Java tutorial
/* =========================================================== * 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.] * * --------------------- * XYSplineRenderer.java * --------------------- * (C) Copyright 2007, by Klaus Rheinwald and Contributors. * * Original Author: Klaus Rheinwald; * Contributor(s): Tobias von Petersdorff (tvp@math.umd.edu, http://www.wam.umd.edu/~petersd/); * David Gilbert (for Object Refinery Limited); * * Changes: * -------- * 25-Jul-2007 : Version 1, contributed by Klaus Rheinwald (DG); * 03-Aug-2007 : Added new constructor (KR); * 25-Oct-2007 : Prevent duplicate control points (KR); */ package de.laures.cewolf.jfree; import java.awt.Graphics2D; import java.awt.geom.Rectangle2D; import java.util.Vector; import org.jfree.chart.axis.ValueAxis; import org.jfree.chart.event.RendererChangeEvent; import org.jfree.chart.plot.PlotOrientation; import org.jfree.chart.plot.PlotRenderingInfo; import org.jfree.chart.plot.XYPlot; import org.jfree.data.xy.XYDataset; import org.jfree.ui.RectangleEdge; import org.jfree.chart.renderer.xy.*; /** * A renderer that connects data points with natural cubic splines and/or draws * shapes at each data point. This renderer is designed for use with the {@link XYPlot} class. */ public class XYSplineRenderer extends XYConditionRenderer { static final long serialVersionUID = 1232510777742238749L; /** * To collect data points for later splining. */ private Vector points; /** * Resolution of splines (number of line segments between points) */ private int precision; /** * Creates a new instance with the 'precision' attribute defaulting to 5. */ public XYSplineRenderer() { this(5); } /** * Creates a new renderer with the specified precision. * * @param precision the number of points between data items. */ public XYSplineRenderer(int precision) { super(true, false); if (precision <= 0) { throw new IllegalArgumentException("Requires precision > 0."); } this.precision = precision; } /** * Get the resolution of splines. * * @return Number of line segments between points. * * @see #setPrecision(int) */ public int getPrecision() { return this.precision; } /** * Set the resolution of splines and sends a {@link RendererChangeEvent} to all registered listeners. * * @param p number of line segments between points (must be > 0). * * @see #getPrecision() */ public void setPrecision(int p) { if (p <= 0) { throw new IllegalArgumentException("Requires p > 0."); } this.precision = p; fireChangeEvent(); } /** * Initialises the renderer. * <P> * This method will be called before the first item is rendered, giving the * renderer an opportunity to initialise any state information it wants to * maintain. The renderer can do nothing if it chooses. * * @param g2 the graphics device. * @param dataArea the area inside the axes. * @param plot the plot. * @param data the data. * @param info an optional info collection object to return data back to the caller. * * @return The renderer state. */ public XYItemRendererState initialise(Graphics2D g2, Rectangle2D dataArea, XYPlot plot, XYDataset data, PlotRenderingInfo info) { State state = (State) super.initialise(g2, dataArea, plot, data, info); state.setProcessVisibleItemsOnly(false); this.points = new Vector(); setDrawSeriesLineAsPath(true); return state; } /** * Draws the item (first pass). This method draws the lines * connecting the items. Instead of drawing separate lines, * a GeneralPath is constructed and drawn at the end of the series painting. * * @param g2 the graphics device. * @param state the renderer state. * @param plot the plot (can be used to obtain standard color information etc). * @param dataset the dataset. * @param pass the pass. * @param series the series index (zero-based). * @param item the item index (zero-based). * @param domainAxis the domain axis. * @param rangeAxis the range axis. * @param dataArea the area within which the data is being drawn. */ protected void drawPrimaryLineAsPath(XYItemRendererState state, Graphics2D g2, XYPlot plot, XYDataset dataset, int pass, int series, int item, ValueAxis domainAxis, ValueAxis rangeAxis, Rectangle2D dataArea) { RectangleEdge xAxisLocation = plot.getDomainAxisEdge(); RectangleEdge yAxisLocation = plot.getRangeAxisEdge(); // get the data points double x1 = dataset.getXValue(series, item); double y1 = dataset.getYValue(series, item); double