ChartDirector Ver 5.0 (Ruby Edition)

Horizontal Linear Meter




This example demonstrates a simple horizontal linear meter.

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

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

Source Code Listing

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

class HlinearmeterController < ApplicationController

    def index()
        @title = "Horizontal Linear 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 = 75.35

        # Create an LinearMeter object of size 250 x 75 pixels, using silver background
        # with a 2 pixel black 3D depressed border.
        m = ChartDirector::LinearMeter.new(250, 75, ChartDirector::silverColor(), 0, -2)

        # Set the scale region top-left corner at (15, 25), with size of 200 x 50 pixels.
        # The scale labels are located on the top (implies horizontal meter)
        m.setMeter(15, 25, 220, 20, ChartDirector::Top)

        # Set meter scale from 0 - 100, with a tick every 10 units
        m.setScale(0, 100, 10)

        # Set 0 - 50 as green (99ff99) zone, 50 - 80 as yellow (ffff66) zone, and 80 - 100
        # as red (ffcccc) zone
        m.addZone(0, 50, 0x99ff99)
        m.addZone(50, 80, 0xffff66)
        m.addZone(80, 100, 0xffcccc)

        # Add a blue (0000cc) pointer at the specified value
        m.addPointer(value, 0x0000cc)

        # Add a label at bottom-left (10, 68) using Arial Bold/8 pts/red (c00000)
        m.addText(10, 68, "Temperature C", "arialbd.ttf", 8, 0xc00000,
            ChartDirector::BottomLeft)

        # Add a text box to show the value formatted to 2 decimal places at bottom right.
        # Use white text on black background with a 1 pixel depressed 3D border.
        m.addText(238, 70, m.formatValue(value, "2"), "arial.ttf", 8, 0xffffff,
            ChartDirector::BottomRight).setBackground(0, 0, -1)

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

# The value to display on the meter
value = 75.35

# Create an LinearMeter object of size 250 x 75 pixels, using silver background with
# a 2 pixel black 3D depressed border.
m = ChartDirector::LinearMeter.new(250, 75, ChartDirector::silverColor(), 0, -2)

# Set the scale region top-left corner at (15, 25), with size of 200 x 50 pixels. The
# scale labels are located on the top (implies horizontal meter)
m.setMeter(15, 25, 220, 20, ChartDirector::Top)

# Set meter scale from 0 - 100, with a tick every 10 units
m.setScale(0, 100, 10)

# Set 0 - 50 as green (99ff99) zone, 50 - 80 as yellow (ffff66) zone, and 80 - 100 as
# red (ffcccc) zone
m.addZone(0, 50, 0x99ff99)
m.addZone(50, 80, 0xffff66)
m.addZone(80, 100, 0xffcccc)

# Add a blue (0000cc) pointer at the specified value
m.addPointer(value, 0x0000cc)

# Add a label at bottom-left (10, 68) using Arial Bold/8 pts/red (c00000)
m.addText(10, 68, "Temperature C", "arialbd.ttf", 8, 0xc00000,
    ChartDirector::BottomLeft)

# Add a text box to show the value formatted to 2 decimal places at bottom right. Use
# white text on black background with a 1 pixel depressed 3D border.
m.addText(238, 70, m.formatValue(value, "2"), "arial.ttf", 8, 0xffffff,
    ChartDirector::BottomRight).setBackground(0, 0, -1)

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