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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.systemui.recent;
     18 
     19 import android.content.Context;
     20 import android.content.res.TypedArray;
     21 import android.graphics.Canvas;
     22 import android.graphics.LinearGradient;
     23 import android.graphics.Matrix;
     24 import android.graphics.Paint;
     25 import android.graphics.Shader;
     26 import android.util.AttributeSet;
     27 import android.view.View;
     28 import android.view.ViewConfiguration;
     29 import android.widget.LinearLayout;
     30 
     31 import com.android.systemui.R;
     32 
     33 public class FadedEdgeDrawHelper {
     34     public static final boolean OPTIMIZE_SW_RENDERED_RECENTS = true;
     35     public static final boolean USE_DARK_FADE_IN_HW_ACCELERATED_MODE = true;
     36     private View mScrollView;
     37 
     38     private int mFadingEdgeLength;
     39     private boolean mIsVertical;
     40     private boolean mSoftwareRendered = false;
     41     private Paint mBlackPaint;
     42     private Paint mFadePaint;
     43     private Matrix mFadeMatrix;
     44     private LinearGradient mFade;
     45 
     46     public static FadedEdgeDrawHelper create(Context context,
     47             AttributeSet attrs, View scrollView, boolean isVertical) {
     48         boolean isTablet = context.getResources().
     49                 getBoolean(R.bool.config_recents_interface_for_tablets);
     50         if (!isTablet && (OPTIMIZE_SW_RENDERED_RECENTS || USE_DARK_FADE_IN_HW_ACCELERATED_MODE)) {
     51             return new FadedEdgeDrawHelper(context, attrs, scrollView, isVertical);
     52         } else {
     53             return null;
     54         }
     55     }
     56 
     57     public FadedEdgeDrawHelper(Context context,
     58             AttributeSet attrs, View scrollView, boolean isVertical) {
     59         mScrollView = scrollView;
     60         TypedArray a = context.obtainStyledAttributes(attrs, com.android.internal.R.styleable.View);
     61         mFadingEdgeLength = a.getDimensionPixelSize(android.R.styleable.View_fadingEdgeLength,
     62                 ViewConfiguration.get(context).getScaledFadingEdgeLength());
     63         mIsVertical = isVertical;
     64     }
     65 
     66     public void onAttachedToWindowCallback(
     67             LinearLayout layout, boolean hardwareAccelerated) {
     68         mSoftwareRendered = !hardwareAccelerated;
     69         if ((mSoftwareRendered && OPTIMIZE_SW_RENDERED_RECENTS)
     70                 || USE_DARK_FADE_IN_HW_ACCELERATED_MODE) {
     71             mScrollView.setVerticalFadingEdgeEnabled(false);
     72             mScrollView.setHorizontalFadingEdgeEnabled(false);
     73         }
     74     }
     75 
     76     public void addViewCallback(View newLinearLayoutChild) {
     77         if (mSoftwareRendered && OPTIMIZE_SW_RENDERED_RECENTS) {
     78             final RecentsPanelView.ViewHolder holder =
     79                     (RecentsPanelView.ViewHolder) newLinearLayoutChild.getTag();
     80             holder.labelView.setDrawingCacheEnabled(true);
     81             holder.labelView.buildDrawingCache();
     82         }
     83     }
     84 
     85     public void drawCallback(Canvas canvas,
     86             int left, int right, int top, int bottom, int scrollX, int scrollY,
     87             float topFadingEdgeStrength, float bottomFadingEdgeStrength,
     88             float leftFadingEdgeStrength, float rightFadingEdgeStrength, int mPaddingTop) {
     89 
     90         if ((mSoftwareRendered && OPTIMIZE_SW_RENDERED_RECENTS)
     91                 || USE_DARK_FADE_IN_HW_ACCELERATED_MODE) {
     92             if (mFadePaint == null) {
     93                 mFadePaint = new Paint();
     94                 mFadeMatrix = new Matrix();
     95                 // use use a height of 1, and then wack the matrix each time we
     96                 // actually use it.
