src/main/java/com/google/android/libraries/feed/piet/ui/RoundedCornerWrapperView.java

// Copyright 2018 The Feed Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package com.google.android.libraries.feed.piet.ui;

import static com.google.android.libraries.feed.common.Validators.checkState;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Outline;
import android.graphics.Rect;
import android.graphics.drawable.shapes.RoundRectShape;
import android.os.Build;
import android.os.Build.VERSION;
import android.os.Build.VERSION_CODES;
import android.view.View;
import android.view.ViewOutlineProvider;
import android.view.ViewParent;
import android.widget.FrameLayout;
import com.google.android.libraries.feed.common.functional.Supplier;
import com.google.android.libraries.feed.common.ui.LayoutUtils;
import com.google.android.libraries.feed.piet.ui.RoundedCornerDelegateFactory.RoundingStrategy;
import com.google.search.now.ui.piet.RoundedCornersProto.RoundedCorners;
import com.google.search.now.ui.piet.RoundedCornersProto.RoundedCorners.RadiusOptionsCase;
import com.google.search.now.ui.piet.StylesProto.Borders;

/**
 * Wrapper for {@link View} instances in Piet that require rounded corners.
 *
 * <p>There are three strategies used to round corners in different situations. This class decides
 * which to use based on the following rules:
 *
 * <p>OUTLINE_PROVIDER: This is always used when possible (unless disallowed by the host). It
 * requires hardware acceleration, does not work if 1-3 corners are rounded, and does not work on
 * K-.
 *
 * <p>CLIP_PATH: This works in all situations, but does not support anti-aliasing. Used when the
 * device does not support hardware acceleration, and in K- where outline provider is not supported.
 * Although BITMAP_MASKING would work for those cases, this strategy is much more performant. Older
 * SDKs or no hw acceleration support typically are signs of less-performant phones. The lack of
 * anti-aliasing does not negatively effect metrics for these users. This strategy can be disallowed
 * by the host, in which case BITMAP_MASKING will be used where OUTLINE_PROVIDER is not possible.
 *
 * <p>BITMAP_MASKING: This implementation should work in all cases for all SDKs, but has the worst
 * performance in CPU and memory usage. It is only used when 1-3 corners are rounded in L+, or if
 * the other strategies are disallowed by the host or not possible.
 *
 * <p>A {@link RoundedCornerDelegate} is called in places where special logic is needed for
 * different rounding strategies. Each strategy has its own delegate, which is created when the
 * strategy is selected. This class doesn't know about the implementation details of the rounding
 * strategies.
 */
public class RoundedCornerWrapperView extends FrameLayout {
  private final int radiusOverride;
  private final RoundedCorners roundedCorners;
  private final Supplier<Boolean> isRtLSupplier;
  private final Context context;
  private final Borders borders;
  private final boolean allowClipPath;
  private final boolean allowOutlineRounding;
  private final boolean hasRoundedCorners;
  private final boolean allFourCornersRounded;
  private final RoundedCornerMaskCache maskCache;

  private RoundedCornerDelegate roundingDelegate;
  private boolean drawSuperCalled;

  // Keep track of current mask configuration so we can use cached values if nothing has changed.
  int lastWidth = -1;
  int lastHeight = -1;

  private int roundedCornerRadius;

  // Doesn't like the call to setOutlineProvider
  @SuppressWarnings("initialization")
  public RoundedCornerWrapperView(
      Context context,
      RoundedCorners roundedCorners,
      RoundedCornerMaskCache maskCache,
      Supplier<Boolean> isRtLSupplier,
      int radiusOverride,
      Borders borders,
      boolean allowClipPath,
      boolean allowOutlineRounding) {
    super(context);

    this.radiusOverride = radiusOverride;
    this.roundedCorners = roundedCorners;
    this.isRtLSupplier = isRtLSupplier;
    this.allowClipPath = allowClipPath;
    this.allowOutlineRounding = allowOutlineRounding;
    this.context = context;
    this.borders = borders;
    this.maskCache = maskCache;
    this.hasRoundedCorners =
        RoundedCornerViewHelper.hasValidRoundedCorners(roundedCorners, radiusOverride);
    this.allFourCornersRounded =
        RoundedCornerViewHelper.allFourCornersRounded(roundedCorners.getBitmask());

    setRoundingStrategy();

