport_rect, FontMetrics const& font_metrics, FontMetrics const& root_font_metrics) const
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{
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if (is_px())
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return {};
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if (is_absolute() || is_relative()) {
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auto px = to_px(viewport_rect, font_metrics, root_font_metrics);
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return CSS::Length::make_px(px);
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}
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return {};
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}
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Length Length::absolutized(CSSPixelRect const& viewport_rect, FontMetrics const& font_metrics, FontMetrics const& root_font_metrics) const
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{
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return absolutize(viewport_rect, font_metrics, root_font_metrics).value_or(*this);
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}
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Length Length::resolve_calculated(NonnullRefPtr<CalculatedStyleValue const> const& calculated, Layout::Node const& layout_node, Length const& reference_value)
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{
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CalculationResolutionContext context {
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.percentage_basis = reference_value,
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.length_resolution_context = ResolutionContext::for_layout_node(layout_node),
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};
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return calculated->resolve_length(context).value();
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}
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Length Length::resolve_calculated(NonnullRefPtr<CalculatedStyleValue const> const& calculated, Layout::Node const& layout_node, CSSPixels reference_value)
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{
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return resolve_calculated(calculated, layout_node, make_px(reference_value));
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}
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}
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