Linear Zone Meter

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

require("chartdirector")

class LinearzonemeterController < ApplicationController

    def index()
        @title = "Linear Zone 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 = 85

        # Create an LinearMeter object of size 210 x 45 pixels, using silver background with a 2
        # pixel black 3D depressed border.
        m = ChartDirector::LinearMeter.new(210, 45, ChartDirector::silverColor(), 0, -2)

        # Set the scale region top-left corner at (5, 5), with size of 200 x 20 pixels. The scale
        # labels are located on the bottom (implies horizontal meter)
        m.setMeter(5, 5, 200, 20, ChartDirector::Bottom)

        # Set meter scale from 0 - 100
        m.setScale(0, 100)

        # Add a title at the bottom of the meter with a 1 pixel raised 3D border
        m.addTitle2(ChartDirector::Bottom, "Battery Level", "arialbd.ttf", 8).setBackground(
            ChartDirector::Transparent, -1, 1)

        # Set 3 zones of different colors to represent Good/Weak/Bad data ranges
        m.addZone(50, 100, 0x99ff99, "Good")
        m.addZone(20, 50, 0xffff66, "Weak")
        m.addZone(0, 20, 0xffcccc, "Bad")

        # Add empty labels (just need the ticks) at 0/20/50/80 as separators for zones
        m.addLabel(0, " ")
        m.addLabel(20, " ")
        m.addLabel(50, " ")
        m.addLabel(100, " ")

        # Add a semi-transparent blue (800000ff) pointer at the specified value, using triangular
        # pointer shape
        m.addPointer(value, 0x800000ff).setShape(ChartDirector::TriangularPointer)

        # 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/linearzonemeter.rb

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

# The value to display on the meter
value = 85

# Create an LinearMeter object of size 210 x 45 pixels, using silver background with a 2 pixel black
# 3D depressed border.
m = ChartDirector::LinearMeter.new(210, 45, ChartDirector::silverColor(), 0, -2)

# Set the scale region top-left corner at (5, 5), with size of 200 x 20 pixels. The scale labels are
# located on the bottom (implies horizontal meter)
m.setMeter(5, 5, 200, 20, ChartDirector::Bottom)

# Set meter scale from 0 - 100
m.setScale(0, 100)

# Add a title at the bottom of the meter with a 1 pixel raised 3D border
m.addTitle2(ChartDirector::Bottom, "Battery Level", "arialbd.ttf", 8).setBackground(
    ChartDirector::Transparent, -1, 1)

# Set 3 zones of different colors to represent Good/Weak/Bad data ranges
m.addZone(50, 100, 0x99ff99, "Good")
m.addZone(20, 50, 0xffff66, "Weak")
m.addZone(0, 20, 0xffcccc, "Bad")

# Add empty labels (just need the ticks) at 0/20/50/80 as separators for zones
m.addLabel(0, " ")
m.addLabel(20, " ")
m.addLabel(50, " ")
m.addLabel(100, " ")

# Add a semi-transparent blue (800000ff) pointer at the specified value, using triangular pointer
# shape
m.addPointer(value, 0x800000ff).setShape(ChartDirector::TriangularPointer)

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