FR: Use Page-turn buttons to increase/decrease widget settings

[Commodore64user]

Does your feature request involve difficulty completing a task? Please describe.
When using widgets like these ones, on non-touch devices. It is quite cumbersome to make multiple increases/decreases pressing the arrows (the ones in the UI not the physical keys). The one on the right is particularly nightmerish as it steps by one, shudders.

Describe the solution you'd like
Mapping the increment/decrement to the page turns buttons, so in this double case, left-pair of page turn buttons would control the columns, and the right-pair one the rows.

on single ones, either side would simply increase or decrease.

and yes, I am aware one can click on the number in the middle and input an exact value, but sometimes you want to see small differences.

[Commodore64user]

Note:

koreader/frontend/ui/widget/spinwidget.lua

Line 68 in e94550a

self.key_events.Close = { { Device.input.group.Back } }

koreader/frontend/ui/widget/numberpickerwidget.lua

Line 92 in e94550a

table.insert(self.layout, {button_up})

[comphilip]

@Commodore64user Hope I understand your idea properly. I tried to implement in spare time.

[Commodore64user]

technically this is not necessarily limited to NT but in practice it would be, so could we get an NT tag, please.