1/*
2 * Copyright (C) 2014 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 */
16package com.android.systemui.recents.views;
17
18import android.content.res.Resources;
19import android.graphics.Canvas;
20import android.graphics.ColorFilter;
21import android.graphics.LinearGradient;
22import android.graphics.Paint;
23import android.graphics.Path;
24import android.graphics.PixelFormat;
25import android.graphics.RadialGradient;
26import android.graphics.Rect;
27import android.graphics.RectF;
28import android.graphics.Shader;
29import android.graphics.drawable.Drawable;
30import android.util.Log;
31
32import com.android.systemui.R;
33import com.android.systemui.recents.RecentsConfiguration;
34
35/**
36 * A rounded rectangle drawable which also includes a shadow around. This is mostly copied from
37 * frameworks/support/v7/cardview/eclair-mr1/android/support/v7/widget/
38 * RoundRectDrawableWithShadow.java revision c42ba8c000d1e6ce85e152dfc17089a0a69e739f with a few
39 * modifications to suit our needs in SystemUI.
40 */
41class FakeShadowDrawable extends Drawable {
42    // used to calculate content padding
43    final static double COS_45 = Math.cos(Math.toRadians(45));
44
45    final static float SHADOW_MULTIPLIER = 1.5f;
46
47    final float mInsetShadow; // extra shadow to avoid gaps between card and shadow
48
49    Paint mCornerShadowPaint;
50
51    Paint mEdgeShadowPaint;
52
53    final RectF mCardBounds;
54
55    float mCornerRadius;
56
57    Path mCornerShadowPath;
58
59    // updated value with inset
60    float mMaxShadowSize;
61
62    // actual value set by developer
63    float mRawMaxShadowSize;
64
65    // multiplied value to account for shadow offset
66    float mShadowSize;
67
68    // actual value set by developer
69    float mRawShadowSize;
70
71    private boolean mDirty = true;
72
73    private final int mShadowStartColor;
74
75    private final int mShadowEndColor;
76
77    private boolean mAddPaddingForCorners = true;
78
79    /**
80     * If shadow size is set to a value above max shadow, we print a warning
81     */
82    private boolean mPrintedShadowClipWarning = false;
83
84    public FakeShadowDrawable(Resources resources, RecentsConfiguration config) {
85        mShadowStartColor = resources.getColor(R.color.fake_shadow_start_color);
86        mShadowEndColor = resources.getColor(R.color.fake_shadow_end_color);
87        mInsetShadow = resources.getDimension(R.dimen.fake_shadow_inset);
88        setShadowSize(resources.getDimensionPixelSize(R.dimen.fake_shadow_size),
89                resources.getDimensionPixelSize(R.dimen.fake_shadow_size));
90        mCornerShadowPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG);
91        mCornerShadowPaint.setStyle(Paint.Style.FILL);
92        mCornerShadowPaint.setDither(true);
93        mCornerRadius = config.taskViewRoundedCornerRadiusPx;
94        mCardBounds = new RectF();
95        mEdgeShadowPaint = new Paint(mCornerShadowPaint);
96    }
97
98    @Override
99    public void setAlpha(int alpha) {
100        mCornerShadowPaint.setAlpha(alpha);
101        mEdgeShadowPaint.setAlpha(alpha);
102    }
103
104    @Override
105    protected void onBoundsChange(Rect bounds) {
106        super.onBoundsChange(bounds);
107        mDirty = true;
108    }
109
110    void setShadowSize(float shadowSize, float maxShadowSize) {
111        if (shadowSize < 0 || maxShadowSize < 0) {
112            throw new IllegalArgumentException("invalid shadow size");
113        }
114        if (shadowSize > maxShadowSize) {
115            shadowSize = maxShadowSize;
116            if (!mPrintedShadowClipWarning) {
117                Log.w("CardView", "Shadow size is being clipped by the max shadow size. See "
