ChartDirector Ver 3.0 (Python Edition)

Dual Horizontal Bar Chart




This example demonstrates combining two horizontal bar charts of opposite direction using a MultiChart, and a number of other ChartDirector features.

Source Code Listing

[File: pythondemo/dualhbar.py] (The CGI version is available as "pythondemo_cgi/dualhbar.py".)
#!/usr/bin/python from pychartdir import * #The age groups labels = ["0 - 4", "5 - 9", "10 - 14", "15 - 19", "20 - 24", "24 - 29", "30 - 34", "35 - 39", "40 - 44", "44 - 49", "50 - 54", "55 - 59", "60 - 64", "65 - 69", "70 - 74", "75 - 79", "80+"] #The male population (in thousands) male = [215, 238, 225, 236, 235, 260, 286, 340, 363, 305, 259, 164, 135, 127, 102, 68, 66] #The female population (in thousands) female = [194, 203, 201, 220, 228, 271, 339, 401, 384, 304, 236, 137, 116, 122, 112, 85, 110] #============================================================= # Draw the right bar chart #============================================================= #Create a XYChart object of size 320 x 300 pixels c = XYChart(320, 300) #Set the plotarea at (50, 0) and of size 250 x 255 pixels. Use pink (0xffdddd) #as the background. c.setPlotArea(50, 0, 250, 255, 0xffdddd) #Add a custom text label at the top right corner of the right bar chart c.addText(300, 0, "Female", "timesbi.ttf", 12, 0xa07070).setAlignment(TopRight) #Add the pink (0xf0c0c0) bar chart layer using the female data femaleLayer = c.addBarLayer(female, 0xf0c0c0) #Swap the axis so that the bars are drawn horizontally c.swapXY(1) #Set the bar to touch each others femaleLayer.setBarGap(TouchBar) #Set the border style of the bars to 1 pixel 3D border femaleLayer.setBorderColor(-1, 1) #Add a Transparent line layer to the chart using the male data. As it is #Transparent, only the female bar chart can be seen. We need to put both male #and female data in both left and right charts, because we want auto-scaling to #produce the same scale for both chart. c.addLineLayer(male, Transparent) #Set the y axis label font to Arial Bold c.yAxis().setLabelStyle("arialbd.ttf") #Set the labels between the two bar charts, which can be considered as the #x-axis labels for the right chart tb = c.xAxis().setLabels(labels) #Use a fix width of 50 for the labels (height = automatic) with center alignment tb.setSize(50, 0) tb.setAlignment(Center) #Set the label font to Arial Bold tb.setFontStyle("arialbd.ttf") #Disable ticks on the x-axis by setting the tick length to 0 c.xAxis().setTickLength(0) #============================================================= # Draw the left bar chart #============================================================= #Create a XYChart object of size 280 x 300 pixels with a transparent background. c2 = XYChart(280, 300, Transparent) #Set the plotarea at (20, 0) and of size 250 x 255 pixels. Use pale blue #(0xddddff) as the background. c2.setPlotArea(20, 0, 250, 255, 0xddddff) #Add a custom text label at the top left corner of the left bar chart c2.addText(20, 0, "Male", "timesbi.ttf", 12, 0x7070a0) #Add the pale blue (0xaaaaff) bar chart layer using the male data maleLayer = c2.addBarLayer(male, 0xaaaaff) #Swap the axis so that the bars are drawn horizontally c2.swapXY(1) #Reverse the direction of the y-axis so it runs from right to left c2.yAxis().setReverse() #Set the bar to touch each others maleLayer.setBarGap(TouchBar) #Set the border style of the bars to 1 pixel 3D border maleLayer.setBorderColor(-1, 1) #Add a Transparent line layer to the chart using the female data. As it is #Transparent, only the male bar chart can be seen. We need to put both male and #female data in both left and right charts, because we want auto-scaling to #produce the same scale for both chart. c.addLineLayer(female, Transparent) #Set the y axis label font to Arial Bold c2.yAxis().setLabelStyle("arialbd.ttf") #============================================================= # Use a MultiChart to contain both bar charts #============================================================= #Create a MultiChart object of size 590 x 320 pixels. m = MultiChart(590, 320) #Add a title to the chart using Arial Bold Italic font m.addTitle("Demographics Hong Kong Year 2002", "arialbi.ttf") #Add another title at the bottom using Arial Bold Italic font m.addTitle2(Bottom, "Population (in thousands)", "arialbi.ttf", 10) #Put the right chatr at (270, 25) m.addChart(270, 25, c) #Put the left char at (0, 25) m.addChart(0, 25, c2) #output the chart m.makeChart("dualhbar.png")