在jFreechart中设置项形状大小

Question

我正在使用jFreeChart绘制一个折线图，它是由一条直线连接的一系列(x，y)值。

但问题是表示数据点的形状，一个圆或一个矩形太大了，因为我在一个数列中有很多值。你可以在这个截图中看到它的样子：

此外，我了解到，当我调整图表面板的大小时，表示数据点的形状不会像绘图的其余部分那样缩放。

    private JFreeChart createChart(XYDataset dataCollection) {

    // create the chart...
    JFreeChart chart = ChartFactory.createXYLineChart(
            fileName, // chart title
            "Count", // x axis label
            "Price", // y axis label
            dataCollection, // data
            PlotOrientation.VERTICAL,
            true, // include legend
            true, // tooltips
            false // urls
    );

    // customize chart
    XYPlot plot = (XYPlot) chart.getPlot();
    // find out the max and min value for price series
    XYSeriesCollection collection = (XYSeriesCollection)plot.getDataset();
    XYSeries priceSeries = collection.getSeries(0);
    double maxY = priceSeries.getMaxY();
    double minY = priceSeries.getMinY();
    // set max and min for range axis (y axis)
    NumberAxis rangeAxis = (NumberAxis)plot.getRangeAxis();
    rangeAxis.setRange(minY, maxY);

    XYLineAndShapeRenderer renderer = new XYLineAndShapeRenderer() {

        public Color getItemColor(int series, int item) {
            // modify code here to change color for different part of the line in one serie line
            if(series == 1) {
                System.out.println("getting color at: " + item);
                int isBuy = 0;
                if(item < kFilter.buySellSignal.size()) {
                    isBuy = kFilter.buySellSignal.get(item);
                }

                if(isBuy == 1) {
                    return Color.red;
                } else {
                    return Color.green;
                }
            } else {
                return Color.yellow;
            }



        }

        @Override
        protected void drawFirstPassShape(Graphics2D g2, int pass, int series, int item, Shape shape) {
            super.drawFirstPassShape(g2, pass, series, item, shape);

            //g2.setStroke(getItemStroke(series, item));
            Color c1 = getItemColor(series, item - 1);
            Color c2 = getItemColor(series, item);

            GradientPaint linePaint = new GradientPaint(0, 0, c1, 0, 300, c2);
            g2.setPaint(linePaint);
            g2.draw(shape);
        }
    };

    plot.setRenderer(renderer);

    return chart;
}

Answer 1

您可以在XyLineAndShapeRenderer中重写getitemshape()，以返回任何所需的形状，如下所示。或者，调用抽象父方法之一，setSeriesShape()、setBaseshape()等。

@Nicolas S.Xu使用如下代码报告：

Rectangle rect = new Rectangle(2, 2);
renderer.setSeriesShape(1, rect);

另请参见shapeutilities。