1 /*
2 * Copyright 2019 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #include "modules/skottie/src/effects/Effects.h"
9
10 #include "include/private/SkColorData.h"
11 #include "include/private/SkTPin.h"
12 #include "modules/skottie/src/SkottieJson.h"
13 #include "modules/skottie/src/SkottieValue.h"
14 #include "modules/sksg/include/SkSGColorFilter.h"
15
16 namespace skottie {
17 namespace internal {
18
19 namespace {
20
21 /*
22 * AE's Shift Channels effect overrides individual channels based on a selectable function:
23 *
24 * C' = {fR(C), fG(C), fB(C), fA(C)}
25 *
26 * where fR, fG, fB, fA can be one of
27 *
28 * C.r, C.g, C.b, C.a, Luminance(C), Hue(C), Saturation(C), Lightness(C), 1 or 0.
29 */
30 class ShiftChannelsEffectAdapter final : public AnimatablePropertyContainer {
31 public:
Make(const skjson::ArrayValue & jprops,sk_sp<sksg::RenderNode> layer,const AnimationBuilder * abuilder)32 static sk_sp<ShiftChannelsEffectAdapter> Make(const skjson::ArrayValue& jprops,
33 sk_sp<sksg::RenderNode> layer,
34 const AnimationBuilder* abuilder) {
35 return sk_sp<ShiftChannelsEffectAdapter>(
36 new ShiftChannelsEffectAdapter(jprops, std::move(layer), abuilder));
37 }
38
node() const39 const sk_sp<sksg::ExternalColorFilter>& node() const { return fColorFilter; }
40
41 private:
ShiftChannelsEffectAdapter(const skjson::ArrayValue & jprops,sk_sp<sksg::RenderNode> layer,const AnimationBuilder * abuilder)42 ShiftChannelsEffectAdapter(const skjson::ArrayValue& jprops,
43 sk_sp<sksg::RenderNode> layer,
44 const AnimationBuilder* abuilder)
45 : fColorFilter(sksg::ExternalColorFilter::Make(std::move(layer))) {
46 enum : size_t {
47 kTakeAlphaFrom_Index = 0,
48 kTakeRedFrom_Index = 1,
49 kTakeGreenFrom_Index = 2,
50 kTakeBlueFrom_Index = 3,
51 };
52
53 EffectBinder(jprops, *abuilder, this)
54 .bind( kTakeRedFrom_Index, fR)
55 .bind(kTakeGreenFrom_Index, fG)
56 .bind( kTakeBlueFrom_Index, fB)
57 .bind(kTakeAlphaFrom_Index, fA);
58 }
59
60 enum class Source : uint8_t {
61 kAlpha = 1,
62 kRed = 2,
63 kGreen = 3,
64 kBlue = 4,
65 kLuminance = 5,
66 kHue = 6,
67 kLightness = 7,
68 kSaturation = 8,
69 kFullOn = 9,
70 kFullOff = 10,
71
72 kMax = kFullOff
73 };
74
onSync()75 void onSync() override {
76 // TODO: support for HSL sources will require a custom color filter.
77
78 static constexpr float gSourceCoeffs[][5] = {
79 { 0, 0, 0, 1, 0}, // kAlpha
80 { 1, 0, 0, 0, 0}, // kRed
81 { 0, 1, 0, 0, 0}, // kGreen
82 { 0, 0, 1, 0, 0}, // kBlue
83 {SK_LUM_COEFF_R, SK_LUM_COEFF_G, SK_LUM_COEFF_B, 0, 0}, // kLuminance
84 { 0, 0, 0, 0, 0}, // TODO: kHue
85 { 0, 0, 0, 0, 0}, // TODO: kLightness
86 { 0, 0, 0, 0, 0}, // TODO: kSaturation
87 { 0, 0, 0, 0, 1}, // kFullOn
88 { 0, 0, 0, 0, 0}, // kFullOff
89 };
90 static_assert(SK_ARRAY_COUNT(gSourceCoeffs) == static_cast<size_t>(Source::kMax), "");
91
92 auto coeffs = [](float src) {
93 // Channel sources are encoded as Source enum values.
94 // We map these onto our coeffs table.
95 src = SkTPin(src, 1.0f, static_cast<float>(Source::kMax));
96 return gSourceCoeffs[static_cast<size_t>(src) - 1];
97 };
98
99 const float* rc = coeffs(fR);
100 const float* gc = coeffs(fG);
101 const float* bc = coeffs(fB);
102 const float* ac = coeffs(fA);
103
104 const float cm[] = {
105 rc[0], rc[1], rc[2], rc[3], rc[4],
106 gc[0], gc[1], gc[2], gc[3], gc[4],
107 bc[0], bc[1], bc[2], bc[3], bc[4],
108 ac[0], ac[1], ac[2], ac[3], ac[4],
109 };
110
111 fColorFilter->setColorFilter(SkColorFilters::Matrix(cm));
112 }
113
114 const sk_sp<sksg::ExternalColorFilter> fColorFilter;
115
116 ScalarValue fR = static_cast<float>(Source::kRed),
117 fG = static_cast<float>(Source::kGreen),
118 fB = static_cast<float>(Source::kBlue),
119 fA = static_cast<float>(Source::kAlpha);
120 };
121
122 } // namespace
123
124
attachShiftChannelsEffect(const skjson::ArrayValue & jprops,sk_sp<sksg::RenderNode> layer) const125 sk_sp<sksg::RenderNode> EffectBuilder::attachShiftChannelsEffect(
126 const skjson::ArrayValue& jprops, sk_sp<sksg::RenderNode> layer) const {
127 return fBuilder->attachDiscardableAdapter<ShiftChannelsEffectAdapter>(jprops,
128 std::move(layer),
129 fBuilder);
130 }
131
132 } // namespace internal
133 } // namespace skottie
134