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 * XYSplineRenderer.java
029 * ---------------------
030 * (C) Copyright 2007, 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
046 package org.jfree.chart.renderer.xy;
047
048 import java.awt.Graphics2D;
049 import java.awt.geom.Rectangle2D;
050 import java.util.Vector;
051
052 import org.jfree.chart.axis.ValueAxis;
053 import org.jfree.chart.event.RendererChangeEvent;
054 import org.jfree.chart.plot.PlotOrientation;
055 import org.jfree.chart.plot.PlotRenderingInfo;
056 import org.jfree.chart.plot.XYPlot;
057 import org.jfree.data.xy.XYDataset;
058 import org.jfree.ui.RectangleEdge;
059
060
061 /**
062 * A renderer that connects data points with natural cubic splines and/or
063 * draws shapes at each data point. This renderer is designed for use with
064 * the {@link XYPlot} class.
065 *
066 * @since 1.0.7
067 */
068 public class XYSplineRenderer extends XYLineAndShapeRenderer {
069
070 /**
071 * To collect data points for later splining.
072 */
073 private Vector points;
074
075 /**
076 * Resolution of splines (number of line segments between points)
077 */
078 private int precision;
079
080 /**
081 * Creates a new instance with the 'precision' attribute defaulting to
082 * 5.
083 */
084 public XYSplineRenderer() {
085 this(5);
086 }
087
088 /**
089 * Creates a new renderer with the specified precision.
090 *
091 * @param precision the number of points between data items.
092 */
093 public XYSplineRenderer(int precision) {
094 super();
095 if (precision <= 0) {
096 throw new IllegalArgumentException("Requires precision > 0.");
097 }
098 this.precision = precision;
099 }
100
101 /**
102 * Get the resolution of splines.
103 *
104 * @return Number of line segments between points.
105 *
106 * @see #setPrecision(int)
107 */
108 public int getPrecision() {
109 return this.precision;
110 }
111
112 /**
113 * Set the resolution of splines and sends a {@link RendererChangeEvent}
114 * to all registered listeners.
115 *
116 * @param p number of line segments between points (must be > 0).
117 *
118 * @see #getPrecision()
119 */
120 public void setPrecision(int p) {
121 if (p <= 0) {
122 throw new IllegalArgumentException("Requires p > 0.");
123 }
124 this.precision = p;
125 fireChangeEvent();
126 }
127
128 /**
129 * Initialises the renderer.
130 * <P>
131 * This method will be called before the first item is rendered, giving the
132 * renderer an opportunity to initialise any state information it wants to
133 * maintain. The renderer can do nothing if it chooses.
134 *
135 * @param g2 the graphics device.
136 * @param dataArea the area inside the axes.
137 * @param plot the plot.
138 * @param data the data.
139 * @param info an optional info collection object to return data back to
140 * the caller.
141 *
142 * @return The renderer state.
143 */
144 public XYItemRendererState initialise(Graphics2D g2, Rectangle2D dataArea,
145 XYPlot plot, XYDataset data, PlotRenderingInfo info) {
146
147 State state = (State) super.initialise(g2, dataArea, plot, data, info);
148 state.setProcessVisibleItemsOnly(false);
149 this.points = new Vector();
150 setDrawSeriesLineAsPath(true);
151 return state;
152 }
153
154 /**
155 * Draws the item (first pass). This method draws the lines
156 * connecting the items. Instead of drawing separate lines,
157 * a GeneralPath is constructed and drawn at the end of
158 * the series painting.
159 *
160 * @param g2 the graphics device.
161 * @param state the renderer state.
162 * @param plot the plot (can be used to obtain standard color information
163 * etc).
164 * @param dataset the dataset.
165 * @param pass the pass.
166 * @param series the series index (zero-based).
167 * @param item the item index (zero-based).
168 * @param domainAxis the domain axis.
169 * @param rangeAxis the range axis.
170 * @param dataArea the area within which the data is being drawn.
