For controls that support scrolls, we need to know the max ctrl width and max ctrl height for scrolls values to make sense, since they are percentages.
`ctrlPosition _ctrl`
returns
`[x, y, w, h, maxW, maxH]`
Alternatively, add a new command that does this, since I'm not sure if this will break backward compatibility.
New command syntax:
```
getCtrlViewPort _ctrl
```
returns the visible part of the control, based on scroll values:
```
[x1, y1, x2, y2]
/*
[x1, y1]
______________
| |
|_____________|
[x2, y2]
*/
```
For controls that don't have sliders, it returns `[x, y, x + w, y + w]`
The coordinate values are relative to the control itself. E.g. if scroll values are 0, the top `[x1, y1]` is `[0, 0]`