当 XYSplineRenderer 被用作渲染时的 JFreeChart setAutoRange
JFreeChart setAutoRange when XYSplineRenderer is used as rendered
图表需要画出平滑的形状，所以使用了XYSplineRenderer。
此外，NumberAxis 需要自动调整到数据段。
但在某些情况下，当计算样条曲线时，一些样条曲线值超出了自动范围，曲线没有完全绘制出来。
似乎在计算样条曲线之前评估了自动范围。
为了缓解它，我通过将此范围增加范围限制的百分比来调整垂直轴的范围。但这会导致图表的曲线拟合不准确，因为根据数据输入的不同，百分比可能高达 25%。
double percentOverRange = 0.05;//2%
double initalRange = series.getMaxY() - series.getMinY();
double increase = initalRange*percentOverRange;
verticalAxis.setRange(new Range(series.getMinY()-increase, series.getMaxY()+increase));
此代码创建了上图并演示了如何在前两个数据点之间不完全绘制曲线。
请注意，域轴是 DateAxis（每日数据），周末没有值
public class MyPlotChart {
private static Color MetalColor = new Color(255, 152, 0);
static double[] yData = new double[] { 0.67, 0.67, 0.69, 0.70, 0.70, 0.71, 0.71 };
static String[] labels = new String[] { "2021-11-09", "2021-11-10", "2021-11-11", "2021-11-12", "2021-11-15", "2021-11-16", "2021-11-17" };
public static void plot(String metal, int samples) throws IOException, ParseException {
SimpleDateFormat dateformatyyyy_MM_dd = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat dateformatdd_MM_yyyy = new SimpleDateFormat("dd-MM-yyyy");
XYSeries series = new XYSeries(metal);
for (int i = 0; i < yData.length; i++) {
Date date = dateformatyyyy_MM_dd.parse(labels[i]);
series.add(date.getTime(), yData[i]);
}
//Configure Vertical Axis
NumberAxis verticalAxis = new NumberAxis(null);
NumberFormat numberFormat = NumberFormat.getInstance(Locale.getDefault());
numberFormat.setRoundingMode(RoundingMode.HALF_DOWN);
numberFormat.setMinimumFractionDigits(2);
numberFormat.setMaximumFractionDigits(2);
double vericalTickUnit = (series.getMaxY() - series.getMinY()) / 7;
NumberTickUnit nt = new NumberTickUnit(vericalTickUnit, numberFormat);
verticalAxis.setTickUnit(nt);
double percentOverRange = 0.05;// 2%
double initalRange = series.getMaxY() - series.getMinY();
double increase = initalRange * percentOverRange;
verticalAxis.setRange(new Range(series.getMinY()-increase, series.getMaxY()+increase));
verticalAxis.setAutoRange(true);
verticalAxis.setAutoRangeIncludesZero(false);
verticalAxis.setTickMarksVisible(true);
verticalAxis.setTickMarkInsideLength(3f);
//Configure Domain Axis
DateAxis domainAxis = new DateAxis(null);
domainAxis.setTickUnit(new DateTickUnit(DateTickUnitType.DAY, 1, dateformatdd_MM_yyyy));
//Configure Renderer
XYSplineRenderer r = new XYSplineRenderer(10);
r.setSeriesPaint(0, MetalColor);
r.setDefaultShapesVisible(true);
r.setSeriesStroke(0, new BasicStroke(3.0f));
XYDataset dataset = new XYSeriesCollection(series);
XYPlot xyplot = new XYPlot(dataset, domainAxis, verticalAxis, r);
xyplot.getDomainAxis().setVerticalTickLabels(true);
xyplot.setDomainGridlinesVisible(false);
xyplot.setBackgroundImage(null);
xyplot.setBackgroundPaint(Color.WHITE);
Font font = xyplot.getDomainAxis().getTickLabelFont();
Font fontnew = new Font(font.getName(), Font.BOLD, 14);
xyplot.getDomainAxis().setTickLabelFont(fontnew);
xyplot.getRangeAxis().setTickLabelFont(fontnew);
JFreeChart chart = new JFreeChart(xyplot);
chart.removeLegend();// Remove legend
chart.setBackgroundPaint(Color.WHITE);
String fileName = "myChart" + metal + samples + "TEST.png";
ChartUtils.saveChartAsPNG(new File(fileName), chart, 600, 600);
}
public static void main(String[] args) throws IOException, ParseException {
MyPlotChart.plot("metal", 7);
}
}
编辑
以下图表来自上面的代码，只是改变了 XYSplineRenderer 的精度。
如 javadoc 中所定义：
XYSplineRenderer: A renderer that connects data points with natural
cubic splines and/or draws shapes at each data point.
public XYSplineRenderer(int precision)
Creates a new renderer with the specified precision and no fill of the
area 'under' (between '0' and) the spline.
Parameters:
precision - the number of points between data items.
这意味着自然三次样条是根据数据点计算的。
另一方面，精度用于定义每对数据点之间的插值点数。
精度 = N - 1，其中 N = 每个数据点段之间的插值点数
我只能看到两个选项：
- XYSplineRenderer 应该有一个返回一组自然三次样条的方法，所以可以计算每个段的最大值，因此可以相应地设置 AutoRange
- JFreeChart 应该实现基于 NURBS（非均匀有理基础样条）的渲染器，而不是自然的三次样条，它通过一组控制点（see）控制曲线的形状
编辑 2
当没有可用数据（周末）并且 DateAxis 在星期五和星期一之间插入两天时，问题会增加：值之间的差距更大，因此样条曲线也更长。
如 JFreeChart adding trend-line outside of actual values 中所述，对于非严格单调的函数，此类异常是不可避免的。如果没有更详细的样条控制，您可以通过在有问题的轴上启用自动范围（默认）并根据经验调整轴边距来获得更好的结果。
rangeAxis.setAutoRange(true); // true by default
rangeAxis.setLowerMargin(0.08); // 8% lower margin
在下面的变体中，请注意以下内容：
setLowerMargin() 将范围轴的下边距减小轴范围的 8%。
setNumberFormatOverride() 和 setDateFormatOverride 用于格式化刻度标签。
XYSplineRenderer 由 15 的任意 precision 构成。
deriveFont()用于改变坐标轴刻度标签字体属性
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.io.File;
import java.io.IOException;
import java.math.RoundingMode;
import java.text.NumberFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.jfree.chart.ChartUtils;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYSplineRenderer;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
/**
* @see
*/
public class SplineTest {
public static void main(String[] args) throws ParseException, IOException {
SimpleDateFormat formatyyyy_MM_dd = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat formatdd_MM_yyyy = new SimpleDateFormat("dd-MM-yyyy");
double[] yData = new double[]{0.67, 0.67, 0.69, 0.70, 0.70, 0.71, 0.71};
String[] labels = new String[]{"2021-11-09", "2021-11-10", "2021-11-11",
"2021-11-12", "2021-11-15", "2021-11-16", "2021-11-17"};
XYSeries series = new XYSeries("Series");
for (int i = 0; i < yData.length; i++) {
Date date = formatyyyy_MM_dd.parse(labels[i]);
series.add(date.getTime(), yData[i]);
}
NumberAxis rangeAxis = new NumberAxis(null);
NumberFormat numberFormat = NumberFormat.getInstance();
numberFormat.setRoundingMode(RoundingMode.HALF_DOWN);
numberFormat.setMinimumFractionDigits(2);
numberFormat.setMaximumFractionDigits(2);
rangeAxis.setNumberFormatOverride(numberFormat);
rangeAxis.setTickMarksVisible(true);
rangeAxis.setAutoRange(true); // true by default
rangeAxis.setLowerMargin(0.08); // 8% lower margin
rangeAxis.setAutoRangeIncludesZero(false);
DateAxis domainAxis = new DateAxis(null);
domainAxis.setDateFormatOverride(formatdd_MM_yyyy);
domainAxis.setVerticalTickLabels(true);
Font font = domainAxis.getTickLabelFont().deriveFont(Font.BOLD, 10);
domainAxis.setTickLabelFont(font);
