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/text/TextAnimator.h"
9
10#include "include/core/SkColor.h"
11#include "include/core/SkPoint.h"
12#include "include/private/SkNx.h"
13#include "modules/skottie/src/SkottieValue.h"
14#include "modules/skottie/src/animator/Animator.h"
15#include "modules/skottie/src/text/RangeSelector.h"
16#include "src/utils/SkJSON.h"
17
18namespace skottie {
19namespace internal {
20
21/*
22 * Text layers can have optional text property animators.
23 *
24 * Each animator consists of
25 *
26 * 1) a list of animated properties (e.g. position, fill color, etc)
27 *
28 * 2) a list of range selectors
29 *
30 * Animated properties yield new values to be applied to the text, while range selectors
31 * determine the text subset these new values are applied to.
32 *
33 * The best way to think of range selectors is in terms of coverage: they combine to generate
34 * a coverage value [0..1] for each text fragment/glyph. This coverage is then used to modulate
35 * how the new property value is applied to a given fragment (interpolation weight).
36 *
37 * Note: Bodymovin currently only supports a single selector.
38 *
39 * JSON structure:
40 *
41 * "t": { // text node
42 * "a": [ // animators list
43 * { // animator node
44 * "s": {...}, // selector node
45 * "a": { // animator properties node
46 * "a": {} // optional anchor point value
47 * "p": {}, // optional position value
48 * "s": {}, // optional scale value
49 * "o": {}, // optional opacity
50 * "fc": {}, // optional fill color value
51 * "sc": {}, // optional stroke color value
52 *
53 * // TODO: more props?
54 * }
55 * },
56 * ...
57 * ],
58 * ...
59 * }
60 */
61sk_sp<TextAnimator> TextAnimator::Make(const skjson::ObjectValue* janimator,
62 const AnimationBuilder* abuilder,
63 AnimatablePropertyContainer* acontainer) {
64 if (!janimator) {
65 return nullptr;
66 }
67
68 const skjson::ObjectValue* jprops = (*janimator)["a"];
69 if (!jprops) {
70 return nullptr;
71 }
72
73 std::vector<sk_sp<RangeSelector>> selectors;
74
75 // Depending on compat mode and whether more than one selector is present,
76 // BM exports either an array or a single object.
77 if (const skjson::ArrayValue* jselectors = (*janimator)["s"]) {
78 selectors.reserve(jselectors->size());
79 for (const skjson::ObjectValue* jselector : *jselectors) {
80 if (auto sel = RangeSelector::Make(*jselector, abuilder, acontainer)) {
81 selectors.push_back(std::move(sel));
82 }
83 }
84 } else {
85 if (auto sel = RangeSelector::Make((*janimator)["s"], abuilder, acontainer)) {
86 selectors.reserve(1);
87 selectors.push_back(std::move(sel));
88 }
89 }
90
91 return sk_sp<TextAnimator>(
92 new TextAnimator(std::move(selectors), *jprops, abuilder, acontainer));
93}
94
95void TextAnimator::modulateProps(const DomainMaps& maps, ModulatorBuffer& buf) const {
96 // No selectors -> full coverage.
97 const auto initial_coverage = fSelectors.empty() ? 1.f : 0.f;
98
99 // Coverage is scoped per animator.
100 for (auto& mod : buf) {
101 mod.coverage = initial_coverage;
102 }
103
104 // Accumulate selector coverage.
105 for (const auto& selector : fSelectors) {
106 selector->modulateCoverage(maps, buf);
107 }
108
109 // Modulate animated props.
110 for (auto& mod : buf) {
111 mod.props = this->modulateProps(mod.props, mod.coverage);
112 }
113}
114
115TextAnimator::ResolvedProps TextAnimator::modulateProps(const ResolvedProps& props,
116 float amount) const {
117 auto modulated_props = props;
118
119 // Transform props compose.
120 modulated_props.position += static_cast<SkV3>(fTextProps.position) * amount;
121 modulated_props.rotation += fTextProps.rotation * amount;
122 modulated_props.tracking += fTextProps.tracking * amount;
123 modulated_props.scale *= SkV3{1,1,1} +
124 (static_cast<SkV3>(fTextProps.scale) * 0.01f - SkV3{1,1,1}) * amount;
125
126 // ... as does blur
127 modulated_props.blur += fTextProps.blur * amount;
128
129 const auto lerp_color = [](SkColor c0, SkColor c1, float t) {
130 const auto c0_4f = SkNx_cast<float>(Sk4b::Load(&c0)),
131 c1_4f = SkNx_cast<float>(Sk4b::Load(&c1)),
132 c_4f = c0_4f + (c1_4f - c0_4f) * t;
133
134 SkColor c;
135 SkNx_cast<uint8_t>(Sk4f_round(c_4f)).store(&c);
136 return c;
137 };
138
139 // Colors and opacity are overridden, and use a clamped amount value.
140 const auto clamped_amount = std::max(amount, 0.0f);
141 if (fHasFillColor) {
142 const auto fc = static_cast<SkColor>(fTextProps.fill_color);
143 modulated_props.fill_color = lerp_color(props.fill_color, fc, clamped_amount);
144 }
145 if (fHasStrokeColor) {
146 const auto sc = static_cast<SkColor>(fTextProps.stroke_color);
147 modulated_props.stroke_color = lerp_color(props.stroke_color, sc, clamped_amount);
148 }
149 modulated_props.opacity *= 1 + (fTextProps.opacity * 0.01f - 1) * clamped_amount; // 100-based
150
151 return modulated_props;
152}
153
154TextAnimator::TextAnimator(std::vector<sk_sp<RangeSelector>>&& selectors,
155 const skjson::ObjectValue& jprops,
156 const AnimationBuilder* abuilder,
157 AnimatablePropertyContainer* acontainer)
158 : fSelectors(std::move(selectors))
159 , fRequiresAnchorPoint(false) {
160
161 acontainer->bind(*abuilder, jprops["p"], fTextProps.position);
162 acontainer->bind(*abuilder, jprops["o"], fTextProps.opacity );
163 acontainer->bind(*abuilder, jprops["t"], fTextProps.tracking);
164
165 // Scale and rotation are anchor-point-dependent.
166 fRequiresAnchorPoint |= acontainer->bind(*abuilder, jprops["s"], fTextProps.scale);
167
168 // Depending on whether we're in 2D/3D mode, some of these will stick and some will not.
169 // It's fine either way.
170 fRequiresAnchorPoint |= acontainer->bind(*abuilder, jprops["rx"], fTextProps.rotation.x);
171 fRequiresAnchorPoint |= acontainer->bind(*abuilder, jprops["ry"], fTextProps.rotation.y);
172 fRequiresAnchorPoint |= acontainer->bind(*abuilder, jprops["r" ], fTextProps.rotation.z);
173
174 fHasFillColor = acontainer->bind(*abuilder, jprops["fc"], fTextProps.fill_color );
175 fHasStrokeColor = acontainer->bind(*abuilder, jprops["sc"], fTextProps.stroke_color);
176 fHasBlur = acontainer->bind(*abuilder, jprops["bl"], fTextProps.blur );
177}
178
179} // namespace internal
180} // namespace skottie
181