Java tutorial
/******************************************************************************* * Copyright (C) 2016 MET Norway * Contact information: * Norwegian Meteorological Institute * Henrik Mohns Plass 1 * 0313 OSLO * NORWAY * * This file is part of jTimeseries * jTimeseries is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * jTimeseries 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 General Public License for more details. * You should have received a copy of the GNU General Public License * along with jTimeseries; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA *******************************************************************************/ package no.met.jtimeseries.chart; 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.chart.renderer.xy.XYItemRendererState; import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer; import org.jfree.data.xy.XYDataset; import org.jfree.ui.RectangleEdge; /** * 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. * * @since 1.0.7 */ public class XYSplineRenderer extends XYLineAndShapeRenderer { private static final long serialVersionUID = -1502457774160520269L; /** * To collect data points for later splining. */ private Vector<ControlPoint> 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(); 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. */ @Override 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<ControlPoint>(); setDrawSeriesLineAsPath(true); setBaseShapesVisible(false); this.setBaseShapesFilled(false); 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. */ @Override 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 = 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 = 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 oldy = 0; float oldt = 0; float[] a = new float[np]; float t1; float t2; float[] h = new float[np]; for (int i = 0; i < np; i++) { ControlPoint cpi = 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 oldt = x[0]; oldy = d[0]; s.seriesPath.moveTo(oldt, oldy); 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); oldt = t; oldy = y; } } } // draw path drawFirstPassShape(g2, pass, series, item, s.seriesPath); } // reset points vector this.points = new Vector<ControlPoint>(); } } /** * 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. */ @Override 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); } /** * 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. */ @Override 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; } } }