[Lazarus] ScrollBox and Touchscreen interaction

Ondrej Pokorny lazarus at kluug.net
Fri Apr 7 23:31:43 CEST 2017


On 07.04.2017 23:17, Sandro Cumerlato via Lazarus wrote:
> Current SVN trunk. Under Windows 10. Sorry for the missing info.

Mouse wheel messages are correctly passed through.

The problem is with touchpad double-finger scrolling because usually the 
mouse driver takes care of it - it finds the TWinControl (control with 
handle) under the mouse and scrolls it according to its scroll info. (At 
least it is what I experienced with my Dell touchpad when I worked on 
scrolling code.)

Currently I don't know how to solve it. Maybe there is a possibility to 
get touchpad scrolling passing through windows as well - I haven't done 
a thorough research yet. You can study the wheel message code in win32 
and maybe you find a way to get touchpad scrolling work the same way.

The idea behind the process is easy - if you cannot scroll the window, 
scroll recursively its parent (that can be scrolled).

Ondrej


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