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
      // Even when not using the outline provider strategy, the outline needs to be set for
      // shadows to render properly.
      setupOutlineProvider();
    }
    setWillNotDraw(false);
  }

  private void setRoundingStrategy() {
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP && allowClipPath) {
      setRoundingDelegate(RoundingStrategy.CLIP_PATH);
      if (VERSION.SDK_INT < VERSION_CODES.JELLY_BEAN_MR2) {
        // clipPath doesn't work with hardware rendering on < 18.
        setLayerType(LAYER_TYPE_SOFTWARE, null);
      }
    } else if (Build.VERSION.SDK_INT >= VERSION_CODES.LOLLIPOP
        && allFourCornersRounded
        && allowOutlineRounding) {
      setRoundingDelegate(RoundingStrategy.OUTLINE_PROVIDER);
    } else {
      setRoundingDelegate(RoundingStrategy.BITMAP_MASKING);
    }
  }

  private void updateRoundingStrategy() {
    if (roundingDelegate instanceof OutlineProviderRoundedCornerDelegate
        && this.isAttachedToWindow()
        && !this.isHardwareAccelerated()) {
      if (allowClipPath) {
        setRoundingDelegate(RoundingStrategy.CLIP_PATH);
      } else {
        setRoundingDelegate(RoundingStrategy.BITMAP_MASKING);
      }
    }
  }

  void setRoundingDelegate(RoundingStrategy strategy) {
    if (roundingDelegate != null) {
      roundingDelegate.destroy(this);
    }
    roundingDelegate =
        RoundedCornerDelegateFactory.getDelegate(
            strategy, maskCache, roundedCorners.getBitmask(), isRtLSupplier.get());
    roundingDelegate.initializeForView(this);
  }

  private void setupOutlineProvider() {
    if (hasRoundedCorners) {
      super.setOutlineProvider(
          new ViewOutlineProvider() {
            @Override
            public void getOutline(View view, Outline outline) {
              int radius = getRadius(view.getWidth(), view.getHeight());
              if (allFourCornersRounded) {
                outline.setRoundRect(0, 0, view.getWidth(), view.getHeight(), radius);
                return;
              }
              float[] radii =
                  RoundedCornerViewHelper.createRoundedCornerBitMask(
                      radius, roundedCorners.getBitmask(), isRtLSupplier.get());
              RoundRectShape outlineShape = new RoundRectShape(radii, null, null);
              outlineShape.resize(view.getWidth(), view.getHeight());
              // This actually sets the outline to use this shape
              outlineShape.getOutline(outline);
            }
          });
    } else {
      super.setOutlineProvider(ViewOutlineProvider.BOUNDS);
    }
  }

  /**
   * Calls the rounding delegate to perform any additional work specific to a certain rounding
   * strategy during dispatchDraw().
   */
  @Override
  protected void dispatchDraw(Canvas canvas) {
    roundingDelegate.dispatchDraw(canvas);
    super.dispatchDraw(canvas);
  }

  /**
   * Allows the {@link RoundedCornerDelegate} to add logic during onDescendantInvalidated().
   *
   * <p>The bitmap masking rounded corner strategy requires this hook, to make sure the wrapper view
   * is invalidated when there are animations. The delegate handles that logic.
   */
  @Override
  public void onDescendantInvalidated(View child, View target) {
    super.onDescendantInvalidated(child, target);
    roundingDelegate.onDescendantInvalidated(this, target);
  }

  /**
   * Allows the {@link RoundedCornerDelegate} to add logic during invalidateChildInParent().
   *
   * <p>The bitmap masking rounded corner strategy requires this hook, to make sure the wrapper view
   * is invalidated when there are animations. The delegate handles that logic.
   */
  @Override
  public ViewParent invalidateChildInParent(final int[] location, final Rect dirty) {
    roundingDelegate.invalidateChildInParent(this, dirty);
    return super.invalidateChildInParent(location, dirty);
  }

  /**
   * Calls the {@link RoundedCornerDelegate} to draw to the {@link Canvas}, in case extra logic is
   * needed to round the corners.
   *
   * <p>Draws as normal for everything except the bitmap masking strategy. The bitmap masking
   * strategy requires manipulating the {@link Canvas}, which the delegate handles.
   */
  @Override
  public void draw(Canvas canvas) {
    drawSuperCalled = false;
    roundingDelegate.draw(this, canvas);
    checkState(drawSuperCalled, "View.draw() never called in RoundedCornerWrapperView.draw()");
  }

  public void drawSuper(Canvas canvas) {
    drawSuperCalled = true;
    super.draw(canvas);
  }

