Source code
Revision control
Copy as Markdown
Other Tools
/* -*- 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/ArrayUtils.h"
#include "mozilla/dom/SVGElement.h"
#include "mozilla/dom/SVGSVGElement.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 {
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_VW = 16;
const unsigned short SVG_LENGTHTYPE_VH = 17;
const unsigned short SVG_LENGTHTYPE_VMIN = 18;
const unsigned short SVG_LENGTHTYPE_VMAX = 19;
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;
}
RangedPtr<const char16_t> iter = SVGContentUtils::GetStartRangedPtr(token);
const RangedPtr<const char16_t> end = SVGContentUtils::GetEndRangedPtr(token);
float value;
if (!SVGContentUtils::ParseNumber(iter, end, value)) {
return false;
}
const nsAString& units = Substring(iter.get(), end.get());
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_CAP);
}
/**
* 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:
/*static*/
float SVGLength::GetPixelsPerUnit(const UserSpaceMetrics& aMetrics,
uint8_t aUnitType, uint8_t aAxis) {
switch (aUnitType) {
case SVG_LENGTHTYPE_NUMBER:
case SVG_LENGTHTYPE_PX:
return 1.0f;
case SVG_LENGTHTYPE_PERCENTAGE:
return aMetrics.GetAxisLength(aAxis) / 100.0f;
case SVG_LENGTHTYPE_EMS:
return aMetrics.GetEmLength(UserSpaceMetrics::Type::This);
case SVG_LENGTHTYPE_EXS:
return aMetrics.GetExLength(UserSpaceMetrics::Type::This);
case SVG_LENGTHTYPE_CH:
return aMetrics.GetChSize(UserSpaceMetrics::Type::This);
case SVG_LENGTHTYPE_REM:
return aMetrics.GetEmLength(UserSpaceMetrics::Type::Root);
case SVG_LENGTHTYPE_IC:
return aMetrics.GetIcWidth(UserSpaceMetrics::Type::This);
case SVG_LENGTHTYPE_CAP:
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;
}
default:
MOZ_ASSERT(IsAbsoluteUnit(aUnitType));
return GetAbsUnitsPerAbsUnit(SVG_LENGTHTYPE_PX, aUnitType);
}
}
/* static */
nsCSSUnit SVGLength::SpecifiedUnitTypeToCSSUnit(uint8_t aSpecifiedUnit) {
switch (aSpecifiedUnit) {
case SVG_LENGTHTYPE_NUMBER:
case SVG_LENGTHTYPE_PX:
return nsCSSUnit::eCSSUnit_Pixel;
case SVG_LENGTHTYPE_MM:
return nsCSSUnit::eCSSUnit_Millimeter;
case SVG_LENGTHTYPE_CM:
return nsCSSUnit::eCSSUnit_Centimeter;
case SVG_LENGTHTYPE_IN:
return nsCSSUnit::eCSSUnit_Inch;
case SVG_LENGTHTYPE_PT:
return nsCSSUnit::eCSSUnit_Point;
case SVG_LENGTHTYPE_PC:
return nsCSSUnit::eCSSUnit_Pica;
case SVG_LENGTHTYPE_PERCENTAGE:
return nsCSSUnit::eCSSUnit_Percent;
case SVG_LENGTHTYPE_EMS:
return nsCSSUnit::eCSSUnit_EM;
case SVG_LENGTHTYPE_EXS:
return nsCSSUnit::eCSSUnit_XHeight;
case SVG_LENGTHTYPE_Q:
return nsCSSUnit::eCSSUnit_Quarter;
case SVG_LENGTHTYPE_CH:
return nsCSSUnit::eCSSUnit_Char;
case SVG_LENGTHTYPE_REM:
return nsCSSUnit::eCSSUnit_RootEM;
case SVG_LENGTHTYPE_IC:
return nsCSSUnit::eCSSUnit_Ideographic;
case SVG_LENGTHTYPE_CAP:
return nsCSSUnit::eCSSUnit_CapHeight;
case SVG_LENGTHTYPE_VW:
return nsCSSUnit::eCSSUnit_VW;
case SVG_LENGTHTYPE_VH:
return nsCSSUnit::eCSSUnit_VH;
case SVG_LENGTHTYPE_VMIN:
return nsCSSUnit::eCSSUnit_VMin;
