ChartDirector 6.0 (Ruby Edition)

Black Semicircle Meters


          

This example demonstrates semicircle meters with black background, silver border and glare effect.

The silver border effect is achieved by using AngularMeter.relativeLinearGradient to create a gradient consisting of varying levels of grey.

Glare effect is added to some of the meters using AngularMeter.addGlare. Glare effect works best in a dark background.

Source Code Listing

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

class BlacksemicirclemeterController < ApplicationController

    def index()
        @title = "Black Semicircle 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 = 72.55

        # Create an AngularMeter object of size 300 x 180 pixels with transparent background
        m = ChartDirector::AngularMeter.new(300, 180, ChartDirector::Transparent)

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

        # Center at (150, 150), scale radius = 128 pixels, scale angle -90 to +90 degrees
        m.setMeter(150, 150, 128, -90, 90)

        # Gradient color for the border to make it silver-like
        ringGradient = [1, 0x909090, 0.5, 0xd6d6d6, 0, 0xeeeeee, -0.5, 0xd6d6d6, -1, 0x909090]

        # Add a black (0x000000) scale background of 148 pixels radius with a 10 pixel thick silver
        # border
        m.addScaleBackground(148, 0, 10, m.relativeLinearGradient(ringGradient, 45, 148))

        # 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 the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
        # 16/16/10 pixels pointing inwards, and their widths to 2/1/1 pixels.
        m.setLabelStyle("ariali.ttf", 16)
        m.setTickLength(-16, -16, -10)
        m.setLineWidth(0, 2, 1, 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, 0x00aa00, 60, 0xddaa00, 80, 0xcc0000, 100]
        highLowColorScale = [0, 0x00ff00, 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 smooth color scale starting at radius 128 with zero width and ending at radius
            # 128 with 16 pixels inner width
            m.addColorScale(smoothColorScale, 128, 0, 128, -16)
        elsif chartIndex == 2
            # Add the smooth color scale starting at radius 70 with zero width and ending at radius
            # 60 with 20 pixels outer width
            m.addColorScale(smoothColorScale, 70, 0, 60, 20)
        elsif chartIndex == 3
            # Add the high/low color scale at the default position
            m.addColorScale(highLowColorScale)
        elsif chartIndex == 4
            # Add the step color scale at the default position
            m.addColorScale(stepColorScale)
        else
            # Add the smooth color scale at radius 60 with 15 pixels outer width
            m.addColorScale(smoothColorScale, 60, 15)
        end

        # Add a text label centered at (150, 125) with 15pt Arial Italic font
        m.addText(150, 125, "CPU", "ariali.ttf", 15, ChartDirector::TextColor,
            ChartDirector::BottomCenter)

        # Add a red (0xff0000) pointer at the specified value
        m.addPointer2(value, 0xff0000)

        # Add glare up to radius 138 (= region inside border)
        if chartIndex % 2 == 0
            m.addGlare(138)
        end

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

def createChart(chartIndex)

    # The value to display on the meter
    value = 72.55

    # Create an AngularMeter object of size 300 x 180 pixels with transparent background
    m = ChartDirector::AngularMeter.new(300, 180, ChartDirector::Transparent)

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

    # Center at (150, 150), scale radius = 128 pixels, scale angle -90 to +90 degrees
    m.setMeter(150, 150, 128, -90, 90)

    # Gradient color for the border to make it silver-like
    ringGradient = [1, 0x909090, 0.5, 0xd6d6d6, 0, 0xeeeeee, -0.5, 0xd6d6d6, -1, 0x909090]

    # Add a black (0x000000) scale background of 148 pixels radius with a 10 pixel thick silver
    # border
    m.addScaleBackground(148, 0, 10, m.relativeLinearGradient(ringGradient, 45, 148))

    # 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 the scale label style to 15pt Arial Italic. Set the major/minor/micro tick lengths to
    # 16/16/10 pixels pointing inwards, and their widths to 2/1/1 pixels.
    m.setLabelStyle("ariali.ttf", 16)
    m.setTickLength(-16, -16, -10)
    m.setLineWidth(0, 2, 1, 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, 0x00aa00, 60, 0xddaa00, 80, 0xcc0000, 100]
    highLowColorScale = [0, 0x00ff00, 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 smooth color scale starting at radius 128 with zero width and ending at radius 128
        # with 16 pixels inner width
        m.addColorScale(smoothColorScale, 128, 0, 128, -16)
    elsif chartIndex == 2
        # Add the smooth color scale starting at radius 70 with zero width and ending at radius 60
        # with 20 pixels outer width
        m.addColorScale(smoothColorScale, 70, 0, 60, 20)
    elsif chartIndex == 3
        # Add the high/low color scale at the default position
        m.addColorScale(highLowColorScale)
    elsif chartIndex == 4
        # Add the step color scale at the default position
        m.addColorScale(stepColorScale)
    else
        # Add the smooth color scale at radius 60 with 15 pixels outer width
        m.addColorScale(smoothColorScale, 60, 15)
    end

    # Add a text label centered at (150, 125) with 15pt Arial Italic font
    m.addText(150, 125, "CPU", "ariali.ttf", 15, ChartDirector::TextColor,
        ChartDirector::BottomCenter)

    # Add a red (0xff0000) pointer at the specified value
    m.addPointer2(value, 0xff0000)

    # Add glare up to radius 138 (= region inside border)
    if chartIndex % 2 == 0
        m.addGlare(138)
    end

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

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