rangeAxis.setTickLabelFont(font);
XYSplineRenderer r = new XYSplineRenderer(15);
r.setSeriesPaint(0, new Color(255, 152, 0));
r.setDefaultShapesVisible(true);
r.setSeriesStroke(0, new BasicStroke(3.0f));
XYDataset dataset = new XYSeriesCollection(series);
XYPlot xyplot = new XYPlot(dataset, domainAxis, rangeAxis, r);
xyplot.setDomainGridlinesVisible(false);
xyplot.setBackgroundImage(null);
xyplot.setBackgroundPaint(Color.WHITE);
JFreeChart chart = new JFreeChart(null, null, xyplot, false);
chart.setBackgroundPaint(Color.WHITE);
ChartUtils.saveChartAsPNG(new File("temp.png"), chart, 400, 300);
}
}
根据问题中指出的内容，一种可能的解决方案是使用基于 NURBS 或贝塞尔曲线的 jfreechart 渲染器而不是自然三次样条曲线。
使用贝塞尔曲线可以通过定义参数（张力）来控制曲线围绕点的弯曲方式。
我从 github 克隆了 jfreechart 并创建了一个 XYBezierRenderer class，它使用参数（张力）扩展 XYLineAndShapeRenderer 以控制曲线的弯曲。
XYBezierRenderer class 的代码如下：
package org.jfree.chart.renderer.xy;
import java.awt.GradientPaint;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.geom.GeneralPath;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
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.util.GradientPaintTransformer;
import org.jfree.chart.api.RectangleEdge;
import org.jfree.chart.util.StandardGradientPaintTransformer;
import org.jfree.chart.internal.Args;
import org.jfree.data.xy.XYDataset;
/**
* A renderer that connects data points with Bezier cubic curves and/or
* draws shapes at each data point. This renderer is designed for use with
* the {@link XYPlot} class.
* <br><br>
*
* @since
*/
public class XYBezierRenderer extends XYLineAndShapeRenderer {
/**
* An enumeration of the fill types for the renderer.
*
* @since 1.0.17
*/
public static enum FillType {
/** No fill. */
NONE,
/** Fill down to zero. */
TO_ZERO,
/** Fill to the lower bound. */
TO_LOWER_BOUND,
/** Fill to the upper bound. */
TO_UPPER_BOUND
}
/**
* Represents state information that applies to a single rendering of
* a chart.
*/
public static class XYBezierState extends State {
/** The area to fill under the curve. */
public GeneralPath fillArea;
/** The points. */
public List<Point2D> points;
/**
* Creates a new state instance.
*
* @param info the plot rendering info.
*/
public XYBezierState(PlotRenderingInfo info) {
super(info);
this.fillArea = new GeneralPath();
this.points = new ArrayList<>();
}
}
/**
* Resolution of splines (number of line segments between points)
*/
private int precision;
/**
* Tension defines how sharply does the curve bends
*/
private double tension;
/**
* A flag that can be set to specify
* to fill the area under the spline.
*/
private FillType fillType;
private GradientPaintTransformer gradientPaintTransformer;
/**
* Creates a new instance with the precision attribute defaulting to 5,
* the tension attribute defaulting to 2
* and no fill of the area 'under' the spline.
*/
public XYBezierRenderer() {
this(5, 25, FillType.NONE);
}
/**
* Creates a new renderer with the specified precision and tension
* and no fill of the area 'under' (between '0' and) the spline.
*
* @param precision the number of points between data items.
* @param tension value to define how sharply the curve bends
*/
public XYBezierRenderer(int precision, double tension) {
this(precision, tension ,FillType.NONE);
}
/**
* Creates a new renderer with the specified precision
* and specified fill of the area 'under' (between '0' and) the spline.
*
* @param precision the number of points between data items.
* @param tension value to define how sharply the curve bends
* @param fillType the type of fill beneath the curve ({@code null}
* not permitted).
*
* @since 1.0.17
*/
public XYBezierRenderer(int precision, double tension, FillType fillType) {
super();
if (precision <= 0) {
throw new IllegalArgumentException("Requires precision > 0.");
}
if (tension <= 0) {
throw new IllegalArgumentException("Requires precision > 0.");
}
Args.nullNotPermitted(fillType, "fillType");
this.precision = precision;
this.tension = tension;
this.fillType = fillType;
this.gradientPaintTransformer = new StandardGradientPaintTransformer();
}
/**
* Returns the number of line segments used to approximate the Bezier
* curve between data points.
*
* @return The number of line segments.
*
* @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();
}
/**
* Returns the value of the tension which defines how sharply
* does the curve bends
*
* @return The value of tesion.
*
* @see #setTension(double)
*/
public double getTension() {
return this.tension;
}
/**
* Set the value of the tension which defines how sharply
* does the curve bends and sends a {@link RendererChangeEvent}
* to all registered listeners.
*
* @param t value of tension (must be > 0).
*
* @see #getTension()
*/
public void setTension(double t) {
if (t <= 0) {
throw new IllegalArgumentException("Requires tension > 0.");
}
this.tension = t;
fireChangeEvent();
}
/**
* Returns the type of fill that the renderer draws beneath the curve.
*
* @return The type of fill (never {@code null}).
*
* @see #setFillType(FillType)
*
* @since 1.0.17
*/
public FillType getFillType() {
return this.fillType;
}
/**
* Set the fill type and sends a {@link RendererChangeEvent}
* to all registered listeners.
*
* @param fillType the fill type ({@code null} not permitted).
*
* @see #getFillType()
*
* @since 1.0.17
*/
public void setFillType(FillType fillType) {
this.fillType = fillType;
fireChangeEvent();
}
/**
* Returns the gradient paint transformer, or {@code null}.
*
* @return The gradient paint transformer (possibly {@code null}).
*
* @since 1.0.17
*/
public GradientPaintTransformer getGradientPaintTransformer() {
return this.gradientPaintTransformer;
}
/**
* Sets the gradient paint transformer and sends a
* {@link RendererChangeEvent} to all registered listeners.
*
* @param gpt the transformer ({@code null} permitted).
*
* @since 1.0.17
*/
public void setGradientPaintTransformer(GradientPaintTransformer gpt) {
this.gradientPaintTransformer = gpt;
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) {
setDrawSeriesLineAsPath(true);
XYBezierState state = new XYBezierState(info);
state.setProcessVisibleItemsOnly(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 xAxis the domain axis.
