ChartDirector 6.0 (Ruby Edition)

Round Meter




This example demonstrates the basic steps in creating a round meter.

A round meter can be created with the following steps:

Source Code Listing

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

class RoundmeterController < ApplicationController

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

    #
    # Render and deliver the chart
    #
    def getchart()
        # The value to display on the meter
        value = 72.3

        # Create an AngularMeter object of size 250 x 250 pixels with transparent background
        m = ChartDirector::AngularMeter.new(250, 250, ChartDirector::Transparent)

        # Center at (125, 125), scale radius = 111 pixels, scale angle -145 to +145 degrees
        m.setMeter(125, 125, 111, -145, 145)

        # Add a very light grey (0xeeeeee) circle with radius 123 pixels as background
        m.addRing(0, 123, 0xeeeeee)
        # Add a grey (0xcccccc) ring between radii 116 and 123 pixels as border
        m.addRing(116, 123, 0xcccccc)

        # Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
        m.setScale(0, 100, 10, 5, 1)

        # Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
        # 12/9/6 pixels pointing inwards, and their widths to 2/1/1 pixels.
        m.setLabelStyle("ariali.ttf", 15)
        m.setTickLength(-12, -9, -6)
        m.setLineWidth(0, 2, 1, 1)

        # Add a smooth color scale to the meter
        smoothColorScale = [0, 0x3333ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100, 0xff0000]
        m.addColorScale(smoothColorScale)

        # Add a text label centered at (125, 175) with 15pt Arial Italic font
        m.addText(125, 175, "CPU", "ariali.ttf", 15, ChartDirector::TextColor, ChartDirector::Center
            )

        # Add a red (0xff0000) pointer at the specified value
        m.addPointer2(value, 0xff0000)

        # Output the chart
        send_data(m.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/roundmeter.rb
#!/usr/bin/env ruby
require("chartdirector")

# The value to display on the meter
value = 72.3

# Create an AngularMeter object of size 250 x 250 pixels with transparent background
m = ChartDirector::AngularMeter.new(250, 250, ChartDirector::Transparent)

# Center at (125, 125), scale radius = 111 pixels, scale angle -145 to +145 degrees
m.setMeter(125, 125, 111, -145, 145)

# Add a very light grey (0xeeeeee) circle with radius 123 pixels as background
m.addRing(0, 123, 0xeeeeee)
# Add a grey (0xcccccc) ring between radii 116 and 123 pixels as border
m.addRing(116, 123, 0xcccccc)

# Meter scale is 0 - 100, with major/minor/micro ticks every 10/5/1 units
m.setScale(0, 100, 10, 5, 1)

# Set the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to 12/9/6
# pixels pointing inwards, and their widths to 2/1/1 pixels.
m.setLabelStyle("ariali.ttf", 15)
m.setTickLength(-12, -9, -6)
m.setLineWidth(0, 2, 1, 1)

# Add a smooth color scale to the meter
smoothColorScale = [0, 0x3333ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100, 0xff0000]
m.addColorScale(smoothColorScale)

# Add a text label centered at (125, 175) with 15pt Arial Italic font
m.addText(125, 175, "CPU", "ariali.ttf", 15, ChartDirector::TextColor, ChartDirector::Center)

# Add a red (0xff0000) pointer at the specified value
m.addPointer2(value, 0xff0000)

# Output the chart
m.makeChart("roundmeter.png")