Rotated Area Chart

This example demonstrates swapping the x and y axes to produce an rotated area chart in which the area goes from left to right (instead of bottom to top).

The x and y axes in the example are configured as follows:

Initially, the x-axis is horizontal from left to right at the bottom of the plot area, while the y-axis is vertical from bottom to top at the left side of the plot area.
Swap the x and y axes using XYChart.swapXY. Now the x-axis is vertical from bottom to top at the left side of the chart, while the y-axis is horizontal from left to right at the bottom of the chart.
Use XYChart.setYAxisOnRight to move the y-axis to the opposite side of the plot area, so that the y-axis is at the top of the plot area. (Note: the "right" word on setYAxisOnRight means the "right" side before "swapXY" rotation. After rotation, the right side will become to top side.)
Use Axis.setReverse to reverse the direction of the x-axis, so that the x-axis is vertical from top to bottom (instead of from bottom to top).

The area in this chart is filled using a gradient color created with BaseChart.gradientColor.

[File: phpdemo/rotatedarea.php]

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

# The data for the area chart
$data = array(30, 28, 40, 55, 75, 68, 54, 60, 50, 62, 75, 65, 75, 89, 60, 55, 53, 35, 50, 66, 56,
    48, 52, 65, 62);

# The labels for the area chart
$labels = array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,
    23, 24);

# Create a XYChart object of size 320 x 320 pixels
$c = new XYChart(320, 320);

# Swap the x and y axis to become a rotated chart
$c->swapXY();

# Set the y axis on the top side (right + rotated = top)
$c->setYAxisOnRight();

# Reverse the x axis so it is pointing downwards
$c->xAxis->setReverse();

# Set the plotarea at (50, 50) and of size 200 x 200 pixels. Enable horizontal and vertical grids by
# setting their colors to grey (0xc0c0c0).
$plotAreaObj = $c->setPlotArea(50, 50, 250, 250);
$plotAreaObj->setGridColor(0xc0c0c0, 0xc0c0c0);

# Add a line chart layer using the given data
$c->addAreaLayer($data, $c->gradientColor(50, 0, 300, 0, 0xffffff, 0x0000ff));

# Set the labels on the x axis. Append "m" after the value to show the unit.
$c->xAxis->setLabels2($labels, "{value} m");

# Display 1 out of 3 labels.
$c->xAxis->setLabelStep(3);

# Add a title to the x axis
$c->xAxis->setTitle("Depth");

# Add a title to the y axis
$c->yAxis->setTitle("Carbon Dioxide Concentration (ppm)");

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