2 Visual Components Manuals

Introduction to Visual Components 2.3
3.3.8.34 Touch Screen Calibration − VA_StartTouchCal
The VA_StartTouchCal function provides touch calibration since different tolerances arise when touch screens
are manufactured.
3.3.8.34.1 Operation
Touch the crosses in the order that they appear on the screen.
This function only needs to be called once.
The status can also be queried with the VA_GetCalStatus function.
3.3.8.34.2 Parameter
I/O Parameter Type Meaning
IN enable BOOL This function is only executed if enable is TRUE.
IN VCHandle UDINT The handle returned by VA_Setup.
OUT Return Value UINT Not equal to 0 if error occurs
3.3.8.34.3 Example for Automation Basic
(* cyclic program *)
if ready 1 then
VC_HANDLE = VA_Setup(1 "vga") ,
if VC_HANDLE 0 then
ready = 1
endif
endif
if ready = 1 then
if VA_Saccess(1,VC_HANDLE)= 0 then
VA_StartTouchCal (1,VC_HANDLE)
VA_Srelease(1,VC_HANDLE)
endif
endif
3.3.8.34.4 Example for C Programming
#include
#include
#include
UINT _GLOBAL ready;
unsigned long VC_HANDLE;
_CYCLIC void Initialization (void)
{
if (!ready)
{
VC_HANDLE = VA_Setup(1 "vga"); ,
if (VC_HANDLE)
ready = 1;
}
if (ready)
{
if (!VA_Saccess(1,VC_HANDLE))
{
VA_StartTouchCal (1,VC_HANDLE);
VA_Srelease(1,VC_HANDLE);
}
}
}
3.3.8.35 Manual Project Control − VA_StopProject
A project can be halted with the VA_StopProject function. This seldom needs to be done unless parameters
need to be changed for used drivers with the VA_SetUserParam function, for example.
3.3.8.34 Touch Screen Calibration − VA_StartTouchCal 169