1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/* -*- 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 {
// 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 {
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 (!IsValidUnitType(unitType)) {
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 || !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 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:
// These items must be at the same index as the SVGLength constants!
static const nsStaticAtom* 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;
}
MOZ_ASSERT_UNREACHABLE(
"Unknown unit type! Someone's using an SVGLength "
"with an invalid unit?");
}
static uint16_t GetUnitTypeForString(const nsAString& unitStr) {
if (unitStr.IsEmpty()) return SVGLength_Binding::SVG_LENGTHTYPE_NUMBER;
nsAtom* unitAtom = NS_GetStaticAtom(unitStr);
if (unitAtom) {
for (uint32_t i = 1; i < ArrayLength(unitMap); i++) {
if (unitMap[i] == unitAtom) {
return i;
}
}
}
return SVGLength_Binding::SVG_LENGTHTYPE_UNKNOWN;
}
} // namespace mozilla
|
