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
|
/*
* Copyright 2016 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 "SkGammaColorFilter.h"
#include "SkImage.h"
// Fill a width x height block with a horizontal ramp from 0 to 255
static void draw_grey_ramp(SkCanvas* canvas, int width, int height, int numSteps) {
int greyPerStep = SkScalarRoundToInt(255.0f / numSteps);
int widthPerStep = SkScalarRoundToInt(width / SkIntToScalar(numSteps));
SkIRect rect = SkIRect::MakeWH(widthPerStep, height);
SkPaint paint;
int grey = 0;
int x = 0;
for (int i = 0; i < numSteps-1; ++i) {
paint.setColor(SkColorSetARGB(255, grey, grey, grey));
rect.offsetTo(x, 0);
canvas->drawRect(SkRect::Make(rect), paint);
x += widthPerStep;
grey += greyPerStep;
}
paint.setColor(SK_ColorWHITE);
rect.setLTRB(x, 0, width, height);
canvas->drawRect(SkRect::Make(rect), paint);
}
static sk_sp<SkImage> create_grey_ramp(int width, int height, int numSteps) {
SkBitmap bm;
bm.allocN32Pixels(width, height);
SkCanvas canvas(bm);
canvas.clear(0x0);
draw_grey_ramp(&canvas, width, height, numSteps);
return SkImage::MakeFromBitmap(bm);
}
namespace skiagm {
class GammaColorFilterGM : public GM {
public:
GammaColorFilterGM() {
this->setBGColor(SK_ColorBLACK);
}
protected:
SkString onShortName() override {
return SkString("gammacolorfilter");
}
SkISize onISize() override {
return SkISize::Make(4 * kCellWidth, kCellHeight);
}
void onDraw(SkCanvas* canvas) override {
GrRenderTargetContext* renderTargetContext =
canvas->internal_private_accessTopLayerRenderTargetContext();
if (!renderTargetContext) {
skiagm::GM::DrawGpuOnlyMessage(canvas);
return;
}
sk_sp<SkImage> image(create_grey_ramp(kCellWidth, kCellHeight/2, kNumGreySteps));
// Leftmost is a non-gamma pair
draw_grey_ramp(canvas, kCellWidth, kCellHeight/2, kNumGreySteps);
canvas->drawImage(image, 0, kCellHeight/2);
canvas->translate(SkIntToScalar(image->width()), 0);
for (auto gamma : { 1.0f, 1.0f / 1.8f, 1.0f / 2.2f }) {
SkPaint paint;
paint.setColorFilter(SkGammaColorFilter::Make(gamma));
draw_grey_ramp(canvas, kCellWidth, kCellHeight/2, kNumGreySteps);
canvas->drawImage(image, 0, kCellHeight/2, &paint);
canvas->translate(SkIntToScalar(image->width()), 0);
}
}
private:
static constexpr int kCellWidth = 64;
static constexpr int kCellHeight = 64;
static constexpr int kNumGreySteps = 16;
typedef GM INHERITED;
};
//////////////////////////////////////////////////////////////////////////////
DEF_GM(return new GammaColorFilterGM;)
}
|
