Black Semicircle Meters

perldemo\blacksemicirclemeter.pl
#!/usr/bin/perl

# The ChartDirector for Perl module is assumed to be in "../lib"
use File::Basename;
use lib (dirname($0)."/../lib") =~ /(.*)/;

use perlchartdir;

sub createChart
{
    my $chartIndex = shift;

    # The value to display on the meter
    my $value = 72.55;

    # Create an AngularMeter object of size 300 x 180 pixels with transparent background
    my $m = new AngularMeter(300, 180, $perlchartdir::Transparent);

    # Set the default text and line colors to white (0xffffff)
    $m->setColor($perlchartdir::TextColor, 0xffffff);
    $m->setColor($perlchartdir::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
    my $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("Arial Italic", 16);
    $m->setTickLength(-16, -16, -10);
    $m->setLineWidth(0, 2, 1, 1);

    # Demostrate different types of color scales and putting them at different positions
    my $smoothColorScale = [0, 0x0000ff, 25, 0x0088ff, 50, 0x00ff00, 75, 0xdddd00, 100, 0xff0000];
    my $stepColorScale = [0, 0x00aa00, 60, 0xddaa00, 80, 0xcc0000, 100];
    my $highLowColorScale = [0, 0x00ff00, 70, $perlchartdir::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);
    }

    # Add a text label centered at (150, 125) with 15pt Arial Italic font
    $m->addText(150, 125, "CPU", "Arial Italic", 15, $perlchartdir::TextColor,
        $perlchartdir::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);
    }

    # Output the chart
    $m->makeChart("blacksemicirclemeter$chartIndex.png");
}

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