This example demonstates using y zone colors - colors that change at certain y value thresholds.

In this example, a y zone color is used as the fill color of an area layer, so that the area fill color changes above a certain threshold.

Y zone colors are created using Layer.yZoneColor. You can use a y zone color in any ChartDirector API that expects a color. For instance, you can use a y zone color as background color, fill color of data sets, line color, etc.

A single y zone color can support one threshold value and change between two colors. The two colors can be any colors, including another y zone colors. You may create y zone colors with multiple thresholds by cascading multiple y zone colors this way.

[File: phpdemo/yzonecolor.php".]

<?php require_once("../lib/phpchartdir.php"); #The data for the 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 chart $labels = array("0", "", "", "3", "", "", "6", "", "", "9", "", "", "12", "", "", "15", "", "", "18", "", "", "21", "", "", "24"); #Create a XYChart object of size 500 x 300 pixels, with a pale yellow (0xffffc0) #background, a black border, and 1 pixel 3D border effect $c = new XYChart(500, 300, 0xffffc0, 0x0, 1); #Set directory for loading images to current script directory #Need when running under Microsoft IIS $c->setSearchPath(dirname(__FILE__)); #Set the plotarea at (55, 50) and of size 420 x 205 pixels, with white #background. Turn on both horizontal and vertical grid lines with light grey #color (0xc0c0c0) $plotAreaObj = $c->setPlotArea(55, 50, 420, 205, 0xffffff); $plotAreaObj->setGridColor(0xc0c0c0, 0xc0c0c0); #Add a legend box at (55, 25) (top of the chart) with horizontal layout. Use 8 #pts Arial font. Set the background and border color to Transparent. $legendBox = $c->addLegend(55, 25, false, "", 8); $legendBox->setBackground(Transparent); #Add keys to the legend box to explain the color zones $legendBox->addKey("Normal Zone", 0x8033ff33); $legendBox->addKey("Alert Zone", 0x80ff3333); #Add a title box to the chart using 13 pts Arial Bold Italic font. The title is #in CDML and includes embedded images for highlight. The text is white #(0xffffff) on a black background, with a 1 pixel 3D border. $titleObj = $c->addTitle( "<*block,valign=absmiddle*><*img=star.png*><*img=star.png*> Y Zone Color ". "Demo <*img=star.png*><*img=star.png*><*/*>", "arialbi.ttf", 13, 0xffffff); $titleObj->setBackground(0x0, -1, 1); #Add a title to the y axis $c->yAxis->setTitle("Energy Concentration (KJ per liter)"); #Set the labels on the x axis $c->xAxis->setLabels($labels); #Add a title to the x axis using CDML $c->xAxis->setTitle( "<*block,valign=absmiddle*><*img=clock.png*> Elapsed Time (hour)<*/*>"); #Set the axes width to 2 pixels $c->xAxis->setWidth(2); $c->yAxis->setWidth(2); #Add an area layer to the chart. The area is using a y zone color, where the #color is semi-transparent green below 60, and semi-transparent red above 60. $layer = $c->addAreaLayer2(); $layer->addDataSet($data, $layer->yZoneColor(60, 0x8033ff33, 0x80ff3333)); #Add a custom CDML text at the bottom right of the plot area as the logo $textObj = $c->addText(475, 255, "<*block,valign=absmiddle*><*img=small_molecule.png*> <*block*>". "<*font=timesbi.ttf,size=10,color=804040*>Molecular\nEngineering<*/*>"); $textObj->setAlignment(BottomRight); #output the chart header("Content-type: image/png"); print($c->makeChart2(PNG)); ?>