transX1 = domainAxis.valueToJava2D(x1, dataArea, xAxisLocation); double transY1 = rangeAxis.valueToJava2D(y1, dataArea, yAxisLocation); // collect points if (!Double.isNaN(transX1) && !Double.isNaN(transY1)) { ControlPoint p = new ControlPoint( plot.getOrientation() == PlotOrientation.HORIZONTAL ? (float) transY1 : (float) transX1, plot.getOrientation() == PlotOrientation.HORIZONTAL ? (float) transX1 : (float) transY1); if (!this.points.contains(p)) { this.points.add(p); } } if (item == dataset.getItemCount(series) - 1) { State s = (State) state; // construct path if (this.points.size() > 1) { // we need at least two points to draw something ControlPoint cp0 = (ControlPoint) this.points.get(0); s.seriesPath.moveTo(cp0.x, cp0.y); if (this.points.size() == 2) { // we need at least 3 points to spline. Draw simple line for two points ControlPoint cp1 = (ControlPoint) this.points.get(1); s.seriesPath.lineTo(cp1.x, cp1.y); } else { // construct spline int np = this.points.size(); // number of points float[] d = new float[np]; // Newton form coefficients float[] x = new float[np]; // x-coordinates of nodes float y; float t; float[] a = new float[np]; float t1; float t2; float[] h = new float[np]; for (int i = 0; i < np; i++) { ControlPoint cpi = (ControlPoint) this.points.get(i); x[i] = cpi.x; d[i] = cpi.y; } for (int i = 1; i <= np - 1; i++) { h[i] = x[i] - x[i - 1]; } float[] sub = new float[np - 1]; float[] diag = new float[np - 1]; float[] sup = new float[np - 1]; for (int i = 1; i <= np - 2; i++) { diag[i] = (h[i] + h[i + 1]) / 3; sup[i] = h[i + 1] / 6; sub[i] = h[i] / 6; a[i] = (d[i + 1] - d[i]) / h[i + 1] - (d[i] - d[i - 1]) / h[i]; } solveTridiag(sub, diag, sup, a, np - 2); // note that a[0]=a[np-1]=0 // draw s.seriesPath.moveTo(x[0], d[0]); for (int i = 1; i <= np - 1; i++) { // loop over intervals between nodes for (int j = 1; j <= this.precision; j++) { t1 = (h[i] * j) / this.precision; t2 = h[i] - t1; y = ((-a[i - 1] / 6 * (t2 + h[i]) * t1 + d[i - 1]) * t2 + (-a[i] / 6 * (t1 + h[i]) * t2 + d[i]) * t1) / h[i]; t = x[i - 1] + t1; s.seriesPath.lineTo(t, y); } } } // draw path drawFirstPassShape(g2, pass, series, item, s.seriesPath); } // reset points vector this.points = new Vector(); } } /** * Document me! * * @param sub * @param diag * @param sup * @param b * @param n */ private void solveTridiag(float[] sub, float[] diag, float[] sup, float[] b, int n) { /* solve linear system with tridiagonal n by n matrix a using Gaussian elimination *without* pivoting where a(i,i-1) = sub[i] for 2<=i<=n a(i,i) = diag[i] for 1<=i<=n a(i,i+1) = sup[i] for 1<=i<=n-1 (the values sub[1], sup[n] are ignored) right hand side vector b[1:n] is overwritten with solution NOTE: 1...n is used in all arrays, 0 is unused */ int i; /* factorization and forward substitution */ for (i = 2; i <= n; i++) { sub[i] = sub[i] / diag[i - 1]; diag[i] = diag[i] - sub[i] * sup[i - 1]; b[i] = b[i] - sub[i] * b[i - 1]; } b[n] = b[n] / diag[n]; for (i = n - 1; i >= 1; i--) { b[i] = (b[i] - sup[i] * b[i + 1]) / diag[i]; } } /** * Tests this renderer for equality with an arbitrary object. * * @param obj the object (<code>null</code> permitted). * * @return A boolean. */ public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof XYSplineRenderer)) { return false; } XYSplineRenderer that = (XYSplineRenderer) obj; if (this.precision != that.precision) { return false; } return super.equals(obj); } public int hashCode() { assert false : "hashCode not designed"; return 42; // any arbitrary constant will do } /** * Represents a control point. */ class ControlPoint { /** The x-coordinate. */ public float x; /** The y-coordinate. */ public float y; /** * Creates a new control point. * * @param x the x-coordinate. * @param y the y-coordinate. */ public ControlPoint(float x, float y) { this.x = x; this.y = y; } /** * Tests this point for equality with an arbitrary object. * * @param obj the object (<code>null</code> permitted. * * @return A boolean. */ public boolean equals(Object obj) { if (obj == this) { return true; } if (!(obj instanceof ControlPoint)) { return false; } ControlPoint that = (ControlPoint) obj; if (this.x != that.x) { return false; } /*&& y == ((ControlPoint) obj).y*/; return true; } public int hashCode() { assert false : "hashCode not designed"; return 42; // any arbitrary constant will do } } }