ChartDirector 6.0 (Ruby Edition)

Color Semicircle Meters

          

This example demonstrates semicircle meters in various gradient colors, as well as various color scales and pointer types.

The background color in this example changes from a specified color at the border, to a brighter version of the color at the center. The brighter color is derived from the specified color using BaseChart.adjustBrightness. To achieve the radial gradient effect, these two colors are passed to AngularMeter.relativeRadialGradient to create a radial gradient color. The gradient color is then passed to AngularMeter.addScaleBackground to fill the background.

BaseMeter.addColorScale is used to create the color scales in this example. The color scales are created by with different colors, different end point positions and different widths at the end points.

Two pointer types are shown in these meters - a sharp very thin triangular pointer, and a line pointer. They are created using AngularMeter.addPointer2 with TriangularPointer2 and LinePointer2 as parameters.

Source Code Listing

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

class ColorsemicirclemeterController < ApplicationController

    def index()
        @title = "Color 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

        # The background and border colors of the meters
        bgColor = [0x88ccff, 0xffdddd, 0xffddaa, 0xffccff, 0xdddddd, 0xccffcc]
        borderColor = [0x000077, 0x880000, 0xee6600, 0x440088, 0x000000, 0x006000]

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

        # Center at (150, 150), scale radius = 124 pixels, scale angle -90 to +90 degrees
        m.setMeter(150, 150, 124, -90, 90)

        # Background gradient color with brighter color at the center
        bgGradient = [0, m.adjustBrightness(bgColor[chartIndex], 3), 0.75, bgColor[chartIndex]]

        # Add a scale background of 148 pixels radius using the background gradient, with a 13 pixel
        # thick border
        m.addScaleBackground(148, m.relativeRadialGradient(bgGradient), 13, borderColor[chartIndex])

        # 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, 0x3333ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100, 0xff0000]
        stepColorScale = [0, 0x00cc00, 60, 0xffdd00, 80, 0xee0000, 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 124 with zero width and ending at radius
            # 124 with 16 pixels inner width
            m.addColorScale(smoothColorScale, 124, 0, 124, -16)
        elsif chartIndex == 2
            # Add the smooth color scale starting at radius 65 with zero width and ending at radius
            # 55 with 20 pixels outer width
            m.addColorScale(smoothColorScale, 65, 0, 55, 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 55 with 20 pixels outer width
            m.addColorScale(smoothColorScale, 55, 20)
        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)

        # Demonstrate two different types of pointers - thin triangular pointer (the default) and
        # line pointer
        if chartIndex % 2 == 0
            m.addPointer2(value, 0xff0000)
        else
            m.addPointer2(value, 0xff0000, -1, ChartDirector::LinePointer2)
        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/colorsemicirclemeter.rb 
#!/usr/bin/env ruby
require("chartdirector")

def createChart(chartIndex)

    # The value to display on the meter
    value = 72.55

    # The background and border colors of the meters
    bgColor = [0x88ccff, 0xffdddd, 0xffddaa, 0xffccff, 0xdddddd, 0xccffcc]
    borderColor = [0x000077, 0x880000, 0xee6600, 0x440088, 0x000000, 0x006000]

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

    # Center at (150, 150), scale radius = 124 pixels, scale angle -90 to +90 degrees
    m.setMeter(150, 150, 124, -90, 90)

    # Background gradient color with brighter color at the center
    bgGradient = [0, m.adjustBrightness(bgColor[chartIndex], 3), 0.75, bgColor[chartIndex]]

    # Add a scale background of 148 pixels radius using the background gradient, with a 13 pixel
    # thick border
    m.addScaleBackground(148, m.relativeRadialGradient(bgGradient), 13, borderColor[chartIndex])

    # 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, 0x3333ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100, 0xff0000]
    stepColorScale = [0, 0x00cc00, 60, 0xffdd00, 80, 0xee0000, 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 124 with zero width and ending at radius 124
        # with 16 pixels inner width
        m.addColorScale(smoothColorScale, 124, 0, 124, -16)
    elsif chartIndex == 2
        # Add the smooth color scale starting at radius 65 with zero width and ending at radius 55
        # with 20 pixels outer width
        m.addColorScale(smoothColorScale, 65, 0, 55, 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 55 with 20 pixels outer width
        m.addColorScale(smoothColorScale, 55, 20)
    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)

    # Demonstrate two different types of pointers - thin triangular pointer (the default) and line
    # pointer
    if chartIndex % 2 == 0
        m.addPointer2(value, 0xff0000)
    else
        m.addPointer2(value, 0xff0000, -1, ChartDirector::LinePointer2)
    end

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

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

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