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
|
/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkHighContrastFilter_DEFINED
#define SkHighContrastFilter_DEFINED
#include "SkColorFilter.h"
#include "SkPaint.h"
/**
* Configuration struct for SkHighContrastFilter.
*
* Provides transformations to improve contrast for users with low vision.
*/
struct SkHighContrastConfig {
enum class InvertStyle {
kNoInvert,
kInvertBrightness,
kInvertLightness,
kLast = kInvertLightness
};
SkHighContrastConfig() {
fGrayscale = false;
fInvertStyle = InvertStyle::kNoInvert;
fContrast = 0.0f;
}
SkHighContrastConfig(bool grayscale,
InvertStyle invertStyle,
SkScalar contrast)
: fGrayscale(grayscale),
fInvertStyle(invertStyle),
fContrast(contrast) {}
// Returns true if all of the fields are set within the valid range.
bool isValid() const {
return fInvertStyle >= InvertStyle::kNoInvert &&
fInvertStyle <= InvertStyle::kInvertLightness &&
fContrast >= -1.0 &&
fContrast <= 1.0;
}
// If true, the color will be converted to grayscale.
bool fGrayscale;
// Whether to invert brightness, lightness, or neither.
InvertStyle fInvertStyle;
// After grayscale and inverting, the contrast can be adjusted linearly.
// The valid range is -1.0 through 1.0, where 0.0 is no adjustment.
SkScalar fContrast;
};
/**
* Color filter that provides transformations to improve contrast
* for users with low vision.
*
* Applies the following transformations in this order. Each of these
* can be configured using SkHighContrastConfig.
*
* - Conversion to grayscale
* - Color inversion (either in RGB or HSL space)
* - Increasing the resulting contrast.
*
* Calling SkHighContrastFilter::Make will return nullptr if the config is
* not valid, e.g. if you try to call it with a contrast outside the range of
* -1.0 to 1.0.
*/
class SK_API SkHighContrastFilter {
public:
// Returns the filter, or nullptr if the config is invalid.
static sk_sp<SkColorFilter> Make(const SkHighContrastConfig& config);
static void InitializeFlattenables();
};
#endif
|
