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
|
/* libs/graphics/effects/SkShaderExtras.cpp
**
** Copyright 2006, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
** http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
#include "SkComposeShader.h"
#include "SkColorFilter.h"
#include "SkColorPriv.h"
#include "SkXfermode.h"
//////////////////////////////////////////////////////////////////////////////////////
SkComposeShader::SkComposeShader(SkShader* sA, SkShader* sB, SkXfermode* mode)
{
fShaderA = sA; sA->ref();
fShaderB = sB; sB->ref();
// mode may be null
fMode = mode; mode->safeRef();
}
SkComposeShader::SkComposeShader(SkFlattenableReadBuffer& buffer) :
INHERITED(buffer)
{
fShaderA = static_cast<SkShader*>(buffer.readFlattenable());
fShaderB = static_cast<SkShader*>(buffer.readFlattenable());
fMode = static_cast<SkXfermode*>(buffer.readFlattenable());
}
SkComposeShader::~SkComposeShader()
{
fMode->safeUnref(); // may be null
fShaderB->unref();
fShaderA->unref();
}
void SkComposeShader::beginSession()
{
this->INHERITED::beginSession();
fShaderA->beginSession();
fShaderB->beginSession();
}
void SkComposeShader::endSession()
{
fShaderA->endSession();
fShaderB->endSession();
this->INHERITED::endSession();
}
class SkAutoAlphaRestore {
public:
SkAutoAlphaRestore(SkPaint* paint, uint8_t newAlpha)
{
fAlpha = paint->getAlpha();
fPaint = paint;
paint->setAlpha(newAlpha);
}
~SkAutoAlphaRestore()
{
fPaint->setAlpha(fAlpha);
}
private:
SkPaint* fPaint;
uint8_t fAlpha;
};
void SkComposeShader::flatten(SkFlattenableWriteBuffer& buffer)
{
this->INHERITED::flatten(buffer);
buffer.writeFlattenable(fShaderA);
buffer.writeFlattenable(fShaderB);
buffer.writeFlattenable(fMode);
}
/* We call setContext on our two worker shaders. However, we
always let them see opaque alpha, and if the paint really
is translucent, then we apply that after the fact.
*/
bool SkComposeShader::setContext(const SkBitmap& device,
const SkPaint& paint,
const SkMatrix& matrix)
{
if (!this->INHERITED::setContext(device, paint, matrix))
return false;
// we preconcat our localMatrix (if any) with the device matrix
// before calling our sub-shaders
SkMatrix tmpM;
(void)this->getLocalMatrix(&tmpM);
tmpM.setConcat(matrix, tmpM);
SkAutoAlphaRestore restore(const_cast<SkPaint*>(&paint), 0xFF);
return fShaderA->setContext(device, paint, tmpM) &&
fShaderB->setContext(device, paint, tmpM);
}
// larger is better (fewer times we have to loop), but we shouldn't
// take up too much stack-space (each element is 4 bytes)
#define TMP_COLOR_COUNT 64
void SkComposeShader::shadeSpan(int x, int y, SkPMColor result[], int count)
{
SkShader* shaderA = fShaderA;
SkShader* shaderB = fShaderB;
SkXfermode* mode = fMode;
unsigned scale = SkAlpha255To256(this->getPaintAlpha());
SkPMColor tmp[TMP_COLOR_COUNT];
if (NULL == mode) // implied SRC_OVER
{
do {
int n = count;
if (n > TMP_COLOR_COUNT)
n = TMP_COLOR_COUNT;
shaderA->shadeSpan(x, y, result, n);
shaderB->shadeSpan(x, y, tmp, n);
if (256 == scale)
{
for (int i = 0; i < n; i++)
result[i] = SkPMSrcOver(tmp[i], result[i]);
}
else
{
for (int i = 0; i < n; i++)
result[i] = SkAlphaMulQ(SkPMSrcOver(tmp[i], result[i]), scale);
}
result += n;
x += n;
count -= n;
} while (count > 0);
}
else // use mode for the composition
{
do {
int n = count;
if (n > TMP_COLOR_COUNT)
n = TMP_COLOR_COUNT;
shaderA->shadeSpan(x, y, result, n);
shaderB->shadeSpan(x, y, tmp, n);
mode->xfer32(result, tmp, n, NULL);
if (256 == scale)
{
for (int i = 0; i < n; i++)
result[i] = SkAlphaMulQ(result[i], scale);
}
result += n;
x += n;
count -= n;
} while (count > 0);
}
}
|