* @param yAxis 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 xAxis, ValueAxis yAxis,
Rectangle2D dataArea) {
XYBezierState s = (XYBezierState) state;
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 = xAxis.valueToJava2D(x1, dataArea, xAxisLocation);
double transY1 = yAxis.valueToJava2D(y1, dataArea, yAxisLocation);
// Collect points
if (!Double.isNaN(transX1) && !Double.isNaN(transY1)) {
Point2D p = plot.getOrientation() == PlotOrientation.HORIZONTAL
? new Point2D.Float((float) transY1, (float) transX1)
: new Point2D.Float((float) transX1, (float) transY1);
if (!s.points.contains(p))
s.points.add(p);
}
if (item == dataset.getItemCount(series) - 1) { // construct path
if (s.points.size() > 1) {
Point2D origin;
if (this.fillType == FillType.TO_ZERO) {
float xz = (float) xAxis.valueToJava2D(0, dataArea,
yAxisLocation);
float yz = (float) yAxis.valueToJava2D(0, dataArea,
yAxisLocation);
origin = plot.getOrientation() == PlotOrientation.HORIZONTAL
? new Point2D.Float(yz, xz)
: new Point2D.Float(xz, yz);
} else if (this.fillType == FillType.TO_LOWER_BOUND) {
float xlb = (float) xAxis.valueToJava2D(
xAxis.getLowerBound(), dataArea, xAxisLocation);
float ylb = (float) yAxis.valueToJava2D(
yAxis.getLowerBound(), dataArea, yAxisLocation);
origin = plot.getOrientation() == PlotOrientation.HORIZONTAL
? new Point2D.Float(ylb, xlb)
: new Point2D.Float(xlb, ylb);
} else {// fillType == TO_UPPER_BOUND
float xub = (float) xAxis.valueToJava2D(
xAxis.getUpperBound(), dataArea, xAxisLocation);
float yub = (float) yAxis.valueToJava2D(
yAxis.getUpperBound(), dataArea, yAxisLocation);
origin = plot.getOrientation() == PlotOrientation.HORIZONTAL
? new Point2D.Float(yub, xub)
: new Point2D.Float(xub, yub);
}
// we need at least two points to draw something
Point2D cp0 = s.points.get(0);
s.seriesPath.moveTo(cp0.getX(), cp0.getY());
if (this.fillType != FillType.NONE) {
if (plot.getOrientation() == PlotOrientation.HORIZONTAL) {
s.fillArea.moveTo(origin.getX(), cp0.getY());
} else {
s.fillArea.moveTo(cp0.getX(), origin.getY());
}
s.fillArea.lineTo(cp0.getX(), cp0.getY());
}
if (s.points.size() == 2) {
// we need at least 3 points to Bezier. Draw simple line
// for two points
Point2D cp1 = s.points.get(1);
if (this.fillType != FillType.NONE) {
s.fillArea.lineTo(cp1.getX(), cp1.getY());
s.fillArea.lineTo(cp1.getX(), origin.getY());
s.fillArea.closePath();
}
s.seriesPath.lineTo(cp1.getX(), cp1.getY());
}
else if (s.points.size() == 3) {
Point2D[] pInitial = getInitalPoints(s);
pintar(pInitial, s);
Point2D[] pFinal = getFinalPoints(s);
pintar(pFinal, s);
}
else {
// construct Bezier curve
//System.out.println("Entra en construir curva larga... " + s.points.size());
int np = s.points.size(); // number of points
for(int i = 0; i < np - 1; i++) {
if(i == 0) {
//System.out.println("Entra en i= 0");
// 3 points, 2 lines (initial an final Bezier curves
Point2D[] initial3Points = new Point2D[3];
initial3Points[0] = s.points.get(0);
initial3Points[1] = s.points.get(1);
initial3Points[2] = s.points.get(2);
Point2D[] pInitial = calcSegmentPointsInitial(initial3Points);// TENSION = 1.5
pintar(pInitial, s);
}
if(i == np - 2) {
//System.out.println("Entra en i = np - 2");
Point2D[] final3Points = new Point2D[4];
final3Points[1] = s.points.get(np-3);
final3Points[2] = s.points.get(np-2);
final3Points[3] = s.points.get(np-1);
//No se define final3Points[4] pq no se usa
Point2D[] pFinal = calcSegmentPointsFinal(final3Points);//TENSION = 1.5
pintar(pFinal, s);
}
if ((i != 0) && (i != (np - 2))){
Point2D[] original4Points = new Point2D[4];
original4Points[0] = s.points.get(i - 1);
original4Points[1] = s.points.get(i);
original4Points[2] = s.points.get(i + 1);
original4Points[3] = s.points.get(i + 2);
Point2D[] pMedium = calculateSegmentPoints(original4Points);
pintar(pMedium, s);
}
}
}
// Add last point @ y=0 for fillPath and close path
if (this.fillType != FillType.NONE) {
if (plot.getOrientation() == PlotOrientation.HORIZONTAL) {
s.fillArea.lineTo(origin.getX(), s.points.get(
s.points.size() - 1).getY());
} else {
s.fillArea.lineTo(s.points.get(
s.points.size() - 1).getX(), origin.getY());
}
s.fillArea.closePath();
}
// fill under the curve...
if (this.fillType != FillType.NONE) {
Paint fp = getSeriesFillPaint(series);
if (this.gradientPaintTransformer != null
&& fp instanceof GradientPaint) {
GradientPaint gp = this.gradientPaintTransformer
.transform((GradientPaint) fp, s.fillArea);
g2.setPaint(gp);
} else {
g2.setPaint(fp);
}
g2.fill(s.fillArea);
s.fillArea.reset();
}
// then draw the line...
