This example illustrates some of the background effects supported by ChartDirector.

ChartDirector supports the use of an image file as the wallpaper of the entire chart background and/or as the background of the plot area only. The former is by using BaseChart.setWallpaper. The latter is by using the PlotArea.setBackground2.

In addition to wallpapers, ChartDirector also supports different kinds of background colors. The plot area background can be alternately colored using PlotArea.setBackground. You can also switch to a dark background with white lines and text in one step by changing the color palette to a whiteOnBlackPalette using BaseChart.setColors.

[File: phpdemo/background.php".]

<?php require_once("../lib/phpchartdir.php"); #The data for the chart $data = array(85, 156, 179.5, 211, 123); $labels = array("Mon", "Tue", "Wed", "Thu", "Fri"); #Create a XYChart object of size 270 x 270 pixels $c = new XYChart(270, 270); #Set the plot area at (40, 32) and of size 200 x 200 pixels $plotarea = $c->setPlotArea(40, 32, 200, 200); #Set the background style based on the input parameter if ($HTTP_GET_VARS["img"] == "0") { #Has wallpaper image $c->setWallpaper(dirname(__FILE__)."/tile.gif"); } else if ($HTTP_GET_VARS["img"] == "1") { #Use a background image as the plot area background $plotarea->setBackground2(dirname(__FILE__)."/bg.png"); } else if ($HTTP_GET_VARS["img"] == "2") { #Use white (0xffffff) and grey (0xe0e0e0) as two alternate plotarea #background colors $plotarea->setBackground(0xffffff, 0xe0e0e0); } else { #Use a dark background palette $c->setColors($whiteOnBlackPalette); } #Set the labels on the x axis $c->xAxis->setLabels($labels); #Add a color bar layer using the given data. Use a 1 pixel 3D border for the #bars. $barLayer3Obj = $c->addBarLayer3($data); $barLayer3Obj->setBorderColor(-1, 1); #output the chart header("Content-type: image/png"); print($c->makeChart2(PNG)); ?>

Argument	Default	Description
topExtension	0.1	The top portion of the axis that no data point should fall into. For example, a value of 0.2 means no data value will fall within the top 20% of the axis. The topExtension must be between 0 to 1.
bottomExtension	0.1	The bottom portion of the axis that no data point should fall into. For example, a value of 0.2 means no data value will fall within the bottom 20% of the axis. The bottomExtension must be between 0 to 1.
zeroAffinity	0.8	The tendency of ChartDirector to include zero in the axis during auto-scaling. The value must be between 0 and 1. A large value encourages ChartDirector to start the axis from zero. A value of 1 means the axis always includes the zero point. A value of 0 means there is no preference for the zero point during auto-scaling.

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