001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2007, by Object Refinery Limited and Contributors.
006 *
007 * Project Info: http://www.jfree.org/jfreechart/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
022 * USA.
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025 * in the United States and other countries.]
026 *
027 * ----------------------
028 * RendererUtilities.java
029 * ----------------------
030 * (C) Copyright 2007, by Object Refinery Limited.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * $Id: RendererUtilities.java,v 1.1.2.1 2007/05/04 11:12:16 mungady Exp $
036 *
037 * Changes
038 * -------
039 * 19-Apr-2007 : Version 1 (DG);
040 *
041 */
042
043 package org.jfree.chart.renderer;
044
045 import org.jfree.data.DomainOrder;
046 import org.jfree.data.xy.XYDataset;
047
048 /**
049 * Utility methods related to the rendering process.
050 *
051 * @since 1.0.6
052 */
053 public class RendererUtilities {
054
055 /**
056 * Finds the lower index of the range of live items in the specified data
057 * series.
058 *
059 * @param dataset the dataset (<code>null</code> not permitted).
060 * @param series the series index.
061 * @param xLow the lowest x-value in the live range.
062 * @param xHigh the highest x-value in the live range.
063 *
064 * @return The index of the required item.
065 *
066 * @since 1.0.6
067 *
068 * @see #findLiveItemsUpperBound(XYDataset, int, double, double)
069 */
070 public static int findLiveItemsLowerBound(XYDataset dataset, int series,
071 double xLow, double xHigh) {
072 int itemCount = dataset.getItemCount(series);
073 if (itemCount <= 1) {
074 return 0;
075 }
076 if (dataset.getDomainOrder() == DomainOrder.ASCENDING) {
077 // for data in ascending order by x-value, we are (broadly) looking
078 // for the index of the highest x-value that is less that xLow
079 int low = 0;
080 int high = itemCount - 1;
081 int mid = (low + high) / 2;
082 double lowValue = dataset.getXValue(series, low);
083 if (lowValue >= xLow) {
084 // special case where the lowest x-value is >= xLow
085 return low;
086 }
087 double highValue = dataset.getXValue(series, high);
088 if (highValue < xLow) {
089 // special case where the highest x-value is < xLow
090 return high;
091 }
092 while (high - low > 1) {
093 double midV = dataset.getXValue(series, mid);
094 if (midV >= xLow) {
095 high = mid;
096 }
097 else {
098 low = mid;
099 }
100 mid = (low + high) / 2;
101 }
102 return mid;
103 }
104 else if (dataset.getDomainOrder() == DomainOrder.DESCENDING) {
105 // when the x-values are sorted in descending order, the lower
106 // bound is found by calculating relative to the xHigh value
107 int low = 0;
108 int high = itemCount - 1;
109 int mid = (low + high) / 2;
110 double lowValue = dataset.getXValue(series, low);
111 if (lowValue <= xHigh) {
112 return low;
113 }
114 double highValue = dataset.getXValue(series, high);
115 if (highValue > xHigh) {
116 return high;
117 }
118 while (high - low > 1) {
119 double midV = dataset.getXValue(series, mid);
120 if (midV > xHigh) {
121 low = mid;
122 }
123 else {
124 high = mid;
125 }
126 mid = (low + high) / 2;
127 }
128 return mid;
129 }
130 else {
131 // we don't know anything about the ordering of the x-values,
132 // but we can still skip any initial values that fall outside the
133 // range...
134 int index = 0;
135 // skip any items that don't need including...
136 while (index < itemCount && dataset.getXValue(series, index)
137 < xLow) {
138 index++;
139 }
140 return Math.max(0, index - 1);
141 }
142 }
143
144 /**
145 * Finds the index of the item in the specified series that...
146 *
147 * @param dataset the dataset (<code>null</code> not permitted).
148 * @param series the series index.
149 * @param xLow the lowest x-value in the live range.
150 * @param xHigh the highest x-value in the live range.
151 *
152 * @return The index of the required item.
153 *
154 * @since 1.0.6
155 *
156 * @see #findLiveItemsLowerBound(XYDataset, int, double, double)
157 */
158 public static int findLiveItemsUpperBound(XYDataset dataset, int series,
159 double xLow, double xHigh) {
160 int itemCount = dataset.getItemCount(series);
161 if (itemCount <= 1) {
162 return 0;
163 }
164 if (dataset.getDomainOrder() == DomainOrder.ASCENDING) {
165 int low = 0;
166 int high = itemCount - 1;
167 int mid = (low + high + 1) / 2;
168 double lowValue = dataset.getXValue(series, low);
169 if (lowValue > xHigh) {
170 return low;
171 }
172 double highValue = dataset.getXValue(series, high);
173 if (highValue <= xHigh) {
174 return high;
175 }
176 while (high - low > 1) {
177 double midV = dataset.getXValue(series, mid);
178 if (midV <= xHigh) {
179 low = mid;
180 }
181 else {
182 high = mid;
183 }
184 mid = (low + high + 1) / 2;
185 }
186 return mid;
187 }
188 else if (dataset.getDomainOrder() == DomainOrder.DESCENDING) {
189 // when the x-values are descending, the upper bound is found by
190 // comparing against xLow
191 int low = 0;
192 int high = itemCount - 1;
193 int mid = (low + high) / 2;
194 double lowValue = dataset.getXValue(series, low);
195 if (lowValue < xLow) {
196 return low;
197 }
198 double highValue = dataset.getXValue(series, high);
199 if (highValue >= xLow) {
200 return high;
201 }
202 while (high - low > 1) {
203 double midV = dataset.getXValue(series, mid);
204 if (midV >= xLow) {
205 low = mid;
206 }
207 else {
208 high = mid;
209 }
210 mid = (low + high) / 2;
211 }
212 return mid;
213 }
214 else {
215 // we don't know anything about the ordering of the x-values,
216 // but we can still skip any trailing values that fall outside the
217 // range...
218 int index = itemCount - 1;
219 // skip any items that don't need including...
220 while (index >= 0 && dataset.getXValue(series, index)
221 > xHigh) {
222 index--;
223 }
224 return Math.min(itemCount - 1, index + 1);
225 }
226 }
227
228 /**
229 * Finds a range of item indices that is guaranteed to contain all the
230 * x-values from x0 to x1 (inclusive).
231 *
232 * @param dataset the dataset (<code>null</code> not permitted).
233 * @param series the series index.
234 * @param xLow the lower bound of the x-value range.
235 * @param xHigh the upper bound of the x-value range.
236 *
237 * @return The indices of the boundary items.
238 */
239 public static int[] findLiveItems(XYDataset dataset, int series,
240 double xLow, double xHigh) {
241 // here we could probably be a little faster by searching for both
242 // indices simultaneously, but I'll look at that later if it seems
243 // like it matters...
244 int i0 = findLiveItemsLowerBound(dataset, series, xLow, xHigh);
245 int i1 = findLiveItemsUpperBound(dataset, series, xLow, xHigh);
246 return new int[] {i0, i1};
247 }
248
249 }