SVGGraph options: data_label_callback

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Option name:
Default value:
Added in version:
Data type:
callback [?]

The datatypes used in this documentation for specifying SVGGraph options are described below. All options can be a literal value of the data type described, a variable containing the data type, or an expression that will produce the data type when evaluated (and they must always be valid PHP expressions).

An array(), the number and data types of its members will depend on the option for which is it used.
A boolean TRUE or FALSE value, or any values that convert easily such as 1, "1", 0 and "".
A callable function, which can be either the name of a function or an anonymous function itself.
Any of the colour values supported by SVG inside a single or double quoted string. These include three and six digit hex codes, RGB and RGBA colours, and colour names. SVG uses "none" for no colour, which generally leaves things transparent.
A colour value or one of the gradients and patterns supported by SVGGraph. See the SVGGraph colours page for details.
A negative or positive whole number or 0.
Any number supported by PHP, for example 1 or -3.2 or 1.63e5 or M_PI.
Single or double quoted strings. Remember to double-quote your strings if you are inserting a line break: "Line 1\nLine 2".
no [?]

Per-dataset options allow specifying one option for all datasets or an array of options to be used for each dataset in turn. If there are more datasets than entries in the option array, the sequence will be repeated.


$settings['widget_taste'] = 'banana';
$settings['widget_colour'] = array('red', 'green', 'blue');

For this example, the widgets for all datasets will taste of banana. The graph will use red widgets for dataset 0, green widgets for dataset 1 and blue widgets for dataset 2. Dataset 3 repeats the sequence so its widgets will be red, dataset 4 will have green widgets and dataset 5 will have blue widgets.

Supported by:
Bar3DGraph BarAndLineGraph BarGraph BoxAndWhiskerGraph BubbleGraph CylinderGraph DonutGraph ExplodedPieGraph FloatingBarGraph GroupedBar3DGraph GroupedBarGraph GroupedCylinderGraph Histogram HorizontalBarGraph HorizontalFloatingBarGraph HorizontalGroupedBarGraph HorizontalStackedBarGraph LineGraph MultiLineGraph MultiRadarGraph MultiScatterGraph Pie3DGraph PieGraph PolarAreaGraph PopulationPyramid RadarGraph ScatterGraph SemiDonutGraph StackedBar3DGraph StackedBarGraph StackedCylinderGraph StackedGroupedBar3DGraph StackedGroupedBarGraph StackedGroupedCylinderGraph StackedLineGraph
global label callback

Callback function for data label text.

This option sets a function that SVGGraph will call to format the text for the data labels. The option can be the name of a function, or an anonymous function itself.

The function should have this signature:

function callback($dataset, $key, $value)

The arguments to the function are the dataset number of the data item, the key for the data item and the value of the data item. The function should return the text to display, or NULL to not display a label for the data item.

Here is an example using an anonymous function:

$settings['data_label_callback'] = function($d, $k, $v) {
  if($v < 1)
    return '< 1';
  if($v > 10)
    return NULL;
  return "Value: $v";

For this example, values greater than 10 will not be labelled, values less than 1 will all be labelled "< 1" and anything else will be labelled with the word "Value" followed by the actual value.

When set, the callback function takes precedence over data label values from structured data.

See also:
show_data_labels structure

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