Android Open Source - helsinki-testbed2-android Color Util

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License

The source code is released under:

GNU General Public License

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Java Source Code

package fi.testbed2.util;
/*from  w  w  w  .jav  a  2  s .co  m*/
/**
 * Utility class for color manipulation.
 */
public class ColorUtil {

    /**
     * Returns the opacity component of the ARGB color as a decimal format.
     *
     * @param argb Color in HEX format (either with or without alpha, e.g.
     *             #CCCCCC or #ffCCCCCC.
     * @return Value between 0.0...1.0 where 0.0 is completely transparent
     * and 1.0 means no transparency.
     */
    public static double getOpacityFromARGB(String argb) {
        int[] components = getARGBComponents(argb);
        double opacity = components[0]/255.0;

        if (opacity>1.0) {
            opacity = 1.0;
        } else if (opacity<0.0) {
            opacity = 0.0;
        }

        return opacity;
    }

    /**
     * Returns the color without alpha channel.
     *
     * @param argb Color in HEX format (either with or without alpha, e.g.
     *             #CCCCCC or #ffCCCCCC.
     * @return
     */
    public static String getColorWithoutAlpha(String argb) {
        int[] components = getARGBComponents(argb);
        return "#"+ getTwoDigitHexString(components[1])+
                getTwoDigitHexString(components[2])+
                getTwoDigitHexString(components[3]);
    }

    /**
     * Returns the ARGB color with inverted alpha channel.
     *
     * @param argb Color in HEX format (either with or without alpha, e.g.
     *             #CCCCCC or #ffCCCCCC.
     * @return
     */
    public static String getColorWithInvertedAplha(String argb) {

        int[] components = getARGBComponents(argb);
        components[0] = 255-components[0];

        return "#"+ getTwoDigitHexString(components[0])+
                    getTwoDigitHexString(components[1])+
                    getTwoDigitHexString(components[2])+
                    getTwoDigitHexString(components[3]);

    }

    /**
     * Return ARGB values in int array
     * @param argb Color in HEX format (either with or without alpha, e.g.
     *             #CCCCCC or #ffCCCCCC.
     * @return
     */
    private static int[] getARGBComponents(String argb) {

        if (argb.startsWith("#")) {
            argb = argb.replace("#", "");
        }

        int alpha = -1, red = -1, green = -1, blue = -1;

        if (argb.length() == 8) {
            alpha = Integer.parseInt(argb.substring(0, 2), 16);
            red = Integer.parseInt(argb.substring(2, 4), 16);
            green = Integer.parseInt(argb.substring(4, 6), 16);
            blue = Integer.parseInt(argb.substring(6, 8), 16);
        }
        else if (argb.length() == 6) {
            alpha = 255;
            red = Integer.parseInt(argb.substring(0, 2), 16);
            green = Integer.parseInt(argb.substring(2, 4), 16);
            blue = Integer.parseInt(argb.substring(4, 6), 16);
        }

        int[] components = {alpha, red, green, blue};

        return components;

    }

    private static String getTwoDigitHexString(int integer) {

        StringBuilder sb = new StringBuilder();
        sb.append(Integer.toHexString(integer));
        if (sb.length() < 2) {
            sb.insert(0, '0'); // pad with leading zero if needed
        }

        return sb.toString();

    }

}

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