src/utils/SkAnimCodecPlayer.cpp

/*
 * Copyright 2018 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkAnimCodecPlayer.h"
#include "SkCodec.h"
#include "SkCodecImageGenerator.h"
#include "SkData.h"
#include "SkImage.h"
#include <algorithm>

SkAnimCodecPlayer::SkAnimCodecPlayer(std::unique_ptr<SkCodec> codec) : fCodec(std::move(codec)) {
    fImageInfo = fCodec->getInfo();
    fFrameInfos = fCodec->getFrameInfo();
    fImages.resize(fFrameInfos.size());

    // change the interpretation of fDuration to a end-time for that frame
    size_t dur = 0;
    for (auto& f : fFrameInfos) {
        dur += f.fDuration;
        f.fDuration = dur;
    }
    fTotalDuration = dur;

    if (!fTotalDuration) {
        // Static image -- may or may not have returned a single frame info.
        fFrameInfos.clear();
        fImages.clear();
        fImages.push_back(SkImage::MakeFromGenerator(
                              SkCodecImageGenerator::MakeFromCodec(std::move(fCodec))));
    }
}

SkAnimCodecPlayer::~SkAnimCodecPlayer() {}

SkISize SkAnimCodecPlayer::dimensions() {
    return { fImageInfo.width(), fImageInfo.height() };
}

sk_sp<SkImage> SkAnimCodecPlayer::getFrameAt(int index) {
    SkASSERT((unsigned)index < fFrameInfos.size());

    if (fImages[index]) {
        return fImages[index];
    }

    size_t rb = fImageInfo.minRowBytes();
    size_t size = fImageInfo.computeByteSize(rb);
    auto data = SkData::MakeUninitialized(size);

    SkCodec::Options opts;
    opts.fFrameIndex = index;

    const int requiredFrame = fFrameInfos[index].fRequiredFrame;
    if (requiredFrame != SkCodec::kNoFrame) {
        auto requiredImage = fImages[requiredFrame];
        SkPixmap requiredPM;
        if (requiredImage && requiredImage->peekPixels(&requiredPM)) {
            sk_careful_memcpy(data->writable_data(), requiredPM.addr(), size);
            opts.fPriorFrame = requiredFrame;
        }
    }
    if (SkCodec::kSuccess == fCodec->getPixels(fImageInfo, data->writable_data(), rb, &opts)) {
        return fImages[index] = SkImage::MakeRasterData(fImageInfo, std::move(data), rb);
    }
    return nullptr;
}

sk_sp<SkImage> SkAnimCodecPlayer::getFrame() {
    SkASSERT(fTotalDuration > 0 || fImages.size() == 1);

    return fTotalDuration > 0
        ? this->getFrameAt(fCurrIndex)
        : fImages.front();
}

bool SkAnimCodecPlayer::seek(uint32_t msec) {
    if (!fTotalDuration) {
        return false;
    }

    msec %= fTotalDuration;

    auto lower = std::lower_bound(fFrameInfos.begin(), fFrameInfos.end(), msec,
                                  [](const SkCodec::FrameInfo& info, uint32_t msec) {
                                      return (uint32_t)info.fDuration < msec;
                                  });
    int prevIndex = fCurrIndex;
    fCurrIndex = lower - fFrameInfos.begin();
    return fCurrIndex != prevIndex;
}