171 */
172 protected void drawPrimaryLineAsPath(XYItemRendererState state,
173 Graphics2D g2, XYPlot plot, XYDataset dataset, int pass,
174 int series, int item, ValueAxis domainAxis, ValueAxis rangeAxis,
175 Rectangle2D dataArea) {
176
177 RectangleEdge xAxisLocation = plot.getDomainAxisEdge();
178 RectangleEdge yAxisLocation = plot.getRangeAxisEdge();
179
180 // get the data points
181 double x1 = dataset.getXValue(series, item);
182 double y1 = dataset.getYValue(series, item);
183 double transX1 = domainAxis.valueToJava2D(x1, dataArea, xAxisLocation);
184 double transY1 = rangeAxis.valueToJava2D(y1, dataArea, yAxisLocation);
185
186 // collect points
187 if (!Double.isNaN(transX1) && !Double.isNaN(transY1)) {
188 ControlPoint p = new ControlPoint(plot.getOrientation()
189 == PlotOrientation.HORIZONTAL ? (float) transY1
190 : (float) transX1, plot.getOrientation()
191 == PlotOrientation.HORIZONTAL ? (float) transX1
192 : (float) transY1);
193 if (!this.points.contains(p)) {
194 this.points.add(p);
195 }
196 }
197 if (item == dataset.getItemCount(series) - 1) {
198 State s = (State) state;
199 // construct path
200 if (this.points.size() > 1) {
201 // we need at least two points to draw something
202 ControlPoint cp0 = (ControlPoint) this.points.get(0);
203 s.seriesPath.moveTo(cp0.x, cp0.y);
204 if (this.points.size() == 2) {
205 // we need at least 3 points to spline. Draw simple line
206 // for two points
207 ControlPoint cp1 = (ControlPoint) this.points.get(1);
208 s.seriesPath.lineTo(cp1.x, cp1.y);
209 }
210 else {
211 // construct spline
212 int np = this.points.size(); // number of points
213 float[] d = new float[np]; // Newton form coefficients
214 float[] x = new float[np]; // x-coordinates of nodes
215 float y;
216 float t;
217 float oldy = 0;
218 float oldt = 0;
219
220 float[] a = new float[np];
221 float t1;
222 float t2;
223 float[] h = new float[np];
224
225 for (int i = 0; i < np; i++) {
226 ControlPoint cpi = (ControlPoint) this.points.get(i);
227 x[i] = cpi.x;
228 d[i] = cpi.y;
229 }
230
231 for (int i = 1; i <= np - 1; i++) {
232 h[i] = x[i] - x[i - 1];
233 }
234 float[] sub = new float[np - 1];
235 float[] diag = new float[np - 1];
236 float[] sup = new float[np - 1];
237
238 for (int i = 1; i <= np - 2; i++) {
239 diag[i] = (h[i] + h[i + 1]) / 3;
240 sup[i] = h[i + 1] / 6;
241 sub[i] = h[i] / 6;
242 a[i] = (d[i + 1] - d[i]) / h[i + 1]
243 - (d[i] - d[i - 1]) / h[i];
244 }
245 solveTridiag(sub, diag, sup, a, np - 2);
246
247 // note that a[0]=a[np-1]=0
248 // draw
249 oldt = x[0];
250 oldy = d[0];
251 s.seriesPath.moveTo(oldt, oldy);
252 for (int i = 1; i <= np - 1; i++) {
253 // loop over intervals between nodes
254 for (int j = 1; j <= this.precision; j++) {
255 t1 = (h[i] * j) / this.precision;
256 t2 = h[i] - t1;
257 y = ((-a[i - 1] / 6 * (t2 + h[i]) * t1 + d[i - 1])
258 * t2 + (-a[i] / 6 * (t1 + h[i]) * t2
259 + d[i]) * t1) / h[i];
260 t = x[i - 1] + t1;
261 s.seriesPath.lineTo(t, y);
262 oldt = t;
263 oldy = y;
264 }
265 }
266 }
267 // draw path
268 drawFirstPassShape(g2, pass, series, item, s.seriesPath);
269 }
270
271 // reset points vector
272 this.points = new Vector();
273 }
274 }
275
276 /**
277 * Document me!
278 *
279 * @param sub
280 * @param diag
281 * @param sup
282 * @param b
283 * @param n
284 */
285 private void solveTridiag(float[] sub, float[] diag, float[] sup,
286 float[] b, int n) {
287 /* solve linear system with tridiagonal n by n matrix a
288 using Gaussian elimination *without* pivoting
289 where a(i,i-1) = sub[i] for 2<=i<=n
290 a(i,i) = diag[i] for 1<=i<=n
291 a(i,i+1) = sup[i] for 1<=i<=n-1
292 (the values sub[1], sup[n] are ignored)
293 right hand side vector b[1:n] is overwritten with solution
294 NOTE: 1...n is used in all arrays, 0 is unused */
295 int i;
296 /* factorization and forward substitution */
297 for (i = 2; i <= n; i++) {
298 sub[i] = sub[i] / diag[i - 1];
299 diag[i] = diag[i] - sub[i] * sup[i - 1];
300 b[i] = b[i] - sub[i] * b[i - 1];
301 }
302 b[n] = b[n] / diag[n];
303 for (i = n - 1; i >= 1; i--) {
304 b[i] = (b[i] - sup[i] * b[i + 1]) / diag[i];
305 }
306 }
307
308 /**
309 * Tests this renderer for equality with an arbitrary object.
310 *
311 * @param obj the object (<code>null</code> permitted).
312 *
313 * @return A boolean.
314 */
315 public boolean equals(Object obj) {
316 if (obj == this) {
317 return true;
318 }
319 if (!(obj instanceof XYSplineRenderer)) {
320 return false;
321 }
322 XYSplineRenderer that = (XYSplineRenderer) obj;
323 if (this.precision != that.precision) {
324 return false;
325 }
326 return super.equals(obj);
327 }
328
329 /**
330 * Represents a control point.
331 */
332 class ControlPoint {
333
334 /** The x-coordinate. */
335 public float x;
336
337 /** The y-coordinate. */
338 public float y;
339
340 /**
341 * Creates a new control point.
342 *
343 * @param x the x-coordinate.
344 * @param y the y-coordinate.
345 */
346 public ControlPoint(float x, float y) {
347 this.x = x;
348 this.y = y;
349 }
350
351 /**
352 * Tests this point for equality with an arbitrary object.
353 *
354 * @param obj the object (<code>null</code> permitted.
355 *
356 * @return A boolean.
357 */
358 public boolean equals(Object obj) {
359 if (obj == this) {
360 return true;
361 }
362 if (!(obj instanceof ControlPoint)) {
363 return false;
364 }
365 ControlPoint that = (ControlPoint) obj;
366 if (this.x != that.x) {
367 return false;
368 }
369 /*&& y == ((ControlPoint) obj).y*/;
370 return true;
371 }
372
373 }
374 }