label-segment

Find suitable segments of a path for its label text.

Getting started

The ES2015 way

To add the dependency to your project, run

npm install --save label-segment

To use in your code, type

import labelSegment from 'label-segment';

The vanilla JavaScript way

Include the following script tag in your HTML:

<script src="http://unpkg.com/label-segment/dist/label-segment.js"></script>

API

labelSegment

Considering a given path, maximum angle and label length, this function returns a straight enough subset of the path in correct direction for an upright label.

Example:

var path = [[20, 33], [40, 31], [60, 30], [80, 31], [100, 33]];
var textLength = 50; // Text has a width of 50 pixels
var textPath = labelSegment(path, Math.PI / 8, 50);
// Now render text along textPath

Parameters

• path Array<Array<number>> Path represented by coordinate pairs.
• maxAngle number Maximum angle in radians for a suitable segment.
• labelLength number Required segment length for the label.

Returns (Array<Array<number>> | undefined) Path to draw the label along, in the correct direction for an upright label. Returns undefined when no suitable subset of the given path was found.