Function scaleFromMidpoint

scaleFromMidpoint(line: Geometry.Line, factor: number): Geometry.Line
Scales a line from its midpoint
Parameters
- line: Geometry.Line
- factor: number
Returns Geometry.Line
Example: Shorten by 50%, anchored at the midpoint
```
import { Lines } from 'https://unpkg.com/ixfx/dist/geometry.js'
const l = {
 a: {x:50, y:50}, b: {x: 100, y: 90}
}
const l2 = Lines.scaleFromMidpoint(l, 0.5);
```