Real Time Graph Update/Replotting

The graph can also be updated automatically using javascript without user intervention. This is useful to potting charts for situation where data points come from a continuous source such as stock and weather. The key is to use standard javascript setInterval function to set replotting interval.

Javascript (partial source. Only to demostrate how setInterval is used. See live demo for complete source):

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 function UpdateGraph() {
     StopGraphLoop();
     interval = parseInt($('#interval').val());
     npoints = parseInt($('#npoints').val());
     maxIterations = parseInt($('#maxIterations').val());
     niters = 0;
     GraphUpdate = setInterval(runUpdate, interval);
 }
 
 
 function runUpdate() {
     if (niters < maxIterations) {
         BuildDataArray();
         Graph.series[0].data = GraphData;
         Graph.replot({resetAxes:true});
         niters++;
     }
     else {
         StopGraphLoop();
     }
 }

 function StopGraphLoop() {
     clearInterval(GraphUpdate);
 }

PHP (partial)

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$pc = new C_PhpChartX(array($GraphData),'Graph');
$pc->add_plugins(array('canvasTextRenderer','canvasAxisTickRenderer','canvasAxisLabelRenderer','highlighter','canvasOverlay','cursor','pointLabels'),true);

$pc->set_title(array('text'=>'Test Data Run'));    
$pc->set_cursor(array('show'=>false));
$pc->set_point_labels(array('show'=>false));
$pc->set_highlighter(array('show'=>false));

$pc->set_axes_default(array(
    'pad'=>0.05,
    'labelRenderer'=>'plugin::CanvasAxisLabelRenderer',
    'tickRenderer'=>'plugin::CanvasAxisTickRenderer',
    'labelOptions'=>array('fontSize'=>'13pt')
));
$pc->set_axes(array(
        'xaxis'=> array('label'=> 'Number'),
        'yaxis'=> array('label'=>'Value')
    ));

// should be the last method to call
$pc->draw(800,500);

Live demo

If you have an array of series of known data that needs to be displayed in sequence, instead of real-time replotting, check out the dynamic replotting example below. Scroll to the bottom and click on “Start” buttons to run the example.

http://phpchart.org/phpChart/examples/dynamicplot.php

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