mirror of
https://github.com/mozilla/gecko-dev.git
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289 lines
9.6 KiB
C++
289 lines
9.6 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "SVGLength.h"
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#include "mozilla/dom/SVGElement.h"
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#include "nsCSSValue.h"
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#include "nsTextFormatter.h"
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#include "SVGContentUtils.h"
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#include <limits>
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#include <algorithm>
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using namespace mozilla::dom;
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using namespace mozilla::dom::SVGLength_Binding;
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namespace mozilla {
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// These types are numbered so that different length categories are in
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// contiguous ranges - See `SVGLength::Is[..]Unit()`.
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const unsigned short SVG_LENGTHTYPE_Q = 11;
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const unsigned short SVG_LENGTHTYPE_CH = 12;
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const unsigned short SVG_LENGTHTYPE_REM = 13;
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const unsigned short SVG_LENGTHTYPE_IC = 14;
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const unsigned short SVG_LENGTHTYPE_CAP = 15;
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const unsigned short SVG_LENGTHTYPE_LH = 16;
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const unsigned short SVG_LENGTHTYPE_RLH = 17;
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const unsigned short SVG_LENGTHTYPE_VW = 18;
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const unsigned short SVG_LENGTHTYPE_VH = 19;
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const unsigned short SVG_LENGTHTYPE_VMIN = 20;
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const unsigned short SVG_LENGTHTYPE_VMAX = 21;
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void SVGLength::GetValueAsString(nsAString& aValue) const {
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nsTextFormatter::ssprintf(aValue, u"%g", (double)mValue);
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nsAutoString unitString;
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GetUnitString(unitString, mUnit);
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aValue.Append(unitString);
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}
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bool SVGLength::SetValueFromString(const nsAString& aString) {
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bool success;
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auto token = SVGContentUtils::GetAndEnsureOneToken(aString, success);
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if (!success) {
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return false;
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}
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RangedPtr<const char16_t> iter = SVGContentUtils::GetStartRangedPtr(token);
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const RangedPtr<const char16_t> end = SVGContentUtils::GetEndRangedPtr(token);
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float value;
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if (!SVGContentUtils::ParseNumber(iter, end, value)) {
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return false;
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}
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const nsAString& units = Substring(iter.get(), end.get());
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uint16_t unitType = GetUnitTypeForString(units);
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if (unitType == SVG_LENGTHTYPE_UNKNOWN) {
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return false;
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}
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mValue = value;
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mUnit = uint8_t(unitType);
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return true;
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}
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/*static*/
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bool SVGLength::IsAbsoluteUnit(uint8_t aUnit) {
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return aUnit == SVG_LENGTHTYPE_NUMBER ||
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(aUnit >= SVG_LENGTHTYPE_PX && aUnit <= SVG_LENGTHTYPE_Q);
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}
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/*static*/
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bool SVGLength::IsFontRelativeUnit(uint8_t aUnit) {
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return aUnit == SVG_LENGTHTYPE_EMS || aUnit == SVG_LENGTHTYPE_EXS ||
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(aUnit >= SVG_LENGTHTYPE_CH && aUnit <= SVG_LENGTHTYPE_RLH);
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}
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/**
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* Helper to convert between different CSS absolute units without the need for
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* an element, which provides more flexibility at the DOM level (and without
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* the need for an intermediary conversion to user units, which avoids
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* unnecessary overhead and rounding error).