  /**
   * Updates rounded corner information when the size changes.
   *
   * <p>At this point, the view will actually be attached to the window, meaning we can detect
   * whether it is hardware accelerated. The outline provider strategy doesn't work without hardware
   * acceleration, so the rounding strategy may need to be updated. The size always changes at least
   * once--from 0 to final dimensions--so it is safe to assume that this will catch devices without
   * hw acceleration.
   *
   * <p>Call the rounding delegate to perform any additional work specific to a certain rounding
   * strategy.
   */
  @Override
  protected void onSizeChanged(int width, int height, int oldWidth, int oldHeight) {
    super.onSizeChanged(width, height, oldWidth, oldHeight);
    updateRoundingStrategy();
    roundingDelegate.onSizeChanged(
        getRadius(width, height), width, height, roundedCorners.getBitmask(), isRtLSupplier.get());
  }

  /**
   * Lays out the view, calling the rounding delegate to perform any additional work specific to a
   * certain rounding strategy.
   *
   * <p>Borders must be created after the radius is known, so they are added from onLayout().
   */
  @Override
  protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
    super.onLayout(changed, left, top, right, bottom);
    if (!changed || !hasRoundedCorners) {
      return;
    }

    int width = getWidth();
    int height = getHeight();
    if (width == 0 || height == 0) {
      // The view is not visible; no further processing is needed.
      return;
    }

    int radius = getRadius(width, height);
    addBorders(radius);

    roundingDelegate.onLayout(radius, isRtLSupplier.get(), width, height);
  }

  /**
   * Creates a border drawable and adds it to this view's foreground.
   *
   * <p>This is called from {@link RoundedCornerWrapperView} because when the corners are rounded,
   * the borders also need to be rounded, and the radius can't properly be calculated until the view
   * has been laid out and the height and width are known. From this class, it is easy to make sure
   * the border is created after layout happens, since we are overriding draw. Draw is guaranteed to
   * happen after layout, so we can make sure that the borders are drawn with the appropriate
   * measurements.
   */
  void addBorders(int radius) {
    if (borders.getWidth() <= 0) {
      return;
    }
    boolean isRtL = isRtLSupplier.get();
    // Set up outline of borders
    float[] outerRadii =
        RoundedCornerViewHelper.createRoundedCornerBitMask(
            radius, roundedCorners.getBitmask(), isRtL);

    // Create a drawable to stroke the border
    BorderDrawable borderDrawable =
        new BorderDrawable(context, borders, outerRadii, isRtL, lastWidth, lastHeight);
    this.setForeground(borderDrawable);
  }

  /**
   * Returns the radius, which is only calculated if necessary.
   *
   * <p>If the width and height are the same as the previous width and height, there's no need to
   * re-calculate, and the previous radius is returned. The width and height are needed for radii
   * calculated as a percentage of width or height, and to make sure that the radius isn't too big
   * for the size of the view.
   */
  public int getRadius(int width, int height) {
    if (!hasRoundedCorners || width == 0 || height == 0) {
      return 0;
    }
    if (radiusOverride > 0) {
      roundedCornerRadius = radiusOverride;
      return roundedCornerRadius;
    }
    if (width == lastWidth && height == lastHeight) {
      return roundedCornerRadius;
    }
    int radius = makeRadius(width, height);
    lastWidth = width;
    lastHeight = height;
    return radius;
  }

  /** Calculates the corner radius, clipping to width or height when necessary. */
  private int makeRadius(int width, int height) {
    int radius = 0;
    RadiusOptionsCase radiusOptions = roundedCorners.getRadiusOptionsCase();

    switch (radiusOptions) {
      case RADIUS_DP:
        radius = (int) LayoutUtils.dpToPx(roundedCorners.getRadiusDp(), context);
        break;
      case RADIUS_PERCENTAGE_OF_HEIGHT:
        radius = roundedCorners.getRadiusPercentageOfHeight() * height / 100;
        break;
      case RADIUS_PERCENTAGE_OF_WIDTH:
        radius = roundedCorners.getRadiusPercentageOfWidth() * width / 100;
        break;
      default:
        // TODO Remove deprecated radius code.
        if (roundedCorners.hasRadius()) {
          radius = (int) LayoutUtils.dpToPx(roundedCorners.getRadius(), context);
        }
    }

    roundedCornerRadius =
        RoundedCornerViewHelper.adjustRadiusIfTooBig(width, height, radius, roundedCorners);
    return roundedCornerRadius;
  }
}