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
|
/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm.h"
#include "Resources.h"
#include "SkGradientShader.h"
DEF_SIMPLE_GM(gamma, canvas, 500, 200) {
SkPaint p;
const SkScalar sz = 50.0f;
const int szInt = SkScalarTruncToInt(sz);
const SkScalar tx = sz + 5.0f;
const SkRect r = SkRect::MakeXYWH(0, 0, sz, sz);
SkShader::TileMode rpt = SkShader::kRepeat_TileMode;
SkBitmap ditherBmp;
ditherBmp.allocN32Pixels(2, 2);
SkPMColor* pixels = reinterpret_cast<SkPMColor*>(ditherBmp.getPixels());
pixels[0] = pixels[3] = SkPackARGB32(0xFF, 0xFF, 0xFF, 0xFF);
pixels[1] = pixels[2] = SkPackARGB32(0xFF, 0, 0, 0);
SkBitmap linearGreyBmp;
SkImageInfo linearGreyInfo = SkImageInfo::MakeN32(szInt, szInt, kOpaque_SkAlphaType,
kLinear_SkColorProfileType);
linearGreyBmp.allocPixels(linearGreyInfo);
linearGreyBmp.eraseARGB(0xFF, 0x7F, 0x7F, 0x7F);
SkBitmap srgbGreyBmp;
SkImageInfo srgbGreyInfo = SkImageInfo::MakeN32(szInt, szInt, kOpaque_SkAlphaType,
kSRGB_SkColorProfileType);
srgbGreyBmp.allocPixels(srgbGreyInfo);
srgbGreyBmp.eraseARGB(0xFF, 0xBC, 0xBC, 0xBC);
SkPaint textPaint;
textPaint.setColor(SK_ColorWHITE);
// Helpers:
auto advance = [&]() {
canvas->translate(tx, 0);
p.reset();
};
auto nextRect = [&](const char* label, const char* label2) {
canvas->drawRect(r, p);
canvas->drawText(label, strlen(label), 0, sz + textPaint.getFontSpacing(), textPaint);
if (label2) {
canvas->drawText(label2, strlen(label2), 0, sz + 2 * textPaint.getFontSpacing(),
textPaint);
}
advance();
};
auto nextBitmap = [&](const SkBitmap& bmp, const char* label) {
canvas->drawBitmap(bmp, 0, 0);
canvas->drawText(label, strlen(label), 0, sz + textPaint.getFontSpacing(), textPaint);
advance();
};
auto nextXferRect = [&](SkColor srcColor, SkXfermode::Mode mode, SkColor dstColor) {
p.setColor(dstColor);
canvas->drawRect(r, p);
p.setColor(srcColor);
p.setXfermodeMode(mode);
canvas->drawRect(r, p);
SkString srcText = SkStringPrintf("%08X", srcColor);
SkString dstText = SkStringPrintf("%08X", dstColor);
canvas->drawText(srcText.c_str(), srcText.size(), 0, sz + textPaint.getFontSpacing(),
textPaint);
const char* modeName = SkXfermode::ModeName(mode);
canvas->drawText(modeName, strlen(modeName), 0, sz + 2 * textPaint.getFontSpacing(),
textPaint);
canvas->drawText(dstText.c_str(), dstText.size(), 0, sz + 3 * textPaint.getFontSpacing(),
textPaint);
advance();
};
// Necessary for certain Xfermode tests to work (ie some of them output white @ 50% alpha):
canvas->clear(SK_ColorBLACK);
// *Everything* should be perceptually 50% grey. Only the first rectangle
// is guaranteed to draw that way, though.
canvas->save();
// Black/white dither, pixel perfect. This is ground truth.
p.setShader(SkShader::MakeBitmapShader(ditherBmp, rpt, rpt));
p.setFilterQuality(SkFilterQuality::kNone_SkFilterQuality);
nextRect("Dither", "Reference");
// Black/white dither, sampled at half-texel offset. Tests bilerp.
