Inter-Line Coloring

perldemo\linefill.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;

# The data for the line chart
my $data0 = [70, 73, 80, 90, 95, 93, 82, 77, 82, 101, 111, 115];
my $data1 = [90, 96, 89, 77, 82, 96, 109, 109, 99, 108, 96, 91];
my $data2 = [58, 34, 25, 49, 64, 10, 16, 40, 25, 49, 40, 22];

# The labels for the line chart
my $labels = ["2008-01", "2008-02", "2008-03", "2008-04", "2008-05", "2008-06", "2008-07",
    "2008-08", "2008-09", "2008-10", "2008-11", "2008-12"];

# Create a XYChart object of size 450 x 450 pixels
my $c = new XYChart(450, 450);

# Add a title to the chart using 15pt Arial Italic font.
my $title = $c->addTitle("Inter-line Coloring", "Arial Italic", 15);

# Add a legend box where the top-center is anchored to the horizontal center of the chart, just
# under the title. Use horizontal layout and 10 points Arial Bold font, and transparent background
# and border. Use line style legend key.
my $legendBox = $c->addLegend($c->getWidth() / 2, $title->getHeight(), 0, "Arial Bold Italic", 10);
$legendBox->setBackground($perlchartdir::Transparent, $perlchartdir::Transparent);
$legendBox->setAlignment($perlchartdir::TopCenter);
$legendBox->setLineStyleKey();

# Tentatively set the plotarea at (70, 65) and of (chart_width - 100) x (chart_height - 110) in
# size. Use light grey (c0c0c0) border and horizontal and vertical grid lines.
my $plotArea = $c->setPlotArea(70, 65, $c->getWidth() - 100, $c->getHeight() - 110, -1, -1,
    0xc0c0c0, 0xc0c0c0, -1);

# Add a title to the y axis using 12pt Arial Bold Italic font
$c->yAxis()->setTitle("Axis Title Placeholder", "Arial Bold Italic", 12);

# Add a title to the x axis using 12pt Arial Bold Italic font
$c->xAxis()->setTitle("Axis Title Placeholder", "Arial Bold Italic", 12);

# Set the axes line width to 3 pixels
$c->xAxis()->setWidth(3);
$c->yAxis()->setWidth(3);

# Set the labels on the x axis.
$c->xAxis()->setLabels($labels);

# Use 8 points Arial rotated by 90 degrees as the x-axis label font
$c->xAxis()->setLabelStyle("Arial", 8, $perlchartdir::TextColor, 90);

# Add a spline curve to the chart
my $layer0 = $c->addSplineLayer($data0, 0xff0000, "Data Set 0");
$layer0->setLineWidth(2);

# Add a normal line to the chart
my $layer1 = $c->addLineLayer($data1, 0x008800, "Data Set 1");
$layer1->setLineWidth(2);

# Color the region between the above spline curve and normal line. Use the semi-transparent red
# (80ff000000) if the spline curve is higher than the normal line, otherwise use semi-transparent
# green (80008800)
$c->addInterLineLayer($layer0->getLine(), $layer1->getLine(), 0x80ff0000, 0x80008800);

# Add another normal line to the chart
my $layer2 = $c->addLineLayer($data2, 0x0000ff, "Data Set 2");
$layer2->setLineWidth(2);

# Add a horizontal mark line to the chart at y = 40
my $mark = $c->yAxis()->addMark(40, -1, "Threshold");
$mark->setLineWidth(2);

# Set the mark line to purple (880088) dash line. Use white (ffffff) for the mark label.
$mark->setMarkColor($c->dashLineColor(0x880088), 0xffffff);

# Put the mark label at the left side of the mark, with a purple (880088) background.
$mark->setAlignment($perlchartdir::Left);
$mark->setBackground(0x880088);

# Color the region between the above normal line and mark line. Use the semi-transparent blue
# (800000ff) if the normal line is higher than the mark line, otherwise use semi-transparent purple
# (80880088)
$c->addInterLineLayer($layer2->getLine(), $mark->getLine(), 0x800000ff, 0x80880088);

# Layout the legend box, so we can get its height
$c->layoutLegend();

# Adjust the plot area size, such that the bounding box (inclusive of axes) is 10 pixels from the
# left edge, just under the legend box, 25 pixels from the right edge, and 10 pixels from the bottom
# edge.
$c->packPlotArea(10, $legendBox->getTopY() + $legendBox->getHeight(), $c->getWidth() - 25,
    $c->getHeight() - 10);

# After determining the exact plot area position, we may adjust the legend box and the title
# positions so that they are centered relative to the plot area (instead of the chart)
$legendBox->setPos($plotArea->getLeftX() + ($plotArea->getWidth() - $legendBox->getWidth()) / 2,
    $legendBox->getTopY());
$title->setPos($plotArea->getLeftX() + ($plotArea->getWidth() - $title->getWidth()) / 2,
    $title->getTopY());

# Output the chart
$c->makeChart("linefill.png");