drawFirstPassShape(g2, pass, series, item, s.seriesPath);
}
// reset points vector
s.points = new ArrayList<>();
}
}
private void pintar(Point2D[] segmentPoints, XYBezierState s) {
double x;
double y;
//System.out.println("Precision: " + this.precision);
for (int t = 0 ; t <= this.precision; t++) {
double k = (double)t / this.precision;
double r = 1- k;
x = Math.pow(r, 3) * segmentPoints[0].getX() + 3 * k * Math.pow(r, 2) * segmentPoints[1].getX()
+ 3 * Math.pow(k, 2) * (1 - k) * segmentPoints[2].getX() + Math.pow(k, 3) * segmentPoints[3].getX();
y = Math.pow(r, 3) * segmentPoints[0].getY() + 3 * k * Math.pow(r, 2) * segmentPoints[1].getY()
+ 3 * Math.pow(k, 2) * (1 - k) * segmentPoints[2].getY() + Math.pow(k, 3) * segmentPoints[3].getY();
s.seriesPath.lineTo(x, y);
//System.out.println("Pintar, t = " + t + "\tk = " + k +"\t" + "\tx = " + x + "\ty = " + y);
}
}
private Point2D[] getFinalPoints(XYBezierState s) {
//System.out.println("getinFinalPoints");
//for(int i = 0; i< s.points.size(); i++) {
// Point2D p = s.points.get(i);
// System.out.println("Point" + i + "\tx = " + p.getX() + "\ty = " + p.getY());
//}
Point2D[] final3Points = new Point2D[4];
final3Points[1] = s.points.get(0);
final3Points[2] = s.points.get(1);
final3Points[3] = s.points.get(2);
//No se define final3Points[4] pq no se usa
Point2D[] pFinal = calcSegmentPointsFinal(final3Points);//TENSION = 1.5
return pFinal;
}
private Point2D[] getInitalPoints(XYBezierState s) {
//System.out.println("getInitialPoints");
//for(int i = 0; i< s.points.size(); i++) {
// Point2D p = s.points.get(i);
// System.out.println("Point" + i + "\tx = " + p.getX() + "\ty = " + p.getY());
//}
// 3 points, 2 lines (initial an final Bezier curves
Point2D[] initial3Points = new Point2D[3];
initial3Points[0] = s.points.get(0);
initial3Points[1] = s.points.get(1);
initial3Points[2] = s.points.get(2);
Point2D[] pInitial = calcSegmentPointsInitial(initial3Points);// TENSION = 1.5
return pInitial;
}
private Point2D[] calculateSegmentPoints(Point2D[] original4Points) {
//System.out.println("calcSegmentPoints");
double relativeTension = calcRelativetension(original4Points, false, false);
Point2D[] points = new Point2D[4];
points[0] = original4Points[1];
points[3] = original4Points[2];
//double modulo = Math.sqrt(Math.pow(original4Points[1].getX() - original4Points[2].getX(), 2) + Math.pow(original4Points[1].getY() - original4Points[2].getY(), 2));
//double tesionRelativa = modulo * tension / 4;
for(int i = 1; i < 3; i++) {
Point2D aux1 = calcUnitaryVector(original4Points[i-1], original4Points[i]);
Point2D aux2 = calcUnitaryVector(original4Points[i+1], original4Points[i]);
Point2D aux3 = calcUnitaryVector(aux2, aux1);
double x = original4Points[i].getX() + Math.pow(-1.0, i+1) * tension * aux3.getX();
double y = original4Points[i].getY() + Math.pow(-1.0, i+1) * tension * aux3.getY();
points[i] = new Point2D.Double(x, y);
}
return points;
}
private Point2D[] calcSegmentPointsInitial(Point2D[] original3P) {
//System.out.println("calcSegmentPointsInitial");
/*
* Each segment is defined by its two endpoints and two control points. A
* control point determines the tangent at the corresponding endpoint.
*/
Point2D[] points = new Point2D[4];
points[0] = original3P[0];// Endpoint 1
points[3] = original3P[1];// Endpoint 2
// Control point 1
Point2D auxInitial = calcUnitaryVector(original3P[0], original3P[1]);
points[1] = original3P[0];// new Point2D.Double(x0, y0);
// Control point 2
// Es el mismo vector que el anterior: Point2D aux1 =
// calcUnitaryVector(original4P[0], original4P[1]);
Point2D aux2 = calcUnitaryVector(original3P[2], original3P[1]);
Point2D aux3 = calcUnitaryVector(auxInitial, aux2);
double relativeTension = calcRelativetension(original3P, true, false);
double x = original3P[1].getX() + tension * aux3.getX();
double y = original3P[1].getY() + tension * aux3.getY();
points[2] = new Point2D.Double(x, y);
//for(int i = 0; i < 4; i++) {
// System.out.println("Point[" + i + "]\tx = " + points[i].getX() + "\ty = " + points[i].getY());
//}
return points;
}
private Point2D[] calcSegmentPointsFinal(Point2D[] original3P) {
//System.out.println("calcSegmentPointsFinal");
/*
* Each segment is defined by its two endpoints and two control points. A
* control point determines the tangent at the corresponding endpoint.
*/
Point2D[] points = new Point2D[4];
points[0] = original3P[2];// Endpoint 1
points[3] = original3P[3];// Endpoint 2
// Control point 2: points[2]
Point2D auxInitial = calcUnitaryVector(original3P[3], original3P[2]);
points[2] = original3P[3];// new Point2D.Double(x0, y0);
// Control point 1
Point2D aux1 = calcUnitaryVector(original3P[3], original3P[2]);
Point2D aux2 = calcUnitaryVector(original3P[1], original3P[2]);
Point2D aux3 = calcUnitaryVector(aux1, aux2);
double relativeTension = calcRelativetension(original3P, false, true);
double x = original3P[2].getX() + tension * aux3.getX();
double y = original3P[2].getY() + tension * aux3.getY();
points[1] = new Point2D.Double(x, y);
//for(int i = 0; i < 4; i++) {
// System.out.println("Point[" + i + "]\tx = " + points[i].getX() + "\ty = " + points[i].getY());
//}
return points;
}
private double calcRelativetension (Point2D[] original4P, boolean initial, boolean end) {
if(initial) {
double module1 = Math.sqrt(
Math.pow(original4P[1].getX() - original4P[0].getX(), 2) +
Math.pow(original4P[1].getY() - original4P[0].getY(), 2));
double module2 = Math.sqrt(
Math.pow(original4P[2].getX() - original4P[1].getX(), 2) +
Math.pow(original4P[2].getY() - original4P[1].getY(), 2));
double moduleTotal = module1 + module2;
return moduleTotal * tension / 3;
}
if(end) {
double module2 = Math.sqrt(
Math.pow(original4P[2].getX() - original4P[1].getX(), 2) +
Math.pow(original4P[2].getY() - original4P[1].getY(), 2));
double module3 = Math.sqrt(
Math.pow(original4P[3].getX() - original4P[2].getX(), 2) +
Math.pow(original4P[3].getY() - original4P[2].getY(), 2));
double moduleTotal = module2 + module3;
return moduleTotal * tension / 3;
}
double module1 = Math.sqrt(
Math.pow(original4P[1].getX() - original4P[0].getX(), 2) +
Math.pow(original4P[1].getY() - original4P[0].getY(), 2));
double module2 = Math.sqrt(
Math.pow(original4P[2].getX() - original4P[1].getX(), 2) +
Math.pow(original4P[2].getY() - original4P[1].getY(), 2));
double module3 = Math.sqrt(
Math.pow(original4P[3].getX() - original4P[2].getX(), 2) +
Math.pow(original4P[3].getY() - original4P[2].getY(), 2));
double moduleTotal = module1 + module2 + module3;
return moduleTotal * tension / 4;
}
private Point2D calcUnitaryVector(Point2D pOrigin, Point2D pEnd) {
double module = Math.sqrt(Math.pow(pEnd.getX() - pOrigin.getX(), 2) +
Math.pow(pEnd.getY() - pOrigin.getY(), 2));
if (module == 0) {
return null;
}
return new Point2D.Double((pEnd.getX() - pOrigin.getX()) / module,
(pEnd.getY() - pOrigin.getY()) /module);
}
/**
* Tests this renderer for equality with an arbitrary object.
*
* @param obj the object ({@code null} permitted).
*
* @return A boolean.