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*
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* Example usage: to find out how many centimeters there are per inch:
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*
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* GetAbsUnitsPerAbsUnit(SVG_LENGTHTYPE_CM, SVG_LENGTHTYPE_IN)
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*/
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/*static*/
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float SVGLength::GetAbsUnitsPerAbsUnit(uint8_t aUnits, uint8_t aPerUnit) {
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MOZ_ASSERT(SVGLength::IsAbsoluteUnit(aUnits), "Not a CSS absolute unit");
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MOZ_ASSERT(SVGLength::IsAbsoluteUnit(aPerUnit), "Not a CSS absolute unit");
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static const float CSSAbsoluteUnitConversionFactors[7][7] = {
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// columns: px, cm, mm, in, pt, pc, q
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// px per...:
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{1.0f, 37.7952755906f, 3.779528f, 96.0f, 1.33333333333333333f, 16.0f,
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0.94488188988f},
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// cm per...:
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{0.02645833333f, 1.0f, 0.1f, 2.54f, 0.035277777777777778f,
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0.42333333333333333f, 0.025f},
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// mm per...:
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{0.26458333333f, 10.0f, 1.0f, 25.4f, 0.35277777777777778f,
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4.2333333333333333f, 0.25f},
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// in per...:
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{0.01041666666f, 0.39370078740157481f, 0.039370078740157481f, 1.0f,
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0.013888888888888889f, 0.16666666666666667f, 0.02204860853f},
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// pt per...:
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{0.75f, 28.346456692913386f, 2.8346456692913386f, 72.0f, 1.0f, 12.0f,
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0.70866141732f},
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// pc per...:
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{0.0625f, 2.3622047244094489f, 0.23622047244094489f, 6.0f,
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0.083333333333333333f, 1.0f, 16.9333333333f},
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// q per...:
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{1.0583333332f, 40.0f, 4.0f, 45.354336f, 1.41111111111f, 16.9333333333f,
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1.0f}};
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auto ToIndex = [](uint8_t aUnit) {
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return aUnit == SVG_LENGTHTYPE_NUMBER ? 0 : aUnit - 5;
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};
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return CSSAbsoluteUnitConversionFactors[ToIndex(aUnits)][ToIndex(aPerUnit)];
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}
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float SVGLength::GetValueInSpecifiedUnit(uint8_t aUnit,
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const SVGElement* aElement,
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uint8_t aAxis) const {
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if (aUnit == mUnit) {
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return mValue;
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}
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if ((aUnit == SVG_LENGTHTYPE_NUMBER && mUnit == SVG_LENGTHTYPE_PX) ||
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(aUnit == SVG_LENGTHTYPE_PX && mUnit == SVG_LENGTHTYPE_NUMBER)) {
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return mValue;
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}
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if (IsAbsoluteUnit(aUnit) && IsAbsoluteUnit(mUnit)) {
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return mValue * GetAbsUnitsPerAbsUnit(aUnit, mUnit);
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}
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// Otherwise we do a two step conversion via user units. This can only
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// succeed if aElement is non-null (although that's not sufficient to
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// guarantee success).
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SVGElementMetrics userSpaceMetrics(aElement);
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float userUnitsPerCurrentUnit = GetPixelsPerUnit(userSpaceMetrics, aAxis);
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float userUnitsPerNewUnit =
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SVGLength(0.0f, aUnit).GetPixelsPerUnit(userSpaceMetrics, aAxis);
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float value = mValue * userUnitsPerCurrentUnit / userUnitsPerNewUnit;
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// userUnitsPerCurrentUnit could be infinity, or userUnitsPerNewUnit could
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// be zero.
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if (std::isfinite(value)) {
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return value;
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}
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return std::numeric_limits<float>::quiet_NaN();
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}
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// Helpers:
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enum class ZoomType { Self, SelfFromRoot, None };
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/*static*/
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float SVGLength::GetPixelsPerUnit(const UserSpaceMetrics& aMetrics,
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uint8_t aUnitType, uint8_t aAxis,
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bool aApplyZoom) {
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auto zoomType = ZoomType::Self;
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float value = [&]() -> float {
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switch (aUnitType) {
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case SVG_LENGTHTYPE_NUMBER:
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case SVG_LENGTHTYPE_PX:
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return 1.0f;
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case SVG_LENGTHTYPE_PERCENTAGE:
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zoomType = ZoomType::None;
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return aMetrics.GetAxisLength(aAxis) / 100.0f;
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case SVG_LENGTHTYPE_EMS:
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zoomType = ZoomType::None;
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return aMetrics.GetEmLength(UserSpaceMetrics::Type::This);
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case SVG_LENGTHTYPE_EXS:
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zoomType = ZoomType::None;
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return aMetrics.GetExLength(UserSpaceMetrics::Type::This);
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case SVG_LENGTHTYPE_CH:
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zoomType = ZoomType::None;
