ChartDirector 6.0 (Ruby Edition)

Horizontal Linear Meter




This example demonstrates the basic steps in creating a horizontal linear meter.

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

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 = 74.25

        # Create an LinearMeter object of size 250 x 65 pixels with a very light grey (0xeeeeee)
        # background, and a rounded 3-pixel thick light grey (0xcccccc) border
        m = ChartDirector::LinearMeter.new(250, 65, 0xeeeeee, 0xcccccc)
        m.setRoundedFrame(ChartDirector::Transparent)
        m.setThickFrame(3)

        # Set the scale region top-left corner at (14, 23), with size of 218 x 20 pixels. The scale
        # labels are located on the top (implies horizontal meter)
        m.setMeter(14, 23, 218, 20, ChartDirector::Top)

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

        # Add a smooth color scale to the meter
        smoothColorScale = [0, 0x6666ff, 25, 0x00bbbb, 50, 0x00ff00, 75, 0xffff00, 100, 0xff0000]
        m.addColorScale(smoothColorScale)

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

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

# The value to display on the meter
value = 74.25

# Create an LinearMeter object of size 250 x 65 pixels with a very light grey (0xeeeeee) background,
# and a rounded 3-pixel thick light grey (0xcccccc) border
m = ChartDirector::LinearMeter.new(250, 65, 0xeeeeee, 0xcccccc)
m.setRoundedFrame(ChartDirector::Transparent)
m.setThickFrame(3)

# Set the scale region top-left corner at (14, 23), with size of 218 x 20 pixels. The scale labels
# are located on the top (implies horizontal meter)
m.setMeter(14, 23, 218, 20, ChartDirector::Top)

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

# Add a smooth color scale to the meter
smoothColorScale = [0, 0x6666ff, 25, 0x00bbbb, 50, 0x00ff00, 75, 0xffff00, 100, 0xff0000]
m.addColorScale(smoothColorScale)

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

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