*/
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof XYBezierRenderer)) {
return false;
}
XYBezierRenderer that = (XYBezierRenderer) obj;
if (this.precision != that.precision) {
return false;
}
if (this.fillType != that.fillType) {
return false;
}
if (!Objects.equals(this.gradientPaintTransformer, that.gradientPaintTransformer)) {
return false;
}
return super.equals(obj);
}
}
图表需要画出平滑的形状，所以使用了XYSplineRenderer。 此外，NumberAxis 需要自动调整到数据段。
但在某些情况下，当计算样条曲线时，一些样条曲线值超出了自动范围，曲线没有完全绘制出来。
似乎在计算样条曲线之前评估了自动范围。
为了缓解它，我通过将此范围增加范围限制的百分比来调整垂直轴的范围。但这会导致图表的曲线拟合不准确，因为根据数据输入的不同，百分比可能高达 25%。
double percentOverRange = 0.05;//2%
double initalRange = series.getMaxY() - series.getMinY();
double increase = initalRange*percentOverRange;
verticalAxis.setRange(new Range(series.getMinY()-increase, series.getMaxY()+increase));
此代码创建了上图并演示了如何在前两个数据点之间不完全绘制曲线。 请注意，域轴是 DateAxis（每日数据），周末没有值
public class MyPlotChart {
private static Color MetalColor = new Color(255, 152, 0);
static double[] yData = new double[] { 0.67, 0.67, 0.69, 0.70, 0.70, 0.71, 0.71 };
static String[] labels = new String[] { "2021-11-09", "2021-11-10", "2021-11-11", "2021-11-12", "2021-11-15", "2021-11-16", "2021-11-17" };
public static void plot(String metal, int samples) throws IOException, ParseException {
SimpleDateFormat dateformatyyyy_MM_dd = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat dateformatdd_MM_yyyy = new SimpleDateFormat("dd-MM-yyyy");
XYSeries series = new XYSeries(metal);
for (int i = 0; i < yData.length; i++) {
Date date = dateformatyyyy_MM_dd.parse(labels[i]);
series.add(date.getTime(), yData[i]);
}
//Configure Vertical Axis
NumberAxis verticalAxis = new NumberAxis(null);
NumberFormat numberFormat = NumberFormat.getInstance(Locale.getDefault());
numberFormat.setRoundingMode(RoundingMode.HALF_DOWN);
numberFormat.setMinimumFractionDigits(2);
numberFormat.setMaximumFractionDigits(2);
double vericalTickUnit = (series.getMaxY() - series.getMinY()) / 7;
NumberTickUnit nt = new NumberTickUnit(vericalTickUnit, numberFormat);
verticalAxis.setTickUnit(nt);
double percentOverRange = 0.05;// 2%
double initalRange = series.getMaxY() - series.getMinY();
double increase = initalRange * percentOverRange;
verticalAxis.setRange(new Range(series.getMinY()-increase, series.getMaxY()+increase));
verticalAxis.setAutoRange(true);
verticalAxis.setAutoRangeIncludesZero(false);
verticalAxis.setTickMarksVisible(true);
verticalAxis.setTickMarkInsideLength(3f);
//Configure Domain Axis
DateAxis domainAxis = new DateAxis(null);
domainAxis.setTickUnit(new DateTickUnit(DateTickUnitType.DAY, 1, dateformatdd_MM_yyyy));
//Configure Renderer
XYSplineRenderer r = new XYSplineRenderer(10);
r.setSeriesPaint(0, MetalColor);
r.setDefaultShapesVisible(true);
r.setSeriesStroke(0, new BasicStroke(3.0f));
XYDataset dataset = new XYSeriesCollection(series);
XYPlot xyplot = new XYPlot(dataset, domainAxis, verticalAxis, r);
xyplot.getDomainAxis().setVerticalTickLabels(true);
xyplot.setDomainGridlinesVisible(false);
xyplot.setBackgroundImage(null);
xyplot.setBackgroundPaint(Color.WHITE);
Font font = xyplot.getDomainAxis().getTickLabelFont();
Font fontnew = new Font(font.getName(), Font.BOLD, 14);
xyplot.getDomainAxis().setTickLabelFont(fontnew);
xyplot.getRangeAxis().setTickLabelFont(fontnew);
JFreeChart chart = new JFreeChart(xyplot);
chart.removeLegend();// Remove legend
chart.setBackgroundPaint(Color.WHITE);
String fileName = "myChart" + metal + samples + "TEST.png";
ChartUtils.saveChartAsPNG(new File(fileName), chart, 600, 600);
}
public static void main(String[] args) throws IOException, ParseException {
MyPlotChart.plot("metal", 7);
}
}
编辑
以下图表来自上面的代码，只是改变了 XYSplineRenderer 的精度。
如 javadoc 中所定义：
XYSplineRenderer: A renderer that connects data points with natural cubic splines and/or draws shapes at each data point.
public XYSplineRenderer(int precision)
Creates a new renderer with the specified precision and no fill of the area 'under' (between '0' and) the spline.
Parameters: precision - the number of points between data items.
这意味着自然三次样条是根据数据点计算的。
另一方面，精度用于定义每对数据点之间的插值点数。
精度 = N - 1，其中 N = 每个数据点段之间的插值点数
我只能看到两个选项：
- XYSplineRenderer 应该有一个返回一组自然三次样条的方法，所以可以计算每个段的最大值，因此可以相应地设置 AutoRange
- JFreeChart 应该实现基于 NURBS（非均匀有理基础样条）的渲染器，而不是自然的三次样条，它通过一组控制点（see）控制曲线的形状
编辑 2
当没有可用数据（周末）并且 DateAxis 在星期五和星期一之间插入两天时，问题会增加：值之间的差距更大，因此样条曲线也更长。
如 JFreeChart adding trend-line outside of actual values 中所述，对于非严格单调的函数，此类异常是不可避免的。如果没有更详细的样条控制，您可以通过在有问题的轴上启用自动范围（默认）并根据经验调整轴边距来获得更好的结果。
rangeAxis.setAutoRange(true); // true by default
rangeAxis.setLowerMargin(0.08); // 8% lower margin
在下面的变体中，请注意以下内容：
setLowerMargin()将范围轴的下边距减小轴范围的 8%。setNumberFormatOverride()和setDateFormatOverride用于格式化刻度标签。XYSplineRenderer由 15 的任意precision构成。deriveFont()用于改变坐标轴刻度标签字体属性
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.io.File;
import java.io.IOException;
import java.math.RoundingMode;
import java.text.NumberFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.jfree.chart.ChartUtils;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.axis.DateAxis;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYSplineRenderer;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
/**
* @see
*/
public class SplineTest {
public static void main(String[] args) throws ParseException, IOException {
SimpleDateFormat formatyyyy_MM_dd = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat formatdd_MM_yyyy = new SimpleDateFormat("dd-MM-yyyy");
double[] yData = new double[]{0.67, 0.67, 0.69, 0.70, 0.70, 0.71, 0.71};
String[] labels = new String[]{"2021-11-09", "2021-11-10", "2021-11-11",
"2021-11-12", "2021-11-15", "2021-11-16", "2021-11-17"};
XYSeries series = new XYSeries("Series");
for (int i = 0; i < yData.length; i++) {
Date date = formatyyyy_MM_dd.parse(labels[i]);
series.add(date.getTime(), yData[i]);
}
NumberAxis rangeAxis = new NumberAxis(null);
NumberFormat numberFormat = NumberFormat.getInstance();
numberFormat.setRoundingMode(RoundingMode.HALF_DOWN);
numberFormat.setMinimumFractionDigits(2);
numberFormat.setMaximumFractionDigits(2);
rangeAxis.setNumberFormatOverride(numberFormat);
rangeAxis.setTickMarksVisible(true);
rangeAxis.setAutoRange(true); // true by default
rangeAxis.setLowerMargin(0.08); // 8% lower margin
rangeAxis.setAutoRangeIncludesZero(false);
DateAxis domainAxis = new DateAxis(null);
