/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2007, 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.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ----------------------
* RendererUtilities.java
* ----------------------
* (C) Copyright 2007, by Object Refinery Limited.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* Changes
* -------
* 19-Apr-2007 : Version 1 (DG);
*
*/
package org.jfree.chart.renderer;
import org.jfree.data.DomainOrder;
import org.jfree.data.xy.XYDataset;
/**
* Utility methods related to the rendering process.
*
* @since 1.0.6
*/
public class RendererUtilities {
/**
* Finds the lower index of the range of live items in the specified data
* series.
*
* @param dataset the dataset (<code>null</code> not permitted).
* @param series the series index.
* @param xLow the lowest x-value in the live range.
* @param xHigh the highest x-value in the live range.
*
* @return The index of the required item.
*
* @since 1.0.6
*
* @see #findLiveItemsUpperBound(XYDataset, int, double, double)
*/
public static int findLiveItemsLowerBound(XYDataset dataset, int series,
double xLow, double xHigh) {
int itemCount = dataset.getItemCount(series);
if (itemCount <= 1) {
return 0;
}
if (dataset.getDomainOrder() == DomainOrder.ASCENDING) {
// for data in ascending order by x-value, we are (broadly) looking
// for the index of the highest x-value that is less that xLow
int low = 0;
int high = itemCount - 1;
int mid = (low + high) / 2;
double lowValue = dataset.getXValue(series, low);
if (lowValue >= xLow) {
// special case where the lowest x-value is >= xLow
return low;
}
double highValue = dataset.getXValue(series, high);
if (highValue < xLow) {
// special case where the highest x-value is < xLow
return high;
}
while (high - low > 1) {
double midV = dataset.getXValue(series, mid);
if (midV >= xLow) {
high = mid;
}
else {
low = mid;
}
mid = (low + high) / 2;
}
return mid;
}
else if (dataset.getDomainOrder() == DomainOrder.DESCENDING) {
// when the x-values are sorted in descending order, the lower
// bound is found by calculating relative to the xHigh value
int low = 0;
int high = itemCount - 1;
int mid = (low + high) / 2;
double lowValue = dataset.getXValue(series, low);
if (lowValue <= xHigh) {
return low;
}
double highValue = dataset.getXValue(series, high);
if (highValue > xHigh) {
return high;
}
while (high - low > 1) {
double midV = dataset.getXValue(series, mid);
if (midV > xHigh) {
low = mid;
}
else {
high = mid;
}
mid = (low + high) / 2;
}
return mid;
}
else {
// we don't know anything about the ordering of the x-values,
// but we can still skip any initial values that fall outside the
// range...
int index = 0;
// skip any items that don't need including...
while (index < itemCount && dataset.getXValue(series, index)
< xLow) {
index++;
}
return Math.max(0, index - 1);
}
}
/**
* Finds the index of the item in the specified series that...
*
* @param dataset the dataset (<code>null</code> not permitted).
* @param series the series index.
* @param xLow the lowest x-value in the live range.
* @param xHigh the highest x-value in the live range.
*
* @return The index of the required item.
*
* @since 1.0.6
*
* @see #findLiveItemsLowerBound(XYDataset, int, double, double)
*/
public static int findLiveItemsUpperBound(XYDataset dataset, int series,
double xLow, double xHigh) {
int itemCount = dataset.getItemCount(series);
if (itemCount <= 1) {
return 0;
}
if (dataset.getDomainOrder() == DomainOrder.ASCENDING) {
int low = 0;
int high = itemCount - 1;
int mid = (low + high + 1) / 2;
double lowValue = dataset.getXValue(series, low);
if (lowValue > xHigh) {
return low;
}
double highValue = dataset.getXValue(series, high);
if (highValue <= xHigh) {
return high;
}
while (high - low > 1) {
double midV = dataset.getXValue(series, mid);
if (midV <= xHigh) {
low = mid;
}
else {
high = mid;
}
mid = (low + high + 1) / 2;
}
return mid;
}
else if (dataset.getDomainOrder() == DomainOrder.DESCENDING) {
// when the x-values are descending, the upper bound is found by
// comparing against xLow
int low = 0;
int high = itemCount - 1;
int mid = (low + high) / 2;
double lowValue = dataset.getXValue(series, low);
if (lowValue < xLow) {
return low;
}
double highValue = dataset.getXValue(series, high);
if (highValue >= xLow) {
return high;
}
while (high - low > 1) {
double midV = dataset.getXValue(series, mid);
if (midV >= xLow) {
low = mid;
}
else {
high = mid;
}
mid = (low + high) / 2;
}
return mid;
}
else {
// we don't know anything about the ordering of the x-values,
// but we can still skip any trailing values that fall outside the
// range...
int index = itemCount - 1;
// skip any items that don't need including...
while (index >= 0 && dataset.getXValue(series, index)
> xHigh) {
index--;
}
return Math.min(itemCount - 1, index + 1);
}
}
/**
* Finds a range of item indices that is guaranteed to contain all the
* x-values from x0 to x1 (inclusive).
*
* @param dataset the dataset (<code>null</code> not permitted).
* @param series the series index.
* @param xLow the lower bound of the x-value range.
* @param xHigh the upper bound of the x-value range.
*
* @return The indices of the boundary items.
*/
public static int[] findLiveItems(XYDataset dataset, int series,
double xLow, double xHigh) {
// here we could probably be a little faster by searching for both
// indices simultaneously, but I'll look at that later if it seems
// like it matters...
int i0 = findLiveItemsLowerBound(dataset, series, xLow, xHigh);
int i1 = findLiveItemsUpperBound(dataset, series, xLow, xHigh);
return new int[] {i0, i1};
}
}
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