001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, 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 * XYSplineRenderer.java
029 * ---------------------
030 * (C) Copyright 2007, 2008, by Klaus Rheinwald and Contributors.
031 *
032 * Original Author: Klaus Rheinwald;
033 * Contributor(s): Tobias von Petersdorff (tvp@math.umd.edu,
034 * http://www.wam.umd.edu/~petersd/);
035 * David Gilbert (for Object Refinery Limited);
036 *
037 * Changes:
038 * --------
039 * 25-Jul-2007 : Version 1, contributed by Klaus Rheinwald (DG);
040 * 03-Aug-2007 : Added new constructor (KR);
041 * 25-Oct-2007 : Prevent duplicate control points (KR);
042 *
043 */
044
045 package org.jfree.chart.renderer.xy;
046
047 import java.awt.Graphics2D;
048 import java.awt.geom.Rectangle2D;
049 import java.util.Vector;
050
051 import org.jfree.chart.axis.ValueAxis;
052 import org.jfree.chart.event.RendererChangeEvent;
053 import org.jfree.chart.plot.PlotOrientation;
054 import org.jfree.chart.plot.PlotRenderingInfo;
055 import org.jfree.chart.plot.XYPlot;
056 import org.jfree.data.xy.XYDataset;
057 import org.jfree.ui.RectangleEdge;
058
059 /**
060 * A renderer that connects data points with natural cubic splines and/or
061 * draws shapes at each data point. This renderer is designed for use with
062 * the {@link XYPlot} class. The example shown here is generated by the
063 * <code>XYSplineRendererDemo1.java</code> program included in the JFreeChart
064 * demo collection:
065 * <br><br>
066 * <img src="../../../../../images/XYSplineRendererSample.png"
067 * alt="XYSplineRendererSample.png" />
068 *
069 * @since 1.0.7
070 */
071 public class XYSplineRenderer extends XYLineAndShapeRenderer {
072
073 /**
074 * To collect data points for later splining.
075 */
076 private Vector points;
077
078 /**
079 * Resolution of splines (number of line segments between points)
080 */
081 private int precision;
082
083 /**
084 * Creates a new instance with the 'precision' attribute defaulting to
085 * 5.
086 */
087 public XYSplineRenderer() {
088 this(5);
089 }
090
091 /**
092 * Creates a new renderer with the specified precision.
093 *
094 * @param precision the number of points between data items.
095 */
096 public XYSplineRenderer(int precision) {
097 super();
098 if (precision <= 0) {
099 throw new IllegalArgumentException("Requires precision > 0.");
100 }
101 this.precision = precision;
102 }
103
104 /**
105 * Get the resolution of splines.
106 *
107 * @return Number of line segments between points.
108 *
109 * @see #setPrecision(int)
110 */
111 public int getPrecision() {
112 return this.precision;
113 }
114
115 /**
116 * Set the resolution of splines and sends a {@link RendererChangeEvent}
117 * to all registered listeners.
118 *
119 * @param p number of line segments between points (must be > 0).
120 *
121 * @see #getPrecision()
122 */
123 public void setPrecision(int p) {
124 if (p <= 0) {
125 throw new IllegalArgumentException("Requires p > 0.");
126 }
127 this.precision = p;
128 fireChangeEvent();
129 }
130
131 /**
132 * Initialises the renderer.
133 * <P>
134 * This method will be called before the first item is rendered, giving the
135 * renderer an opportunity to initialise any state information it wants to
136 * maintain. The renderer can do nothing if it chooses.
137 *
138 * @param g2 the graphics device.
139 * @param dataArea the area inside the axes.
140 * @param plot the plot.
141 * @param data the data.
142 * @param info an optional info collection object to return data back to
143 * the caller.
144 *
145 * @return The renderer state.
