Push/pull (or drag) with increment ?

[TBoy]

In scripts when we drag with mouse, code looks like:

view.draw_line startPossition, endPossition

'start Position' is defined by click, 'end Position' is moving with mouse.
Is it possible while dragging mouse to snap on every next 0,5cm or 1cm (for example) instead of smooth dragging.
What code can I use to obtain such a behavior?

[sdmitch]

In scripts when we drag with mouse, code looks like:

view.draw_line startPossition, endPossition

'start Position' is defined by click, 'end Position' is moving with mouse.
Is it possible while dragging mouse to snap on every next 0,5cm or 1cm (for example) instead of smooth dragging.
What code can I use to obtain such a behavior?

Here is a simple example of how I would do it.

[TBoy]

Thank you !
Exactly as I wanted to be.