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
|
/* -*- 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/. */
#ifndef mozilla_AspectRatio_h
#define mozilla_AspectRatio_h
/* The aspect ratio of a box, in a "width / height" format. */
#include "mozilla/Attributes.h"
#include "mozilla/gfx/BaseSize.h"
#include "nsCoord.h"
#include <algorithm>
#include <limits>
namespace IPC {
template <typename T>
struct ParamTraits;
} // namespace IPC
namespace mozilla {
enum LogicalAxis : uint8_t;
class LogicalSize;
class WritingMode;
enum class UseBoxSizing : uint8_t {
// The aspect ratio works with content box dimensions always.
No,
// The aspect ratio works with the dimensions of the box specified by
// box-sizing.
Yes,
};
struct AspectRatio {
friend struct IPC::ParamTraits<mozilla::AspectRatio>;
AspectRatio() = default;
explicit AspectRatio(float aRatio,
UseBoxSizing aUseBoxSizing = UseBoxSizing::No)
: mRatio(std::max(aRatio, 0.0f)), mUseBoxSizing(aUseBoxSizing) {}
static AspectRatio FromSize(float aWidth, float aHeight,
UseBoxSizing aUseBoxSizing = UseBoxSizing::No) {
if (aWidth == 0.0f || aHeight == 0.0f) {
// For the degenerate ratio, we don't care about which box sizing we are
// using, so using default constructor is fine.
return AspectRatio();
}
return AspectRatio(aWidth / aHeight, aUseBoxSizing);
}
template <typename T, typename Sub, typename Coord>
static AspectRatio FromSize(const gfx::BaseSize<T, Sub, Coord>& aSize) {
return FromSize(aSize.Width(), aSize.Height());
}
explicit operator bool() const { return mRatio != 0.0f; }
nscoord ApplyTo(nscoord aCoord) const {
MOZ_DIAGNOSTIC_ASSERT(*this);
return NSCoordSaturatingNonnegativeMultiply(aCoord, mRatio);
}
float ApplyToFloat(float aFloat) const {
MOZ_DIAGNOSTIC_ASSERT(*this);
return mRatio * aFloat;
}
// Inverts the ratio, in order to get the height / width ratio.
[[nodiscard]] AspectRatio Inverted() const {
if (!*this) {
return AspectRatio();
}
// Clamp to a small epsilon, in case mRatio is absurdly large & produces
// 0.0f in the division here (so that valid ratios always generate other
// valid ratios when inverted).
return AspectRatio(
std::max(std::numeric_limits<float>::epsilon(), 1.0f / mRatio),
mUseBoxSizing);
}
[[nodiscard]] inline AspectRatio ConvertToWritingMode(
const WritingMode& aWM) const;
/**
* This method computes the ratio-dependent size by the ratio-determining size
* and aspect-ratio (i.e. preferred aspect ratio). Basically this function
* will be used in the calculation of 'auto' sizes when the preferred
* aspect ratio is not 'auto'.
*
* @param aRatioDependentAxis The ratio depenedent axis of the box.
* @param aWM The writing mode of the box.
* @param aRatioDetermingSize The content-box size on the ratio determining
* axis. Basically, we use this size and |mRatio|
* to compute the size on the ratio-dependent
* axis.
* @param aContentBoxSizeToBoxSizingAdjust The border padding box size
* adjustment. We need this because
* aspect-ratio should take the
* box-sizing into account if its
* style is '<ratio>'. If its style
* is 'auto & <ratio>', we should use
* content-box dimensions always.
* If the callers want the ratio to
* apply to the content-box size, we
* should pass a zero LogicalSize.
* If mUseBoxSizing is No, we ignore
* this parameter because we should
* use content box dimensions always.
*
* The return value is the content-box size on the ratio-dependent axis.
* Plese see the definition of the ratio-dependent axis and the
* ratio-determining axis in the spec:
* https://drafts.csswg.org/css-sizing-4/#aspect-ratio
*/
[[nodiscard]] nscoord ComputeRatioDependentSize(
LogicalAxis aRatioDependentAxis, const WritingMode& aWM,
nscoord aRatioDeterminingSize,
const LogicalSize& aContentBoxSizeToBoxSizingAdjust) const;
bool operator==(const AspectRatio& aOther) const {
return mRatio == aOther.mRatio && mUseBoxSizing == aOther.mUseBoxSizing;
}
bool operator!=(const AspectRatio& aOther) const {
return !(*this == aOther);
}
bool operator<(const AspectRatio& aOther) const {
MOZ_ASSERT(
mUseBoxSizing == aOther.mUseBoxSizing,
"Do not compare AspectRatio if their mUseBoxSizing are different.");
return mRatio < aOther.mRatio;
}
private:
// 0.0f represents no aspect ratio.
float mRatio = 0.0f;
UseBoxSizing mUseBoxSizing = UseBoxSizing::No;
};
} // namespace mozilla
#endif // mozilla_AspectRatio_h
|