146 */
147 public XYItemRendererState initialise(Graphics2D g2, Rectangle2D dataArea,
148 XYPlot plot, XYDataset data, PlotRenderingInfo info) {
149
150 State state = (State) super.initialise(g2, dataArea, plot, data, info);
151 state.setProcessVisibleItemsOnly(false);
152 this.points = new Vector();
153 setDrawSeriesLineAsPath(true);
154 return state;
155 }
156
157 /**
158 * Draws the item (first pass). This method draws the lines
159 * connecting the items. Instead of drawing separate lines,
160 * a GeneralPath is constructed and drawn at the end of
161 * the series painting.
162 *
163 * @param g2 the graphics device.
164 * @param state the renderer state.
165 * @param plot the plot (can be used to obtain standard color information
166 * etc).
167 * @param dataset the dataset.
168 * @param pass the pass.
169 * @param series the series index (zero-based).
170 * @param item the item index (zero-based).
171 * @param domainAxis the domain axis.
172 * @param rangeAxis the range axis.
173 * @param dataArea the area within which the data is being drawn.
174 */
175 protected void drawPrimaryLineAsPath(XYItemRendererState state,
176 Graphics2D g2, XYPlot plot, XYDataset dataset, int pass,
177 int series, int item, ValueAxis domainAxis, ValueAxis rangeAxis,
178 Rectangle2D dataArea) {
179
180 RectangleEdge xAxisLocation = plot.getDomainAxisEdge();
181 RectangleEdge yAxisLocation = plot.getRangeAxisEdge();
182
183 // get the data points
184 double x1 = dataset.getXValue(series, item);
185 double y1 = dataset.getYValue(series, item);
186 double transX1 = domainAxis.valueToJava2D(x1, dataArea, xAxisLocation);
187 double transY1 = rangeAxis.valueToJava2D(y1, dataArea, yAxisLocation);
188
189 // collect points
190 if (!Double.isNaN(transX1) && !Double.isNaN(transY1)) {
191 ControlPoint p = new ControlPoint(plot.getOrientation()
192 == PlotOrientation.HORIZONTAL ? (float) transY1
193 : (float) transX1, plot.getOrientation()
194 == PlotOrientation.HORIZONTAL ? (float) transX1
195 : (float) transY1);
196 if (!this.points.contains(p)) {
197 this.points.add(p);
198 }
199 }
200 if (item == dataset.getItemCount(series) - 1) {
201 State s = (State) state;
202 // construct path
203 if (this.points.size() > 1) {
204 // we need at least two points to draw something
205 ControlPoint cp0 = (ControlPoint) this.points.get(0);
206 s.seriesPath.moveTo(cp0.x, cp0.y);
207 if (this.points.size() == 2) {
208 // we need at least 3 points to spline. Draw simple line
209 // for two points
210 ControlPoint cp1 = (ControlPoint) this.points.get(1);
211 s.seriesPath.lineTo(cp1.x, cp1.y);
212 }
213 else {
214 // construct spline
215 int np = this.points.size(); // number of points
216 float[] d = new float[np]; // Newton form coefficients
217 float[] x = new float[np]; // x-coordinates of nodes
218 float y;
219 float t;
220 float oldy = 0;
221 float oldt = 0;
222
223 float[] a = new float[np];
224 float t1;
225 float t2;
226 float[] h = new float[np];
227
228 for (int i = 0; i < np; i++) {
229 ControlPoint cpi = (ControlPoint) this.points.get(i);
230 x[i] = cpi.x;
231 d[i] = cpi.y;
232 }
233
234 for (int i = 1; i <= np - 1; i++) {
235 h[i] = x[i] - x[i - 1];
236 }
237 float[] sub = new float[np - 1];
