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Reimplementation of some Color related Methods for Android versions < O (26)
/**
*
* Copyright © 2019 Paul Schaub
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package de.vanitasvitae.colors;
import androidx.annotation.ColorInt;
/**
* Utility class for colors. This class is necessary, since many useful methods for dealing with
* colors (eg. {@link android.graphics.Color#rgb(int, int, int)} were only introduced in API level
* 26 ({@link android.os.Build.VERSION_CODES#O}).
*/
public class ColorUtil {
/**
* Encode ARGB values as a color int.
* Reimplementation of {@link android.graphics.Color#argb(float, float, float, float)} for
* API levels < 26.
*
* @param a alpha
* @param r red
* @param g green
* @param b blue
* @return color int
*/
@ColorInt
public static int argb(float a, float r, float g, float b) {
int A = float2int(a);
int R = float2int(r);
int G = float2int(g);
int B = float2int(b);
return argb(A, R, G, B);
}
/**
* Encode ARGB values as a color int.
* Reimplementation of {@link android.graphics.Color#argb(int, int, int, int)} for
* API levels < 26.
*
* @see <a href="https://developer.android.com/reference/android/graphics/Color#encoding">
* Android developer reference: Color - Encoding</a>
*
* @param a alpha
* @param r red
* @param g green
* @param b blue
* @return color int
*/
@ColorInt
public static int argb(int a, int r, int g, int b) {
return (a & 0xff) << 24 | (r & 0xff) << 16 | (g & 0xff) << 8 | (b & 0xff);
}
/**
* Encode RGB values as a color int.
* Reimplementation of {@link android.graphics.Color#rgb(float, float, float)} for API levels
* < 26.
* @param r red
* @param g green
* @param b blue
* @return color int
*/
@ColorInt
public static int rgb(float r, float g, float b) {
return argb(1f, r, g, b);
}
/**
* Encode RGB values as a color int.
* Reimplementation of {@link android.graphics.Color#rgb(int, int, int)} for API levels
* < 26.
*
* @param r red
* @param g green
* @param b blue
* @return color int
*/
@ColorInt
public static int rgb(int r, int g, int b) {
return argb(255, r, g, b);
}
/**
* Return the alpha component of the color.
* Reimplementation of {@link android.graphics.Color#alpha(int)} for APIs lower than 26.
*
* @param color color
* @return alpha component
*
* @see <a href="https://developer.android.com/reference/android/graphics/Color#decoding">
* Android developer reference: Color - Decoding</a>
*/
public static int alpha(@ColorInt int color) {
return (color >> 24) & 0xff;
}
/**
* Return the red component of the color.
* Reimplementation of {@link android.graphics.Color#red(int)} for APIs lower than 26.
*
* @param color color
* @return red component
*
* @see <a href="https://developer.android.com/reference/android/graphics/Color#decoding">
* * Android developer reference: Color - Decoding</a>
*/
public static int red(@ColorInt int color) {
return (color >> 16) & 0xff;
}
/**
* Return the green component of the color.
* Reimplementation of {@link android.graphics.Color#green(int)} for APIs lower than 26.
*
* @param color color
* @return green component
*
* @see <a href="https://developer.android.com/reference/android/graphics/Color#decoding">
* * Android developer reference: Color - Decoding</a>
*/
public static int green(@ColorInt int color) {
return (color >> 8) & 0xff;
}
/**
* Return the blue component of the color.
* Reimplementation of {@link android.graphics.Color#blue(int)} for APIs lower than 26.
*
* @param color color
* @return blue component
*
* @see <a href="https://developer.android.com/reference/android/graphics/Color#decoding">
* * Android developer reference: Color - Decoding</a>
*/
public static int blue(@ColorInt int color) {
return (color ) & 0xff;
}
private static int float2int(float f) {
return Math.round(255 * f);
}
public static String toString(int color) {
return "#" + String.format("%08x", color);
}
}
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