Black Vertical Linear Meters

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

require("chartdirector")

class BlackvlinearmeterController < ApplicationController

    def index()
        @title = "Black Vertical Linear Meters"
        @ctrl_file = File.expand_path(__FILE__)
        @noOfCharts = 6
        render :template => "templates/chartview"
    end

    #
    # Render and deliver the chart
    #
    def getchart()
        # This script can draw different charts depending on the chartIndex
        chartIndex = (params["img"]).to_i

        # The value to display on the meter
        value = 74.25

        # Create a LinearMeter object of size 70 x 260 pixels with black background and rounded
        # corners
        m = ChartDirector::LinearMeter.new(70, 260, 0x000000)
        m.setRoundedFrame(ChartDirector::Transparent)

        # Set the default text and line colors to white (0xffffff)
        m.setColor(ChartDirector::TextColor, 0xffffff)
        m.setColor(ChartDirector::LineColor, 0xffffff)

        # Set the scale region top-left corner at (28, 30), with size of 20 x 196 pixels. The scale
        # labels are located on the left (default - implies vertical meter)
        m.setMeter(28, 30, 20, 196)

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

        # The tick line width to 1 pixel
        m.setLineWidth(0, 1)

        # Demostrate different types of color scales and putting them at different positions
        smoothColorScale = [0, 0x0000ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100, 0xff0000]
        stepColorScale = [0, 0x00cc00, 50, 0xeecc00, 80, 0xdd0000, 100]
        highLowColorScale = [0, 0x0000ff, 70, ChartDirector::Transparent, 100, 0xff0000]

        if chartIndex == 0
            # Add the smooth color scale at the default position
            m.addColorScale(smoothColorScale)
        elsif chartIndex == 1
            # Add the step color scale at the default position
            m.addColorScale(stepColorScale)
        elsif chartIndex == 2
            # Add the high low scale at the default position
            m.addColorScale(highLowColorScale)
        elsif chartIndex == 3
            # Add the smooth color scale starting at x = 28 (left of scale) with zero width and
            # ending at x = 28 with 20 pixels width
            m.addColorScale(smoothColorScale, 28, 0, 28, 20)
        elsif chartIndex == 4
            # Add the smooth color scale starting at x = 38 (center of scale) with zero width and
            # ending at x = 28 with 20 pixels width
            m.addColorScale(smoothColorScale, 38, 0, 28, 20)
        else
            # Add the smooth color scale starting at x = 48 (right of scale) with zero width and
            # ending at x = 28 with 20 pixels width
            m.addColorScale(smoothColorScale, 48, 0, 28, 20)
        end

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

        # Add a label at the top-center using 8pt Arial Bold font
        m.addText(m.getWidth() / 2, 5, "Temp C", "arialbd.ttf", 8, ChartDirector::TextColor,
            ChartDirector::Top)

        # Add a text box at the bottom-center. Display the value using white (0xffffff) 8pt Arial
        # Bold font on a black (0x000000) background with depressed grey (0x444444) rounded border.
        t = m.addText(m.getWidth() / 2, m.getHeight() - 7, m.formatValue(value, "2"), "arialbd.ttf",
            8, 0xffffff, ChartDirector::Bottom)
        t.setBackground(0x000000, 0x444444, -1)
        t.setRoundedCorners(3)

        # 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/blackvlinearmeter.rb

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

def createChart(chartIndex)

    # The value to display on the meter
    value = 74.25

    # Create a LinearMeter object of size 70 x 260 pixels with black background and rounded corners
    m = ChartDirector::LinearMeter.new(70, 260, 0x000000)
    m.setRoundedFrame(ChartDirector::Transparent)

    # Set the default text and line colors to white (0xffffff)
    m.setColor(ChartDirector::TextColor, 0xffffff)
    m.setColor(ChartDirector::LineColor, 0xffffff)

    # Set the scale region top-left corner at (28, 30), with size of 20 x 196 pixels. The scale
    # labels are located on the left (default - implies vertical meter)
    m.setMeter(28, 30, 20, 196)

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

    # The tick line width to 1 pixel
    m.setLineWidth(0, 1)

    # Demostrate different types of color scales and putting them at different positions
    smoothColorScale = [0, 0x0000ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100, 0xff0000]
    stepColorScale = [0, 0x00cc00, 50, 0xeecc00, 80, 0xdd0000, 100]
    highLowColorScale = [0, 0x0000ff, 70, ChartDirector::Transparent, 100, 0xff0000]

    if chartIndex == 0
        # Add the smooth color scale at the default position
        m.addColorScale(smoothColorScale)
    elsif chartIndex == 1
        # Add the step color scale at the default position
        m.addColorScale(stepColorScale)
    elsif chartIndex == 2
        # Add the high low scale at the default position
        m.addColorScale(highLowColorScale)
    elsif chartIndex == 3
        # Add the smooth color scale starting at x = 28 (left of scale) with zero width and ending
        # at x = 28 with 20 pixels width
        m.addColorScale(smoothColorScale, 28, 0, 28, 20)
    elsif chartIndex == 4
        # Add the smooth color scale starting at x = 38 (center of scale) with zero width and ending
        # at x = 28 with 20 pixels width
        m.addColorScale(smoothColorScale, 38, 0, 28, 20)
    else
        # Add the smooth color scale starting at x = 48 (right of scale) with zero width and ending
        # at x = 28 with 20 pixels width
        m.addColorScale(smoothColorScale, 48, 0, 28, 20)
    end

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

    # Add a label at the top-center using 8pt Arial Bold font
    m.addText(m.getWidth() / 2, 5, "Temp C", "arialbd.ttf", 8, ChartDirector::TextColor,
        ChartDirector::Top)

    # Add a text box at the bottom-center. Display the value using white (0xffffff) 8pt Arial Bold
    # font on a black (0x000000) background with depressed grey (0x444444) rounded border.
    t = m.addText(m.getWidth() / 2, m.getHeight() - 7, m.formatValue(value, "2"), "arialbd.ttf", 8,
        0xffffff, ChartDirector::Bottom)
    t.setBackground(0x000000, 0x444444, -1)
    t.setRoundedCorners(3)

    # Output the chart
    m.makeChart("blackvlinearmeter%s.png" % chartIndex)
end

createChart(0)
createChart(1)
createChart(2)
createChart(3)
createChart(4)
createChart(5)