Lazarus

Programming => LCL => Topic started by: dsiders on January 10, 2019, 01:36:35 pm

Title: [SOLVED] How to detect touchscreen?
Post by: dsiders on January 10, 2019, 01:36:35 pm

I am wondering how to detect if a touch-enabled device is attached during form creation/display. It is needed to adjust font and control sizes and alignment for UI controls that are just too small for touch usage.

Any ideas? Neither Google nor Forum Search were very helpful on this topic.

Thanks in advance.

Title: Re: How to detect touchscreen?
Post by: tr_escape on January 10, 2019, 02:25:42 pm

Maybe this can be help for windows:

https://stackoverflow.com/questions/20923853/why-i-cant-detect-touch-screen (https://stackoverflow.com/questions/20923853/why-i-cant-detect-touch-screen)

and related:

https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-getsystemmetrics (https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-getsystemmetrics)

Note : I never used yet

Title: Re: How to detect touchscreen?
Post by: Josh on January 10, 2019, 02:27:17 pm

Hi

Windows getsystemmetrics maybe the route to go.

I have not tested; but should be ok.

Code: [Select]

VAR Touch_Screen_Enabled:Boolean=True;
begin
  Touch_Screen_Enabled:=GetSystemMetrics(SM_MAXIMUMTOUCHES)>0;                                   
note need to add windows to uses

Title: Re: How to detect touchscreen?
Post by: dsiders on January 10, 2019, 02:49:17 pm

Quote from: josh on January 10, 2019, 02:27:17 pm

Windows getsystemmetrics maybe the route to go.

I have not tested; but should be ok.

Code: [Select]

VAR Touch_Screen_Enabled:Boolean=True;
begin
  Touch_Screen_Enabled:=GetSystemMetrics(SM_MAXIMUMTOUCHES)>0;                                   
note need to add windows to uses

Thanks Josh. This does in fact work for Windows. Looks like lcltype.pp needs a refresh though... it doesn't have some the SM_* values from the MSDN docs.

Now I need to poke around and see how Linux handles this.

Thanks again.

Title: Re: How to detect touchscreen?
Post by: dsiders on January 10, 2019, 03:47:16 pm

Quote from: dsiders on January 10, 2019, 02:49:17 pm

Now I need to poke around and see how Linux handles this.

So far, all I have found that seems remotely distro-independent is capturing output from udevadm info. The search continues...