ColorFilterDimmer.java revision cf94c5fa8ae8edb7e26a623133207415ceeed187 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
5 * in compliance with the License. You may obtain a copy of the License at
6 *
7 * http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software distributed under the License
10 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
11 * or implied. See the License for the specific language governing permissions and limitations under
12 * the License.
13 */
14package android.support.v17.leanback.graphics;
15
16import android.content.Context;
17import android.graphics.ColorFilter;
18import android.graphics.Paint;
19import android.view.View;
20import android.support.v17.leanback.R;
21
22/**
23 * Helper class for applying dim level to view(s).  The ColorFilterDimmer
24 * holds a Paint object and ColorFilter corresponding to current "active" level.
25 */
26public final class ColorFilterDimmer {
27
28    private final ColorFilterCache mColorDimmer;
29
30    private final float mActiveLevel;
31    private final float mDimmedLevel;
32
33    private final Paint mPaint;
34    private ColorFilter mFilter;
35
36    /**
37     * Create a default ColorFilterDimmer.
38     */
39    public static ColorFilterDimmer createDefault(Context context) {
40        return new ColorFilterDimmer(ColorFilterCache.getColorFilterCache(
41                context.getResources().getColor(R.color.lb_view_dim_mask_color)),
42                0, context.getResources().getFraction(R.dimen.lb_view_dimmed_level, 1, 1));
43    }
44
45    /**
46     * Create a ColorFilterDimmer.
47     *
48     * @param dimmer      The ColorFilterCache for dim color.
49     * @param activeLevel The level of dimming for when the view is in its active state. Must be a
50     *                    float value between 0.0 and 1.0.
51     * @param dimmedLevel The level of dimming for when the view is in its dimmed state. Must be a
52     *                    float value between 0.0 and 1.0.
53     */
54    public static ColorFilterDimmer create(ColorFilterCache dimmer,
55            float activeLevel, float dimmedLevel) {
56        return new ColorFilterDimmer(dimmer, activeLevel, dimmedLevel);
57    }
58
59    private ColorFilterDimmer(ColorFilterCache dimmer, float activeLevel, float dimmedLevel) {
60        mColorDimmer = dimmer;
61        mActiveLevel = activeLevel;
62        mDimmedLevel = dimmedLevel;
63        mPaint = new Paint();
64    }
65
66    /**
67     * Apply current ColorFilter to a view, will assign and remove hardware layer of the view.
68     */
69    public void applyFilterToView(View view) {
70        if (mFilter != null) {
71            view.setLayerType(View.LAYER_TYPE_HARDWARE, mPaint);
72        } else {
73            view.setLayerType(View.LAYER_TYPE_NONE, null);
74        }
75        // FIXME: Current framework has bug that not triggering invalidate when change layer
76        // paint.  Will add conditional sdk version check once bug is fixed in released
77        // framework.
78        view.invalidate();
79    }
80
81    /**
82     * Sets the active level and change internal filter and paint.
83     * @param level Between 0 for dim and 1 for fully active.
84     */
85    public void setActiveLevel(float level) {
86        mFilter = mColorDimmer.getFilterForLevel(
87                mDimmedLevel + level * (mActiveLevel - mDimmedLevel));
88        mPaint.setColorFilter(mFilter);
89    }
90
91    /**
92     * Gets the color filter set to current dim level.
93     */
94    public ColorFilter getColorFilter() {
95        return mFilter;
96    }
97
98    /**
99     * Gets the paint object set to current dim level.
100     */
101    public Paint getPaint() {
102        return mPaint;
103    }
104
105}
106