case SVG_LENGTHTYPE_VMAX:
return nsCSSUnit::eCSSUnit_VMax;
default:
MOZ_ASSERT_UNREACHABLE("Unknown unit type");
return nsCSSUnit::eCSSUnit_Pixel;
}
}
/* static */
void SVGLength::GetUnitString(nsAString& aUnit, uint16_t aUnitType) {
switch (aUnitType) {
case SVG_LENGTHTYPE_NUMBER:
aUnit.Truncate();
return;
case SVG_LENGTHTYPE_PERCENTAGE:
aUnit.AssignLiteral("%");
return;
case SVG_LENGTHTYPE_EMS:
aUnit.AssignLiteral("em");
return;
case SVG_LENGTHTYPE_EXS:
aUnit.AssignLiteral("ex");
return;
case SVG_LENGTHTYPE_PX:
aUnit.AssignLiteral("px");
return;
case SVG_LENGTHTYPE_CM:
aUnit.AssignLiteral("cm");
return;
case SVG_LENGTHTYPE_MM:
aUnit.AssignLiteral("mm");
return;
case SVG_LENGTHTYPE_IN:
aUnit.AssignLiteral("in");
return;
case SVG_LENGTHTYPE_PT:
aUnit.AssignLiteral("pt");
return;
case SVG_LENGTHTYPE_PC:
aUnit.AssignLiteral("pc");
return;
case SVG_LENGTHTYPE_Q:
aUnit.AssignLiteral("q");
return;
case SVG_LENGTHTYPE_CH:
aUnit.AssignLiteral("ch");
return;
case SVG_LENGTHTYPE_REM:
aUnit.AssignLiteral("rem");
return;
case SVG_LENGTHTYPE_IC:
aUnit.AssignLiteral("ic");
return;
case SVG_LENGTHTYPE_CAP:
aUnit.AssignLiteral("cap");
return;
case SVG_LENGTHTYPE_VW:
aUnit.AssignLiteral("vw");
return;
case SVG_LENGTHTYPE_VH:
aUnit.AssignLiteral("vh");
return;
case SVG_LENGTHTYPE_VMIN:
aUnit.AssignLiteral("vmin");
return;
case SVG_LENGTHTYPE_VMAX:
aUnit.AssignLiteral("vmax");
return;
}
MOZ_ASSERT_UNREACHABLE(
"Unknown unit type! Someone's using an SVGLength "
"with an invalid unit?");
}
/* static */
uint16_t SVGLength::GetUnitTypeForString(const nsAString& aUnit) {
if (aUnit.IsEmpty()) {
return SVG_LENGTHTYPE_NUMBER;
}
if (aUnit.EqualsLiteral("%")) {
return SVG_LENGTHTYPE_PERCENTAGE;
}
if (aUnit.LowerCaseEqualsLiteral("em")) {
return SVG_LENGTHTYPE_EMS;
}
if (aUnit.LowerCaseEqualsLiteral("ex")) {
return SVG_LENGTHTYPE_EXS;
}
if (aUnit.LowerCaseEqualsLiteral("px")) {
return SVG_LENGTHTYPE_PX;
}
if (aUnit.LowerCaseEqualsLiteral("cm")) {
return SVG_LENGTHTYPE_CM;
}
if (aUnit.LowerCaseEqualsLiteral("mm")) {
return SVG_LENGTHTYPE_MM;
}
if (aUnit.LowerCaseEqualsLiteral("in")) {
return SVG_LENGTHTYPE_IN;
}
if (aUnit.LowerCaseEqualsLiteral("pt")) {
return SVG_LENGTHTYPE_PT;
}
if (aUnit.LowerCaseEqualsLiteral("pc")) {
return SVG_LENGTHTYPE_PC;
}
if (aUnit.LowerCaseEqualsLiteral("q")) {
return SVG_LENGTHTYPE_Q;
}
if (aUnit.LowerCaseEqualsLiteral("ch")) {
return SVG_LENGTHTYPE_CH;
}
if (aUnit.LowerCaseEqualsLiteral("rem")) {
return SVG_LENGTHTYPE_REM;
}
if (aUnit.LowerCaseEqualsLiteral("ic")) {
return SVG_LENGTHTYPE_IC;
}
if (aUnit.LowerCaseEqualsLiteral("cap")) {
return SVG_LENGTHTYPE_CAP;
}
if (aUnit.LowerCaseEqualsLiteral("vw")) {
return SVG_LENGTHTYPE_VW;
}
if (aUnit.LowerCaseEqualsLiteral("vh")) {
return SVG_LENGTHTYPE_VH;
}
if (aUnit.LowerCaseEqualsLiteral("vmin")) {
return SVG_LENGTHTYPE_VMIN;
}
if (aUnit.LowerCaseEqualsLiteral("vmax")) {
return SVG_LENGTHTYPE_VMAX;
}
return SVG_LENGTHTYPE_UNKNOWN;
}
} // namespace mozilla