This example shows a bubbles plot. A data array for a bubbles plot uses the data-data-xyz data type, in which three coordinate values specify each point: X and Y are the position on the plot, and Z maps to the bubble diameter.
In this example, X is the flavor, Y is the age group, and Z represents the percentage of participants who liked that flavor. Note that there are two missing points in the Y=1 row. No bubbles are drawn at X=3,Y=1 or X=5,Y=1. Presumably, no-one under 12 would try the pear or kiwi flavors, so there are no valid data points there. This is different from a value Z=0, which would be plotted with a bubble of the smallest size.
This plot type was added in PHPlot-5.5.0.
This example also shows the use of custom Y labels. A function
get_label() is defined to map the Y tick value
into a string from an array of strings. This method allows the display
of arbitrary labels along the Y axis.
See SetYLabelType for details.
Example 5.40. Bubbles Plot
<?php
# PHPlot Example - Bubble Plot
require_once 'phplot.php';
# Array of custom labels for the Y axis. See the get_label callback.
$y_labels = array("", "Age\n12 and under", "Age 13-17", "Age 18-29",
"Age 30-39", "Age 40-54", "Age\n55 and older");
# Return the string for a Y label:
function get_label($value, $labels)
{
if (isset($labels[(int)$value])) return $labels[(int)$value];
return $value;
}
# <=12 13-17 17-28 30-39 40-54 >=55
$data = array(
array('Cherry', 1, 1, 2, 2, 4, 3, 3, 4, 3, 5, 5, 6, 6),
array('Apple', 2, 1, 9, 2, 7, 3, 4, 4, 7, 5, 3, 6, 7),
array('Pear', 3, '', 2, 2, 2, 3, 3, 4, 4, 5, 3, 6, 2),
array('Grape', 4, 1, 8, 2, 5, 3, 5, 4, 6, 5, 3, 6, 4),
array('Kiwi', 5, '', 0, 2, 3, 3, 4, 4, 4, 5, 5, 6, 2),
array('Banana', 6, 1, 5, 2, 4, 3, 6, 4, 3, 5, 3, 6, 4),
);
$plot = new PHPlot(600, 600);
$plot->SetTitle("Flavor Preference By Age Group");
$plot->SetDataType('data-data-xyz');
$plot->SetDataValues($data);
$plot->SetPlotType('bubbles');
$plot->SetDataColors('yellow'); // Use same color for all data sets
$plot->SetDrawPlotAreaBackground(True);
$plot->SetPlotBgColor('plum');
$plot->SetLightGridColor('red'); // Change grid color to make it visible
$plot->SetImageBorderType('plain');
$plot->SetPlotBorderType('full');
$plot->SetXTickIncrement(1); // For grid line spacing
$plot->SetYTickIncrement(1);
$plot->SetPlotAreaWorld(0, 0, 6.5, 6.5);
# Establish the handler for the Y label text:
$plot->SetYLabelType('custom', 'get_label', $y_labels);
$plot->SetXTickPos('both'); // Tick marks on both sides
$plot->SetYTickPos('both'); // Tick marks on top and bottom too
$plot->SetXDataLabelPos('both'); // X axis data labels top and bottom
$plot->SetYTickLabelPos('both'); // Y axis labels left and right
$plot->SetDrawXGrid(True);
$plot->DrawGraph();