domainAxis.setDateFormatOverride(formatdd_MM_yyyy);
domainAxis.setVerticalTickLabels(true);
Font font = domainAxis.getTickLabelFont().deriveFont(Font.BOLD, 10);
domainAxis.setTickLabelFont(font);
rangeAxis.setTickLabelFont(font);
XYSplineRenderer r = new XYSplineRenderer(15);
r.setSeriesPaint(0, new Color(255, 152, 0));
r.setDefaultShapesVisible(true);
r.setSeriesStroke(0, new BasicStroke(3.0f));
XYDataset dataset = new XYSeriesCollection(series);
XYPlot xyplot = new XYPlot(dataset, domainAxis, rangeAxis, r);
xyplot.setDomainGridlinesVisible(false);
xyplot.setBackgroundImage(null);
xyplot.setBackgroundPaint(Color.WHITE);
JFreeChart chart = new JFreeChart(null, null, xyplot, false);
chart.setBackgroundPaint(Color.WHITE);
ChartUtils.saveChartAsPNG(new File("temp.png"), chart, 400, 300);
}
}
根据问题中指出的内容，一种可能的解决方案是使用基于 NURBS 或贝塞尔曲线的 jfreechart 渲染器而不是自然三次样条曲线。
使用贝塞尔曲线可以通过定义参数（张力）来控制曲线围绕点的弯曲方式。
我从 github 克隆了 jfreechart 并创建了一个 XYBezierRenderer class，它使用参数（张力）扩展 XYLineAndShapeRenderer 以控制曲线的弯曲。
XYBezierRenderer class 的代码如下：
package org.jfree.chart.renderer.xy;
import java.awt.GradientPaint;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.geom.GeneralPath;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
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.util.GradientPaintTransformer;
import org.jfree.chart.api.RectangleEdge;
import org.jfree.chart.util.StandardGradientPaintTransformer;
import org.jfree.chart.internal.Args;
import org.jfree.data.xy.XYDataset;
/**
* A renderer that connects data points with Bezier cubic curves and/or
* draws shapes at each data point. This renderer is designed for use with
* the {@link XYPlot} class.
* <br><br>
*
* @since
*/
public class XYBezierRenderer extends XYLineAndShapeRenderer {
/**
* An enumeration of the fill types for the renderer.
*
* @since 1.0.17
*/
public static enum FillType {
/** No fill. */
NONE,
/** Fill down to zero. */
TO_ZERO,
/** Fill to the lower bound. */
TO_LOWER_BOUND,
/** Fill to the upper bound. */
TO_UPPER_BOUND
}
/**
* Represents state information that applies to a single rendering of
* a chart.
*/
public static class XYBezierState extends State {
/** The area to fill under the curve. */
public GeneralPath fillArea;
/** The points. */
public List<Point2D> points;
/**
* Creates a new state instance.
*
* @param info the plot rendering info.
*/
public XYBezierState(PlotRenderingInfo info) {
super(info);
this.fillArea = new GeneralPath();
this.points = new ArrayList<>();
}
}
/**
* Resolution of splines (number of line segments between points)
*/
private int precision;
/**
* Tension defines how sharply does the curve bends
*/
private double tension;
/**
* A flag that can be set to specify
* to fill the area under the spline.
*/
private FillType fillType;
private GradientPaintTransformer gradientPaintTransformer;
/**
* Creates a new instance with the precision attribute defaulting to 5,
* the tension attribute defaulting to 2
* and no fill of the area 'under' the spline.
*/
public XYBezierRenderer() {
this(5, 25, FillType.NONE);
}
/**
* Creates a new renderer with the specified precision and tension
* and no fill of the area 'under' (between '0' and) the spline.
*
* @param precision the number of points between data items.
* @param tension value to define how sharply the curve bends
*/
public XYBezierRenderer(int precision, double tension) {
this(precision, tension ,FillType.NONE);
}
/**
* Creates a new renderer with the specified precision
* and specified fill of the area 'under' (between '0' and) the spline.
*
* @param precision the number of points between data items.
* @param tension value to define how sharply the curve bends
* @param fillType the type of fill beneath the curve ({@code null}
* not permitted).
*
* @since 1.0.17
*/
public XYBezierRenderer(int precision, double tension, FillType fillType) {
super();
if (precision <= 0) {
throw new IllegalArgumentException("Requires precision > 0.");
}
if (tension <= 0) {
throw new IllegalArgumentException("Requires precision > 0.");
}
Args.nullNotPermitted(fillType, "fillType");
this.precision = precision;
this.tension = tension;
this.fillType = fillType;
this.gradientPaintTransformer = new StandardGradientPaintTransformer();
}
/**
* Returns the number of line segments used to approximate the Bezier
* curve between data points.
*
* @return The number of line segments.
*
* @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();
}
/**
* Returns the value of the tension which defines how sharply
* does the curve bends
*
* @return The value of tesion.
*
* @see #setTension(double)
*/
public double getTension() {
return this.tension;
}
/**
* Set the value of the tension which defines how sharply
* does the curve bends and sends a {@link RendererChangeEvent}
* to all registered listeners.
*
* @param t value of tension (must be > 0).
*
* @see #getTension()
*/
public void setTension(double t) {
if (t <= 0) {
throw new IllegalArgumentException("Requires tension > 0.");
}
this.tension = t;
fireChangeEvent();
}
/**
* Returns the type of fill that the renderer draws beneath the curve.
*
* @return The type of fill (never {@code null}).
*
* @see #setFillType(FillType)
*
* @since 1.0.17
*/
public FillType getFillType() {
return this.fillType;
}
/**
* Set the fill type and sends a {@link RendererChangeEvent}
* to all registered listeners.
*
* @param fillType the fill type ({@code null} not permitted).
*
* @see #getFillType()
*
* @since 1.0.17
*/
public void setFillType(FillType fillType) {
this.fillType = fillType;
fireChangeEvent();
}
/**
* Returns the gradient paint transformer, or {@code null}.
*
* @return The gradient paint transformer (possibly {@code null}).
*
* @since 1.0.17
*/
public GradientPaintTransformer getGradientPaintTransformer() {
return this.gradientPaintTransformer;
}
/**
* Sets the gradient paint transformer and sends a
* {@link RendererChangeEvent} to all registered listeners.
*
* @param gpt the transformer ({@code null} permitted).
*
* @since 1.0.17
*/
public void setGradientPaintTransformer(GradientPaintTransformer gpt) {
this.gradientPaintTransformer = gpt;
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) {
setDrawSeriesLineAsPath(true);
XYBezierState state = new XYBezierState(info);
state.setProcessVisibleItemsOnly(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 xAxis the domain axis.