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return aMetrics.GetChSize(UserSpaceMetrics::Type::This);
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case SVG_LENGTHTYPE_REM:
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zoomType = ZoomType::SelfFromRoot;
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return aMetrics.GetEmLength(UserSpaceMetrics::Type::Root);
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case SVG_LENGTHTYPE_IC:
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zoomType = ZoomType::None;
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return aMetrics.GetIcWidth(UserSpaceMetrics::Type::This);
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case SVG_LENGTHTYPE_CAP:
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zoomType = ZoomType::None;
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return aMetrics.GetCapHeight(UserSpaceMetrics::Type::This);
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case SVG_LENGTHTYPE_VW:
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return aMetrics.GetCSSViewportSize().width / 100.f;
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case SVG_LENGTHTYPE_VH:
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return aMetrics.GetCSSViewportSize().height / 100.f;
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case SVG_LENGTHTYPE_VMIN: {
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auto sz = aMetrics.GetCSSViewportSize();
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return std::min(sz.width, sz.height) / 100.f;
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}
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case SVG_LENGTHTYPE_VMAX: {
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auto sz = aMetrics.GetCSSViewportSize();
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return std::max(sz.width, sz.height) / 100.f;
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}
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case SVG_LENGTHTYPE_LH:
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zoomType = ZoomType::None;
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return aMetrics.GetLineHeight(UserSpaceMetrics::Type::This);
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case SVG_LENGTHTYPE_RLH:
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zoomType = ZoomType::SelfFromRoot;
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return aMetrics.GetLineHeight(UserSpaceMetrics::Type::Root);
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default:
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MOZ_ASSERT(IsAbsoluteUnit(aUnitType));
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return GetAbsUnitsPerAbsUnit(SVG_LENGTHTYPE_PX, aUnitType);
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}
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}();
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if (aApplyZoom) {
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switch (zoomType) {
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case ZoomType::None:
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break;
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case ZoomType::Self:
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value *= aMetrics.GetZoom();
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break;
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case ZoomType::SelfFromRoot:
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value *= aMetrics.GetZoom() / aMetrics.GetRootZoom();
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break;
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}
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}
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return value;
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}
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/* static */
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nsCSSUnit SVGLength::SpecifiedUnitTypeToCSSUnit(uint8_t aSpecifiedUnit) {
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switch (aSpecifiedUnit) {
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#define SVG_LENGTH_EMPTY_UNIT(id, cssValue) \
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case id: \
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return cssValue;
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#define SVG_LENGTH_UNIT(id, name, cssValue) SVG_LENGTH_EMPTY_UNIT(id, cssValue)
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#include "mozilla/dom/SVGLengthUnits.h"
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#undef SVG_LENGTH_UNIT
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#undef SVG_LENGTH_EMPTY_UNIT
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default:
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MOZ_ASSERT_UNREACHABLE("Unknown unit type");
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return nsCSSUnit::eCSSUnit_Pixel;
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}
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}
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/* static */
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void SVGLength::GetUnitString(nsAString& aUnit, uint16_t aUnitType) {
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switch (aUnitType) {
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#define SVG_LENGTH_EMPTY_UNIT(id, cssValue) \
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case id: \
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aUnit.Truncate(); \
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return;
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#define SVG_LENGTH_UNIT(id, name, cssValue) \
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case id: \
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aUnit.AssignLiteral(name); \
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return;
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#include "mozilla/dom/SVGLengthUnits.h"
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#undef SVG_LENGTH_UNIT
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#undef SVG_LENGTH_EMPTY_UNIT
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}
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MOZ_ASSERT_UNREACHABLE(
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"Unknown unit type! Someone's using an SVGLength "
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"with an invalid unit?");
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}
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/* static */
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uint16_t SVGLength::GetUnitTypeForString(const nsAString& aUnit) {
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#define SVG_LENGTH_EMPTY_UNIT(id, cssValue) \
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if (aUnit.IsEmpty()) { \
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return id; \
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}
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#define SVG_LENGTH_UNIT(id, name, cssValue) \
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if (aUnit.LowerCaseEqualsLiteral(name)) { \
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return id; \
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}
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#include "mozilla/dom/SVGLengthUnits.h"
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#undef SVG_LENGTH_UNIT
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#undef SVG_LENGTH_EMPTY_UNIT
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return SVG_LENGTHTYPE_UNKNOWN;
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}
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} // namespace mozilla
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