SVGGraph options: data_label_callback

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Option name:
data_label_callback
Default value:
NULL
Added in version:
2.18.1
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).

array
An array(), the number and data types of its members will depend on the option for which is it used.
boolean
A boolean TRUE or FALSE value, or any values that convert easily such as 1, "1", 0 and "".
callback
A callable function, which can be either the name of a function or an anonymous function itself.
colour
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.
fill
A colour value or one of the gradients and patterns supported by SVGGraph. See the SVGGraph colours page for details.
integer
A negative or positive whole number or 0.
number
Any number supported by PHP, for example 1 or -3.2 or 1.63e5 or M_PI.
string
Single or double quoted strings. Remember to double-quote your strings if you are inserting a line break: "Line 1\nLine 2".
Per-dataset:
no
Supported by:
ArrayGraph Bar3DGraph BarAndLineGraph BarGraph BoxAndWhiskerGraph BubbleGraph CandlestickGraph CylinderGraph Donut3DGraph DonutGraph EmptyGraph ExplodedDonut3DGraph ExplodedDonutGraph ExplodedPie3DGraph ExplodedPieGraph ExplodedSemiDonut3DGraph ExplodedSemiDonutGraph FloatingBarGraph GanttChart GroupedBar3DGraph GroupedBarGraph GroupedCylinderGraph Histogram HorizontalBar3DGraph HorizontalBarGraph HorizontalFloatingBarGraph HorizontalGroupedBar3DGraph HorizontalGroupedBarGraph HorizontalStackedBar3DGraph HorizontalStackedBarGraph LineGraph MultiLineGraph MultiRadarGraph MultiScatterGraph MultiSteppedLineGraph Pie3DGraph PieGraph PolarArea3DGraph PolarAreaGraph PopulationPyramid RadarGraph ScatterGraph SemiDonut3DGraph SemiDonutGraph StackedBar3DGraph StackedBarAndLineGraph StackedBarGraph StackedCylinderGraph StackedGroupedBar3DGraph StackedGroupedBarGraph StackedGroupedCylinderGraph StackedLineGraph SteppedLineGraph
Tags:
global label callback data-label

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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