lottie/src/main/java/com/airbnb/lottie/parser/ShapeDataParser.java

package com.airbnb.lottie.parser;

import android.graphics.PointF;
import android.util.JsonReader;
import android.util.JsonToken;

import com.airbnb.lottie.model.CubicCurveData;
import com.airbnb.lottie.model.content.ShapeData;
import com.airbnb.lottie.utils.MiscUtils;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class ShapeDataParser implements ValueParser<ShapeData> {
  public static final ShapeDataParser INSTANCE = new ShapeDataParser();

  private ShapeDataParser() {}

  @Override public ShapeData parse(JsonReader reader, float scale) throws IOException {
    // Sometimes the points data is in a array of length 1. Sometimes the data is at the top
    // level.
    if (reader.peek() == JsonToken.BEGIN_ARRAY) {
      reader.beginArray();
    }

    boolean closed = false;
    List<PointF> pointsArray = null;
    List<PointF> inTangents = null;
    List<PointF> outTangents = null;
    reader.beginObject();

    while (reader.hasNext()) {
      switch (reader.nextName()) {
        case "c":
          closed = reader.nextBoolean();
          break;
        case "v":
          pointsArray =  JsonUtils.jsonToPoints(reader, scale);
          break;
        case "i":
          inTangents =  JsonUtils.jsonToPoints(reader, scale);
          break;
        case "o":
          outTangents =  JsonUtils.jsonToPoints(reader, scale);
          break;
      }
    }

    reader.endObject();

    if (reader.peek() == JsonToken.END_ARRAY) {
      reader.endArray();
    }

    if (pointsArray == null || inTangents == null || outTangents == null) {
      throw new IllegalArgumentException("Shape data was missing information.");
    }

    if (pointsArray.isEmpty()) {
      return new ShapeData(new PointF(), false, Collections.<CubicCurveData>emptyList());
    }

    int length = pointsArray.size();
    PointF vertex = pointsArray.get(0);
    PointF initialPoint = vertex;
    List<CubicCurveData> curves = new ArrayList<>(length);

    for (int i = 1; i < length; i++) {
      vertex = pointsArray.get(i);
      PointF previousVertex = pointsArray.get(i - 1);
      PointF cp1 = outTangents.get(i - 1);
      PointF cp2 = inTangents.get(i);
      PointF shapeCp1 = MiscUtils.addPoints(previousVertex, cp1);
      PointF shapeCp2 = MiscUtils.addPoints(vertex, cp2);
      curves.add(new CubicCurveData(shapeCp1, shapeCp2, vertex));
    }

    if (closed) {
      vertex = pointsArray.get(0);
      PointF previousVertex = pointsArray.get(length - 1);
      PointF cp1 = outTangents.get(length - 1);
      PointF cp2 = inTangents.get(0);

      PointF shapeCp1 = MiscUtils.addPoints(previousVertex, cp1);
      PointF shapeCp2 = MiscUtils.addPoints(vertex, cp2);

      curves.add(new CubicCurveData(shapeCp1, shapeCp2, vertex));
    }
    return new ShapeData(initialPoint, closed, curves);
  }
}