Function pointScaler

pointScaler(
    reference?: PointSpaces,
): (
    a: Readonly<number | number[] | Geometry.Point>,
    b?: number,
) => Readonly<{ x: number; y: number }>
Convert an absolute point to relative, in different coordinate spaces.

When calling the returned function, the input value must be in the same scale as the intended output scale.

Viewport-relative is used by default.
Parameters
- reference: PointSpaces = ...
Returns (
a: Readonly<number | number[] | Geometry.Point>,
b?: number,
) => Readonly<{ x: number; y: number }>
Example: Get relative position of click in screen coordinates
```
const f = pointScaler({ to: 'screen' });
document.addEventListener('click', evt => {
 const screenRelative = f(evt.screenX, evt.screenY);
 // Yields {x,y} on 0..1 scale
});
```
Example: Get relative position of click in viewport coordinates
```
const f = pointScaler({ to: 'viewport' });
document.addEventListener('click', evt => {
 const viewportRelative = f(evt.clientX, evt.clientY);
 // Yields {x,y} on 0..1 scale
});
```
Example: Get relative position of click in document coordinates
```
const f = pointScaler({ to: 'document' });
document.addEventListener('click', evt => {
 const documentRelative = f(evt.pageX, evt.pageY);
 // Yields {x,y} on 0..1 scale
});
```