118                        + "{CardView#setMaxCardElevation}.");
119                mPrintedShadowClipWarning = true;
120            }
121        }
122        if (mRawShadowSize == shadowSize && mRawMaxShadowSize == maxShadowSize) {
123            return;
124        }
125        mRawShadowSize = shadowSize;
126        mRawMaxShadowSize = maxShadowSize;
127        mShadowSize = shadowSize * SHADOW_MULTIPLIER + mInsetShadow;
128        mMaxShadowSize = maxShadowSize + mInsetShadow;
129        mDirty = true;
130        invalidateSelf();
131    }
132
133    @Override
134    public boolean getPadding(Rect padding) {
135        int vOffset = (int) Math.ceil(calculateVerticalPadding(mRawMaxShadowSize, mCornerRadius,
136                mAddPaddingForCorners));
137        int hOffset = (int) Math.ceil(calculateHorizontalPadding(mRawMaxShadowSize, mCornerRadius,
138                mAddPaddingForCorners));
139        padding.set(hOffset, vOffset, hOffset, vOffset);
140        return true;
141    }
142
143    static float calculateVerticalPadding(float maxShadowSize, float cornerRadius,
144            boolean addPaddingForCorners) {
145        if (addPaddingForCorners) {
146            return (float) (maxShadowSize * SHADOW_MULTIPLIER + (1 - COS_45) * cornerRadius);
147        } else {
148            return maxShadowSize * SHADOW_MULTIPLIER;
149        }
150    }
151
152    static float calculateHorizontalPadding(float maxShadowSize, float cornerRadius,
153            boolean addPaddingForCorners) {
154        if (addPaddingForCorners) {
155            return (float) (maxShadowSize + (1 - COS_45) * cornerRadius);
156        } else {
157            return maxShadowSize;
158        }
159    }
160
161    @Override
162    public void setColorFilter(ColorFilter cf) {
163        mCornerShadowPaint.setColorFilter(cf);
164        mEdgeShadowPaint.setColorFilter(cf);
165    }
166
167    @Override
168    public int getOpacity() {
169        return PixelFormat.OPAQUE;
170    }
171
172    @Override
173    public void draw(Canvas canvas) {
174        if (mDirty) {
175            buildComponents(getBounds());
176            mDirty = false;
177        }
178        canvas.translate(0, mRawShadowSize / 4);
179        drawShadow(canvas);
180        canvas.translate(0, -mRawShadowSize / 4);
181    }
182
183    private void drawShadow(Canvas canvas) {
184        final float edgeShadowTop = -mCornerRadius - mShadowSize;
185        final float inset = mCornerRadius + mInsetShadow + mRawShadowSize / 2;
186        final boolean drawHorizontalEdges = mCardBounds.width() - 2 * inset > 0;
187        final boolean drawVerticalEdges = mCardBounds.height() - 2 * inset > 0;
188        // LT
189        int saved = canvas.save();
190        canvas.translate(mCardBounds.left + inset, mCardBounds.top + inset);
191        canvas.drawPath(mCornerShadowPath, mCornerShadowPaint);
192        if (drawHorizontalEdges) {
193            canvas.drawRect(0, edgeShadowTop,
194                    mCardBounds.width() - 2 * inset, -mCornerRadius,
195                    mEdgeShadowPaint);
196        }
197        canvas.restoreToCount(saved);
198        // RB
199        saved = canvas.save();
200        canvas.translate(mCardBounds.right - inset, mCardBounds.bottom - inset);
201        canvas.rotate(180f);
202        canvas.drawPath(mCornerShadowPath, mCornerShadowPaint);
203        if (drawHorizontalEdges) {
204            canvas.drawRect(0, edgeShadowTop,
205                    mCardBounds.width() - 2 * inset, -mCornerRadius + mShadowSize,
206                    mEdgeShadowPaint);
207        }
208        canvas.restoreToCount(saved);
209        // LB
210        saved = canvas.save();
211        canvas.translate(mCardBounds.left + inset, mCardBounds.bottom - inset);
