org.jpedal.parser.image.downsample.KernelUtils Maven / Gradle / Ivy
/*
* ===========================================
* Java Pdf Extraction Decoding Access Library
* ===========================================
*
* Project Info: http://www.idrsolutions.com
* Help section for developers at http://www.idrsolutions.com/support/
*
* (C) Copyright 1997-2017 IDRsolutions and Contributors.
*
* This file is part of JPedal/JPDF2HTML5
*
This library 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 2.1 of the License, or (at your option) any later version.
This library 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 GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* ---------------
* KernelUtils.java
* ---------------
*/
package org.jpedal.parser.image.downsample;
import org.jpedal.images.SamplingFactory;
import org.jpedal.parser.image.data.ImageData;
/**
* @author Bethan
*/
class KernelUtils {
protected static ImageData applyKernel(final ImageData imageData) {
final double[][] kernel = SamplingFactory.getSharpenKernel();
final byte[] input = imageData.getObjectData();
final int w = imageData.getWidth();
final int h = imageData.getHeight();
int compCount = imageData.getCompCount();
if (compCount == 3) { //really it's rgba not rgb
compCount = 4;
}
final byte[] output = new byte[w * h * compCount];
int imageX, imageY, currentPixel;
int value = 0;
final int lineBytes = w * compCount;
//get matrix size (usually 3)
final int matrixSize = kernel.length;
for (int x = 0; x < w; x++) {
for (int y = 0; y < h; y++) {
for (int comp = 0; comp < compCount; comp++) {
//multiply by nxn matrix to get new pixel value
for (int i = 0; i < matrixSize; i++) {
for (int j = 0; j < matrixSize; j++) {
imageX = (x - matrixSize / 2 + i + w) % w;
imageY = (y - matrixSize / 2 + j + h) % h;
currentPixel = input[(imageY * lineBytes) + (imageX * compCount) + comp] & 255;
value += (currentPixel * kernel[i][j]);
}
}
if (value < 0) { //ensure in range
value = 0;
} else if (value > 255) {
value = 255;
}
output[(y * lineBytes) + (x * compCount) + comp] = (byte) value;
value = 0; //reset for next calculation
}
}
}
imageData.setObjectData(output);
return imageData;
}
}