ChartDirector 7.0 (PHP Edition)

Multi-Color Line Chart




This example demonstrates a line chart with line segments of different colors.

In this example, each line segment has a type specified in the pointType array. Note that with N data points, there will only be (N - 1) line segments. So the pointType array size is one less than the data point array size.

A loop is used to separate the line segments by type into different line layers, The line layers are configured with different colors and names. This generates the multi-color line and the legend entries.

Source Code Listing

[File: phpdemo/multicolorline.php]
<?php require_once("../lib/phpchartdir.php"); # Data points for the line chart $dataX = array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25); $dataY = 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, 70); # The data point type. The color of the line segment will be based on the starting point type of the # segment. In this example, we have 4 point types for 4 different colors. Note that for a line with # N points, there will be (N - 1) line segments, so we only need (N - 1) values in the point type # array. $pointType = array(0, 0, 0, 1, 1, 0, 2, 3, 1, 1, 0, 0, 1, 1, 2, 2, 2, 3, 3, 2, 0, 1, 2, 3, 3); $colors = array(0xff0000, 0x0066ff, 0xcc00cc, 0x00cc00); $pointTypeLabels = array("Alpha", "Beta", "Gamma", "Delta"); # Create a XYChart object of size 600 x 430 pixels $c = new XYChart(600, 430); # Set default text color to dark grey (0x333333) $c->setColor(TextColor, 0x333333); # Add a title box using grey (0x555555) 20pt Arial font $c->addTitle(" Multi-Color Line Chart", "Arial", 20, 0x555555); # Set the plotarea at (70, 70) and of size 500 x 300 pixels, with transparent background and border # and light grey (0xcccccc) horizontal grid lines $c->setPlotArea(70, 70, 500, 300, Transparent, -1, Transparent, 0xcccccc); # Add a legend box with horizontal layout above the plot area at (70, 35). Use 12pt Arial font, # transparent background and border, and line style legend icon. $b = $c->addLegend(70, 35, false, "Arial", 12); $b->setBackground(Transparent, Transparent); $b->setLineStyleKey(); # Set axis label font to 12pt Arial $c->xAxis->setLabelStyle("Arial", 12); $c->yAxis->setLabelStyle("Arial", 12); # Set the x and y axis stems to transparent, and the x-axis tick color to grey (0xaaaaaa) $c->xAxis->setColors(Transparent, TextColor, TextColor, 0xaaaaaa); $c->yAxis->setColors(Transparent); # Set the major/minor tick lengths for the x-axis to 10 and 0. $c->xAxis->setTickLength(10, 0); # For the automatic axis labels, set the minimum spacing to 80/40 pixels for the x/y axis. $c->xAxis->setTickDensity(80); $c->yAxis->setTickDensity(40); # Add a title to the y axis using dark grey (0x555555) 14pt Arial font $c->xAxis->setTitle("X-Axis Title Placeholder", "Arial", 14, 0x555555); $c->yAxis->setTitle("Y-Axis Title Placeholder", "Arial", 14, 0x555555); # In ChartDirector, each line layer can only have one line color, so we use 4 line layers to draw # the 4 different colors of line segments. # In general, the line segments for each color will not be continuous. In ChartDirector, # non-continuous line segments can be achieved by inserting NoValue points. To allow for these extra # points, we use a buffer twice the size of the original data arrays. $lineX = array_fill(0, count($dataX) * 2, 0); $lineY = array_fill(0, count($dataY) * 2, 0); # Use a loop to create a line layer for each color for($i = 0; $i < count($colors); ++$i) { $n = 0; for($j = 0; $j < count($dataX); ++$j) { # We include data points of the target type in the line layer. if (($j < count($pointType)) && ($pointType[$j] == $i)) { $lineX[$n] = $dataX[$j]; $lineY[$n] = $dataY[$j]; $n = $n + 1; } else if (($j > 0) && ($pointType[$j - 1] == $i)) { # If the current point is not of the target, but the previous point is of the target # type, we still need to include the current point in the line layer, as it takes two # points to draw a line segment. We also need an extra NoValue point so that the current # point will not join with the next point. $lineX[$n] = $dataX[$j]; $lineY[$n] = $dataY[$j]; $n = $n + 1; $lineX[$n] = $dataX[$j]; $lineY[$n] = NoValue; $n = $n + 1; } } # Draw the layer that contains all segments of the target color $layer = $c->addLineLayer(array_slice($lineY, 0, $n - 0), $colors[$i], $pointTypeLabels[$i]); $layer->setXData(array_slice($lineX, 0, $n - 0)); $layer->setLineWidth(2); } # Output the chart $viewer = new WebChartViewer("chart1"); $viewer->setChart($c, SVG); ?> <!DOCTYPE html> <html> <head> <title>Multi-Color Line Chart</title> <!-- Include ChartDirector Javascript Library to support chart interactions --> <script type="text/javascript" src="cdjcv.js"></script> </head> <body style="margin:5px 0px 0px 5px"> <div style="font:bold 18pt verdana;"> Multi-Color Line Chart </div> <hr style="border:solid 1px #000080; background:#000080" /> <div style="font:10pt verdana; margin-bottom:1.5em"> <a href="viewsource.php?file=<?=basename(__FILE__)?>">View Chart Source Code</a> </div> <!-- ****** Here is the chart image ****** --> <?php echo $viewer->renderHTML(); ?> </body> </html>