Class: ezcGraphChartElementDateAxis  - X-Ref

Class to represent date axis.

Axis elements represent the axis in a bar, line or radar chart. They are
chart elements (ezcGraphChartElement) extending from
ezcGraphChartElementAxis, where additional formatting options can be found.
You should generally use the axis, which matches your input data best, so
that the automatic chart layouting works best. Aavailable axis types are:

- ezcGraphChartElementDateAxis
- ezcGraphChartElementLabeledAxis
- ezcGraphChartElementLogarithmicalAxis
- ezcGraphChartElementNumericAxis

Date axis will try to find a "nice" interval based on the values on the x
axis. If non numeric values are given, ezcGraphChartElementDateAxis will
convert them to timestamps using PHPs strtotime function.

It is always possible to set start date, end date and the interval manually
by yourself.

The $dateFormat option provides an additional way of formatting the labels
used on the axis. The options from the parent class $formatString and
$labelCallback do still apply.

You may use a date axis like in the following example:

<code>
$graph = new ezcGraphLineChart();
$graph->options->fillLines = 210;
$graph->title = 'Concurrent requests';
$graph->legend = false;

$graph->xAxis = new ezcGraphChartElementDateAxis();

// Add data
$graph->data['Machine 1'] = new ezcGraphArrayDataSet( array(
'8:00' => 3241,
'8:13' => 934,
'8:24' => 1201,
'8:27' => 1752,
'8:51' => 123,
) );
$graph->data['Machine 2'] = new ezcGraphArrayDataSet( array(
'8:05' => 623,
'8:12' => 2103,
'8:33' => 543,
'8:43' => 2034,
'8:59' => 3410,
) );

$graph->data['Machine 1']->symbol = ezcGraph::BULLET;
$graph->data['Machine 2']->symbol = ezcGraph::BULLET;

$graph->render( 400, 150, 'tutorial_axis_datetime.svg' );
</code>