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
17package com.android.systemui.recent;
18
19import android.content.Context;
20import android.content.res.TypedArray;
21import android.graphics.Canvas;
22import android.graphics.LinearGradient;
23import android.graphics.Matrix;
24import android.graphics.Paint;
25import android.graphics.Shader;
26import android.util.AttributeSet;
27import android.view.View;
28import android.view.ViewConfiguration;
29import android.widget.LinearLayout;
30
31import com.android.systemui.R;
32
33public 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                mFadePaint.setShader(mFade);
146                canvas.drawRect(left, top, right, top + length, mFadePaint);
147
148                if (mBlackPaint == null) {
149                    // Draw under the status bar at the top
150                    mBlackPaint = new Paint();
151                    mBlackPaint.setColor(0xFF000000);
152                }
153                canvas.drawRect(left, top - mPaddingTop, right, top, mBlackPaint);
154            }
155
156            if (drawBottom) {
157                mFadeMatrix.setScale(1, fadeHeight * bottomFadeStrength);
158                mFadeMatrix.postRotate(180);
159                mFadeMatrix.postTranslate(left, bottom);
160                mFade.setLocalMatrix(mFadeMatrix);
161                mFadePaint.setShader(mFade);
162                canvas.drawRect(left, bottom - length, right, bottom, mFadePaint);
163            }
164
165            if (drawLeft) {
166                mFadeMatrix.setScale(1, fadeHeight * leftFadeStrength);
167                mFadeMatrix.postRotate(-90);
168                mFadeMatrix.postTranslate(left, top);
169                mFade.setLocalMatrix(mFadeMatrix);
170                mFadePaint.setShader(mFade);
171                canvas.drawRect(left, top, left + length, bottom, mFadePaint);
172            }
173
174            if (drawRight) {
175                mFadeMatrix.setScale(1, fadeHeight * rightFadeStrength);
176                mFadeMatrix.postRotate(90);
177                mFadeMatrix.postTranslate(right, top);
178                mFade.setLocalMatrix(mFadeMatrix);
179                mFadePaint.setShader(mFade);
180                canvas.drawRect(right - length, top, right, bottom, mFadePaint);
181            }
182        }
183    }
184
185    public int getVerticalFadingEdgeLength() {
186        return mFadingEdgeLength;
187    }
188
189    public int getHorizontalFadingEdgeLength() {
190        return mFadingEdgeLength;
191    }
192
193}
194