Creates a new color with the hue taken from color c, but adjusted in brightness to match the desired perceived brightness. - Java 2D Graphics

Java examples for 2D Graphics:Color

Description

Creates a new color with the hue taken from color c, but adjusted in brightness to match the desired perceived brightness.

Demo Code

/*//from ww w  .j ava  2 s . c o  m

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 */
//package com.java2s;
import java.awt.Color;

public class Main {
    private static final float[] PERCEIVED_BRIGHTNESS = { 0.299f, 0.587f,
            0.114f };

    /**
     * Creates a new color with the hue taken from color <code>c</code>, but adjusted
     * in brightness to match the desired perceived brightness.
     * @param c
     * @param perceivedBrightness
     * @return
     */
    public static Color createColor(Color c, float perceivedBrightness) {
        float[] cc = c.getRGBComponents(null);

        float pb = perceivedBrightness(c);
        if (pb == 0f)
            return new Color(pb, pb, pb, cc[3]);

        float f = perceivedBrightness / perceivedBrightness(c);
        float surplusBrightness = 0f;
        float sum = 0f;
        for (int i = 0; i < 3; i++) {
            cc[i] *= f;
            if (cc[i] < 1f) {
                sum += PERCEIVED_BRIGHTNESS[i];
            } else {
                surplusBrightness += (cc[i] - 1f) * PERCEIVED_BRIGHTNESS[i];
                cc[i] = 1f;
            }
        }
        if (surplusBrightness != 0) {
            float remainingBrightness = 0f;
            for (int i = 0; i < 3; i++) {
                if (cc[i] < 1f) {
                    cc[i] += surplusBrightness / sum;
                    if (cc[i] > 1f) {
                        remainingBrightness += (cc[i] - 1f)
                                * PERCEIVED_BRIGHTNESS[i];
                        cc[i] = 1f;
                    }
                }
            }
            if (remainingBrightness != 0f) {
                for (int i = 0; i < 3; i++) {
                    if (cc[i] < 1f) {
                        cc[i] += remainingBrightness
                                / PERCEIVED_BRIGHTNESS[i];
                        if (cc[i] > 1f) {
                            cc[i] = 1f;
                        }
                    }
                }
            }
        }

        return new Color(cc[0], cc[1], cc[2], cc[3]);
    }

    /**
     * This is a color's perceived brightness by the human eye
     * @param c
     * @return brightness from 0.0 to 1.0
     */
    public static float perceivedBrightness(Color c) {
        return (c == null) ? 1.0f
                : (PERCEIVED_BRIGHTNESS[0] * c.getRed()
                        + PERCEIVED_BRIGHTNESS[1] * c.getGreen() + PERCEIVED_BRIGHTNESS[2]
                        * c.getBlue()) / 255f;
    }
}

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