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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 "mozilla/ArrayUtils.h"
#include "SVGLength.h"
#include "nsSVGElement.h"
#include "mozilla/dom/SVGSVGElement.h"
#include "nsTextFormatter.h"
#include "SVGContentUtils.h"
#include <limits>
#include <algorithm>
namespace mozilla {
// Declare some helpers defined below:
static void GetUnitString(nsAString& unit, uint16_t unitType);
static uint16_t GetUnitTypeForString(const nsAString& unitStr);
void
SVGLength::GetValueAsString(nsAString &aValue) const
{
char16_t buf[24];
nsTextFormatter::snprintf(buf, sizeof(buf)/sizeof(char16_t),
u"%g",
(double)mValue);
aValue.Assign(buf);
nsAutoString unitString;
GetUnitString(unitString, mUnit);
aValue.Append(unitString);
}
bool
SVGLength::SetValueFromString(const nsAString &aString)
{
RangedPtr<const char16_t> iter =
SVGContentUtils::GetStartRangedPtr(aString);
const RangedPtr<const char16_t> end =
SVGContentUtils::GetEndRangedPtr(aString);
float value;
if (!SVGContentUtils::ParseNumber(iter, end, value)) {
return false;
}
const nsAString& units = Substring(iter.get(), end.get());
uint16_t unitType = GetUnitTypeForString(units);
if (!IsValidUnitType(unitType)) {
return false;
}
mValue = value;
mUnit = uint8_t(unitType);
return true;
}
inline static bool
IsAbsoluteUnit(uint8_t aUnit)
{
return aUnit >= nsIDOMSVGLength::SVG_LENGTHTYPE_CM &&
aUnit <= nsIDOMSVGLength::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(nsIDOMSVGLength::SVG_LENGTHTYPE_CM,
* nsIDOMSVGLength::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 nsSVGElement *aElement,
uint8_t aAxis) const
{
if (aUnit == mUnit) {
return mValue;
}
if ((aUnit == nsIDOMSVGLength::SVG_LENGTHTYPE_NUMBER &&
mUnit == nsIDOMSVGLength::SVG_LENGTHTYPE_PX) ||
(aUnit == nsIDOMSVGLength::SVG_LENGTHTYPE_PX &&
mUnit == nsIDOMSVGLength::SVG_LENGTHTYPE_NUMBER)) {
return mValue;
}
if (IsAbsoluteUnit(aUnit) && IsAbsoluteUnit(mUnit)) {
return mValue * GetAbsUnitsPerAbsUnit(aUnit, mUnit);
}
// Otherwise we do a two step convertion via user units. This can only
// succeed if aElement is non-null (although that's not sufficent to
// guarantee success).
float userUnitsPerCurrentUnit = GetUserUnitsPerUnit(aElement, aAxis);
float userUnitsPerNewUnit =
SVGLength(0.0f, aUnit).GetUserUnitsPerUnit(aElement, aAxis);
NS_ASSERTION(userUnitsPerCurrentUnit >= 0 ||
!IsFinite(userUnitsPerCurrentUnit),
"bad userUnitsPerCurrentUnit");
NS_ASSERTION(userUnitsPerNewUnit >= 0 ||
!IsFinite(userUnitsPerNewUnit),
"bad userUnitsPerNewUnit");
float value = mValue * userUnitsPerCurrentUnit / userUnitsPerNewUnit;
// userUnitsPerCurrentUnit could be infinity, or userUnitsPerNewUnit could
// be zero.
if (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 nsSVGElement *aElement, uint8_t aAxis) const
{
switch (mUnit) {
case nsIDOMSVGLength::SVG_LENGTHTYPE_NUMBER:
case nsIDOMSVGLength::SVG_LENGTHTYPE_PX:
return 1.0f;
case nsIDOMSVGLength::SVG_LENGTHTYPE_MM:
return INCHES_PER_MM_FLOAT * GetUserUnitsPerInch();
case nsIDOMSVGLength::SVG_LENGTHTYPE_CM:
return INCHES_PER_CM_FLOAT * GetUserUnitsPerInch();
case nsIDOMSVGLength::SVG_LENGTHTYPE_IN:
return GetUserUnitsPerInch();
case nsIDOMSVGLength::SVG_LENGTHTYPE_PT:
return (1.0f/POINTS_PER_INCH_FLOAT) * GetUserUnitsPerInch();
case nsIDOMSVGLength::SVG_LENGTHTYPE_PC:
return (12.0f/POINTS_PER_INCH_FLOAT) * GetUserUnitsPerInch();
case nsIDOMSVGLength::SVG_LENGTHTYPE_PERCENTAGE:
return GetUserUnitsPerPercent(aElement, aAxis);
case nsIDOMSVGLength::SVG_LENGTHTYPE_EMS:
return SVGContentUtils::GetFontSize(const_cast<nsSVGElement*>(aElement));
case nsIDOMSVGLength::SVG_LENGTHTYPE_EXS:
return SVGContentUtils::GetFontXHeight(const_cast<nsSVGElement*>(aElement));
default:
NS_NOTREACHED("Unknown unit type");
return std::numeric_limits<float>::quiet_NaN();
}
}
/* static */ float
SVGLength::GetUserUnitsPerPercent(const nsSVGElement *aElement, uint8_t aAxis)
{
if (aElement) {
dom::SVGSVGElement *viewportElement = aElement->GetCtx();
if (viewportElement) {
return std::max(viewportElement->GetLength(aAxis) / 100.0f, 0.0f);
}
}
return std::numeric_limits<float>::quiet_NaN();
}
// Helpers:
// These items must be at the same index as the nsIDOMSVGLength constants!
static nsIAtom** const unitMap[] =
{
nullptr, /* SVG_LENGTHTYPE_UNKNOWN */
nullptr, /* SVG_LENGTHTYPE_NUMBER */
&nsGkAtoms::percentage,
&nsGkAtoms::em,
&nsGkAtoms::ex,
&nsGkAtoms::px,
&nsGkAtoms::cm,
&nsGkAtoms::mm,
&nsGkAtoms::in,
&nsGkAtoms::pt,
&nsGkAtoms::pc
};
static void
GetUnitString(nsAString& unit, uint16_t unitType)
{
if (SVGLength::IsValidUnitType(unitType)) {
if (unitMap[unitType]) {
(*unitMap[unitType])->ToString(unit);
}
return;
}
NS_NOTREACHED("Unknown unit type"); // Someone's using an SVGLength with an invalid unit?
return;
}
static uint16_t
GetUnitTypeForString(const nsAString& unitStr)
{
if (unitStr.IsEmpty())
return nsIDOMSVGLength::SVG_LENGTHTYPE_NUMBER;
nsIAtom* unitAtom = NS_GetStaticAtom(unitStr);
if (unitAtom) {
for (uint32_t i = 1 ; i < ArrayLength(unitMap) ; i++) {
if (unitMap[i] && *unitMap[i] == unitAtom) {
return i;
}
}
}
return nsIDOMSVGLength::SVG_LENGTHTYPE_UNKNOWN;
}
} // namespace mozilla
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