Waterfall Chart

[Ruby On Rails Version - Controller] app/controllers/waterfall_controller.rb

require("chartdirector")

class WaterfallController < ApplicationController

    def index()
        @title = "Waterfall Chart"
        @ctrl_file = File.expand_path(__FILE__)
        @noOfCharts = 1
        render :template => "templates/chartview"
    end

    #
    # Render and deliver the chart
    #
    def getchart()
        # 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 = ChartDirector::ArrayMath.new(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 = ChartDirector::ArrayMath.new(boxTop).shift(1, 0).result()

        # The last point (total) is different. Its bottom side is always 0.
        boxBottom[boxBottom.length - 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 = ChartDirector::XYChart.new(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", "arialbi.ttf", 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("arialbd.ttf")

        # 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("arialbd.ttf")

        # 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("arialbd.ttf").setAlignment(ChartDirector::Center)

        # Output the chart
        send_data(c.makeChart2(ChartDirector::PNG), :type => "image/png", :disposition => "inline")

    end

end

[Ruby On Rails Version - View] app/views/templates/chartview.html.erb

<html>
<body style="margin:5px 0px 0px 5px">

<!-- Title -->
<div style="font-size:18pt; font-family:verdana; font-weight:bold">
    <%= @title %>
</div>
<hr style="border:solid 1px #000080" />

<!-- Source Code Listing Link -->
<div style="font-size:9pt; font-family:verdana; margin-bottom:1.5em">
    <%= link_to "Source Code Listing", 
        :controller => "cddemo", :action => "viewsource",
        :ctrl_file => @ctrl_file, :view_file => File.expand_path(__FILE__) %>
</div>

<!-- Create one or more IMG tags to display the demo chart(s) -->
<% 0.upto(@noOfCharts - 1) do |i| %>
    <img src="<%= url_for(:action => "getchart", :img => i) %>">
<% end %>

</body>
</html>

[Command Line Version] rubydemo/waterfall.rb

#!/usr/bin/env ruby
require("chartdirector")

# 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 = ChartDirector::ArrayMath.new(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 = ChartDirector::ArrayMath.new(boxTop).shift(1, 0).result()

# The last point (total) is different. Its bottom side is always 0.
boxBottom[boxBottom.length - 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 = ChartDirector::XYChart.new(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", "arialbi.ttf", 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("arialbd.ttf")

# 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("arialbd.ttf")

# 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("arialbd.ttf").setAlignment(ChartDirector::Center)

# Output the chart
c.makeChart("waterfall.png")