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.content.res.TypedArray;
18import android.graphics.Canvas;
19import android.graphics.Color;
20import android.graphics.Paint;
21import android.support.v17.leanback.R;
22import android.view.View;
23
24/**
25 * Helper class for assigning a dim color to Paint. It holds the alpha value for
26 * the current active level.
27 */
28public final class ColorOverlayDimmer {
29
30    private final float mActiveLevel;
31    private final float mDimmedLevel;
32
33    private final Paint mPaint;
34
35    private int mAlpha;
36    private float mAlphaFloat;
37
38    /**
39     * Creates a default ColorOverlayDimmer.
40     */
41    public static ColorOverlayDimmer createDefault(Context context) {
42        TypedArray a = context.obtainStyledAttributes(R.styleable.LeanbackTheme);
43
44        int dimColor = a.getColor(R.styleable.LeanbackTheme_overlayDimMaskColor,
45                context.getResources().getColor(R.color.lb_view_dim_mask_color));
46        float activeLevel = a.getFraction(R.styleable.LeanbackTheme_overlayDimActiveLevel, 1, 1,
47                context.getResources().getFraction(R.fraction.lb_view_active_level, 1, 0));
48        float dimmedLevel = a.getFraction(R.styleable.LeanbackTheme_overlayDimDimmedLevel, 1, 1,
49                context.getResources().getFraction(R.fraction.lb_view_dimmed_level, 1, 1));
50        a.recycle();
51        return new ColorOverlayDimmer(dimColor, activeLevel, dimmedLevel);
52    }
53
54    /**
55     * Creates a ColorOverlayDimmer for the given color and levels.
56     *
57     * @param dimColor    The color for fully dimmed. Only the RGB values are
58     *                    used; the alpha channel is ignored.
59     * @param activeLevel The level of dimming when the View is in its active
60     *                    state. Must be a float value between 0.0 and 1.0.
61     * @param dimmedLevel The level of dimming when the View is in its dimmed
62     *                    state. Must be a float value between 0.0 and 1.0.
63     */
64    public static ColorOverlayDimmer createColorOverlayDimmer(int dimColor, float activeLevel,
65            float dimmedLevel) {
66        return new ColorOverlayDimmer(dimColor, activeLevel, dimmedLevel);
67    }
68
69    private ColorOverlayDimmer(int dimColor, float activeLevel, float dimmedLevel) {
70        if (activeLevel > 1.0f) activeLevel = 1.0f;
71        if (activeLevel < 0.0f) activeLevel = 0.0f;
72        if (dimmedLevel > 1.0f) dimmedLevel = 1.0f;
73        if (dimmedLevel < 0.0f) dimmedLevel = 0.0f;
74        mPaint = new Paint();
75        dimColor = Color.rgb(Color.red(dimColor), Color.green(dimColor), Color.blue(dimColor));
76        mPaint.setColor(dimColor);
77        mActiveLevel = activeLevel;
78        mDimmedLevel = dimmedLevel;
79        setActiveLevel(1);
80    }
81
82    /**
83     * Sets the active level of the dimmer. Updates the alpha value based on the
84     * level.
85     *
86     * @param level A float between 0 (fully dim) and 1 (fully active).
87     */
88    public void setActiveLevel(float level) {
89        mAlphaFloat = (mDimmedLevel + level * (mActiveLevel - mDimmedLevel));
90        mAlpha = (int) (255 * mAlphaFloat);
91        mPaint.setAlpha(mAlpha);
92    }
93
94    /**
95     * Returns whether the dimmer needs to draw.
96     */
97    public boolean needsDraw() {
98        return mAlpha != 0;
99    }
100
101    /**
102     * Returns the alpha value for the dimmer.
103     */
104    public int getAlpha() {
105        return mAlpha;
106    }
107
108    /**
109     * Returns the float value between 0 and 1 corresponding to alpha between
110     * 0 and 255.
111     */
112    public float getAlphaFloat() {
113        return mAlphaFloat;
114    }
115
116    /**
117     * Returns the Paint object set to the current alpha value.
118     */
119    public Paint getPaint() {
120        return mPaint;
121    }
122
123    /**
124     * Change the RGB of the color according to current dim level. Maintains the
125     * alpha value of the color.
126     *
127     * @param color The color to apply the dim level to.
128     * @return A color with the RGB values adjusted by the alpha of the current
129     *         dim level.
130     */
131    public int applyToColor(int color) {
132        float f = 1 - mAlphaFloat;
133        return Color.argb(Color.alpha(color),
134                (int)(Color.red(color) * f),
135                (int)(Color.green(color) * f),
136                (int)(Color.blue(color) * f));
137    }
138
139    /**
140     * Draw a dim color overlay on top of a child View inside the canvas of
141     * the parent View.
142     *
143     * @param c Canvas of the parent View.
144     * @param v A child of the parent View.
145     * @param includePadding Set to true to draw overlay on padding area of the
146     *        View.
147     */
148    public void drawColorOverlay(Canvas c, View v, boolean includePadding) {
149        c.save();
150        float dx = v.getLeft() + v.getTranslationX();
151        float dy = v.getTop() + v.getTranslationY();
152        c.translate(dx, dy);
153        c.concat(v.getMatrix());
154        c.translate(-dx, -dy);
155        if (includePadding) {
156            c.drawRect(v.getLeft(), v.getTop(), v.getRight(), v.getBottom(), mPaint);
157        } else {
158            c.drawRect(v.getLeft() + v.getPaddingLeft(),
159                    v.getTop() + v.getPaddingTop(),
160                    v.getRight() - v.getPaddingRight(),
161                    v.getBottom() - v.getPaddingBottom(), mPaint);
162        }
163        c.restore();
164    }
165}
166