ChartDirector Ver 4.1 (Ruby Edition)

Side Label Layout




This method demonstrates the "side label layout" method for positioning the sector labels.

With "side label layout", the sector labels are positioned on the left and right sides of the chart. In contrast, all previous examples use "circular label layout", in which the labels are positioned circularly around the pie.

"Circular label layout" typically uses less space and is the default layout method. However, if the pie chart contains a lot of small sectors, the labels may overlap with each others. It is because there may be insufficient space on the perimeter to position the labels.

"Side label layout" has the advantages that the labels will automatically shift up and down to avoid overlapping. By default, the labels are joined to the sectors with join lines.

The label layout method to use is specified with PieChart.setLabelLayout.

Source Code Listing

[Ruby On Rails Version - Controller] app/controllers/sidelabelpie_controller.rb
require("chartdirector")

class SidelabelpieController < ApplicationController

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

    #
    # Render and deliver the chart
    #
    def getchart()
        # The data for the pie chart
        data = [25, 18, 15, 12, 8, 30, 35]

        # The labels for the pie chart
        labels = ["Labor", "Licenses", "Taxes", "Legal", "Insurance", "Facilities",
            "Production"]

        # Create a PieChart object of size 500 x 230 pixels
        c = ChartDirector::PieChart.new(500, 230)

        # Set the center of the pie at (250, 120) and the radius to 100 pixels
        c.setPieSize(250, 120, 100)

        # Add a title box using 15 points Times Bold Italic as font
        c.addTitle("Project Cost Breakdown", "timesbi.ttf", 15)

        # Draw the pie in 3D
        c.set3D()

        # Use the side label layout method
        c.setLabelLayout(ChartDirector::SideLayout)

        # Set the pie data and the pie labels
        c.setData(data, labels)

        # 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.rhtml
<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/sidelabelpie.rb
#!/usr/bin/env ruby
require("chartdirector")

# The data for the pie chart
data = [25, 18, 15, 12, 8, 30, 35]

# The labels for the pie chart
labels = ["Labor", "Licenses", "Taxes", "Legal", "Insurance", "Facilities",
    "Production"]

# Create a PieChart object of size 500 x 230 pixels
c = ChartDirector::PieChart.new(500, 230)

# Set the center of the pie at (250, 120) and the radius to 100 pixels
c.setPieSize(250, 120, 100)

# Add a title box using 15 points Times Bold Italic as font
c.addTitle("Project Cost Breakdown", "timesbi.ttf", 15)

# Draw the pie in 3D
c.set3D()

# Use the side label layout method
c.setLabelLayout(ChartDirector::SideLayout)

# Set the pie data and the pie labels
c.setData(data, labels)

# output the chart
c.makeChart("sidelabelpie.png")