lottie/src/main/java/com/airbnb/lottie/ShapeKeyframeAnimation.java

package com.airbnb.lottie;

import android.graphics.Path;
import android.view.animation.Interpolator;

import java.util.List;

class ShapeKeyframeAnimation extends KeyframeAnimation<Path> {
  private final Path tempPath = new Path();
  private final ShapeData tempShapeData = new ShapeData();
  private final List<ShapeData> shapeData;

  ShapeKeyframeAnimation(long duration, LottieComposition composition, List<Float> keyTimes,
      List<ShapeData> shapeData, List<Interpolator> interpolators) {
    super(duration, composition, keyTimes, interpolators);
    this.shapeData = shapeData;
  }

  @Override public Path getValue() {
    if (progress <= 0f) {
      MiscUtils.getPathFromData(shapeData.get(0), tempPath);
      return tempPath;
    } else if (progress >= 1f) {
      MiscUtils.getPathFromData(shapeData.get(shapeData.size() - 1), tempPath);
      return tempPath;
    }

    int keyframeIndex = getKeyframeIndex();

    float startKeytime = keyTimes.get(keyframeIndex);
    float endKeytime = keyTimes.get(keyframeIndex + 1);

    float percentageIntoFrame = 0;
    if (!isDiscrete) {
      percentageIntoFrame = (progress - startKeytime) / (endKeytime - startKeytime);
      if (interpolators != null) {
        percentageIntoFrame =
            interpolators.get(keyframeIndex).getInterpolation(percentageIntoFrame);
      }
    }

    ShapeData startShapeData = shapeData.get(keyframeIndex);
    ShapeData endShapeData = shapeData.get(keyframeIndex + 1);

    tempShapeData.interpolateBetween(startShapeData, endShapeData, percentageIntoFrame);
    MiscUtils.getPathFromData(tempShapeData, tempPath);
    return tempPath;
  }
}