ChartDirector 7.0 (ASP/COM/VB Edition)

Multi-Color Line Chart This example demonstrates a line chart with line segments of different colors.

In this example, each line segment has a type specified in the pointType array. Note that with N data points, there will only be (N - 1) line segments. So the pointType array size is one less than the data point array size.

A loop is used to separate the line segments by type into different line layers, The line layers are configured with different colors and names. This generates the multi-color line and the legend entries.

Source Code Listing

[Web Version (in ASP)] aspdemo\multicolorline.asp
<%@ language="vbscript" %> <% Set cd = CreateObject("ChartDirector.API") ' Data points for the line chart dataX = Array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, _ 23, 24, 25) dataY = Array(30, 28, 40, 55, 75, 68, 54, 60, 50, 62, 75, 65, 75, 89, 60, 55, 53, 35, 50, 66, 56, _ 48, 52, 65, 62, 70) ' The data point type. The color of the line segment will be based on the starting point type of the ' segment. In this example, we have 4 point types for 4 different colors. Note that for a line with ' N points, there will be (N - 1) line segments, so we only need (N - 1) values in the point type ' array. pointType = Array(0, 0, 0, 1, 1, 0, 2, 3, 1, 1, 0, 0, 1, 1, 2, 2, 2, 3, 3, 2, 0, 1, 2, 3, 3) colors = Array(&Hff0000, &H0066ff, &Hcc00cc, &H00cc00) pointTypeLabels = Array("Alpha", "Beta", "Gamma", "Delta") ' Create a XYChart object of size 600 x 430 pixels Set c = cd.XYChart(600, 430) ' Set default text color to dark grey (0x333333) Call c.setColor(cd.TextColor, &H333333) ' Add a title box using grey (0x555555) 20pt Arial font Call c.addTitle(" Multi-Color Line Chart", "Arial", 20, &H555555) ' Set the plotarea at (70, 70) and of size 500 x 300 pixels, with transparent background and border ' and light grey (0xcccccc) horizontal grid lines Call c.setPlotArea(70, 70, 500, 300, cd.Transparent, -1, cd.Transparent, &Hcccccc) ' Add a legend box with horizontal layout above the plot area at (70, 35). Use 12pt Arial font, ' transparent background and border, and line style legend icon. Set b = c.addLegend(70, 35, False, "Arial", 12) Call b.setBackground(cd.Transparent, cd.Transparent) Call b.setLineStyleKey() ' Set axis label font to 12pt Arial Call c.xAxis().setLabelStyle("Arial", 12) Call c.yAxis().setLabelStyle("Arial", 12) ' Set the x and y axis stems to transparent, and the x-axis tick color to grey (0xaaaaaa) Call c.xAxis().setColors(cd.Transparent, cd.TextColor, cd.TextColor, &Haaaaaa) Call c.yAxis().setColors(cd.Transparent) ' Set the major/minor tick lengths for the x-axis to 10 and 0. Call c.xAxis().setTickLength(10, 0) ' For the automatic axis labels, set the minimum spacing to 80/40 pixels for the x/y axis. Call c.xAxis().setTickDensity(80) Call c.yAxis().setTickDensity(40) ' Add a title to the y axis using dark grey (0x555555) 14pt Arial font Call c.xAxis().setTitle("X-Axis Title Placeholder", "Arial", 14, &H555555) Call c.yAxis().setTitle("Y-Axis Title Placeholder", "Arial", 14, &H555555) ' In ChartDirector, each line layer can only have one line color, so we use 4 line layers to draw ' the 4 different colors of line segments. ' In general, the line segments for each color will not be continuous. In ChartDirector, ' non-continuous line segments can be achieved by inserting NoValue points. To allow for these extra ' points, we use a buffer twice the size of the original data arrays. ReDim lineX((UBound(dataX) + 1) * 2 - 1) ReDim lineY((UBound(dataY) + 1) * 2 - 1) ' Use a loop to create a line layer for each color For i = 0 To UBound(colors) n = 0 For j = 0 To UBound(dataX) matched = False If j <= UBound(pointType) Then matched = pointType(j) = i End If If matched Then ' We include data points of the target type in the line layer. lineX(n) = dataX(j) lineY(n) = dataY(j) n = n + 1 ElseIf j > 0 Then If pointType(j - 1) = i Then ' If the current point is not of the target, but the previous point is of the target ' type, we still need to include the current point in the line layer, as it takes two ' points to draw a line segment. We also need an extra NoValue point so that the current ' point will not join with the next point. lineX(n) = dataX(j) lineY(n) = dataY(j) n = n + 1 lineX(n) = dataX(j) lineY(n) = cd.NoValue n = n + 1 End If End If Next ' Draw the layer that contains all segments of the target color Set layer = c.addLineLayer(cd.ArrayMath(lineY).Trim(0, n).result(), colors(i), _ pointTypeLabels(i)) Call layer.setXData(cd.ArrayMath(lineX).Trim(0, n).result()) Call layer.setLineWidth(2) Next ' Output the chart Set viewer = cd.WebChartViewer(Request, "chart1") Call viewer.setChart(c, cd.SVG) %> <!DOCTYPE html> <html> <head> <title>Multi-Color Line Chart</title> <!-- Include ChartDirector Javascript Library to support chart interactions --> <script type="text/javascript" src="cdjcv.js"></script> </head> <body style="margin:5px 0px 0px 5px"> <div style="font:bold 18pt verdana;"> Multi-Color Line Chart </div> <hr style="border:solid 1px #000080; background:#000080" /> <div style="font:10pt verdana; margin-bottom:1.5em"> <a href="viewsource.asp?file=<%= Request("SCRIPT_NAME") %>">View Chart Source Code</a> </div> <!-- ****** Here is the chart image ****** --> <%= viewer.renderHTML() %> </body> </html>