* @param yAxis 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 xAxis, ValueAxis yAxis,
Rectangle2D dataArea) {
XYBezierState s = (XYBezierState) state;
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 = xAxis.valueToJava2D(x1, dataArea, xAxisLocation);
double transY1 = yAxis.valueToJava2D(y1, dataArea, yAxisLocation);
// Collect points
if (!Double.isNaN(transX1) && !Double.isNaN(transY1)) {
Point2D p = plot.getOrientation() == PlotOrientation.HORIZONTAL
? new Point2D.Float((float) transY1, (float) transX1)
: new Point2D.Float((float) transX1, (float) transY1);
if (!s.points.contains(p))
s.points.add(p);
}
if (item == dataset.getItemCount(series) - 1) { // construct path
if (s.points.size() > 1) {
Point2D origin;
if (this.fillType == FillType.TO_ZERO) {
float xz = (float) xAxis.valueToJava2D(0, dataArea,
yAxisLocation);
float yz = (float) yAxis.valueToJava2D(0, dataArea,
yAxisLocation);
origin = plot.getOrientation() == PlotOrientation.HORIZONTAL
? new Point2D.Float(yz, xz)
: new Point2D.Float(xz, yz);
} else if (this.fillType == FillType.TO_LOWER_BOUND) {
float xlb = (float) xAxis.valueToJava2D(
xAxis.getLowerBound(), dataArea, xAxisLocation);
float ylb = (float) yAxis.valueToJava2D(
yAxis.getLowerBound(), dataArea, yAxisLocation);
origin = plot.getOrientation() == PlotOrientation.HORIZONTAL
? new Point2D.Float(ylb, xlb)
: new Point2D.Float(xlb, ylb);
} else {// fillType == TO_UPPER_BOUND
float xub = (float) xAxis.valueToJava2D(
xAxis.getUpperBound(), dataArea, xAxisLocation);
float yub = (float) yAxis.valueToJava2D(
yAxis.getUpperBound(), dataArea, yAxisLocation);
origin = plot.getOrientation() == PlotOrientation.HORIZONTAL
? new Point2D.Float(yub, xub)
: new Point2D.Float(xub, yub);
}
// we need at least two points to draw something
Point2D cp0 = s.points.get(0);
s.seriesPath.moveTo(cp0.getX(), cp0.getY());
if (this.fillType != FillType.NONE) {
if (plot.getOrientation() == PlotOrientation.HORIZONTAL) {
s.fillArea.moveTo(origin.getX(), cp0.getY());
} else {
s.fillArea.moveTo(cp0.getX(), origin.getY());
}
s.fillArea.lineTo(cp0.getX(), cp0.getY());
}
if (s.points.size() == 2) {
// we need at least 3 points to Bezier. Draw simple line
// for two points
Point2D cp1 = s.points.get(1);
if (this.fillType != FillType.NONE) {
s.fillArea.lineTo(cp1.getX(), cp1.getY());
s.fillArea.lineTo(cp1.getX(), origin.getY());
s.fillArea.closePath();
}
s.seriesPath.lineTo(cp1.getX(), cp1.getY());
}
else if (s.points.size() == 3) {
Point2D[] pInitial = getInitalPoints(s);
pintar(pInitial, s);
Point2D[] pFinal = getFinalPoints(s);
pintar(pFinal, s);
}
else {
// construct Bezier curve
//System.out.println("Entra en construir curva larga... " + s.points.size());
int np = s.points.size(); // number of points
for(int i = 0; i < np - 1; i++) {
if(i == 0) {
//System.out.println("Entra en i= 0");
// 3 points, 2 lines (initial an final Bezier curves
Point2D[] initial3Points = new Point2D[3];
initial3Points[0] = s.points.get(0);
initial3Points[1] = s.points.get(1);
initial3Points[2] = s.points.get(2);
Point2D[] pInitial = calcSegmentPointsInitial(initial3Points);// TENSION = 1.5
pintar(pInitial, s);
}
if(i == np - 2) {
//System.out.println("Entra en i = np - 2");
Point2D[] final3Points = new Point2D[4];
final3Points[1] = s.points.get(np-3);
final3Points[2] = s.points.get(np-2);
final3Points[3] = s.points.get(np-1);
//No se define final3Points[4] pq no se usa
Point2D[] pFinal = calcSegmentPointsFinal(final3Points);//TENSION = 1.5
pintar(pFinal, s);
}
if ((i != 0) && (i != (np - 2))){
Point2D[] original4Points = new Point2D[4];
original4Points[0] = s.points.get(i - 1);
original4Points[1] = s.points.get(i);
original4Points[2] = s.points.get(i + 1);
original4Points[3] = s.points.get(i + 2);
Point2D[] pMedium = calculateSegmentPoints(original4Points);
pintar(pMedium, s);
}
}
}
// Add last point @ y=0 for fillPath and close path
if (this.fillType != FillType.NONE) {
if (plot.getOrientation() == PlotOrientation.HORIZONTAL) {
s.fillArea.lineTo(origin.getX(), s.points.get(
s.points.size() - 1).getY());
} else {
s.fillArea.lineTo(s.points.get(
s.points.size() - 1).getX(), origin.getY());
}
s.fillArea.closePath();
}
// fill under the curve...
if (this.fillType != FillType.NONE) {
Paint fp = getSeriesFillPaint(series);
if (this.gradientPaintTransformer != null
&& fp instanceof GradientPaint) {
GradientPaint gp = this.gradientPaintTransformer
.transform((GradientPaint) fp, s.fillArea);
g2.setPaint(gp);
} else {
g2.setPaint(fp);
}
g2.fill(s.fillArea);
s.fillArea.reset();
}
// then draw the line...
