Returns a copy of the rgb colour brightened up by the given amount. - Java 2D Graphics

Java examples for 2D Graphics:Color RGB

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Description

Returns a copy of the rgb colour brightened up by the given amount.

Demo Code


//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        float[] rgb = new float[] { 34.45f, 35.45f, 36.67f, 37.78f,
                37.0000f, 37.1234f, 67.2344f, 68.34534f, 69.87700f };
        float luminosity = 2.45678f;
        System.out.println(java.util.Arrays.toString(brighten(rgb,
                luminosity)));/*from w w  w  .  j  ava 2  s.  c om*/
    }

    /** 
     * Returns a copy of the rgb colour brightened up by the given amount.
     * @param rgb The RGB color.
     * @param luminosity The new luminosity amount in [0, 1]
     * @return
     */
    public static float[] brighten(float[] rgb, float luminosity) {
        float[] hsl = rgbToHsl(rgb);
        hsl[2] = luminosity;
        return hslToRgb(hsl);
    }

    /**
     * Converts an RGB color value to HSL. Conversion formula
     * adapted from http://en.wikipedia.org/wiki/HSL_color_space.
     * Assumes r, g, and b are contained in the set [0, 255] and
     * returns h, s, and l in the set [0, 1].
     *
     * @param   Number  r       The red color value
     * @param   Number  g       The green color value
     * @param   Number  b       The blue color value
     * @return  Array           The HSL representation
     */
    public static float[] rgbToHsl(float[] rgb) {
        float r, g, b;
        r = rgb[0];
        g = rgb[1];
        b = rgb[2];
        float max = Math.max(r, Math.max(g, b));
        float min = Math.min(r, Math.min(g, b));
        float avg = (max + min) / 2;
        float h = avg, s = avg, l = avg;

        if (max == min) {
            h = s = 0; // achromatic
        } else {
            float d = max - min;
            s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
            if (max == r) {
                h = (g - b) / d + (g < b ? 6 : 0);
            } else if (max == g) {
                h = (b - r) / d + 2;
            } else if (max == b) {
                h = (r - g) / d + 4;
            }
            h /= 6;
        }

        return new float[] { h, s, l };
    }

    /**
     * Converts an HSL color value to RGB. Conversion formula
     * adapted from http://en.wikipedia.org/wiki/HSL_color_space.
     * Assumes h, s, and l are contained in the set [0, 1] and
     * returns r, g, and b in the set [0, 255].
     *
     * @param   Number  h       The hue
     * @param   Number  s       The saturation
     * @param   Number  l       The lightness
     * @return  Array           The RGB representation
     */
    public static float[] hslToRgb(float[] hsl) {
        float r, g, b;
        float h, s, l;
        h = hsl[0];
        s = hsl[1];
        l = hsl[2];

        if (s == 0) {
            r = g = b = l; // achromatic
        } else {

            float q = l < 0.5 ? l * (1 + s) : l + s - l * s;
            float p = 2 * l - q;
            r = hue2rgb(p, q, h + 1 / 3);
            g = hue2rgb(p, q, h);
            b = hue2rgb(p, q, h - 1 / 3);
        }

        return new float[] { r, g, b };
    }

    private static float hue2rgb(float p, float q, float t) {
        if (t < 0)
            t += 1;
        if (t > 1)
            t -= 1;
        if (t < 1 / 6)
            return p + (q - p) * 6 * t;
        if (t < 1 / 2)
            return q;
        if (t < 2 / 3)
            return p + (q - p) * (2 / 3 - t) * 6;
        return p;
    }
}

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