/*
* Gray16Gray8.java
*
* Created on August 27, 2006, 9:02 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.Gray16Image;
import jjil.core.Gray8Image;
import jjil.core.Image;
import jjil.core.PipelineStage;
/** Gray16Gray8 converts an 16-bit gray image to an 8-bit
* gray image. The most significant 8 bits of each pixel are dropped.
*
* @author webb
*/
public class Gray16Gray8 extends PipelineStage {
/** Creates a new instance of Gray16Gray8 */
public Gray16Gray8() {
}
/** Converts an 16-bit gray image into an 8-bit image by and'ing off
* the top 8 bits of every pixel.
*
* @param image the input image.
* @throws jjil.core.Error if the input is not a Gray8Image
*/
public void push(Image image) throws jjil.core.Error {
if (!(image instanceof Gray16Image)) {
throw new Error(
Error.PACKAGE.ALGORITHM,
ErrorCodes.IMAGE_NOT_GRAY16IMAGE,
image.toString(),
null,
null);
}
Gray16Image gray = (Gray16Image) image;
Gray8Image gray8 = new Gray8Image(image.getWidth(), image.getHeight());
short[] grayData = gray.getData();
byte[] gray8Data = gray8.getData();
for (int i=0; i<gray.getWidth() * gray.getHeight(); i++) {
/* Convert from 16-bit value to 8-bit value, discarding
* most significant bits.
*/
gray8Data[i] = (byte) (grayData[i] & 0xff);
}
super.setOutput(gray8);
}
}