lottie/src/main/java/com/airbnb/lottie/animation/content/ContentGroup.java

package com.airbnb.lottie.animation.content;

import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.RectF;

import com.airbnb.lottie.LottieDrawable;
import com.airbnb.lottie.animation.LPaint;
import com.airbnb.lottie.animation.keyframe.BaseKeyframeAnimation;
import com.airbnb.lottie.animation.keyframe.TransformKeyframeAnimation;
import com.airbnb.lottie.model.KeyPath;
import com.airbnb.lottie.model.KeyPathElement;
import com.airbnb.lottie.model.animatable.AnimatableTransform;
import com.airbnb.lottie.model.content.ContentModel;
import com.airbnb.lottie.model.content.ShapeGroup;
import com.airbnb.lottie.model.layer.BaseLayer;
import com.airbnb.lottie.utils.Utils;
import com.airbnb.lottie.value.LottieValueCallback;

import java.util.ArrayList;
import java.util.List;

import androidx.annotation.Nullable;

public class ContentGroup implements DrawingContent, PathContent,
    BaseKeyframeAnimation.AnimationListener, KeyPathElement {

  private Paint offScreenPaint = new LPaint();
  private RectF offScreenRectF = new RectF();

  private static List<Content> contentsFromModels(LottieDrawable drawable, BaseLayer layer,
      List<ContentModel> contentModels) {
    List<Content> contents = new ArrayList<>(contentModels.size());
    for (int i = 0; i < contentModels.size(); i++) {
      Content content = contentModels.get(i).toContent(drawable, layer);
      if (content != null) {
        contents.add(content);
      }
    }
    return contents;
  }

  @Nullable static AnimatableTransform findTransform(List<ContentModel> contentModels) {
    for (int i = 0; i < contentModels.size(); i++) {
      ContentModel contentModel = contentModels.get(i);
      if (contentModel instanceof AnimatableTransform) {
        return (AnimatableTransform) contentModel;
      }
    }
    return null;
  }

  private final Matrix matrix = new Matrix();
  private final Path path = new Path();
  private final RectF rect = new RectF();

  private final String name;
  private final boolean hidden;
  private final List<Content> contents;
  private final LottieDrawable lottieDrawable;
  @Nullable private List<PathContent> pathContents;
  @Nullable private TransformKeyframeAnimation transformAnimation;

  public ContentGroup(final LottieDrawable lottieDrawable, BaseLayer layer, ShapeGroup shapeGroup) {
    this(lottieDrawable, layer, shapeGroup.getName(),
        shapeGroup.isHidden(), contentsFromModels(lottieDrawable, layer, shapeGroup.getItems()),
        findTransform(shapeGroup.getItems()));
  }

  ContentGroup(final LottieDrawable lottieDrawable, BaseLayer layer,
      String name, boolean hidden, List<Content> contents, @Nullable AnimatableTransform transform) {
    this.name = name;
    this.lottieDrawable = lottieDrawable;
    this.hidden = hidden;
    this.contents = contents;

    if (transform != null) {
      transformAnimation = transform.createAnimation();
      transformAnimation.addAnimationsToLayer(layer);
      transformAnimation.addListener(this);
    }

    List<GreedyContent> greedyContents = new ArrayList<>();
    for (int i = contents.size() - 1; i >= 0; i--) {
      Content content = contents.get(i);
      if (content instanceof GreedyContent) {
        greedyContents.add((GreedyContent) content);
      }
    }

    for (int i = greedyContents.size() - 1; i >= 0; i--) {
      greedyContents.get(i).absorbContent(contents.listIterator(contents.size()));
    }
  }

  @Override public void onValueChanged() {
    lottieDrawable.invalidateSelf();
  }

  @Override public String getName() {
    return name;
  }

  @Override public void setContents(List<Content> contentsBefore, List<Content> contentsAfter) {
    // Do nothing with contents after.
    List<Content> myContentsBefore = new ArrayList<>(contentsBefore.size() + contents.size());
    myContentsBefore.addAll(contentsBefore);

    for (int i = contents.size() - 1; i >= 0; i--) {
      Content content = contents.get(i);
      content.setContents(myContentsBefore, contents.subList(0, i));
      myContentsBefore.add(content);
    }
  }

  List<PathContent> getPathList() {
    if (pathContents == null) {
      pathContents = new ArrayList<>();
      for (int i = 0; i < contents.size(); i++) {
        Content content = contents.get(i);
        if (content instanceof PathContent) {
          pathContents.add((PathContent) content);
        }
      }
    }
    return pathContents;
  }