238 float[] diag = new float[np - 1];
239 float[] sup = new float[np - 1];
240
241 for (int i = 1; i <= np - 2; i++) {
242 diag[i] = (h[i] + h[i + 1]) / 3;
243 sup[i] = h[i + 1] / 6;
244 sub[i] = h[i] / 6;
245 a[i] = (d[i + 1] - d[i]) / h[i + 1]
246 - (d[i] - d[i - 1]) / h[i];
247 }
248 solveTridiag(sub, diag, sup, a, np - 2);
249
250 // note that a[0]=a[np-1]=0
251 // draw
252 oldt = x[0];
253 oldy = d[0];
254 s.seriesPath.moveTo(oldt, oldy);
255 for (int i = 1; i <= np - 1; i++) {
256 // loop over intervals between nodes
257 for (int j = 1; j <= this.precision; j++) {
258 t1 = (h[i] * j) / this.precision;
259 t2 = h[i] - t1;
260 y = ((-a[i - 1] / 6 * (t2 + h[i]) * t1 + d[i - 1])
261 * t2 + (-a[i] / 6 * (t1 + h[i]) * t2
262 + d[i]) * t1) / h[i];
263 t = x[i - 1] + t1;
264 s.seriesPath.lineTo(t, y);
265 oldt = t;
266 oldy = y;
267 }
268 }
269 }
270 // draw path
271 drawFirstPassShape(g2, pass, series, item, s.seriesPath);
272 }
273
274 // reset points vector
275 this.points = new Vector();
276 }
277 }
278
279 private void solveTridiag(float[] sub, float[] diag, float[] sup,
280 float[] b, int n) {
281 /* solve linear system with tridiagonal n by n matrix a
282 using Gaussian elimination *without* pivoting
283 where a(i,i-1) = sub[i] for 2<=i<=n
284 a(i,i) = diag[i] for 1<=i<=n
285 a(i,i+1) = sup[i] for 1<=i<=n-1
286 (the values sub[1], sup[n] are ignored)
287 right hand side vector b[1:n] is overwritten with solution
288 NOTE: 1...n is used in all arrays, 0 is unused */
289 int i;
290 /* factorization and forward substitution */
291 for (i = 2; i <= n; i++) {
292 sub[i] = sub[i] / diag[i - 1];
293 diag[i] = diag[i] - sub[i] * sup[i - 1];
294 b[i] = b[i] - sub[i] * b[i - 1];
295 }
296 b[n] = b[n] / diag[n];
297 for (i = n - 1; i >= 1; i--) {
298 b[i] = (b[i] - sup[i] * b[i + 1]) / diag[i];
299 }
300 }
301
302 /**
303 * Tests this renderer for equality with an arbitrary object.
304 *
305 * @param obj the object (<code>null</code> permitted).
306 *
307 * @return A boolean.
308 */
309 public boolean equals(Object obj) {
310 if (obj == this) {
311 return true;
312 }
313 if (!(obj instanceof XYSplineRenderer)) {
314 return false;
315 }
316 XYSplineRenderer that = (XYSplineRenderer) obj;
317 if (this.precision != that.precision) {
318 return false;
319 }
320 return super.equals(obj);
321 }
322
323 /**
324 * Represents a control point.
325 */
326 class ControlPoint {
327
328 /** The x-coordinate. */
329 public float x;
330
331 /** The y-coordinate. */
332 public float y;
333
334 /**
335 * Creates a new control point.
336 *
337 * @param x the x-coordinate.
338 * @param y the y-coordinate.
339 */
340 public ControlPoint(float x, float y) {
341 this.x = x;
342 this.y = y;
343 }
344
345 /**
346 * Tests this point for equality with an arbitrary object.
347 *
348 * @param obj the object (<code>null</code> permitted.
349 *
350 * @return A boolean.
351 */
352 public boolean equals(Object obj) {
353 if (obj == this) {
354 return true;
355 }
356 if (!(obj instanceof ControlPoint)) {
357 return false;
358 }
359 ControlPoint that = (ControlPoint) obj;
360 if (this.x != that.x) {
361 return false;
362 }
363 /*&& y == ((ControlPoint) obj).y*/;
364 return true;
365 }
366
367 }
368 }