KeyguardUserSwitcherScrim.java revision 2d1ef3012c98c07877816f3587514cca98609550 
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 */
16
17package com.android.systemui.statusbar.policy;
18
19import android.graphics.Canvas;
20import android.graphics.Color;
21import android.graphics.ColorFilter;
22import android.graphics.LightingColorFilter;
23import android.graphics.Paint;
24import android.graphics.PixelFormat;
25import android.graphics.RadialGradient;
26import android.graphics.Rect;
27import android.graphics.Shader;
28import android.graphics.drawable.Drawable;
29import android.util.LayoutDirection;
30import android.view.View;
31
32import com.android.systemui.R;
33
34/**
35 * Gradient background for the user switcher on Keyguard.
36 */
37public class KeyguardUserSwitcherScrim extends Drawable
38        implements View.OnLayoutChangeListener {
39
40    private static final float OUTER_EXTENT = 2.5f;
41    private static final float INNER_EXTENT = 0.75f;
42
43    private int mDarkColor;
44    private int mTop;
45    private int mAlpha = 255;
46    private Paint mRadialGradientPaint = new Paint();
47    private int mLayoutWidth;
48
49    public KeyguardUserSwitcherScrim(View host) {
50        host.addOnLayoutChangeListener(this);
51        mDarkColor = host.getResources().getColor(
52                R.color.keyguard_user_switcher_background_gradient_color);
53    }
54
55    @Override
56    public void draw(Canvas canvas) {
57        boolean isLtr = getLayoutDirection() == LayoutDirection.LTR;
58        Rect bounds = getBounds();
59        float width = bounds.width() * OUTER_EXTENT;
60        float height = (mTop + bounds.height()) * OUTER_EXTENT;
61        canvas.translate(0, -mTop);
62        canvas.scale(1, height / width);
63        canvas.drawRect(isLtr ? bounds.right - width : 0, 0,
64                isLtr ? bounds.right : bounds.left + width, width, mRadialGradientPaint);
65    }
66
67    @Override
68    public void setAlpha(int alpha) {
69        mAlpha = alpha;
70        updatePaint();
71        invalidateSelf();
72    }
73
74    @Override
75    public int getAlpha() {
76        return mAlpha;
77    }
78
79    @Override
80    public void setColorFilter(ColorFilter cf) {
81    }
82
83    @Override
84    public int getOpacity() {
85        return PixelFormat.TRANSLUCENT;
86    }
87
88    @Override
89    public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft,
90            int oldTop, int oldRight, int oldBottom) {
91        if (left != oldLeft || top != oldTop || right != oldRight || bottom != oldBottom) {
92            mLayoutWidth = right - left;
93            mTop = top;
94            updatePaint();
95        }
96    }
97
98    private void updatePaint() {
99        if (mLayoutWidth == 0) {
100            return;
101        }
102        float radius = mLayoutWidth * OUTER_EXTENT;
103        boolean isLtr = getLayoutDirection() == LayoutDirection.LTR;
104        mRadialGradientPaint.setShader(
105                new RadialGradient(isLtr ? mLayoutWidth : 0, 0, radius,
106                        new int[] { Color.argb(
107                                        (int) (Color.alpha(mDarkColor) * mAlpha / 255f), 0, 0, 0),
108                                Color.TRANSPARENT },
109                        new float[] { Math.max(0f, mLayoutWidth * INNER_EXTENT / radius), 1f },
110                        Shader.TileMode.CLAMP));
111    }
112}
113