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jfreechart example source code file (SamplingXYLineRenderer.java)

This example jfreechart source code file (SamplingXYLineRenderer.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - jfreechart tags/keywords

awt, generalpath, generalpath, geometry, io, legenditem, plotrenderinginfo, rectangle2d, samplingxylinerenderer, samplingxylinerenderer, shape, state, state, xydataset, xyitemrendererstate, xyplot, xyplot

The jfreechart SamplingXYLineRenderer.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2009, 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.]
 *
 * ---------------------------
 * SamplingXYLineRenderer.java
 * ---------------------------
 * (C) Copyright 2008, 2009, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes:
 * --------
 * 02-Oct-2008 : Version 1 (DG);
 *
 */

package org.jfree.chart.renderer.xy;

import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Shape;
import java.awt.geom.GeneralPath;
import java.awt.geom.Line2D;
import java.awt.geom.PathIterator;
import java.awt.geom.Rectangle2D;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

import org.jfree.chart.LegendItem;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.event.RendererChangeEvent;
import org.jfree.chart.plot.CrosshairState;
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.io.SerialUtilities;
import org.jfree.ui.RectangleEdge;
import org.jfree.util.PublicCloneable;
import org.jfree.util.ShapeUtilities;

/**
 * A renderer that...  This renderer is designed for use with the {@link XYPlot}
 * class.
 */
public class SamplingXYLineRenderer extends AbstractXYItemRenderer
        implements XYItemRenderer, Cloneable, PublicCloneable, Serializable {

    /** The shape that is used to represent a line in the legend. */
    private transient Shape legendLine;

    /**
     * Creates a new renderer.
     */
    public SamplingXYLineRenderer() {
        this.legendLine = new Line2D.Double(-7.0, 0.0, 7.0, 0.0);
    }

    /**
     * Returns the shape used to represent a line in the legend.
     *
     * @return The legend line (never <code>null).
     *
     * @see #setLegendLine(Shape)
     */
    public Shape getLegendLine() {
        return this.legendLine;
    }

    /**
     * Sets the shape used as a line in each legend item and sends a
     * {@link RendererChangeEvent} to all registered listeners.
     *
     * @param line  the line (<code>null not permitted).
     *
     * @see #getLegendLine()
     */
    public void setLegendLine(Shape line) {
        if (line == null) {
            throw new IllegalArgumentException("Null 'line' argument.");
        }
        this.legendLine = line;
        fireChangeEvent();
    }

    /**
     * Returns the number of passes through the data that the renderer requires
     * in order to draw the chart.  Most charts will require a single pass, but
     * some require two passes.
     *
     * @return The pass count.
     */
    public int getPassCount() {
        return 1;
    }

    /**
     * Records the state for the renderer.  This is used to preserve state
     * information between calls to the drawItem() method for a single chart
     * drawing.
     */
    public static class State extends XYItemRendererState {

        /** The path for the current series. */
        GeneralPath seriesPath;

        /**
         * A second path that draws vertical intervals to cover any extreme
         * values.
         */
        GeneralPath intervalPath;

        /**
         * The minimum change in the x-value needed to trigger an update to
         * the seriesPath.
         */
        double dX = 1.0;

        /** The last x-coordinate visited by the seriesPath. */
        double lastX;

        /** The initial y-coordinate for the current x-coordinate. */
        double openY = 0.0;

        /** The highest y-coordinate for the current x-coordinate. */
        double highY = 0.0;

        /** The lowest y-coordinate for the current x-coordinate. */
        double lowY = 0.0;

        /** The final y-coordinate for the current x-coordinate. */
        double closeY = 0.0;

        /**
         * A flag that indicates if the last (x, y) point was 'good'
         * (non-null).
         */
        boolean lastPointGood;

        /**
         * Creates a new state instance.
         *
         * @param info  the plot rendering info.
         */
        public State(PlotRenderingInfo info) {
            super(info);
        }

        /**
         * This method is called by the {@link XYPlot} at the start of each
         * series pass.  We reset the state for the current series.
         *
         * @param dataset  the dataset.
         * @param series  the series index.
         * @param firstItem  the first item index for this pass.
         * @param lastItem  the last item index for this pass.
         * @param pass  the current pass index.
         * @param passCount  the number of passes.
         */
        public void startSeriesPass(XYDataset dataset, int series,
                int firstItem, int lastItem, int pass, int passCount) {
            this.seriesPath.reset();
            this.lastPointGood = false;
            super.startSeriesPass(dataset, series, firstItem, lastItem, pass,
                    passCount);
        }

    }

    /**
     * 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) {

        double dpi = 72;
    //        Integer dpiVal = (Integer) g2.getRenderingHint(HintKey.DPI);
    //        if (dpiVal != null) {
    //            dpi = dpiVal.intValue();
    //        }
        State state = new State(info);
        state.seriesPath = new GeneralPath();
        state.intervalPath = new GeneralPath();
        state.dX = 72.0 / dpi;
        return state;
    }

