diff options
Diffstat (limited to 'dom/svg/SVGLength.cpp')
| -rw-r--r-- | dom/svg/SVGLength.cpp | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/dom/svg/SVGLength.cpp b/dom/svg/SVGLength.cpp new file mode 100644 index 0000000000..7a0bbf6437 --- /dev/null +++ b/dom/svg/SVGLength.cpp @@ -0,0 +1,255 @@ +/* -*- 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 |