ChartDirector 7.0 (Python Edition)

Waterfall Chart



This example demonstrates creating a multi-color waterfall chart.

This chart is created as a multi-color box-whisker layer using XYChart.addBoxWhiskerLayer2. Only the "box" part of the box-whisker layer is used.

The top-edges of the boxes are obtained by accumulating the raw data using the ArrayMath utility. The bottom-edges of the boxes are simply the top-edges of previous boxes, with the exception of the last "total" box which always starts at 0.

Source Code Listing

pythondemo\waterfall.py
#!/usr/bin/python # The ChartDirector for Python module is assumed to be in "../lib" import sys, os sys.path.insert(0, os.path.join(os.path.abspath(sys.path[0]), "..", "lib")) from pychartdir import * # 4 data points to represent the cash flow for the Q1 - Q4 data = [230, 140, 220, 330, 150] # We want to plot a waterfall chart showing the 4 quarters as well as the total labels = ["Product 1", "Product 2", "Product 3", "Product 4", "Product 5", "Total"] # The top side of the bars in a waterfall chart is the accumulated data. We use the ChartDirector # ArrayMath utility to accumulate the data. The "total" is handled by inserting a zero point at the # end before accumulation (after accumulation it will become the total). boxTop = ArrayMath(data).insert2(0, 1).acc().result() # The botom side of the bars is just the top side of the previous bar. So we shifted the top side # data to obtain the bottom side data. boxBottom = ArrayMath(boxTop).shift(1, 0).result() # The last point (total) is different. Its bottom side is always 0. boxBottom[len(boxBottom) - 1] = 0 # Create a XYChart object of size 500 x 280 pixels. Set background color to light blue (ccccff), # with 1 pixel 3D border effect. c = XYChart(500, 290, 0xccccff, 0x000000, 1) # Add a title to the chart using 13 points Arial Bold Itatic font, with white (ffffff) text on a # deep blue (0x80) background c.addTitle("Product Revenue - Year 2004", "Arial Bold Italic", 13, 0xffffff).setBackground(0x000080) # Set the plotarea at (55, 50) and of size 430 x 215 pixels. Use alternative white/grey background. c.setPlotArea(55, 45, 430, 215, 0xffffff, 0xeeeeee) # Set the labels on the x axis using Arial Bold font c.xAxis().setLabels(labels).setFontStyle("Arial Bold") # Set the x-axis ticks and grid lines to be between the bars c.xAxis().setTickOffset(0.5) # Use Arial Bold as the y axis label font c.yAxis().setLabelStyle("Arial Bold") # Add a title to the y axis c.yAxis().setTitle("USD (in millions)") # Add a multi-color box-whisker layer to represent the waterfall bars layer = c.addBoxWhiskerLayer2(boxTop, boxBottom) # Put data labels on the bars to show the cash flow using Arial Bold font layer.setDataLabelFormat("{={top}-{bottom}}M") layer.setDataLabelStyle("Arial Bold").setAlignment(Center) # Output the chart c.makeChart("waterfall.png")

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