ChartDirector Ver 5.0 (PHP Edition)

4 Quadrant Chart

This example demonstrates 4 quadrant charts in which the x-axis and y-axis meet at the origin at the center of the plot area.
By default, ChartDirector puts the axes at the border of the plot area. This avoids the axis labels and the chart contents from overlapping and making the chart hard to read.
In some cases, it may be desirable to have one or both axes to intersect with the zero point of the other axis, where the zero point can be inside the plot area. In ChartDirector, these kinds of axis configurations may be set up with XYChart.setAxisAtOrigin.
This example also demonstrates using PlotArea.set4QBgColor to specify 4 background colors for the 4 quadrants.

Source Code Listing

[File: phpdemo/fourq.php]

    <?php
    require_once("../lib/phpchartdir.php");

    # XY points for the scatter chart
    $dataX0 = array(10, 15, 6, -12, 14, -8, 13, -13, 16, 12, 10.5);
    $dataY0 = array(130, 150, 80, 110, -110, -105, -130, 115, -170, 125, 125);

    $dataX1 = array(6, 7, -4, 3.5, 7, 8, -9, -10, -12, 11, 8);
    $dataY1 = array(65, -40, -40, 45, -70, -80, 80, 10, -100, 105, 60);

    $dataX2 = array(-10, -12, 11, 8, 6, 12, -4, 3.5, 7, 8, -9);
    $dataY2 = array(65, -80, -40, 45, -70, -80, 80, 90, -100, 105, 60);

    # Create a XYChart object of size 600 x 300 pixels, with a light blue (ccccff)
    # background, a black border, and 1 pixel 3D border effect
    $c = new XYChart(600, 480, 0xccccff, 0x000000, 1);

    # Add a title box to the chart using 16 pts Arial Bold Italic font, with white text
    # on deep blue background
    $textBoxObj = $c->addTitle("Four Quadrant Chart Demonstration", "arialbi.ttf", 16,
        0xffffff);
    $textBoxObj->setBackground(0x000080);

    # Set the plotarea at (20, 60) and of size 560 x 360 pixels, with grey (808080)
    # border, and light grey (c0c0c0) horizontal and vertical grid lines. Set 4 quadrant
    # coloring, where the colors of the quadrants alternate between lighter and deeper
    # grey (dddddd/eeeeee)
    $plotAreaObj = $c->setPlotArea(20, 60, 560, 360, -1, -1, 0x808080, 0xc0c0c0, 0xc0c0c0
        );
    $plotAreaObj->set4QBgColor(0xdddddd, 0xeeeeee, 0xdddddd, 0xeeeeee);

    # Set 4 quadrant mode, with both x and y axes symetrical around the origin
    $c->setAxisAtOrigin(XYAxisAtOrigin, XAxisSymmetric + YAxisSymmetric);

    # Add a legend box at (300, 460) (bottom center of the chart) with horizontal layout.
    # Use 8 pts Arial Bold font.
    $legendBox = $c->addLegend(300, 460, false, "arialbd.ttf", 8);
    $legendBox->setAlignment(BottomCenter);

    # Set legend box background to light grey (dddddd) with a black border
    $legendBox->setBackground(0xdddddd, 0);

    # Set left/right margin to 20 pixels and top/bottom margin to 5 pixels
    $legendBox->setMargin2(20, 20, 5, 5);

    # Add a titles to axes
    $c->xAxis->setTitle("Alpha Index");
    $c->yAxis->setTitle("Beta Index");

    # Set axes width to 2 pixels
    $c->xAxis->setWidth(2);
    $c->yAxis->setWidth(2);

    # Add scatter layer, using 15 pixels red (ff33333) X shape symbols
    $c->addScatterLayer($dataX0, $dataY0, "Group A", Cross2Shape(), 15, 0xff3333);

    # Add scatter layer, using 15 pixels green (33ff33) 6-sided polygon symbols
    $c->addScatterLayer($dataX1, $dataY1, "Group B", PolygonShape(6), 15, 0x33ff33);

    # Add scatter layer, using 15 pixels blue (3333ff) triangle symbols
    $c->addScatterLayer($dataX2, $dataY2, "Group C", TriangleSymbol, 15, 0x3333ff);

    # Output the chart
    header("Content-type: image/png");
    print($c->makeChart2(PNG));
    ?>

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