/**
* Java Modular Image Synthesis Toolkit (JMIST)
* Copyright (C) 2008-2013 Bradley W. Kimmel
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
package ca.eandb.jmist.framework.tone;
import ca.eandb.jmist.framework.color.CIEXYZ;
import ca.eandb.jmist.framework.color.CIExyY;
/**
* A <code>ToneMapperFactory</code> that builds linear tone maps.
* @author Brad Kimmel
*/
public final class LinearToneMapperFactory implements ToneMapperFactory {
/** Serialization version ID. */
private static final long serialVersionUID = -246622078552676822L;
private static final double DEFAULT_DELTA = 1.0;
private final double delta;
public LinearToneMapperFactory(double delta) {
this.delta = delta;
}
public LinearToneMapperFactory() {
this(DEFAULT_DELTA);
}
/* (non-Javadoc)
* @see ca.eandb.jmist.framework.tone.ToneMapperFactory#createToneMapper(java.lang.Iterable)
*/
public ToneMapper createToneMapper(Iterable<CIEXYZ> samples) {
double Yavg = 0.0;
double Ymax = 0.0;
int n = 0;
for (CIEXYZ sample : samples) {
if (sample != null) {
double Y = Math.abs(sample.Y());
if (Y > Ymax) {
Ymax = Y;
}
Yavg += Math.log(delta + Y);
n++;
}
}
Yavg /= (double) n;
Yavg = Math.exp(Yavg) - delta;
double Ymid = 1.03 - 2.0 / (2.0 + Math.log10(Yavg + 1.0));
CIExyY white = new CIExyY(1.0 / 3.0, 1.0 / 3.0, Yavg / Ymid);
return new LinearToneMapper(white.toXYZ());
}
}