// NOTE: We need to apply a non-identity scale and/or rotation to trick
// the raster pipeline into *not* snapping to nearest.
SkMatrix offsetMatrix = SkMatrix::Concat(
SkMatrix::MakeScale(-1.0f), SkMatrix::MakeTrans(0.5f, 0.0f));
p.setShader(SkShader::MakeBitmapShader(ditherBmp, rpt, rpt, &offsetMatrix));
p.setFilterQuality(SkFilterQuality::kMedium_SkFilterQuality);
nextRect("Dither", "Bilerp");
// Black/white dither, scaled down by 2x. Tests minification.
SkMatrix scaleMatrix = SkMatrix::MakeScale(0.5f);
p.setShader(SkShader::MakeBitmapShader(ditherBmp, rpt, rpt, &scaleMatrix));
p.setFilterQuality(SkFilterQuality::kMedium_SkFilterQuality);
nextRect("Dither", "Scale");
// 50% grey via paint color.
p.setColor(0xff7f7f7f);
nextRect("Color", 0);
// Black -> White gradient, scaled to sample just the middle.
// Tests gradient interpolation.
SkPoint points[2] = {
SkPoint::Make(0 - (sz * 10), 0),
SkPoint::Make(sz + (sz * 10), 0)
};
SkColor colors[2] = { SK_ColorBLACK, SK_ColorWHITE };
p.setShader(SkGradientShader::MakeLinear(points, colors, nullptr, 2,
SkShader::kClamp_TileMode));
nextRect("Gradient", 0);
// 50% grey from linear bitmap, with drawBitmap
nextBitmap(linearGreyBmp, "Lnr BMP");
// 50% grey from sRGB bitmap, with drawBitmap
nextBitmap(srgbGreyBmp, "sRGB BMP");
// Bitmap wrapped in a shader (linear):
p.setShader(SkShader::MakeBitmapShader(linearGreyBmp, rpt, rpt));
p.setFilterQuality(SkFilterQuality::kMedium_SkFilterQuality);
nextRect("Lnr BMP", "Shader");
// Bitmap wrapped in a shader (sRGB):
p.setShader(SkShader::MakeBitmapShader(srgbGreyBmp, rpt, rpt));
p.setFilterQuality(SkFilterQuality::kMedium_SkFilterQuality);
nextRect("sRGB BMP", "Shader");
// Carriage return.
canvas->restore();
canvas->translate(0, 2 * sz);
const U8CPU sqrtHalf = 0xB4;
const SkColor sqrtHalfAlpha = SkColorSetARGB(sqrtHalf, 0, 0, 0);
const SkColor sqrtHalfWhite = SkColorSetARGB(0xFF, sqrtHalf, sqrtHalf, sqrtHalf);
// Xfermode tests, all done off-screen so certain modes work...
canvas->saveLayer(nullptr, nullptr);
nextXferRect(0x7fffffff, SkXfermode::kSrcOver_Mode, SK_ColorBLACK);
nextXferRect(0x7f000000, SkXfermode::kSrcOver_Mode, SK_ColorWHITE);
nextXferRect(SK_ColorBLACK, SkXfermode::kDstOver_Mode, 0x7fffffff);
nextXferRect(SK_ColorWHITE, SkXfermode::kSrcIn_Mode, 0x7fff00ff);
nextXferRect(0x7fff00ff, SkXfermode::kDstIn_Mode, SK_ColorWHITE);
nextXferRect(sqrtHalfWhite, SkXfermode::kSrcIn_Mode, sqrtHalfAlpha);
nextXferRect(sqrtHalfAlpha, SkXfermode::kDstIn_Mode, sqrtHalfWhite);
nextXferRect(0xff3f3f3f, SkXfermode::kPlus_Mode, 0xff3f3f3f);
nextXferRect(sqrtHalfWhite, SkXfermode::kModulate_Mode, sqrtHalfWhite);
canvas->restore();
}
|
