Donut Width

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

require("chartdirector")

class DonutwidthController < ApplicationController

    def index()
        @title = "Donut Width"
        @ctrl_file = File.expand_path(__FILE__)
        @noOfCharts = 5
        render :template => "templates/chartview"
    end

    #
    # Render and deliver the chart
    #
    def getchart()
        # This script can draw different charts depending on the chartIndex
        chartIndex = (params["img"]).to_i

        # Determine the donut inner radius (as percentage of outer radius) based on input parameter
        donutRadius = chartIndex * 25

        # The data for the pie chart
        data = [10, 10, 10, 10, 10]

        # The labels for the pie chart
        labels = ["Marble", "Wood", "Granite", "Plastic", "Metal"]

        # Create a PieChart object of size 150 x 120 pixels, with a grey (EEEEEE) background, black
        # border and 1 pixel 3D border effect
        c = ChartDirector::PieChart.new(150, 120, 0xeeeeee, 0x000000, 1)

        # Set donut center at (75, 65) and the outer radius to 50 pixels. Inner radius is computed
        # according donutWidth
        c.setDonutSize(75, 60, 50, (50 * donutRadius / 100).to_i)

        # Add a title to show the donut width
        c.addTitle(sprintf("Inner Radius = %s %%", donutRadius), "arial.ttf", 10).setBackground(
            0xcccccc, 0)

        # Draw the pie in 3D
        c.set3D(12)

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

        # Disable the sector labels by setting the color to Transparent
        c.setLabelStyle("", 8, ChartDirector::Transparent)

        # 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/donutwidth.rb

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

def createChart(chartIndex)

    # Determine the donut inner radius (as percentage of outer radius) based on input parameter
    donutRadius = chartIndex * 25

    # The data for the pie chart
    data = [10, 10, 10, 10, 10]

    # The labels for the pie chart
    labels = ["Marble", "Wood", "Granite", "Plastic", "Metal"]

    # Create a PieChart object of size 150 x 120 pixels, with a grey (EEEEEE) background, black
    # border and 1 pixel 3D border effect
    c = ChartDirector::PieChart.new(150, 120, 0xeeeeee, 0x000000, 1)

    # Set donut center at (75, 65) and the outer radius to 50 pixels. Inner radius is computed
    # according donutWidth
    c.setDonutSize(75, 60, 50, (50 * donutRadius / 100).to_i)

    # Add a title to show the donut width
    c.addTitle(sprintf("Inner Radius = %s %%", donutRadius), "arial.ttf", 10).setBackground(
        0xcccccc, 0)

    # Draw the pie in 3D
    c.set3D(12)

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

    # Disable the sector labels by setting the color to Transparent
    c.setLabelStyle("", 8, ChartDirector::Transparent)

    # Output the chart
    c.makeChart("donutwidth%s.png" % chartIndex)
end

createChart(0)
createChart(1)
createChart(2)
createChart(3)
createChart(4)