drawFirstPassShape(g2, pass, series, item, s.seriesPath);
}
// reset points vector
s.points = new ArrayList<>();
}
}
private void pintar(Point2D[] segmentPoints, XYBezierState s) {
double x;
double y;
//System.out.println("Precision: " + this.precision);
for (int t = 0 ; t <= this.precision; t++) {
double k = (double)t / this.precision;
double r = 1- k;
x = Math.pow(r, 3) * segmentPoints[0].getX() + 3 * k * Math.pow(r, 2) * segmentPoints[1].getX()
+ 3 * Math.pow(k, 2) * (1 - k) * segmentPoints[2].getX() + Math.pow(k, 3) * segmentPoints[3].getX();
y = Math.pow(r, 3) * segmentPoints[0].getY() + 3 * k * Math.pow(r, 2) * segmentPoints[1].getY()
+ 3 * Math.pow(k, 2) * (1 - k) * segmentPoints[2].getY() + Math.pow(k, 3) * segmentPoints[3].getY();
s.seriesPath.lineTo(x, y);
//System.out.println("Pintar, t = " + t + "\tk = " + k +"\t" + "\tx = " + x + "\ty = " + y);
}
}
private Point2D[] getFinalPoints(XYBezierState s) {
//System.out.println("getinFinalPoints");
//for(int i = 0; i< s.points.size(); i++) {
// Point2D p = s.points.get(i);
// System.out.println("Point" + i + "\tx = " + p.getX() + "\ty = " + p.getY());
//}
Point2D[] final3Points = new Point2D[4];
final3Points[1] = s.points.get(0);
final3Points[2] = s.points.get(1);
final3Points[3] = s.points.get(2);
//No se define final3Points[4] pq no se usa
Point2D[] pFinal = calcSegmentPointsFinal(final3Points);//TENSION = 1.5
return pFinal;
}
private Point2D[] getInitalPoints(XYBezierState s) {
//System.out.println("getInitialPoints");
//for(int i = 0; i< s.points.size(); i++) {
// Point2D p = s.points.get(i);
// System.out.println("Point" + i + "\tx = " + p.getX() + "\ty = " + p.getY());
//}
// 3 points, 2 lines (initial an final Bezier curves
Point2D[] initial3Points = new Point2D[3];
initial3Points[0] = s.points.get(0);
initial3Points[1] = s.points.get(1);
initial3Points[2] = s.points.get(2);
Point2D[] pInitial = calcSegmentPointsInitial(initial3Points);// TENSION = 1.5
return pInitial;
}
private Point2D[] calculateSegmentPoints(Point2D[] original4Points) {
//System.out.println("calcSegmentPoints");
double relativeTension = calcRelativetension(original4Points, false, false);
Point2D[] points = new Point2D[4];
points[0] = original4Points[1];
points[3] = original4Points[2];
//double modulo = Math.sqrt(Math.pow(original4Points[1].getX() - original4Points[2].getX(), 2) + Math.pow(original4Points[1].getY() - original4Points[2].getY(), 2));
//double tesionRelativa = modulo * tension / 4;
for(int i = 1; i < 3; i++) {
Point2D aux1 = calcUnitaryVector(original4Points[i-1], original4Points[i]);
Point2D aux2 = calcUnitaryVector(original4Points[i+1], original4Points[i]);
Point2D aux3 = calcUnitaryVector(aux2, aux1);
double x = original4Points[i].getX() + Math.pow(-1.0, i+1) * tension * aux3.getX();
double y = original4Points[i].getY() + Math.pow(-1.0, i+1) * tension * aux3.getY();
points[i] = new Point2D.Double(x, y);
}
return points;
}
private Point2D[] calcSegmentPointsInitial(Point2D[] original3P) {
//System.out.println("calcSegmentPointsInitial");
/*
* Each segment is defined by its two endpoints and two control points. A
* control point determines the tangent at the corresponding endpoint.
*/
Point2D[] points = new Point2D[4];
points[0] = original3P[0];// Endpoint 1
points[3] = original3P[1];// Endpoint 2
// Control point 1
Point2D auxInitial = calcUnitaryVector(original3P[0], original3P[1]);
points[1] = original3P[0];// new Point2D.Double(x0, y0);
// Control point 2
// Es el mismo vector que el anterior: Point2D aux1 =
// calcUnitaryVector(original4P[0], original4P[1]);
Point2D aux2 = calcUnitaryVector(original3P[2], original3P[1]);
Point2D aux3 = calcUnitaryVector(auxInitial, aux2);
double relativeTension = calcRelativetension(original3P, true, false);
double x = original3P[1].getX() + tension * aux3.getX();
double y = original3P[1].getY() + tension * aux3.getY();
points[2] = new Point2D.Double(x, y);
//for(int i = 0; i < 4; i++) {
// System.out.println("Point[" + i + "]\tx = " + points[i].getX() + "\ty = " + points[i].getY());
//}
return points;
}
private Point2D[] calcSegmentPointsFinal(Point2D[] original3P) {
//System.out.println("calcSegmentPointsFinal");
/*
* Each segment is defined by its two endpoints and two control points. A
* control point determines the tangent at the corresponding endpoint.
*/
Point2D[] points = new Point2D[4];
points[0] = original3P[2];// Endpoint 1
points[3] = original3P[3];// Endpoint 2
// Control point 2: points[2]
Point2D auxInitial = calcUnitaryVector(original3P[3], original3P[2]);
points[2] = original3P[3];// new Point2D.Double(x0, y0);
// Control point 1
Point2D aux1 = calcUnitaryVector(original3P[3], original3P[2]);
Point2D aux2 = calcUnitaryVector(original3P[1], original3P[2]);
Point2D aux3 = calcUnitaryVector(aux1, aux2);
double relativeTension = calcRelativetension(original3P, false, true);
double x = original3P[2].getX() + tension * aux3.getX();
double y = original3P[2].getY() + tension * aux3.getY();
points[1] = new Point2D.Double(x, y);
//for(int i = 0; i < 4; i++) {
// System.out.println("Point[" + i + "]\tx = " + points[i].getX() + "\ty = " + points[i].getY());
//}
return points;
}
private double calcRelativetension (Point2D[] original4P, boolean initial, boolean end) {
if(initial) {
double module1 = Math.sqrt(
Math.pow(original4P[1].getX() - original4P[0].getX(), 2) +
Math.pow(original4P[1].getY() - original4P[0].getY(), 2));
double module2 = Math.sqrt(
Math.pow(original4P[2].getX() - original4P[1].getX(), 2) +
Math.pow(original4P[2].getY() - original4P[1].getY(), 2));
double moduleTotal = module1 + module2;
return moduleTotal * tension / 3;
}
if(end) {
double module2 = Math.sqrt(
Math.pow(original4P[2].getX() - original4P[1].getX(), 2) +
Math.pow(original4P[2].getY() - original4P[1].getY(), 2));
double module3 = Math.sqrt(
Math.pow(original4P[3].getX() - original4P[2].getX(), 2) +
Math.pow(original4P[3].getY() - original4P[2].getY(), 2));
double moduleTotal = module2 + module3;
return moduleTotal * tension / 3;
}
double module1 = Math.sqrt(
Math.pow(original4P[1].getX() - original4P[0].getX(), 2) +
Math.pow(original4P[1].getY() - original4P[0].getY(), 2));
double module2 = Math.sqrt(
Math.pow(original4P[2].getX() - original4P[1].getX(), 2) +
Math.pow(original4P[2].getY() - original4P[1].getY(), 2));
double module3 = Math.sqrt(
Math.pow(original4P[3].getX() - original4P[2].getX(), 2) +
Math.pow(original4P[3].getY() - original4P[2].getY(), 2));
double moduleTotal = module1 + module2 + module3;
return moduleTotal * tension / 4;
}
private Point2D calcUnitaryVector(Point2D pOrigin, Point2D pEnd) {
double module = Math.sqrt(Math.pow(pEnd.getX() - pOrigin.getX(), 2) +
Math.pow(pEnd.getY() - pOrigin.getY(), 2));
if (module == 0) {
return null;
}
return new Point2D.Double((pEnd.getX() - pOrigin.getX()) / module,
(pEnd.getY() - pOrigin.getY()) /module);
}
/**
* Tests this renderer for equality with an arbitrary object.
*
* @param obj the object ({@code null} permitted).
*
* @return A boolean.
*/
@Override
public boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof XYBezierRenderer)) {
return false;
}
XYBezierRenderer that = (XYBezierRenderer) obj;
if (this.precision != that.precision) {
return false;
}
if (this.fillType != that.fillType) {
return false;
}
if (!Objects.equals(this.gradientPaintTransformer, that.gradientPaintTransformer)) {
return false;
}
return super.equals(obj);
}
}