    /**
     * Draws the visual representation of a single data item.
     *
     * @param g2  the graphics device.
     * @param state  the renderer state.
     * @param dataArea  the area within which the data is being drawn.
     * @param info  collects information about the drawing.
     * @param plot  the plot (can be used to obtain standard color
     *              information etc).
     * @param domainAxis  the domain axis.
     * @param rangeAxis  the range axis.
     * @param dataset  the dataset.
     * @param series  the series index (zero-based).
     * @param item  the item index (zero-based).
     * @param crosshairState  crosshair information for the plot
     *                        (<code>null permitted).
     * @param pass  the pass index.
     */
    public void drawItem(Graphics2D g2,
                         XYItemRendererState state,
                         Rectangle2D dataArea,
                         PlotRenderingInfo info,
                         XYPlot plot,
                         ValueAxis domainAxis,
                         ValueAxis rangeAxis,
                         XYDataset dataset,
                         int series,
                         int item,
                         CrosshairState crosshairState,
                         int pass) {

        // do nothing if item is not visible
        if (!getItemVisible(series, item)) {
            return;
        }
        RectangleEdge xAxisLocation = plot.getDomainAxisEdge();
        RectangleEdge yAxisLocation = plot.getRangeAxisEdge();

        // get the data point...
        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);

        State s = (State) state;
        // update path to reflect latest point
        if (!Double.isNaN(transX1) && !Double.isNaN(transY1)) {
            float x = (float) transX1;
            float y = (float) transY1;
            PlotOrientation orientation = plot.getOrientation();
            if (orientation == PlotOrientation.HORIZONTAL) {
                x = (float) transY1;
                y = (float) transX1;
            }
            if (s.lastPointGood) {
                if ((Math.abs(x - s.lastX) > s.dX)) {
                    s.seriesPath.lineTo(x, y);
                    if (s.lowY < s.highY) {
                        s.intervalPath.moveTo((float) s.lastX, (float) s.lowY);
                        s.intervalPath.lineTo((float) s.lastX, (float) s.highY);
                    }
                    s.lastX = x;
                    s.openY = y;
                    s.highY = y;
                    s.lowY = y;
                    s.closeY = y;
                }
                else {
                    s.highY = Math.max(s.highY, y);
                    s.lowY = Math.min(s.lowY, y);
                    s.closeY = y;
                }
            }
            else {
                s.seriesPath.moveTo(x, y);
                s.lastX = x;
                s.openY = y;
                s.highY = y;
                s.lowY = y;
                s.closeY = y;
            }
            s.lastPointGood = true;
        }
        else {
            s.lastPointGood = false;
        }
        // if this is the last item, draw the path ...
        if (item == s.getLastItemIndex()) {
            // draw path
            PathIterator pi = s.seriesPath.getPathIterator(null);
            int count = 0;
            while (!pi.isDone()) {
                count++;
                pi.next();
            }
            g2.setStroke(getItemStroke(series, item));
            g2.setPaint(getItemPaint(series, item));
            g2.draw(s.seriesPath);
            g2.draw(s.intervalPath);
        }
    }

    /**
     * Returns a legend item for the specified series.
     *
     * @param datasetIndex  the dataset index (zero-based).
     * @param series  the series index (zero-based).
     *
     * @return A legend item for the series.
     */
    public LegendItem getLegendItem(int datasetIndex, int series) {

        XYPlot plot = getPlot();
        if (plot == null) {
            return null;
        }

        LegendItem result = null;
        XYDataset dataset = plot.getDataset(datasetIndex);
        if (dataset != null) {
            if (getItemVisible(series, 0)) {
                String label = getLegendItemLabelGenerator().generateLabel(
                        dataset, series);
                result = new LegendItem(label);
                result.setLabelFont(lookupLegendTextFont(series));
                Paint labelPaint = lookupLegendTextPaint(series);
                if (labelPaint != null) {
                    result.setLabelPaint(labelPaint);
                }
                result.setSeriesKey(dataset.getSeriesKey(series));
                result.setSeriesIndex(series);
                result.setDataset(dataset);
                result.setDatasetIndex(datasetIndex);
            }
        }
        return result;

    }

    /**
     * Returns a clone of the renderer.
     *
     * @return A clone.
     *
     * @throws CloneNotSupportedException if the clone cannot be created.
     */
    public Object clone() throws CloneNotSupportedException {
        SamplingXYLineRenderer clone = (SamplingXYLineRenderer) super.clone();
        if (this.legendLine != null) {
            clone.legendLine = ShapeUtilities.clone(this.legendLine);
        }
        return clone;
    }

    /**
     * Tests this renderer for equality with an arbitrary object.
     *
     * @param obj  the object (<code>null permitted).
     *
     * @return <code>true or false.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof SamplingXYLineRenderer)) {
            return false;
        }
        if (!super.equals(obj)) {
            return false;
        }
        SamplingXYLineRenderer that = (SamplingXYLineRenderer) obj;
        if (!ShapeUtilities.equal(this.legendLine, that.legendLine)) {
            return false;
        }
        return true;
    }

    /**
     * Provides serialization support.
     *
     * @param stream  the input stream.
     *
     * @throws IOException  if there is an I/O error.
     * @throws ClassNotFoundException  if there is a classpath problem.
     */
    private void readObject(ObjectInputStream stream)
            throws IOException, ClassNotFoundException {
        stream.defaultReadObject();
        this.legendLine = SerialUtilities.readShape(stream);
    }

    /**
     * Provides serialization support.
     *
     * @param stream  the output stream.
     *
     * @throws IOException  if there is an I/O error.
     */
    private void writeObject(ObjectOutputStream stream) throws IOException {
        stream.defaultWriteObject();
        SerialUtilities.writeShape(this.legendLine, stream);
    }

}

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