ChartDirector Ver 3.0 (Python Edition)

Positive Negative Bar




This example is achieved by using zones and zone colors.

Source Code Listing

[File: pythondemo/posnegbar.py] (The CGI version is available as "pythondemo_cgi/posnegbar.py".)
#!/usr/bin/python from pychartdir import * #The data for the bar chart data = [-6.3, 2.3, 0.7, -3.4, 2.2, -2.9, -0.1, -0.1, 3.3, 6.2, 4.3, 1.6] #The labels for the bar chart labels = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"] #Create a XYChart object of size 500 x 320 pixels c = XYChart(500, 320) #Add a title to the chart using Arial Bold Italic font c.addTitle("Productivity Change - Year 2001", "arialbi.ttf") #Set the plotarea at (50, 30) and of size 400 x 250 pixels c.setPlotArea(50, 30, 400, 250) #Add a bar layer to the chart layer = c.addBarLayer2() #Add a data set to the bar using a y zone color. The color is configured to be #orange (0xff6600) below zero, and blue (0x6666ff) above zero. layer.addDataSet(data, layer.yZoneColor(0, 0xff6600, 0x6666ff)) #Add labels to the top of the bar using 8 pt Arial Bold font. The font color is #configured to be red (0xcc3300) below zero, and blue (0x3333ff) above zero. layer.setAggregateLabelStyle("arialbd.ttf", 8, layer.yZoneColor(0, 0xcc3300, 0x3333ff)) #Set the labels on the x axis and use Arial Bold as the label font c.xAxis().setLabels(labels).setFontStyle("arialbd.ttf") #Draw the y axis on the right of the plot area c.setYAxisOnRight(1) #Use Arial Bold as the y axis label font c.yAxis().setLabelStyle("arialbd.ttf") #Add a title to the y axis c.yAxis().setTitle("Percentage") #Add a light blue (0xccccff) zone for positive part of the plot area c.yAxis().addZone(0, 9999, 0xccccff) #Add a pink (0xffffcc) zone for negative part of the plot area c.yAxis().addZone(-9999, 0, 0xffcccc) #output the chart c.makeChart("posnegbar.png")