Home | History | Annotate | Download | only in util 
      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 
     17 package com.android.launcher3.util;
     18 
     19 import android.content.Context;
     20 import android.content.res.TypedArray;
     21 import android.graphics.Color;
     22 import android.graphics.ColorMatrix;
     23 import android.view.ContextThemeWrapper;
     24 
     25 /**
     26  * Various utility methods associated with theming.
     27  */
     28 public class Themes {
     29 
     30     public static int getColorAccent(Context context) {
     31         return getAttrColor(context, android.R.attr.colorAccent);
     32     }
     33 
     34     public static int getColorPrimary(Context context, int theme) {
     35         return getAttrColor(new ContextThemeWrapper(context, theme), android.R.attr.colorPrimary);
     36     }
     37 
     38     public static int getAttrColor(Context context, int attr) {
     39         TypedArray ta = context.obtainStyledAttributes(new int[]{attr});
     40         int colorAccent = ta.getColor(0, 0);
     41         ta.recycle();
     42         return colorAccent;
     43     }
     44 
     45     /**
     46      * Returns the alpha corresponding to the theme attribute {@param attr}, in the range [0, 255].
     47      */
     48     public static int getAlpha(Context context, int attr) {
     49         TypedArray ta = context.obtainStyledAttributes(new int[]{attr});
     50         float alpha = ta.getFloat(0, 0);
     51         ta.recycle();
     52         return (int) (255 * alpha + 0.5f);
     53     }
     54 
     55     /**
     56      * Scales a color matrix such that, when applied to color R G B A, it produces R' G' B' A' where
     57      * R' = r * R
     58      * G' = g * G
     59      * B' = b * B
     60      * A' = a * A
     61      *
     62      * The matrix will, for instance, turn white into r g b a, and black will remain black.
     63      *
     64      * @param color The color r g b a
     65      * @param target The ColorMatrix to scale
     66      */
     67     public static void setColorScaleOnMatrix(int color, ColorMatrix target) {
     68         target.setScale(Color.red(color) / 255f, Color.green(color) / 255f,
     69                 Color.blue(color) / 255f, Color.alpha(color) / 255f);
     70     }
     71 }
     72