ChartDirector 6.0 (ASP/COM/VB Edition)

Parametric Curve Fitting

This example demonstrates parametric curve fitting.

In addition to linear regression, ChartDirector also supports polynomial, exponential and logarithmic regression. To create these curves, a TrendLayer object is created using XYChart.addTrendLayer, and the regressive type is set using TrendLayer.setRegressionType.

Source Code Listing

[Web Version (in ASP)] aspdemo\paramcurve.asp
 ```<%@ language="vbscript" %> <% Set cd = CreateObject("ChartDirector.API") ' The XY data of the first data series dataX0 = Array(10, 35, 17, 4, 22, 29, 45, 52, 63, 39) dataY0 = Array(2.0, 3.2, 2.7, 1.2, 2.8, 2.9, 3.1, 3.0, 2.3, 3.3) ' The XY data of the second data series dataX1 = Array(30, 35, 17, 4, 22, 59, 43, 52, 63, 39) dataY1 = Array(1.0, 1.3, 0.7, 0.6, 0.8, 3.0, 1.8, 2.3, 3.4, 1.5) ' The XY data of the third data series dataX2 = Array(28, 35, 15, 10, 22, 60, 46, 64, 39) dataY2 = Array(2.0, 2.2, 1.2, 0.4, 1.8, 2.7, 2.4, 2.8, 2.4) ' Create a XYChart object of size 540 x 480 pixels Set c = cd.XYChart(540, 480) ' Set the plotarea at (70, 65) and of size 400 x 350 pixels, with white background and a light grey ' border (0xc0c0c0). Turn on both horizontal and vertical grid lines with light grey color ' (0xc0c0c0) Call c.setPlotArea(70, 65, 400, 350, &Hffffff, -1, &Hc0c0c0, &Hc0c0c0, -1) ' Add a legend box with the top center point anchored at (270, 30). Use horizontal layout. Use 10pt ' Arial Bold Italic font. Set the background and border color to Transparent. Set legendBox = c.addLegend(270, 30, False, "arialbi.ttf", 10) Call legendBox.setAlignment(cd.TopCenter) Call legendBox.setBackground(cd.Transparent, cd.Transparent) ' Add a title to the chart using 18 point Times Bold Itatic font. Call c.addTitle("Parametric Curve Fitting", "timesbi.ttf", 18) ' Add titles to the axes using 12pt Arial Bold Italic font Call c.yAxis().setTitle("Axis Title Placeholder", "arialbi.ttf", 12) Call c.xAxis().setTitle("Axis Title Placeholder", "arialbi.ttf", 12) ' Set the axes line width to 3 pixels Call c.yAxis().setWidth(3) Call c.xAxis().setWidth(3) ' Add a scatter layer using (dataX0, dataY0) Call c.addScatterLayer(dataX0, dataY0, "Polynomial", cd.GlassSphere2Shape, 11, &Hff0000) ' Add a degree 2 polynomial trend line layer for (dataX0, dataY0) Set trend0 = c.addTrendLayer2(dataX0, dataY0, &Hff0000) Call trend0.setLineWidth(3) Call trend0.setRegressionType(cd.PolynomialRegression(2)) ' Add a scatter layer for (dataX1, dataY1) Call c.addScatterLayer(dataX1, dataY1, "Exponential", cd.GlassSphere2Shape, 11, &H00aa00) ' Add an exponential trend line layer for (dataX1, dataY1) Set trend1 = c.addTrendLayer2(dataX1, dataY1, &H00aa00) Call trend1.setLineWidth(3) Call trend1.setRegressionType(cd.ExponentialRegression) ' Add a scatter layer using (dataX2, dataY2) Call c.addScatterLayer(dataX2, dataY2, "Logarithmic", cd.GlassSphere2Shape, 11, &H0000ff) ' Add a logarithmic trend line layer for (dataX2, dataY2) Set trend2 = c.addTrendLayer2(dataX2, dataY2, &H0000ff) Call trend2.setLineWidth(3) Call trend2.setRegressionType(cd.LogarithmicRegression) ' Output the chart Response.ContentType = "image/png" Response.BinaryWrite c.makeChart2(cd.PNG) Response.End %>```

