content: /*
   * Copyright (C) 2008 The Android Open Source Project
   *
   * 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.android.launcher3.graphics;
  
  import android.content.Context;
  import android.content.res.Resources;
  import android.graphics.Bitmap;
  import android.graphics.BlurMaskFilter;
  import android.graphics.Canvas;
  import android.graphics.Color;
  import android.graphics.Paint;
  import android.graphics.PorterDuff;
  import android.graphics.PorterDuffXfermode;
  import android.graphics.Rect;
  import android.graphics.drawable.Drawable;
  import android.util.SparseArray;
  
  import com.android.launcher3.BubbleTextView;
  import com.android.launcher3.R;
  import com.android.launcher3.config.FeatureFlags;
  
  import java.nio.ByteBuffer;
  
  /**
   * Utility class to generate shadow and outline effect, which are used for click feedback
   * and drag-n-drop respectively.
   */
  public class HolographicOutlineHelper {
  
      private static HolographicOutlineHelper sInstance;
  
      private final Canvas mCanvas = new Canvas();
      private final Paint mDrawPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
      private final Paint mBlurPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
      private final Paint mErasePaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
  
      private final BlurMaskFilter mMediumOuterBlurMaskFilter;
      private final BlurMaskFilter mThinOuterBlurMaskFilter;
      private final BlurMaskFilter mMediumInnerBlurMaskFilter;
  
      private final float mShadowBitmapShift;
      private final BlurMaskFilter mShadowBlurMaskFilter;
  
      // We have 4 different icon sizes: homescreen, hotseat, folder & all-apps
      private final SparseArray<Bitmap> mBitmapCache = new SparseArray<>(4);
  
      private HolographicOutlineHelper(Context context) {
          Resources res = context.getResources();
  
          float mediumBlur = res.getDimension(R.dimen.blur_size_medium_outline);
          mMediumOuterBlurMaskFilter = new BlurMaskFilter(mediumBlur, BlurMaskFilter.Blur.OUTER);
          mMediumInnerBlurMaskFilter = new BlurMaskFilter(mediumBlur, BlurMaskFilter.Blur.NORMAL);
  
          mThinOuterBlurMaskFilter = new BlurMaskFilter(
                  res.getDimension(R.dimen.blur_size_thin_outline), BlurMaskFilter.Blur.OUTER);
  
          mShadowBitmapShift = res.getDimension(R.dimen.blur_size_click_shadow);
          mShadowBlurMaskFilter = new BlurMaskFilter(mShadowBitmapShift, BlurMaskFilter.Blur.NORMAL);
  
          mErasePaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));
      }
  
      public static HolographicOutlineHelper getInstance(Context context) {
          if (sInstance == null) {
              sInstance = new HolographicOutlineHelper(context.getApplicationContext());
          }
          return sInstance;
      }
  
      /**
       * Applies a more expensive and accurate outline to whatever is currently drawn in a specified
       * bitmap.
       */
      public void applyExpensiveOutlineWithBlur(Bitmap srcDst, Canvas srcDstCanvas) {
          if (FeatureFlags.IS_DOGFOOD_BUILD && srcDst.getConfig() != Bitmap.Config.ALPHA_8) {
              throw new RuntimeException("Outline blue is only supported on alpha bitmaps");
          }
  
          // We start by removing most of the alpha channel so as to ignore shadows, and
          // other types of partial transparency when defining the shape of the object
          byte[] pixels = new byte[srcDst.getWidth() * srcDst.getHeight()];
          ByteBuffer buffer = ByteBuffer.wrap(pixels);
          buffer.rewind();
          srcDst.copyPixelsToBuffer(buffer);
  
          for (int i = 0; i < pixels.length; i++) {
              if ((pixels[i] & 0xFF) < 188) {
                  pixels[i] = 0;
              }
          }
  
          buffer.rewind();
          srcDst.copyPixelsFromBuffer(buffer);
  
          // calculate the outer blur first
          mBlurPaint.setMaskFilter(mMediumOuterBlurMaskFilter);
          int[] outerBlurOffset = new int[2];
          Bitmap thickOuterBlur = srcDst.extractAlpha(mBlurPaint, outerBlurOffset);
  
          mBlurPaint.setMaskFilter(mThinOuterBlurMaskFilter);
          int[] brightOutlineOffset = new int[2];
          Bitmap brightOutline = srcDst.extractAlpha(mBlurPaint, brightOutlineOffset);
  
