gets miter normals for a 2D polyline
npm install polyline-normals
!img
Computes the normals of a polyline, using miter joins where multiple segments meet. This is mainly useful to expand thick lines in a vertex shader on the GPU.
``js
var getNormals = require('polyline-normals')
//a triangle
var path = [ [0, 122], [0, 190], [90, 190] ]
//get the normals as a closed loop
var normals = getNormals(path, true)
//now draw our thick line in 2D/3D/etc
`
See the 2d test for an example of how these lines would be extruded.
For more complex line joins and end caps, see extrude-polyline (which builds an indexed mesh).
For an example of how to use this within a shader, see three-line-2d.
#### normals(path[, closed])
For the given path, produces a new array of the same length with normal information for each point. The data contains a normal, [nx, ny] and the length of the miter (default to 1.0 where no join occurs).
`js`
[
[ [nx, ny], miterLength ],
[ [nx, ny], miterLength ]
]
If closed` is true, it assumes a segment will be drawn from the last point to the first point, and adjusts those normals accordingly.
MIT, see LICENSE.md for details.