ChartDirector Ver 3.0 (Python Edition)

Rotated Line Chart




This example demonstrates swapping the x and y axes to produce a rotated line chart in which the line goes from top to bottom (instead of left to right).

The x and y axes in the example are configured as follows:

For demo purposes, this example uses RanTable to simulate a database table with 4 columns, in which one is a date/time column and the remaining three are data columns. The date/time column is passed to ChartDirector as the x values using Layer.setXData, while the data columns are passed to ChartDirector as y values using Layer.addDataSet.

Source Code Listing

[File: pythondemo/rotatedline.py] (The CGI version is available as "pythondemo_cgi/rotatedline.py".)
#!/usr/bin/python from pychartdir import * # # We use a random table to simulate generating 12 months of data # #Create the random table object with 4 cols * 12 rows, using 3 as seed rantable = RanTable(3, 4, 12) #Set the 1st column to be the 12 months of year 2002 rantable.setDateCol(0, chartTime(2002, 1, 1), 86400 * 30) #Set the 2nd, 3rd and 4th columns to be random numbers starting from 125, 75, #and 100 respectively. The change between rows is set to -35 to + 35. The #minimum value of any cell is 0. rantable.setCol(1, 125, -35, 35, 0) rantable.setCol(2, 75, -35, 35, 0) rantable.setCol(3, 100, -35, 35, 0) #Get the 1st column (time) as the x data dataX = rantable.getCol(0) #Get the 2nd, 3rd and 4th columns as 3 data sets dataY0 = rantable.getCol(1) dataY1 = rantable.getCol(2) dataY2 = rantable.getCol(3) #Create a XYChart object of size 360 x 400 pixels c = XYChart(360, 400) #Add a title to the chart c.addTitle("<*underline=2*>Rotated Line Chart Demo", "timesbi.ttf", 14) #Set the plotarea at (60, 75) and of size 190 x 320 pixels. Turn on both #horizontal and vertical grid lines with light grey color (0xc0c0c0) c.setPlotArea(60, 75, 190, 320).setGridColor(0xc0c0c0, 0xc0c0c0) #Add a legend box at (270, 75) c.addLegend(270, 75) #Swap the x and y axis to become a rotated chart c.swapXY() #Set the y axis on the top side (right + rotated = top) c.setYAxisOnRight() #Add a title to the y axis c.yAxis().setTitle("Throughput (MBytes)") #Reverse the x axis so it is pointing downwards c.xAxis().setReverse() #Add a line chart layer using the given data layer = c.addLineLayer2() layer.setXData(dataX) layer.addDataSet(dataY0, 0xff0000, "Server A") layer.addDataSet(dataY1, 0x338033, "Server B") layer.addDataSet(dataY2, 0xff, "Server C") #Set the line width to 2 pixels layer.setLineWidth(2) #output the chart c.makeChart("rotatedline.png")