ChartDirector Ver 5.0 (PHP Edition)

X Zone Coloring

This example demonstrates using x zone colors - colors that change at certain x value thresholds.
In this example, a x zone colors are used as the color of the line, and as the fill color of the band surrounding the line.
The x zone color for the line is configured to change from solid blue color to a red dash line color upon reaching a certain x value threshold. The x zone color for the band is configured to change from semi-transparent blue to semi-transparent red upon reaching the same threshold.
X zone colors are created using Layer.xZoneColor. You can use a x zone color in any ChartDirector API that expects a color. For instance, you can use a x zone color as background color, fill color of data sets, line color, etc.
A single x zone color can support one threshold value and change between two colors. The two colors can be any colors, including another x zone color. You may create x zone colors with multiple thresholds by cascading multiple x zone colors this way.

Source Code Listing

[File: phpdemo/xzonecolor.php]

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

    # The data for the chart
    $data = array(50, 55, 47, 34, 42, 49, 63, 62, 73, 59, 56, 50, 64, 60, 67, 67, 58, 59,
        73, 77, 84, 82, 80, 84, 89);

    # The error data representing the error band around the data points
    $errData = array(5, 6, 5.1, 6.5, 6.6, 8, 5.4, 5.1, 4.6, 5.0, 5.2, 6.0, 4.9, 5.6, 4.8,
        6.2, 7.4, 7.1, 6.5, 9.6, 12.1, 15.3, 18.5, 20.9, 24.1);

    # The timestamps for the data
    $labels = array(chartTime(2001, 1, 1), chartTime(2001, 2, 1), chartTime(2001, 3, 1),
        chartTime(2001, 4, 1), chartTime(2001, 5, 1), chartTime(2001, 6, 1), chartTime(
        2001, 7, 1), chartTime(2001, 8, 1), chartTime(2001, 9, 1), chartTime(2001, 10, 1
        ), chartTime(2001, 11, 1), chartTime(2001, 12, 1), chartTime(2002, 1, 1),
        chartTime(2002, 2, 1), chartTime(2002, 3, 1), chartTime(2002, 4, 1), chartTime(
        2002, 5, 1), chartTime(2002, 6, 1), chartTime(2002, 7, 1), chartTime(2002, 8, 1),
        chartTime(2002, 9, 1), chartTime(2002, 10, 1), chartTime(2002, 11, 1), chartTime(
        2002, 12, 1), chartTime(2003, 1, 1));

    # Create a XYChart object of size 550 x 220 pixels
    $c = new XYChart(550, 220);

    # Set the plot area at (50, 10) and of size 480 x 180 pixels. Enabled both vertical
    # and horizontal grids by setting their colors to light grey (cccccc)
    $plotAreaObj = $c->setPlotArea(50, 10, 480, 180);
    $plotAreaObj->setGridColor(0xcccccc, 0xcccccc);

    # Add a legend box (50, 10) (top of plot area) using horizontal layout. Use 8 pts
    # Arial font. Disable bounding box (set border to transparent).
    $legendBox = $c->addLegend(50, 10, false, "", 8);
    $legendBox->setBackground(Transparent);

    # Add keys to the legend box to explain the color zones
    $legendBox->addKey("Historical", 0x9999ff);
    $legendBox->addKey("Forecast", 0xff9966);

    # Add a title to the y axis.
    $c->yAxis->setTitle("Energy Consumption");

    # Set the labels on the x axis
    $c->xAxis->setLabels2($labels);

    # Set multi-style axis label formatting. Use Arial Bold font for yearly labels and
    # display them as "yyyy". Use default font for monthly labels and display them as
    # "mmm". Replace some labels with minor ticks to ensure the labels are at least 3
    # units apart.
    $c->xAxis->setMultiFormat(StartOfYearFilter(), "<*font=arialbd.ttf*>{value|yyyy}",
        StartOfMonthFilter(), "{value|mmm}", 3);

    # Add a line layer to the chart
    $layer = $c->addLineLayer2();

    # Create the color to draw the data line. The line is blue (0x333399) to the left of
    # x = 18, and become a red (0xd04040) dash line to the right of x = 18.
    $lineColor = $layer->xZoneColor(18, 0x333399, $c->dashLineColor(0xd04040, DashLine));

    # Add the data line
    $layer->addDataSet($data, $lineColor);

    # Create the color to draw the err zone. The color is semi-transparent blue
    # (0x809999ff) to the left of x = 18, and become semi-transparent red (0x80ff9966) to
    # the right of x = 18.
    $errColor = $layer->xZoneColor(18, 0x809999ff, 0x80ff9966);

    # Add the upper border of the err zone
    $upperBorder = new ArrayMath($data);
    $upperBorder->add($errData);
    $layer->addDataSet($upperBorder->result(), $errColor);

    # Add the lower border of the err zone
    $lowerBorder = new ArrayMath($data);
    $lowerBorder->sub($errData);
    $layer->addDataSet($lowerBorder->result(), $errColor);

    # Set the default line width to 2 pixels
    $layer->setLineWidth(2);

    # Color the region between the err zone lines
    $c->addInterLineLayer($layer->getLine(1), $layer->getLine(2), $errColor);

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

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