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 * Changes
036 * -------
037 * 19-Apr-2007 : Version 1 (DG);
038 *
039 */
040
041 package org.jfree.chart.renderer;
042
043 import org.jfree.data.DomainOrder;
044 import org.jfree.data.xy.XYDataset;
045
046 /**
047 * Utility methods related to the rendering process.
048 *
049 * @since 1.0.6
050 */
051 public class RendererUtilities {
052
053 /**
054 * Finds the lower index of the range of live items in the specified data
055 * series.
056 *
057 * @param dataset the dataset (<code>null</code> not permitted).
058 * @param series the series index.
059 * @param xLow the lowest x-value in the live range.
060 * @param xHigh the highest x-value in the live range.
061 *
062 * @return The index of the required item.
063 *
064 * @since 1.0.6
065 *
066 * @see #findLiveItemsUpperBound(XYDataset, int, double, double)
067 */
068 public static int findLiveItemsLowerBound(XYDataset dataset, int series,
069 double xLow, double xHigh) {
070 int itemCount = dataset.getItemCount(series);
071 if (itemCount <= 1) {
072 return 0;
073 }
074 if (dataset.getDomainOrder() == DomainOrder.ASCENDING) {
075 // for data in ascending order by x-value, we are (broadly) looking
076 // for the index of the highest x-value that is less that xLow
077 int low = 0;
078 int high = itemCount - 1;
079 int mid = (low + high) / 2;
080 double lowValue = dataset.getXValue(series, low);
081 if (lowValue >= xLow) {
082 // special case where the lowest x-value is >= xLow
083 return low;
084 }
085 double highValue = dataset.getXValue(series, high);
086 if (highValue < xLow) {
087 // special case where the highest x-value is < xLow
088 return high;
089 }
090 while (high - low > 1) {
091 double midV = dataset.getXValue(series, mid);
092 if (midV >= xLow) {
093 high = mid;
094 }
095 else {
096 low = mid;
097 }
098 mid = (low + high) / 2;
099 }
100 return mid;
101 }
102 else if (dataset.getDomainOrder() == DomainOrder.DESCENDING) {
103 // when the x-values are sorted in descending order, the lower
104 // bound is found by calculating relative to the xHigh value
105 int low = 0;
106 int high = itemCount - 1;
107 int mid = (low + high) / 2;
108 double lowValue = dataset.getXValue(series, low);
109 if (lowValue <= xHigh) {
110 return low;
111 }
112 double highValue = dataset.getXValue(series, high);
113 if (highValue > xHigh) {
114 return high;
115 }
116 while (high - low > 1) {
117 double midV = dataset.getXValue(series, mid);
118 if (midV > xHigh) {
119 low = mid;
120 }
121 else {
122 high = mid;
123 }
124 mid = (low + high) / 2;
125 }
126 return mid;
127 }
128 else {
129 // we don't know anything about the ordering of the x-values,
130 // but we can still skip any initial values that fall outside the
131 // range...
132 int index = 0;
133 // skip any items that don't need including...
134 while (index < itemCount && dataset.getXValue(series, index)
135 < xLow) {
136 index++;
137 }
138 return Math.max(0, index - 1);
139 }
140 }
141
142 /**
143 * Finds the index of the item in the specified series that...
144 *
145 * @param dataset the dataset (<code>null</code> not permitted).
146 * @param series the series index.
147 * @param xLow the lowest x-value in the live range.
148 * @param xHigh the highest x-value in the live range.
149 *
150 * @return The index of the required item.
151 *
152 * @since 1.0.6
153 *
154 * @see #findLiveItemsLowerBound(XYDataset, int, double, double)
155 */
156 public static int findLiveItemsUpperBound(XYDataset dataset, int series,
157 double xLow, double xHigh) {
158 int itemCount = dataset.getItemCount(series);
159 if (itemCount <= 1) {
160 return 0;
161 }
162 if (dataset.getDomainOrder() == DomainOrder.ASCENDING) {
163 int low = 0;
164 int high = itemCount - 1;
165 int mid = (low + high + 1) / 2;
166 double lowValue = dataset.getXValue(series, low);
167 if (lowValue > xHigh) {
168 return low;
169 }
170 double highValue = dataset.getXValue(series, high);
171 if (highValue <= xHigh) {
172 return high;
173 }
174 while (high - low > 1) {
175 double midV = dataset.getXValue(series, mid);
176 if (midV <= xHigh) {
177 low = mid;
178 }
179 else {
180 high = mid;
181 }
182 mid = (low + high + 1) / 2;
183 }
184 return mid;
185 }
186 else if (dataset.getDomainOrder() == DomainOrder.DESCENDING) {
187 // when the x-values are descending, the upper bound is found by
188 // comparing against xLow
189 int low = 0;
190 int high = itemCount - 1;
191 int mid = (low + high) / 2;
192 double lowValue = dataset.getXValue(series, low);
193 if (lowValue < xLow) {
194 return low;
195 }
196 double highValue = dataset.getXValue(series, high);
197 if (highValue >= xLow) {
198 return high;
199 }
200 while (high - low > 1) {
201 double midV = dataset.getXValue(series, mid);
202 if (midV >= xLow) {
203 low = mid;
204 }
205 else {
206 high = mid;
207 }
208 mid = (low + high) / 2;
209 }
210 return mid;
211 }
212 else {
213 // we don't know anything about the ordering of the x-values,
214 // but we can still skip any trailing values that fall outside the
215 // range...
216 int index = itemCount - 1;
217 // skip any items that don't need including...
218 while (index >= 0 && dataset.getXValue(series, index)
219 > xHigh) {
220 index--;
221 }
222 return Math.min(itemCount - 1, index + 1);
223 }
224 }
225
226 /**
227 * Finds a range of item indices that is guaranteed to contain all the
228 * x-values from x0 to x1 (inclusive).
229 *
230 * @param dataset the dataset (<code>null</code> not permitted).
231 * @param series the series index.
232 * @param xLow the lower bound of the x-value range.
233 * @param xHigh the upper bound of the x-value range.
234 *
235 * @return The indices of the boundary items.
236 */
237 public static int[] findLiveItems(XYDataset dataset, int series,
238 double xLow, double xHigh) {
239 // here we could probably be a little faster by searching for both
240 // indices simultaneously, but I'll look at that later if it seems
241 // like it matters...
242 int i0 = findLiveItemsLowerBound(dataset, series, xLow, xHigh);
243 int i1 = findLiveItemsUpperBound(dataset, series, xLow, xHigh);
244 return new int[] {i0, i1};
245 }
246
247 }