<?php
require_once("/usr/local/lib/php/20100525/phpchartdir.php");

# Use random table to generate a random series. The random table is set to 1 col x 51
# rows, with 9 as the seed
$rantable = new RanTable(9, 1, 51);

# Set the 1st column to start from 100, with changes between rows from -5 to +5
$rantable->setCol(0, 100, -5, 5);

# Get the 1st column of the random table as the data set
$data = $rantable->getCol(0);

# Create a XYChart object of size 600 x 300 pixels
$c = new XYChart(600, 300);

# Set the plotarea at (50, 35) and of size 500 x 240 pixels. Enable both the
# horizontal and vertical grids by setting their colors to grey (0xc0c0c0)
$plotAreaObj = $c->setPlotArea(50, 35, 500, 240);
$plotAreaObj->setGridColor(0xc0c0c0, 0xc0c0c0);

# Add a title to the chart using 18 point Times Bold Itatic font.
$c->addTitle("LOWESS Generic Curve Fitting Algorithm", "timesbi.ttf", 18);

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

# Add a title to the x axis using 12 pts Arial Bold Italic font
$c->xAxis->setTitle("Server Load (TPS)", "arialbi.ttf", 12);

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

# Set the x axis scale from 0 - 50, with major tick every 5 units and minor tick
# every 1 unit
$c->xAxis->setLinearScale(0, 50, 5, 1);

# Add a blue layer to the chart
$layer = $c->addLineLayer2();

# Add a red (0x80ff0000) data set to the chart with square symbols
$dataSetObj = $layer->addDataSet($data, 0x80ff0000);
$dataSetObj->setDataSymbol(SquareSymbol);

# Set the line width to 2 pixels
$layer->setLineWidth(2);

# Use lowess for curve fitting, and plot the fitted data using a spline layer with
# line width set to 3 pixels
$curve = new ArrayMath($data);
$curve->lowess();
$splineLayerObj = $c->addSplineLayer($curve->result(), 0x0000ff);
$splineLayerObj->setLineWidth(3);

# Set zero affinity to 0 to make sure the line is displayed in the most detail scale
$c->yAxis->setAutoScale(0, 0, 0);

# Output the chart
header("Content-type: image/png");
print($c->makeChart2(PNG));
?>
