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 androidx.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.view.View;
22
23import androidx.leanback.R;
24
25/**
26 * Helper class for assigning a dim color to Paint. It holds the alpha value for
27 * the current active level.
28 */
29public final class ColorOverlayDimmer {
30
31    private final float mActiveLevel;
32    private final float mDimmedLevel;
33
34    private final Paint mPaint;
35
36    private int mAlpha;
37    private float mAlphaFloat;
38
39    /**
40     * Creates a default ColorOverlayDimmer.
41     */
42    public static ColorOverlayDimmer createDefault(Context context) {
43        TypedArray a = context.obtainStyledAttributes(R.styleable.LeanbackTheme);
44
45        int dimColor = a.getColor(R.styleable.LeanbackTheme_overlayDimMaskColor,
46                context.getResources().getColor(R.color.lb_view_dim_mask_color));
47        float activeLevel = a.getFraction(R.styleable.LeanbackTheme_overlayDimActiveLevel, 1, 1,
48                context.getResources().getFraction(R.fraction.lb_view_active_level, 1, 0));
49        float dimmedLevel = a.getFraction(R.styleable.LeanbackTheme_overlayDimDimmedLevel, 1, 1,
50                context.getResources().getFraction(R.fraction.lb_view_dimmed_level, 1, 1));
51        a.recycle();
52        return new ColorOverlayDimmer(dimColor, activeLevel, dimmedLevel);
53    }
54
55    /**
56     * Creates a ColorOverlayDimmer for the given color and levels.
57     *
58     * @param dimColor    The color for fully dimmed. Only the RGB values are
59     *                    used; the alpha channel is ignored.
60     * @param activeLevel The level of dimming when the View is in its active
61     *                    state. Must be a float value between 0.0 and 1.0.
62     * @param dimmedLevel The level of dimming when the View is in its dimmed
63     *                    state. Must be a float value between 0.0 and 1.0.
64     */
65    public static ColorOverlayDimmer createColorOverlayDimmer(int dimColor, float activeLevel,
66            float dimmedLevel) {
67        return new ColorOverlayDimmer(dimColor, activeLevel, dimmedLevel);
68    }
69
70    private ColorOverlayDimmer(int dimColor, float activeLevel, float dimmedLevel) {
71        if (activeLevel > 1.0f) activeLevel = 1.0f;
72        if (activeLevel < 0.0f) activeLevel = 0.0f;
73        if (dimmedLevel > 1.0f) dimmedLevel = 1.0f;
74        if (dimmedLevel < 0.0f) dimmedLevel = 0.0f;
75        mPaint = new Paint();
76        dimColor = Color.rgb(Color.red(dimColor), Color.green(dimColor), Color.blue(dimColor));
77        mPaint.setColor(dimColor);
78        mActiveLevel = activeLevel;
79        mDimmedLevel = dimmedLevel;
80        setActiveLevel(1);
81    }
82
83    /**
84     * Sets the active level of the dimmer. Updates the alpha value based on the
85     * level.
86     *
87     * @param level A float between 0 (fully dim) and 1 (fully active).
88     */
89    public void setActiveLevel(float level) {
90        mAlphaFloat = (mDimmedLevel + level * (mActiveLevel - mDimmedLevel));
91        mAlpha = (int) (255 * mAlphaFloat);
92        mPaint.setAlpha(mAlpha);
93    }
94
95    /**
96     * Returns whether the dimmer needs to draw.
97     */
98    public boolean needsDraw() {
99        return mAlpha != 0;
100    }
101
102    /**
103     * Returns the alpha value for the dimmer.
104     */
105    public int getAlpha() {
106        return mAlpha;
107    }
108
109    /**
110     * Returns the float value between 0 and 1 corresponding to alpha between
111     * 0 and 255.
112     */
113    public float getAlphaFloat() {
114        return mAlphaFloat;
115    }
116
117    /**
118     * Returns the Paint object set to the current alpha value.
119     */
120    public Paint getPaint() {
121        return mPaint;
122    }
123
124    /**
125     * Change the RGB of the color according to current dim level. Maintains the
126     * alpha value of the color.
127     *
128     * @param color The color to apply the dim level to.
129     * @return A color with the RGB values adjusted by the alpha of the current
130     *         dim level.
131     */
132    public int applyToColor(int color) {
133        float f = 1 - mAlphaFloat;
134        return Color.argb(Color.alpha(color),
135                (int)(Color.red(color) * f),
136                (int)(Color.green(color) * f),
137                (int)(Color.blue(color) * f));
138    }
139
140    /**
141     * Draw a dim color overlay on top of a child View inside the canvas of
142     * the parent View.
143     *
144     * @param c Canvas of the parent View.
145     * @param v A child of the parent View.
146     * @param includePadding Set to true to draw overlay on padding area of the
147     *        View.
148     */
149    public void drawColorOverlay(Canvas c, View v, boolean includePadding) {
150        c.save();
151        float dx = v.getLeft() + v.getTranslationX();
152        float dy = v.getTop() + v.getTranslationY();
153        c.translate(dx, dy);
154        c.concat(v.getMatrix());
155        c.translate(-dx, -dy);
156        if (includePadding) {
157            c.drawRect(v.getLeft(), v.getTop(), v.getRight(), v.getBottom(), mPaint);
158        } else {
159            c.drawRect(v.getLeft() + v.getPaddingLeft(),
160                    v.getTop() + v.getPaddingTop(),
161                    v.getRight() - v.getPaddingRight(),
162                    v.getBottom() - v.getPaddingBottom(), mPaint);
163        }
164        c.restore();
165    }
166}
167