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