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曾经尝试用Excel做三维散点图，但发现Excel绘制出来的实质还是一个二维图表，无法满足需求，后来下载了Web图表控件ChartDirector，刚好它支持三维散点图样式，做出来的效果还不错。今天就跟大家演示一下如何用ChartDirector创建三维散点图。

三维散点图效果：

主要有以下几个步骤：

1、用ThreeDScatterChart.ThreeDScatterChart创建一个ThreeDScatterChart对象
2、用ThreeDChart.setPlotRegion指定绘图区域的位置和大小
3、用ThreeDScatterChart.addScatterGroup向图表添加一组散点。在本例中，标记颜色设置为SameAsMainColor，颜色会根据Z坐标的颜色轴进行变化，颜色轴的访问可以用ThreeDChart.colorAxis。
4、用ThreeDChart.setColorAxis设置颜色轴的位置
5、分别用BaseChart.addTitle 和 Axis.setTitle添加图表和轴标题
6、最后用BaseChart.makeChart生成图表

下面是ChartDirector生成三维散点图的部分代码：

#include "chartdir.h"

int main(int argc, char *argv[])
{
    // The XYZ data for the 3D scatter chart as 3 random data series
    RanSeries *r = new RanSeries(0);
    DoubleArray xData = r->getSeries(100, 100, -10, 10);
    DoubleArray yData = r->getSeries(100, 0, 0, 20);
    DoubleArray zData = r->getSeries(100, 100, -10, 10);

    // Create a ThreeDScatterChart object of size 720 x 600 pixels
    ThreeDScatterChart *c = new ThreeDScatterChart(720, 600);

    // Add a title to the chart using 20 points Times New Roman Italic font
    c->addTitle("3D Scatter Chart (1)  ", "timesi.ttf", 20);

    // Set the center of the plot region at (350, 280), and set width x depth x
    // height to 360 x 360 x 270 pixels
    c->setPlotRegion(350, 280, 360, 360, 270);

    // Add a scatter group to the chart using 11 pixels glass sphere symbols, in
    // which the color depends on the z value of the symbol
    c->addScatterGroup(xData, yData, zData, "", Chart::GlassSphere2Shape, 11,
        Chart::SameAsMainColor);

    // Add a color axis (the legend) in which the left center is anchored at (645,
    // 270). Set the length to 200 pixels and the labels on the right side.
    c->setColorAxis(645, 270, Chart::Left, 200, Chart::Right);

    // Set the x, y and z axis titles using 10 points Arial Bold font
    c->xAxis()->setTitle("X-Axis Place Holder", "arialbd.ttf", 10);
    c->yAxis()->setTitle("Y-Axis Place Holder", "arialbd.ttf", 10);
    c->zAxis()->setTitle("Z-Axis Place Holder", "arialbd.ttf", 10);

    // Output the chart
    c->makeChart("threedscatter.png");

    //free up resources
    delete r;
    delete c;
    return 0;
}