  Matrix getTransformationMatrix() {
    if (transformAnimation != null) {
      return transformAnimation.getMatrix();
    }
    matrix.reset();
    return matrix;
  }

  @Override public Path getPath() {
    // TODO: cache this somehow.
    matrix.reset();
    if (transformAnimation != null) {
      matrix.set(transformAnimation.getMatrix());
    }
    path.reset();
    if (hidden) {
      return path;
    }
    for (int i = contents.size() - 1; i >= 0; i--) {
      Content content = contents.get(i);
      if (content instanceof PathContent) {
        path.addPath(((PathContent) content).getPath(), matrix);
      }
    }
    return path;
  }

  @Override public void draw(Canvas canvas, Matrix parentMatrix, int parentAlpha) {
    if (hidden) {
      return;
    }
    matrix.set(parentMatrix);
    int layerAlpha;
    if (transformAnimation != null) {
      matrix.preConcat(transformAnimation.getMatrix());
      int opacity = transformAnimation.getOpacity() == null ? 100 : transformAnimation.getOpacity().getValue();
      layerAlpha = (int) ((opacity / 100f * parentAlpha / 255f) * 255);
    } else {
      layerAlpha = parentAlpha;
    }

    // Apply off-screen rendering only when needed in order to improve rendering performance.
    boolean isRenderingWithOffScreen = lottieDrawable.isApplyingOpacityToLayersEnabled() && hasTwoOrMoreDrawableContent() && layerAlpha != 255;
    if (isRenderingWithOffScreen) {
      offScreenRectF.set(0, 0, 0, 0);
      getBounds(offScreenRectF, matrix, true);
      offScreenPaint.setAlpha(layerAlpha);
      Utils.saveLayerCompat(canvas, offScreenRectF, offScreenPaint);
    }

    int childAlpha = isRenderingWithOffScreen ? 255 : layerAlpha;
    for (int i = contents.size() - 1; i >= 0; i--) {
      Object content = contents.get(i);
      if (content instanceof DrawingContent) {
        ((DrawingContent) content).draw(canvas, matrix, childAlpha);
      }
    }

    if (isRenderingWithOffScreen) {
      canvas.restore();
    }
  }

  private boolean hasTwoOrMoreDrawableContent() {
    int drawableContentCount = 0;
    for (int i = 0; i < contents.size(); i++) {
      if (contents.get(i) instanceof DrawingContent) {
        drawableContentCount += 1;
        if (drawableContentCount >= 2) {
          return true;
        }
      }
    }
    return false;
  }

  @Override public void getBounds(RectF outBounds, Matrix parentMatrix, boolean applyParents) {
    matrix.set(parentMatrix);
    if (transformAnimation != null) {
      matrix.preConcat(transformAnimation.getMatrix());
    }
    rect.set(0, 0, 0, 0);
    for (int i = contents.size() - 1; i >= 0; i--) {
      Content content = contents.get(i);
      if (content instanceof DrawingContent) {
        ((DrawingContent) content).getBounds(rect, matrix, applyParents);
        outBounds.union(rect);
      }
    }
  }

  @Override public void resolveKeyPath(
      KeyPath keyPath, int depth, List<KeyPath> accumulator, KeyPath currentPartialKeyPath) {
    if (!keyPath.matches(getName(), depth) && !"__container".equals(getName())) {
      return;
    }

    if (!"__container".equals(getName())) {
      currentPartialKeyPath = currentPartialKeyPath.addKey(getName());

      if (keyPath.fullyResolvesTo(getName(), depth)) {
        accumulator.add(currentPartialKeyPath.resolve(this));
      }
    }

    if (keyPath.propagateToChildren(getName(), depth)) {
      int newDepth = depth + keyPath.incrementDepthBy(getName(), depth);
      for (int i = 0; i < contents.size(); i++) {
        Content content = contents.get(i);
        if (content instanceof KeyPathElement) {
          KeyPathElement element = (KeyPathElement) content;
          element.resolveKeyPath(keyPath, newDepth, accumulator, currentPartialKeyPath);
        }
      }
    }
  }

  @Override
  public <T> void addValueCallback(T property, @Nullable LottieValueCallback<T> callback) {
    if (transformAnimation != null) {
      transformAnimation.applyValueCallback(property, callback);
    }
  }
}