ChartDirector 5.1 (Ruby Edition)

Semi-Circle Meter




This example demonstrates a simple half circle angular meter.

A basic angular meter can be created using the following steps:

In addition to the basic angular meter, this example demonstrates the following features:

Note that by default, the drawing ordering of the text box objects and meter pointer follow the order in which they are added to the chart. Thus this sample code adds the meter pointer last, to ensure it stays on top of the custom text boxes.

Source Code Listing

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

class SemicirclemeterController < ApplicationController

    def index()
        @title = "Semi-Circle 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 = 27.48

        # Create an AngularMeter object of size 200 x 115 pixels, with silver background
        # color, black border, 2 pixel 3D border border and rounded corners
        m = ChartDirector::AngularMeter.new(200, 115, ChartDirector::silverColor(),
            0x000000, 2)
        m.setRoundedFrame()

        # Set the meter center at (100, 100), with radius 85 pixels, and span from -90 to
        # +90 degress (semi-circle)
        m.setMeter(100, 100, 85, -90, 90)

        # Meter scale is 0 - 100, with major tick every 20 units, minor tick every 10
        # units, and micro tick every 5 units
        m.setScale(0, 100, 20, 10, 5)

        # Set 0 - 60 as green (66FF66) zone
        m.addZone(0, 60, 0, 85, 0x66ff66)

        # Set 60 - 80 as yellow (FFFF33) zone
        m.addZone(60, 80, 0, 85, 0xffff33)

        # Set 80 - 100 as red (FF6666) zone
        m.addZone(80, 100, 0, 85, 0xff6666)

        # Add a text label centered at (100, 60) with 12 pts Arial Bold font
        m.addText(100, 60, "PSI", "arialbd.ttf", 12, ChartDirector::TextColor,
            ChartDirector::Center)

        # Add a text box at the top right corner of the meter showing the value formatted
        # to 2 decimal places, using white text on a black background, and with 1 pixel 3D
        # depressed border
        m.addText(156, 8, m.formatValue(value, "2"), "arial.ttf", 8, 0xffffff
            ).setBackground(0x000000, 0, -1)

        # Add a semi-transparent blue (40666699) pointer with black border at the
        # specified value
        m.addPointer(value, 0x40666699, 0x000000)

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

# The value to display on the meter
value = 27.48

# Create an AngularMeter object of size 200 x 115 pixels, with silver background
# color, black border, 2 pixel 3D border border and rounded corners
m = ChartDirector::AngularMeter.new(200, 115, ChartDirector::silverColor(), 0x000000,
    2)
m.setRoundedFrame()

# Set the meter center at (100, 100), with radius 85 pixels, and span from -90 to +90
# degress (semi-circle)
m.setMeter(100, 100, 85, -90, 90)

# Meter scale is 0 - 100, with major tick every 20 units, minor tick every 10 units,
# and micro tick every 5 units
m.setScale(0, 100, 20, 10, 5)

# Set 0 - 60 as green (66FF66) zone
m.addZone(0, 60, 0, 85, 0x66ff66)

# Set 60 - 80 as yellow (FFFF33) zone
m.addZone(60, 80, 0, 85, 0xffff33)

# Set 80 - 100 as red (FF6666) zone
m.addZone(80, 100, 0, 85, 0xff6666)

# Add a text label centered at (100, 60) with 12 pts Arial Bold font
m.addText(100, 60, "PSI", "arialbd.ttf", 12, ChartDirector::TextColor,
    ChartDirector::Center)

# Add a text box at the top right corner of the meter showing the value formatted to
# 2 decimal places, using white text on a black background, and with 1 pixel 3D
# depressed border
m.addText(156, 8, m.formatValue(value, "2"), "arial.ttf", 8, 0xffffff).setBackground(
    0x000000, 0, -1)

# Add a semi-transparent blue (40666699) pointer with black border at the specified
# value
m.addPointer(value, 0x40666699, 0x000000)

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