     97                 mFade = new LinearGradient(0, 0, 0, 1, 0xCC000000, 0, Shader.TileMode.CLAMP);
     98                 // PULL OUT THIS CONSTANT
     99                 mFadePaint.setShader(mFade);
    100             }
    101 
    102             // draw the fade effect
    103             boolean drawTop = false;
    104             boolean drawBottom = false;
    105             boolean drawLeft = false;
    106             boolean drawRight = false;
    107 
    108             float topFadeStrength = 0.0f;
    109             float bottomFadeStrength = 0.0f;
    110             float leftFadeStrength = 0.0f;
    111             float rightFadeStrength = 0.0f;
    112 
    113             final float fadeHeight = mFadingEdgeLength;
    114             int length = (int) fadeHeight;
    115 
    116             // clip the fade length if top and bottom fades overlap
    117             // overlapping fades produce odd-looking artifacts
    118             if (mIsVertical && (top + length > bottom - length)) {
    119                 length = (bottom - top) / 2;
    120             }
    121 
    122             // also clip horizontal fades if necessary
    123             if (!mIsVertical && (left + length > right - length)) {
    124                 length = (right - left) / 2;
    125             }
    126 
    127             if (mIsVertical) {
    128                 topFadeStrength = Math.max(0.0f, Math.min(1.0f, topFadingEdgeStrength));
    129                 drawTop = topFadeStrength * fadeHeight > 1.0f;
    130                 bottomFadeStrength = Math.max(0.0f, Math.min(1.0f, bottomFadingEdgeStrength));
    131                 drawBottom = bottomFadeStrength * fadeHeight > 1.0f;
    132             }
    133 
    134             if (!mIsVertical) {
    135                 leftFadeStrength = Math.max(0.0f, Math.min(1.0f, leftFadingEdgeStrength));
    136                 drawLeft = leftFadeStrength * fadeHeight > 1.0f;
    137                 rightFadeStrength = Math.max(0.0f, Math.min(1.0f, rightFadingEdgeStrength));
    138                 drawRight = rightFadeStrength * fadeHeight > 1.0f;
    139             }
    140 
    141             if (drawTop) {
    142                 mFadeMatrix.setScale(1, fadeHeight * topFadeStrength);
    143                 mFadeMatrix.postTranslate(left, top);
    144                 mFade.setLocalMatrix(mFadeMatrix);
    145                 canvas.drawRect(left, top, right, top + length, mFadePaint);
    146 
    147                 if (mBlackPaint == null) {
    148                     // Draw under the status bar at the top
    149                     mBlackPaint = new Paint();
    150                     mBlackPaint.setColor(0xFF000000);
    151                 }
    152                 canvas.drawRect(left, top - mPaddingTop, right, top, mBlackPaint);
    153             }
    154 
    155             if (drawBottom) {
    156                 mFadeMatrix.setScale(1, fadeHeight * bottomFadeStrength);
    157                 mFadeMatrix.postRotate(180);
    158                 mFadeMatrix.postTranslate(left, bottom);
    159                 mFade.setLocalMatrix(mFadeMatrix);
    160                 canvas.drawRect(left, bottom - length, right, bottom, mFadePaint);
    161             }
    162 
    163             if (drawLeft) {
    164                 mFadeMatrix.setScale(1, fadeHeight * leftFadeStrength);
    165                 mFadeMatrix.postRotate(-90);
    166                 mFadeMatrix.postTranslate(left, top);
    167                 mFade.setLocalMatrix(mFadeMatrix);
    168                 canvas.drawRect(left, top, left + length, bottom, mFadePaint);
    169             }
    170 
    171             if (drawRight) {
    172                 mFadeMatrix.setScale(1, fadeHeight * rightFadeStrength);
    173                 mFadeMatrix.postRotate(90);
    174                 mFadeMatrix.postTranslate(right, top);
    175                 mFade.setLocalMatrix(mFadeMatrix);
    176                 canvas.drawRect(right - length, top, right, bottom, mFadePaint);
    177             }
    178         }
    179     }
    180 
    181     public int getVerticalFadingEdgeLength() {
    182         return mFadingEdgeLength;
    183     }
    184 
    185     public int getHorizontalFadingEdgeLength() {
    186         return mFadingEdgeLength;
    187     }
    188 
    189 }
    190