pixel.java

图像检索的代码b

/*
 * Pixel.java
 * Created on 16. April 2003, 10:30
 * Copyright (C) 2003 Florian Ledermann, Vienna University of Technology
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Contact address: [e-mail]
 */

package org.vizir.media;

/**
 * Description: A class representing a pixel with three (color) components.
 *
 * @author flo ledermann [e-mail]
 * @version $Id: Pixel.java,v 1.2 2004/02/12 09:20:29 mr Exp $
 */
public class Pixel {

	/** Internal storage of pixel data. */
	int[] data = {0,0,0};

	/** No conversion. */
	public static final int NO_CONVERSION = 0;
	/** RGB to YUV color space conversion. */
	public static final int RGB2YUV = 1;
	/** YUV to RGB color space converison. */
	public static final int YUV2RGB = 2;

        /**
         * Create one Pixel object of one pixel represented as int value in RGB.
         *
         *
         * @param data pixel-data in RGB
         * @param convert Color space conversion to apply (RGB2YUV, YUV2RGB or NO_CONVERSION)
         * @param rMask Masking bits for red component.
         * @param gMask Masking bits for green component.
         * @param bMask Masking bits for blue component.
         * @return
         */
        public static Pixel createFromInt(int data, int convert, int rMask, int gMask, int bMask ){
          int rShift = 0, gShift = 0, bShift = 0;
          if (rMask != 0) while ((rMask >> rShift) % 2 == 0) rShift++;
          if (gMask != 0) while ((gMask >> gShift) % 2 == 0) gShift++;
          if (bMask != 0) while ((bMask >> bShift) % 2 == 0) bShift++;

          Pixel p = new Pixel((data & rMask) >> rShift, (data & gMask) >> gShift, (data & bMask) >> bShift );
          if (convert == RGB2YUV) p.RGB2YUV();
          else if (convert == YUV2RGB) p.YUV2RGB();
          return p;
        }

	/**
	 * Convert the internal data from RGB to YUV.
	 */
	void RGB2YUV(){
		float y = 0.299f * data[0] + 0.587f * data[1] + 0.114f * data[2];
		data[1] = norm((data[2]-y) * 0.565f);
		data[2] = norm((data[0]-y) * 0.713f);
		data[0] = norm(y);
	}

	/**
	 * Convert the internal data from YUV to RGB.
	 */
	void YUV2RGB(){
		float y = data[0];
		float u = data[1];
		data[0] = norm(y + 1.403f * data[2]);
		data[1] = norm(y - 0.344f * u - 0.714f * data[2]);
		data[2] = norm(y + 1.770f * u);
	}

	/**
	 * Helper method to cast & normalize the components to
	 * integers in the range of 0..255
	 * @param num Float value to normalize.
	 * @return Normalized value.
	 */
	int norm(float num){
		if (num < 0) return 0;
		if (num > 255) return 255;
		return (int)num;
	}

	/**
	 * Constructor, takes three components.
	 * @param a R or Y component.
	 * @param b G or U component.
	 * @param c B or V component.
	 */
	public Pixel(int a, int b, int c){
		data[0] = a;
		data[1] = b;
		data[2] = c;
	}

	/**
	 * Returns the i'th color component.
	 * @param i 0 = R/Y; 1 = G/U; 2 = B/V.
	 * @return The desired color component.
	 */
	public int getComponent(int i){
		return data[i];
	}

	/**
	 * Check for equality. A Pixel is equal to another pixel if all
	 * three components are equal.
	 * @param obj Object to compare to.
	 * @return true, if Pixels are equal.
	 */
	public boolean equals(Object obj) {
		if (obj instanceof Pixel) {
			if (((Pixel)obj).getComponent(0) == getComponent(0) &&
			    ((Pixel)obj).getComponent(1) == getComponent(1) &&
			    ((Pixel)obj).getComponent(2) == getComponent(2))
			    	return true;
		}
		return false;
	}

	/**
	 * Returns a string representation of the Pixel.
	 * @return The three component values, concatenated by colons.
	 */
	public String toString() {
		return data[0] + ":" + data[1] + ":" + data[2];
	}

}