[Windows Version (in Visual Basic)] vbdemo\paramcurve.cls
 ```Public Sub createChart(viewer As Object, chartIndex As Integer) Dim cd As New ChartDirector.API ' The XY data of the first data series Dim dataX0() dataX0 = Array(10, 35, 17, 4, 22, 29, 45, 52, 63, 39) Dim dataY0() dataY0 = Array(2.0, 3.2, 2.7, 1.2, 2.8, 2.9, 3.1, 3.0, 2.3, 3.3) ' The XY data of the second data series Dim dataX1() dataX1 = Array(30, 35, 17, 4, 22, 59, 43, 52, 63, 39) Dim dataY1() dataY1 = Array(1.0, 1.3, 0.7, 0.6, 0.8, 3.0, 1.8, 2.3, 3.4, 1.5) ' The XY data of the third data series Dim dataX2() dataX2 = Array(28, 35, 15, 10, 22, 60, 46, 64, 39) Dim dataY2() dataY2 = Array(2.0, 2.2, 1.2, 0.4, 1.8, 2.7, 2.4, 2.8, 2.4) ' Create a XYChart object of size 540 x 480 pixels Dim c As XYChart Set c = cd.XYChart(540, 480) ' Set the plotarea at (70, 65) and of size 400 x 350 pixels, with white background and a light ' grey border (0xc0c0c0). Turn on both horizontal and vertical grid lines with light grey color ' (0xc0c0c0) Call c.setPlotArea(70, 65, 400, 350, &Hffffff, -1, &Hc0c0c0, &Hc0c0c0, -1) ' Add a legend box with the top center point anchored at (270, 30). Use horizontal layout. Use ' 10pt Arial Bold Italic font. Set the background and border color to Transparent. Dim legendBox As LegendBox Set legendBox = c.addLegend(270, 30, False, "arialbi.ttf", 10) Call legendBox.setAlignment(cd.TopCenter) Call legendBox.setBackground(cd.Transparent, cd.Transparent) ' Add a title to the chart using 18 point Times Bold Itatic font. Call c.addTitle("Parametric Curve Fitting", "timesbi.ttf", 18) ' Add titles to the axes using 12pt Arial Bold Italic font Call c.yAxis().setTitle("Axis Title Placeholder", "arialbi.ttf", 12) Call c.xAxis().setTitle("Axis Title Placeholder", "arialbi.ttf", 12) ' Set the axes line width to 3 pixels Call c.yAxis().setWidth(3) Call c.xAxis().setWidth(3) ' Add a scatter layer using (dataX0, dataY0) Call c.addScatterLayer(dataX0, dataY0, "Polynomial", cd.GlassSphere2Shape, 11, &Hff0000) ' Add a degree 2 polynomial trend line layer for (dataX0, dataY0) Dim trend0 As TrendLayer Set trend0 = c.addTrendLayer2(dataX0, dataY0, &Hff0000) Call trend0.setLineWidth(3) Call trend0.setRegressionType(cd.PolynomialRegression(2)) Call trend0.setHTMLImageMap("{disable}") ' Add a scatter layer for (dataX1, dataY1) Call c.addScatterLayer(dataX1, dataY1, "Exponential", cd.GlassSphere2Shape, 11, &H00aa00) ' Add an exponential trend line layer for (dataX1, dataY1) Dim trend1 As TrendLayer Set trend1 = c.addTrendLayer2(dataX1, dataY1, &H00aa00) Call trend1.setLineWidth(3) Call trend1.setRegressionType(cd.ExponentialRegression) Call trend1.setHTMLImageMap("{disable}") ' Add a scatter layer using (dataX2, dataY2) Call c.addScatterLayer(dataX2, dataY2, "Logarithmic", cd.GlassSphere2Shape, 11, &H0000ff) ' Add a logarithmic trend line layer for (dataX2, dataY2) Dim trend2 As TrendLayer Set trend2 = c.addTrendLayer2(dataX2, dataY2, &H0000ff) Call trend2.setLineWidth(3) Call trend2.setRegressionType(cd.LogarithmicRegression) Call trend2.setHTMLImageMap("{disable}") ' Output the chart Set viewer.Picture = c.makePicture() 'include tool tip for the chart viewer.ImageMap = c.getHTMLImageMap("clickable", "", "title='[{dataSetName}] ({x}, {value})'") End Sub```