60 lines
1.8 KiB
PHP
60 lines
1.8 KiB
PHP
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<?php // content="text/plain; charset=utf-8"
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// Example on how to treat and format timestamp as human readable labels
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require_once ('jpgraph/jpgraph.php');
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require_once ('jpgraph/jpgraph_line.php');
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// Number of "fake" data points
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DEFINE('NDATAPOINTS',500);
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// Assume data points are sample every 10th second
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DEFINE('SAMPLERATE',10);
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// Callback formatting function for the X-scale to convert timestamps
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// to hour and minutes.
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function TimeCallback($aVal) {
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return Date('H:i', $aVal);
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}
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// Get start time
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$start = time();
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// Set the start time to be on the closest minute just before the "start" timestamp
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$adjstart = floor($start / 60);
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// Create a data set in range (20,100) and X-positions
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// We also apply a simple low pass filter on the data to make it less
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// random and a little smoother
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$data = array();
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$xdata = array();
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$data[0] = rand(20,100);
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$xdata[0] = $adjstart;
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for( $i=1; $i < NDATAPOINTS; ++$i ) {
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$data[$i] = rand(20,100)*0.2 + $data[$i-1]*0.8;
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$xdata[$i] = $adjstart + $i * SAMPLERATE;
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}
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// Assume that the data points represents data that is sampled every 10s
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// when determing the end value on the scale. We also add some extra
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// length to end on an even label tick.
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$adjend = $adjstart + (NDATAPOINTS+10)*10;
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$graph = new Graph(500,250);
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$graph->SetMargin(40,20,30,50);
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// Now specify the X-scale explicit but let the Y-scale be auto-scaled
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$graph->SetScale("intlin",0,0,$adjstart,$adjend);
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$graph->title->Set("Example on TimeStamp Callback");
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// Setup the callback and adjust the angle of the labels
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$graph->xaxis->SetLabelFormatCallback('TimeCallback');
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$graph->xaxis->SetLabelAngle(90);
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// Set the labels every 5min (i.e. 300seconds) and minor ticks every minute
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$graph->xaxis->scale->ticks->Set(300,60);
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$line = new LinePlot($data,$xdata);
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$line->SetColor('lightblue');
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$graph->Add($line);
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$graph->Stroke();
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?>
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