212        canvas.rotate(270f);
213        canvas.drawPath(mCornerShadowPath, mCornerShadowPaint);
214        if (drawVerticalEdges) {
215            canvas.drawRect(0, edgeShadowTop,
216                    mCardBounds.height() - 2 * inset, -mCornerRadius, mEdgeShadowPaint);
217        }
218        canvas.restoreToCount(saved);
219        // RT
220        saved = canvas.save();
221        canvas.translate(mCardBounds.right - inset, mCardBounds.top + inset);
222        canvas.rotate(90f);
223        canvas.drawPath(mCornerShadowPath, mCornerShadowPaint);
224        if (drawVerticalEdges) {
225            canvas.drawRect(0, edgeShadowTop,
226                    mCardBounds.height() - 2 * inset, -mCornerRadius, mEdgeShadowPaint);
227        }
228        canvas.restoreToCount(saved);
229    }
230
231    private void buildShadowCorners() {
232        RectF innerBounds = new RectF(-mCornerRadius, -mCornerRadius, mCornerRadius, mCornerRadius);
233        RectF outerBounds = new RectF(innerBounds);
234        outerBounds.inset(-mShadowSize, -mShadowSize);
235
236        if (mCornerShadowPath == null) {
237            mCornerShadowPath = new Path();
238        } else {
239            mCornerShadowPath.reset();
240        }
241        mCornerShadowPath.setFillType(Path.FillType.EVEN_ODD);
242        mCornerShadowPath.moveTo(-mCornerRadius, 0);
243        mCornerShadowPath.rLineTo(-mShadowSize, 0);
244        // outer arc
245        mCornerShadowPath.arcTo(outerBounds, 180f, 90f, false);
246        // inner arc
247        mCornerShadowPath.arcTo(innerBounds, 270f, -90f, false);
248        mCornerShadowPath.close();
249
250        float startRatio = mCornerRadius / (mCornerRadius + mShadowSize);
251        mCornerShadowPaint.setShader(new RadialGradient(0, 0, mCornerRadius + mShadowSize,
252                new int[]{mShadowStartColor, mShadowStartColor, mShadowEndColor},
253                new float[]{0f, startRatio, 1f}
254                , Shader.TileMode.CLAMP));
255
256        // we offset the content shadowSize/2 pixels up to make it more realistic.
257        // this is why edge shadow shader has some extra space
258        // When drawing bottom edge shadow, we use that extra space.
259        mEdgeShadowPaint.setShader(new LinearGradient(0, -mCornerRadius + mShadowSize, 0,
260                -mCornerRadius - mShadowSize,
261                new int[]{mShadowStartColor, mShadowStartColor, mShadowEndColor},
262                new float[]{0f, .5f, 1f}, Shader.TileMode.CLAMP));
263    }
264
265    private void buildComponents(Rect bounds) {
266        // Card is offset SHADOW_MULTIPLIER * maxShadowSize to account for the shadow shift.
267        // We could have different top-bottom offsets to avoid extra gap above but in that case
268        // center aligning Views inside the CardView would be problematic.
269        final float verticalOffset = mMaxShadowSize * SHADOW_MULTIPLIER;
270        mCardBounds.set(bounds.left + mMaxShadowSize, bounds.top + verticalOffset,
271                bounds.right - mMaxShadowSize, bounds.bottom - verticalOffset);
272        buildShadowCorners();
273    }
274
275    float getMinWidth() {
276        final float content = 2 *
277                Math.max(mRawMaxShadowSize, mCornerRadius + mInsetShadow + mRawMaxShadowSize / 2);
278        return content + (mRawMaxShadowSize + mInsetShadow) * 2;
279    }
280
281    float getMinHeight() {
282        final float content = 2 * Math.max(mRawMaxShadowSize, mCornerRadius + mInsetShadow
283                        + mRawMaxShadowSize * SHADOW_MULTIPLIER / 2);
284        return content + (mRawMaxShadowSize * SHADOW_MULTIPLIER + mInsetShadow) * 2;
285    }
286}