          // calculate the inner blur
          srcDstCanvas.setBitmap(srcDst);
          srcDstCanvas.drawColor(0xFF000000, PorterDuff.Mode.SRC_OUT);
          mBlurPaint.setMaskFilter(mMediumInnerBlurMaskFilter);
          int[] thickInnerBlurOffset = new int[2];
          Bitmap thickInnerBlur = srcDst.extractAlpha(mBlurPaint, thickInnerBlurOffset);
  
          // mask out the inner blur
          srcDstCanvas.setBitmap(thickInnerBlur);
          srcDstCanvas.drawBitmap(srcDst, -thickInnerBlurOffset[0],
                  -thickInnerBlurOffset[1], mErasePaint);
          srcDstCanvas.drawRect(0, 0, -thickInnerBlurOffset[0], thickInnerBlur.getHeight(),
                  mErasePaint);
          srcDstCanvas.drawRect(0, 0, thickInnerBlur.getWidth(), -thickInnerBlurOffset[1],
                  mErasePaint);
  
          // draw the inner and outer blur
          srcDstCanvas.setBitmap(srcDst);
          srcDstCanvas.drawColor(0, PorterDuff.Mode.CLEAR);
          srcDstCanvas.drawBitmap(thickInnerBlur, thickInnerBlurOffset[0], thickInnerBlurOffset[1],
                  mDrawPaint);
          srcDstCanvas.drawBitmap(thickOuterBlur, outerBlurOffset[0], outerBlurOffset[1],
                  mDrawPaint);
  
          // draw the bright outline
          srcDstCanvas.drawBitmap(brightOutline, brightOutlineOffset[0], brightOutlineOffset[1],
                  mDrawPaint);
  
          // cleanup
          srcDstCanvas.setBitmap(null);
          brightOutline.recycle();
          thickOuterBlur.recycle();
          thickInnerBlur.recycle();
      }
  
      public Bitmap createMediumDropShadow(BubbleTextView view) {
          Drawable drawable = view.getIcon();
          if (drawable == null) {
              return null;
          }
  
          float scaleX = view.getScaleX();
          float scaleY = view.getScaleY();
          Rect rect = drawable.getBounds();
  
          int bitmapWidth = (int) (rect.width() * scaleX);
          int bitmapHeight = (int) (rect.height() * scaleY);
          if (bitmapHeight <= 0 || bitmapWidth <= 0) {
              return null;
          }
  
          int key = (bitmapWidth << 16) | bitmapHeight;
          Bitmap cache = mBitmapCache.get(key);
          if (cache == null) {
              cache = Bitmap.createBitmap(bitmapWidth, bitmapHeight, Bitmap.Config.ALPHA_8);
              mCanvas.setBitmap(cache);
              mBitmapCache.put(key, cache);
          } else {
              mCanvas.setBitmap(cache);
              mCanvas.drawColor(Color.BLACK, PorterDuff.Mode.CLEAR);
          }
  
          int saveCount = mCanvas.save();
          mCanvas.scale(scaleX, scaleY);
          mCanvas.translate(-rect.left, -rect.top);
          drawable.draw(mCanvas);
          mCanvas.restoreToCount(saveCount);
          mCanvas.setBitmap(null);
  
          mBlurPaint.setMaskFilter(mShadowBlurMaskFilter);
  
          int extraSize = (int) (2 * mShadowBitmapShift);
  
          int resultWidth = bitmapWidth + extraSize;
          int resultHeight = bitmapHeight + extraSize;
          key = (resultWidth << 16) | resultHeight;
          Bitmap result = mBitmapCache.get(key);
          if (result == null) {
              result = Bitmap.createBitmap(resultWidth, resultHeight, Bitmap.Config.ALPHA_8);
              mCanvas.setBitmap(result);
          } else {
              // Use put instead of delete, to avoid unnecessary shrinking of cache array
              mBitmapCache.put(key, null);
              mCanvas.setBitmap(result);
              mCanvas.drawColor(Color.BLACK, PorterDuff.Mode.CLEAR);
          }
          mCanvas.drawBitmap(cache, mShadowBitmapShift, mShadowBitmapShift, mBlurPaint);
          mCanvas.setBitmap(null);
          return result;
      }
  
      public void recycleShadowBitmap(Bitmap bitmap) {
          if (bitmap != null) {
              mBitmapCache.put((bitmap.getWidth() << 16) | bitmap.getHeight(), bitmap);
          }
      }
  }
  