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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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "SVGLength.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/dom/SVGElement.h"
#include "mozilla/dom/SVGSVGElement.h"
#include "nsTextFormatter.h"
#include "SVGContentUtils.h"
#include <limits>
#include <algorithm>
using namespace mozilla::dom;
using namespace mozilla::dom::SVGLength_Binding;
namespace mozilla {
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;
}
inline static bool IsAbsoluteUnit(uint8_t aUnit) {
return aUnit >= SVGLength_Binding::SVG_LENGTHTYPE_CM &&
aUnit <= SVGLength_Binding::SVG_LENGTHTYPE_PC;
}
/**
* 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(SVGLength_Binding::SVG_LENGTHTYPE_CM,
* SVGLength_Binding::SVG_LENGTHTYPE_IN)
*/
inline static float GetAbsUnitsPerAbsUnit(uint8_t aUnits, uint8_t aPerUnit) {
MOZ_ASSERT(IsAbsoluteUnit(aUnits), "Not a CSS absolute unit");
MOZ_ASSERT(IsAbsoluteUnit(aPerUnit), "Not a CSS absolute unit");
float CSSAbsoluteUnitConversionFactors[5][5] = {
// columns: cm, mm, in, pt, pc
// cm per...:
{1.0f, 0.1f, 2.54f, 0.035277777777777778f, 0.42333333333333333f},
// mm per...:
{10.0f, 1.0f, 25.4f, 0.35277777777777778f, 4.2333333333333333f},
// in per...:
{0.39370078740157481f, 0.039370078740157481f, 1.0f, 0.013888888888888889f,
0.16666666666666667f},
// pt per...:
{28.346456692913386f, 2.8346456692913386f, 72.0f, 1.0f, 12.0f},
// pc per...:
{2.3622047244094489f, 0.23622047244094489f, 6.0f, 0.083333333333333333f,
1.0f}};
// First absolute unit is SVG_LENGTHTYPE_CM = 6
return CSSAbsoluteUnitConversionFactors[aUnits - 6][aPerUnit - 6];
}
float SVGLength::GetValueInSpecifiedUnit(uint8_t aUnit,
const SVGElement* aElement,
uint8_t aAxis) const {
if (aUnit == mUnit) {
return mValue;
}
if ((aUnit == SVGLength_Binding::SVG_LENGTHTYPE_NUMBER &&
mUnit == SVGLength_Binding::SVG_LENGTHTYPE_PX) ||
(aUnit == SVGLength_Binding::SVG_LENGTHTYPE_PX &&
mUnit == SVGLength_Binding::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).
float userUnitsPerCurrentUnit = GetUserUnitsPerUnit(aElement, aAxis);
float userUnitsPerNewUnit =
SVGLength(0.0f, aUnit).GetUserUnitsPerUnit(aElement, aAxis);
NS_ASSERTION(
userUnitsPerCurrentUnit >= 0 || !std::isfinite(userUnitsPerCurrentUnit),
"bad userUnitsPerCurrentUnit");
NS_ASSERTION(userUnitsPerNewUnit >= 0 || !std::isfinite(userUnitsPerNewUnit),
"bad userUnitsPerNewUnit");
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();
}
#define INCHES_PER_MM_FLOAT float(0.0393700787)
#define INCHES_PER_CM_FLOAT float(0.393700787)
float SVGLength::GetUserUnitsPerUnit(const SVGElement* aElement,
uint8_t aAxis) const {
switch (mUnit) {
case SVGLength_Binding::SVG_LENGTHTYPE_NUMBER:
case SVGLength_Binding::SVG_LENGTHTYPE_PX:
return 1.0f;
case SVGLength_Binding::SVG_LENGTHTYPE_MM:
return INCHES_PER_MM_FLOAT * GetUserUnitsPerInch();
case SVGLength_Binding::SVG_LENGTHTYPE_CM:
return INCHES_PER_CM_FLOAT * GetUserUnitsPerInch();
case SVGLength_Binding::SVG_LENGTHTYPE_IN:
return GetUserUnitsPerInch();
case SVGLength_Binding::SVG_LENGTHTYPE_PT:
return (1.0f / POINTS_PER_INCH_FLOAT) * GetUserUnitsPerInch();
case SVGLength_Binding::SVG_LENGTHTYPE_PC:
return (12.0f / POINTS_PER_INCH_FLOAT) * GetUserUnitsPerInch();
case SVGLength_Binding::SVG_LENGTHTYPE_PERCENTAGE:
return GetUserUnitsPerPercent(aElement, aAxis);
case SVGLength_Binding::SVG_LENGTHTYPE_EMS:
return SVGContentUtils::GetFontSize(const_cast<SVGElement*>(aElement));
case SVGLength_Binding::SVG_LENGTHTYPE_EXS:
return SVGContentUtils::GetFontXHeight(const_cast<SVGElement*>(aElement));
default:
MOZ_ASSERT_UNREACHABLE("Unknown unit type");
return std::numeric_limits<float>::quiet_NaN();
}
}
/* static */
float SVGLength::GetUserUnitsPerPercent(const SVGElement* aElement,
uint8_t aAxis) {
if (aElement) {
dom::SVGViewportElement* viewportElement = aElement->GetCtx();
if (viewportElement) {
return std::max(viewportElement->GetLength(aAxis) / 100.0f, 0.0f);
}
}
return std::numeric_limits<float>::quiet_NaN();
}
// Helpers:
/* 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;
}
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;
}
return SVG_LENGTHTYPE_UNKNOWN;
}
} // namespace mozilla
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