lotte/src/main/java/com/airbnb/lotte/utils/LottePathKeyframeAnimation.java

package com.airbnb.lotte.utils;

import android.graphics.Path;
import android.graphics.PathMeasure;
import android.graphics.PointF;
import android.support.annotation.FloatRange;

import com.airbnb.lotte.animation.LotteAnimatableProperty.AnimatableProperty;

import java.util.List;


public class LottePathKeyframeAnimation extends LotteKeyframeAnimation<PointF> {
    private final PointF point = new PointF();
    private final float[] pos = new float[2];
    private final PathMeasure pathMeasure;

    public LottePathKeyframeAnimation(@AnimatableProperty int property, long duration, List<Float> keyTimes, Path path) {
        super(property, duration, keyTimes);
        pathMeasure = new PathMeasure(path, false);
    }

    @Override
    public PointF getValueForProgress(@FloatRange(from = 0f, to = 1f) float progress) {
        if (progress <= 0f) {
            pathMeasure.getPosTan(0, pos, null);
            point.set(pos[0], pos[1]);
            return point;
        } else if (progress >= 1f) {
            pathMeasure.getPosTan(pathMeasure.getLength(), pos, null);
            point.set(pos[0], pos[1]);
            return point;
        }

        pathMeasure.getPosTan(progress * pathMeasure.getLength(), pos, null);
        point.set(pos[0], pos[1]);
        return point;
    }
}