ChartDirector Ver 4.1 (Ruby Edition)

Circular Label Layout


  

This example demonstrates various options in the "circular label layout" method. It also demonstrates the use of alternative sector label format.

By default, in "circular label layout", the sector labels will be external and close to the perimeter of the pie.

The PieChart.setLabelPos method can be used to control the distance between the sector labels and the perimeter. It also allows enabling join lines to connect the labels to the sectors, which are useful if the labels are far away from the perimeter.

The distance between the sector labels and the perimeter can be negative, in which case the sectors will be internal to the pie.

Note also the sector label format in this example, which consists of 3 lines. It is specified using PieChart.setLabelFormat.

Source Code Listing

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

class CirclelabelpieController < ApplicationController

    def index()
        @title = "Circular Label Layout"
        @ctrl_file = File.expand_path(__FILE__)
        @noOfCharts = 2
        render :template => "templates/chartview"
    end

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

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

        # Create a PieChart object of size 300 x 300 pixels
        c = ChartDirector::PieChart.new(300, 300)

        if params["img"] == "0"
        #============================================================
        #    Draw a pie chart where the label is on top of the pie
        #============================================================

            # Set the center of the pie at (150, 150) and the radius to 120 pixels
            c.setPieSize(150, 150, 120)

            # Set the label position to -40 pixels from the perimeter of the pie (-ve
            # means label is inside the pie)
            c.setLabelPos(-40)

        else
        #============================================================
        #    Draw a pie chart where the label is outside the pie
        #============================================================

            # Set the center of the pie at (150, 150) and the radius to 80 pixels
            c.setPieSize(150, 150, 80)

            # Set the sector label position to be 20 pixels from the pie. Use a join line
            # to connect the labels to the sectors.
            c.setLabelPos(20, ChartDirector::LineColor)

        end

        # Set the label format to three lines, showing the sector name, value, and
        # percentage. The value 999 will be formatted as US$999K.
        c.setLabelFormat("{label}\nUS${value}K\n({percent}%)")

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

        # Explode the 1st sector (index = 0)
        c.setExplode(0)

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

def createChart(img)

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

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

    # Create a PieChart object of size 300 x 300 pixels
    c = ChartDirector::PieChart.new(300, 300)

    if img == "0"
    #============================================================
    #    Draw a pie chart where the label is on top of the pie
    #============================================================

        # Set the center of the pie at (150, 150) and the radius to 120 pixels
        c.setPieSize(150, 150, 120)

        # Set the label position to -40 pixels from the perimeter of the pie (-ve
        # means label is inside the pie)
        c.setLabelPos(-40)

    else
    #============================================================
    #    Draw a pie chart where the label is outside the pie
    #============================================================

        # Set the center of the pie at (150, 150) and the radius to 80 pixels
        c.setPieSize(150, 150, 80)

        # Set the sector label position to be 20 pixels from the pie. Use a join line
        # to connect the labels to the sectors.
        c.setLabelPos(20, ChartDirector::LineColor)

    end

    # Set the label format to three lines, showing the sector name, value, and
    # percentage. The value 999 will be formatted as US$999K.
    c.setLabelFormat("{label}\nUS${value}K\n({percent}%)")

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

    # Explode the 1st sector (index = 0)
    c.setExplode(0)

    # output the chart
    c.makeChart("circlelabelpie%s.png" % img)
end

createChart("0")
createChart("1")