chromium/third_party/skia/modules/skottie/src/text/TextAnimator.cpp

/*
 * Copyright 2019 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "modules/skottie/src/text/TextAnimator.h"

#include "include/core/SkColor.h"
#include "include/private/base/SkCPUTypes.h"
#include "modules/skottie/src/SkottieValue.h"
#include "modules/skottie/src/animator/Animator.h"
#include "modules/skottie/src/text/RangeSelector.h"
#include "src/base/SkVx.h"
#include "src/core/SkSwizzlePriv.h"
#include "src/utils/SkJSON.h"

#include <algorithm>
#include <cmath>
#include <cstdint>
#include <utility>

namespace skottie {
namespace internal {

/*
 * Text layers can have optional text property animators.
 *
 * Each animator consists of
 *
 *   1) a list of animated properties (e.g. position, fill color, etc)
 *
 *   2) a list of range selectors
 *
 * Animated properties yield new values to be applied to the text, while range selectors
 * determine the text subset these new values are applied to.
 *
 * The best way to think of range selectors is in terms of coverage: they combine to generate
 * a coverage value [0..1] for each text fragment/glyph.  This coverage is then used to modulate
 * how the new property value is applied to a given fragment (interpolation weight).
 *
 * Note: Bodymovin currently only supports a single selector.
 *
 * JSON structure:
 *
 * "t": {              // text node
 *   "a": [            // animators list
 *     {               // animator node
 *       "s": {...},   // selector node
 *       "a": {        // animator properties node
 *         "a":  {}    // optional anchor point value
 *         "p":  {},   // optional position value
 *         "s":  {},   // optional scale value
 *         "o":  {},   // optional opacity
 *         "fc": {},   // optional fill color value
 *         "sc": {},   // optional stroke color value
 *
 *         // TODO: more props?
 *       }
 *     },
 *     ...
 *   ],
 *   ...
 * }
 */
sk_sp<TextAnimator> TextAnimator::Make(const skjson::ObjectValue* janimator,
                                       const AnimationBuilder* abuilder,
                                       AnimatablePropertyContainer* acontainer) { … }

void TextAnimator::modulateProps(const DomainMaps& maps, ModulatorBuffer& buf) const { … }

TextAnimator::ResolvedProps TextAnimator::modulateProps(const ResolvedProps& props,
                                                        float amount) const { … }

TextAnimator::TextAnimator(std::vector<sk_sp<RangeSelector>>&& selectors,
                           const skjson::ObjectValue& jprops,
                           const AnimationBuilder* abuilder,
                           AnimatablePropertyContainer* acontainer)
    : … { … }

} // namespace internal
} // namespace skottie