A pareto chart is a bar chart with the data sorted in descending order, together with a line chart showing the same data in accumulated form. In the current example, the data is shown as both percentages and value on the two y-axes.

The chart in this example is composed of two layers - a BarLayer added using XYChart.addBarLayer, and a LineLayer added using XYChart.addLineLayer.

This example employs the ArrayMath object for computing the accumulated line, obtaining the scaling factor between the two y-axes, and re-scaling the line data as percentages.

The two y-axes are synchronized using XYChart.syncYAxis.

[File: phpdemo/pareto.php".]

<?php require_once("../lib/phpchartdir.php"); #The data for the chart $data = array(40, 15, 7, 5, 2); #The labels for the chart $labels = array("Hard Disk", "PCB", "Printer", "CDROM", "Keyboard"); #Create a XYChart object of size 400 x 225 pixels $c = new XYChart(400, 225); #Set the background color of the chart to gold (goldGradient). Use a 2 pixel 3D #border. $c->setBackground($c->gradientColor($goldGradient), -1, 2); #Add a title box using 11 point Arial Bold font. Set the background color to #blue metallic (blueMetalGradient). Use a 1 pixel 3D border. $titleObj = $c->addTitle("Hardware Defects", "arialbd.ttf", 11); $titleObj->setBackground($c->gradientColor($blueMetalGradient), -1, 1); #Set the plotarea at (50, 40) and of 300 x 150 pixels in size. Use 0x80ccccff as #the background color. $c->setPlotArea(50, 40, 300, 150, 0x80ccccff); #Add a line layer for the pareto line $lineLayer = $c->addLineLayer(); #Compute the pareto line by accumulating the data $lineData = new ArrayMath($data); $lineData->acc(); #Set a scaling factor such as the maximum point of the line is scaled to 100 $scaleFactor = 100 / $lineData->max(); $lineData->mul2($scaleFactor); #Add the pareto line using the scaled data. Use deep blue (0x80) as the line #color, with light blue (0x9999ff) diamond symbols $dataSetObj = $lineLayer->addDataSet($lineData->result(), 0x80); $dataSetObj->setDataSymbol(DiamondSymbol, 9, 0x9999ff); #Set the line width to 2 pixel $lineLayer->setLineWidth(2); #Add a multi-color bar layer using the given data. Bind the layer to the #secondary (right) y-axis. $barLayer3Obj = $c->addBarLayer3($data); $barLayer3Obj->setUseYAxis2(); #Set the x axis labels using the given labels $c->xAxis->setLabels($labels); #Set the primary y-axis scale as 0 - 100 with a tick every 20 units $c->yAxis->setLinearScale(0, 100, 20); #Set the label format of the y-axis label to include a percentage sign $c->yAxis->setLabelFormat("{value}%"); #Add a title to the secondary y-axis $yAxis2Obj = $c->yAxis2(); $yAxis2Obj->setTitle("Frequency"); #Set the secondary y-axis label foramt to show no decimal point $yAxis2Obj = $c->yAxis2(); $yAxis2Obj->setLabelFormat("{value|0}"); #Set the relationship between the two y-axes, which only differ by a scaling #factor $c->syncYAxis(1 / $scaleFactor); #Output the chart header("Content-type: image/png"); print($c->makeChart2(PNG)); ?>