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
|
/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrSwizzle_DEFINED
#define GrSwizzle_DEFINED
#include "GrColor.h"
#include "SkRandom.h"
/** Represents a rgba swizzle. It can be converted either into a string or a eight bit int.
Currently there is no way to specify an arbitrary swizzle, just some static swizzles and an
assignment operator. That could be relaxed. */
class GrSwizzle {
public:
GrSwizzle() { *this = RGBA(); }
GrSwizzle(const GrSwizzle& that) { *this = that; }
GrSwizzle& operator=(const GrSwizzle& that) {
memcpy(this, &that, sizeof(GrSwizzle));
return *this;
}
/** Recreates a GrSwizzle from the output of asKey() */
void setFromKey(uint8_t key) {
fKey = key;
for (int i = 0; i < 4; ++i) {
fSwiz[i] = IdxToChar(key & 3);
key >>= 2;
}
SkASSERT(fSwiz[4] == 0);
}
bool operator==(const GrSwizzle& that) const { return this->asUInt() == that.asUInt(); }
bool operator!=(const GrSwizzle& that) const { return !(*this == that); }
/** Compact representation of the swizzle suitable for a key. */
uint8_t asKey() const { return fKey; }
/** 4 char null terminated string consisting only of chars 'r', 'g', 'b', 'a'. */
const char* c_str() const { return fSwiz; }
/** Applies this swizzle to the input color and returns the swizzled color. */
GrColor applyTo(GrColor color) const {
int idx;
uint32_t key = fKey;
// Index of the input color that should be mapped to output r.
idx = (key & 3);
uint32_t outR = (color >> idx * 8) & 0xFF;
key >>= 2;
idx = (key & 3);
uint32_t outG = (color >> idx * 8) & 0xFF;
key >>= 2;
idx = (key & 3);
uint32_t outB = (color >> idx * 8) & 0xFF;
key >>= 2;
idx = (key & 3);
uint32_t outA = (color >> idx * 8) & 0xFF;
return GrColorPackRGBA(outR, outG, outB, outA);
}
static const GrSwizzle& RGBA() {
static GrSwizzle gRGBA("rgba");
return gRGBA;
}
static const GrSwizzle& AAAA() {
static GrSwizzle gAAAA("aaaa");
return gAAAA;
}
static const GrSwizzle& RRRR() {
static GrSwizzle gRRRR("rrrr");
return gRRRR;
}
static const GrSwizzle& BGRA() {
static GrSwizzle gBGRA("bgra");
return gBGRA;
}
static const GrSwizzle& CreateRandom(SkRandom* random) {
switch (random->nextU() % 4) {
case 0:
return RGBA();
case 1:
return BGRA();
case 2:
return RRRR();
case 3:
return AAAA();
default:
SkFAIL("Mod is broken?!?");
return RGBA();
}
}
private:
char fSwiz[5];
uint8_t fKey;
static int CharToIdx(char c) {
switch (c) {
case 'r':
return (GrColor_SHIFT_R / 8);
case 'g':
return (GrColor_SHIFT_G / 8);
case 'b':
return (GrColor_SHIFT_B / 8);
case 'a':
return (GrColor_SHIFT_A / 8);
default:
SkFAIL("Invalid swizzle char");
return 0;
}
}
static /* constexpr */ char IToC(int idx) {
return (8*idx) == GrColor_SHIFT_R ? 'r' :
(8*idx) == GrColor_SHIFT_G ? 'g' :
(8*idx) == GrColor_SHIFT_B ? 'b' : 'a';
}
static char IdxToChar(int c) {
// Hopefully this array gets computed at compile time.
static const char gStr[4] = { IToC(0), IToC(1), IToC(2), IToC(3) };
return gStr[c];
}
explicit GrSwizzle(const char* str) {
SkASSERT(strlen(str) == 4);
fSwiz[0] = str[0];
fSwiz[1] = str[1];
fSwiz[2] = str[2];
fSwiz[3] = str[3];
fSwiz[4] = 0;
fKey = SkToU8(CharToIdx(fSwiz[0]) | (CharToIdx(fSwiz[1]) << 2) |
(CharToIdx(fSwiz[2]) << 4) | (CharToIdx(fSwiz[3]) << 6));
}
uint32_t* asUIntPtr() { return SkTCast<uint32_t*>(fSwiz); }
uint32_t asUInt() const { return *SkTCast<const uint32_t*>(fSwiz); }
GR_STATIC_ASSERT(sizeof(char[4]) == sizeof(uint32_t));
};
#endif
|
