1/*
2 * Copyright (C) 2017 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.launcher3.util;
18
19import android.content.Context;
20import android.content.res.TypedArray;
21import android.graphics.Color;
22import android.graphics.ColorMatrix;
23import android.graphics.drawable.Drawable;
24
25/**
26 * Various utility methods associated with theming.
27 */
28public class Themes {
29
30    public static int getColorAccent(Context context) {
31        return getAttrColor(context, android.R.attr.colorAccent);
32    }
33
34    public static int getAttrColor(Context context, int attr) {
35        TypedArray ta = context.obtainStyledAttributes(new int[]{attr});
36        int colorAccent = ta.getColor(0, 0);
37        ta.recycle();
38        return colorAccent;
39    }
40
41    public static boolean getAttrBoolean(Context context, int attr) {
42        TypedArray ta = context.obtainStyledAttributes(new int[]{attr});
43        boolean value = ta.getBoolean(0, false);
44        ta.recycle();
45        return value;
46    }
47
48    public static Drawable getAttrDrawable(Context context, int attr) {
49        TypedArray ta = context.obtainStyledAttributes(new int[]{attr});
50        Drawable value = ta.getDrawable(0);
51        ta.recycle();
52        return value;
53    }
54
55    public static int getAttrInteger(Context context, int attr) {
56        TypedArray ta = context.obtainStyledAttributes(new int[]{attr});
57        int value = ta.getInteger(0, 0);
58        ta.recycle();
59        return value;
60    }
61
62    /**
63     * Returns the alpha corresponding to the theme attribute {@param attr}, in the range [0, 255].
64     */
65    public static int getAlpha(Context context, int attr) {
66        TypedArray ta = context.obtainStyledAttributes(new int[]{attr});
67        float alpha = ta.getFloat(0, 0);
68        ta.recycle();
69        return (int) (255 * alpha + 0.5f);
70    }
71
72    /**
73     * Scales a color matrix such that, when applied to color R G B A, it produces R' G' B' A' where
74     * R' = r * R
75     * G' = g * G
76     * B' = b * B
77     * A' = a * A
78     *
79     * The matrix will, for instance, turn white into r g b a, and black will remain black.
80     *
81     * @param color The color r g b a
82     * @param target The ColorMatrix to scale
83     */
84    public static void setColorScaleOnMatrix(int color, ColorMatrix target) {
85        target.setScale(Color.red(color) / 255f, Color.green(color) / 255f,
86                Color.blue(color) / 255f, Color.alpha(color) / 255f);
87    }
88
89    /**
90     * Changes a color matrix such that, when applied to srcColor, it produces dstColor.
91     *
92     * Note that values on the last column of target ColorMatrix can be negative, and may result in
93     * negative values when applied on a color. Such negative values will be automatically shifted
94     * up to 0 by the framework.
95     *
96     * @param srcColor The color to start from
97     * @param dstColor The color to create by applying target on srcColor
98     * @param target The ColorMatrix to transform the color
99     */
100    public static void setColorChangeOnMatrix(int srcColor, int dstColor, ColorMatrix target) {
101        target.reset();
102        target.getArray()[4] = Color.red(dstColor) - Color.red(srcColor);
103        target.getArray()[9] = Color.green(dstColor) - Color.green(srcColor);
104        target.getArray()[14] = Color.blue(dstColor) - Color.blue(srcColor);
105        target.getArray()[19] = Color.alpha(dstColor) - Color.alpha(srcColor);
106    }
107}
108