Positive Negative Bars

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

require("chartdirector")

class PosnegbarController < ApplicationController

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

    #
    # Render and deliver the chart
    #
    def getchart()
        # 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 = ChartDirector::XYChart.new(500, 320)

        # Add a title to the chart using Arial Bold Italic font
        c.addTitle("Productivity Change - Year 2005", "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 using the Overlay data combine method
        layer = c.addBarLayer2(ChartDirector::Overlay)

        # Select positive data and add it as data set with blue (6666ff) color
        layer.addDataSet(ChartDirector::ArrayMath.new(data).selectGEZ(nil, ChartDirector::NoValue
            ).result(), 0x6666ff)

        # Select negative data and add it as data set with orange (ff6600) color
        layer.addDataSet(ChartDirector::ArrayMath.new(data).selectLTZ(nil, ChartDirector::NoValue
            ).result(), 0xff6600)

        # 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(true)

        # 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
        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/posnegbar.rb

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

# 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 = ChartDirector::XYChart.new(500, 320)

# Add a title to the chart using Arial Bold Italic font
c.addTitle("Productivity Change - Year 2005", "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 using the Overlay data combine method
layer = c.addBarLayer2(ChartDirector::Overlay)

# Select positive data and add it as data set with blue (6666ff) color
layer.addDataSet(ChartDirector::ArrayMath.new(data).selectGEZ(nil, ChartDirector::NoValue).result(),
    0x6666ff)

# Select negative data and add it as data set with orange (ff6600) color
layer.addDataSet(ChartDirector::ArrayMath.new(data).selectLTZ(nil, ChartDirector::NoValue).result(),
    0xff6600)

# 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(true)

# 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")