org.jpedal.function.PDFExponential Maven / Gradle / Ivy
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/*
* ===========================================
* Java Pdf Extraction Decoding Access Library
* ===========================================
*
* Project Info: http://www.idrsolutions.com
* Help section for developers at http://www.idrsolutions.com/java-pdf-library-support/
*
* (C) Copyright 1997-2013, IDRsolutions and Contributors.
*
* This file is part of JPedal
*
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
*
* ---------------
* PDFExponential.java
* ---------------
*/
package org.jpedal.function;
/**
* Class to handle Type 2 shading (Exponential)
*/
public class PDFExponential extends PDFGenericFunction implements PDFFunction {
private static final long serialVersionUID = 5385374201115057519L;
private float[] C0 = { 0.0f }, C1 = { 1.0f };
private float N;
int returnValues;
public PDFExponential(float N, float[] C0, float[] C1, float[] domain, float[] range) {
super(domain, range);
this.N = N;
if (C0 != null) this.C0 = C0;
if (C1 != null) this.C1 = C1;
// note C0 might be null so use this.C0
this.returnValues = this.C0.length;
}
/**
* Compute the required values for exponential shading (Only used by Stitching)
*
* @param subinput
* : input values
* @return The shading values as float[]
*/
@Override
public float[] computeStitch(float[] subinput) {
return compute(subinput);
}
@Override
public float[] compute(float[] values) {
float[] output = new float[this.returnValues];
float[] result = new float[this.returnValues];
// Only first value required
float x = min(max(values[0], this.domain[0 * 2]), this.domain[0 * 2 + 1]);
if (this.N == 1f) {// special case
for (int i = 0; i < this.C0.length; i++) {
// x^1 = x so don't bother finding the power
output[i] = this.C0[i] + x * (this.C1[i] - this.C0[i]);
// clip to range if present
if (this.range != null) output[i] = min(max(output[i], this.range[i * 2]), this.range[i * 2 + 1]); // Clip output
result[i] = output[i];
}
}
else {
for (int i = 0; i < this.C0.length; i++) {
output[i] = this.C0[i] + (float) Math.pow(x, this.N) * (this.C1[i] - this.C0[i]);
// clip to range if present.
if (this.range != null) output[i] = min(max(output[i], this.range[i * 2]), this.range[i * 2 + 1]); // Clip output
result[i] = output[i];
}
}
return result;
}
}