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JFreeChart is a class library, written in Java, for generating charts.
Utilising the Java2D APIs, it currently supports bar charts, pie charts,
line charts, XY-plots and time series plots.
/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2020, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jfreechart/index.html
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
* Other names may be trademarks of their respective owners.]
*
* -------------------
* GrayPaintScale.java
* -------------------
* (C) Copyright 2006-2009, by Object Refinery Limited.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* Changes
* -------
* 05-Jul-2006 : Version 1 (DG);
* 31-Jan-2007 : Renamed min and max to lowerBound and upperBound (DG);
* 26-Sep-2007 : Fixed bug 1767315, problem in getPaint() method (DG);
* 29-Jan-2009 : Added alpha transparency field and hashCode() method (DG);
*
*/
package org.jfree.chart.renderer;
import java.awt.Color;
import java.awt.Paint;
import java.io.Serializable;
import org.jfree.chart.HashUtils;
import org.jfree.chart.util.PublicCloneable;
/**
* A paint scale that returns shades of gray.
*
* @since 1.0.4
*/
public class GrayPaintScale
implements PaintScale, PublicCloneable, Serializable {
/** The lower bound. */
private double lowerBound;
/** The upper bound. */
private double upperBound;
/**
* The alpha transparency (0-255).
*
* @since 1.0.13
*/
private int alpha;
/**
* Creates a new {@code GrayPaintScale} instance with default values.
*/
public GrayPaintScale() {
this(0.0, 1.0);
}
/**
* Creates a new paint scale for values in the specified range.
*
* @param lowerBound the lower bound.
* @param upperBound the upper bound.
*
* @throws IllegalArgumentException if {@code lowerBound} is not
* less than {@code upperBound}.
*/
public GrayPaintScale(double lowerBound, double upperBound) {
this(lowerBound, upperBound, 255);
}
/**
* Creates a new paint scale for values in the specified range.
*
* @param lowerBound the lower bound.
* @param upperBound the upper bound.
* @param alpha the alpha transparency (0-255).
*
* @throws IllegalArgumentException if {@code lowerBound} is not
* less than {@code upperBound}, or {@code alpha} is not in
* the range 0 to 255.
*
* @since 1.0.13
*/
public GrayPaintScale(double lowerBound, double upperBound, int alpha) {
if (lowerBound >= upperBound) {
throw new IllegalArgumentException(
"Requires lowerBound < upperBound.");
}
if (alpha < 0 || alpha > 255) {
throw new IllegalArgumentException(
"Requires alpha in the range 0 to 255.");
}
this.lowerBound = lowerBound;
this.upperBound = upperBound;
this.alpha = alpha;
}
/**
* Returns the lower bound.
*
* @return The lower bound.
*
* @see #getUpperBound()
*/
@Override
public double getLowerBound() {
return this.lowerBound;
}
/**
* Returns the upper bound.
*
* @return The upper bound.
*
* @see #getLowerBound()
*/
@Override
public double getUpperBound() {
return this.upperBound;
}
/**
* Returns the alpha transparency that was specified in the constructor.
*
* @return The alpha transparency (in the range 0 to 255).
*
* @since 1.0.13
*/
public int getAlpha() {
return this.alpha;
}
/**
* Returns a paint for the specified value.
*
* @param value the value (must be within the range specified by the
* lower and upper bounds for the scale).
*
* @return A paint for the specified value.
*/
@Override
public Paint getPaint(double value) {
double v = Math.max(value, this.lowerBound);
v = Math.min(v, this.upperBound);
int g = (int) ((v - this.lowerBound) / (this.upperBound
- this.lowerBound) * 255.0);
// FIXME: it probably makes sense to allocate an array of 256 Colors
// and lazily populate this array...
return new Color(g, g, g, this.alpha);
}
/**
* Tests this {@code GrayPaintScale} instance for equality with an
* arbitrary object. This method returns {@code true} if and only
* if:
*
* - {@code obj} is not {@code null};
* - {@code obj} is an instance of {@code GrayPaintScale};
*
*
* @param obj the object ({@code null} permitted).
*
* @return A boolean.
*/
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof GrayPaintScale)) {
return false;
}
GrayPaintScale that = (GrayPaintScale) obj;
if (this.lowerBound != that.lowerBound) {
return false;
}
if (this.upperBound != that.upperBound) {
return false;
}
if (this.alpha != that.alpha) {
return false;
}
return true;
}
/**
* Returns a hash code for this instance.
*
* @return A hash code.
*/
@Override
public int hashCode() {
int hash = 7;
hash = HashUtils.hashCode(hash, this.lowerBound);
hash = HashUtils.hashCode(hash, this.upperBound);
hash = 43 * hash + this.alpha;
return hash;
}
/**
* Returns a clone of this {@code GrayPaintScale} instance.
*
* @return A clone.
*
* @throws CloneNotSupportedException if there is a problem cloning this
* instance.
*/
@Override
public Object clone() throws CloneNotSupportedException {
return super.clone();
}
}