/*
* Gray8Sub.java
*
* Created on September 9, 2006, 10:25 AM
*
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
*
* Copyright 2007 by Jon A. Webb
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 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 Lesser General Public License for more details.
*
* You should have received a copy of the Lesser GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package jjil.algorithm;
import jjil.core.Error;
import jjil.core.Gray8Image;
import jjil.core.Image;
import jjil.core.Ladder;
/**
* Subtracts one gray image from another. To be used as a join operation in a
* Ladder operation.
* @author webb
*/
public class Gray8Sub implements Ladder.Join {
/** Creates a new instance of Gray8Sub */
public Gray8Sub() {
}
/**
* Subtracts one gray image from another. Result is clamped between
* Byte.MIN_VALUE and Byte.MAX_VALUE.
* @param imageFirst the first image (and output)
* @param imageSecond the second image
* @return the difference of the two byte images, replacing the first
* @throws jjil.core.Error if either image is not a gray 8-bit
* image, or they are of different sizes.
*/
public Image doJoin(Image imageFirst, Image imageSecond)
throws jjil.core.Error
{
if (!(imageFirst instanceof Gray8Image)) {
throw new Error(
Error.PACKAGE.ALGORITHM,
ErrorCodes.IMAGE_NOT_GRAY8IMAGE,
imageFirst.toString(),
null,
null);
}
if (!(imageSecond instanceof Gray8Image)) {
throw new Error(
Error.PACKAGE.ALGORITHM,
ErrorCodes.IMAGE_NOT_GRAY8IMAGE,
imageSecond.toString(),
null,
null);
}
if (imageFirst.getWidth() != imageSecond.getWidth() ||
imageSecond.getHeight() != imageSecond.getHeight()) {
throw new Error(
Error.PACKAGE.ALGORITHM,
ErrorCodes.IMAGE_SIZES_DIFFER,
imageFirst.toString(),
imageSecond.toString(),
null);
}
Gray8Image gray1 = (Gray8Image) imageFirst;
Gray8Image gray2 = (Gray8Image) imageSecond;
byte[] data1 = gray1.getData();
byte[] data2 = gray2.getData();
for (int i=0; i<data1.length; i++) {
data1[i] = (byte) Math.min(
Byte.MAX_VALUE,
Math.max(Byte.MIN_VALUE, (data1[i] - data2[i])));
}
return gray1;
}
}