2 Visual Components Manuals

Introduction to Visual Components 2.3
The fixed position of the HotSpot in the key grid is assigned in the dialog box. This allows the old key matrix to
be reestablished.
This method is somewhat elaborate and is only meant as a transition.
In the long term, the project should be changed to use button and HotSpot technology.
4.14.2.2 Calculating the Key Matrix
Another possibility exists to convert old matrix information by reading the matrix position using the VISAPI. The
VA_GetTouchAction() function from the VISAPI Library
The following is an excerpt of code for converting the key matrix for a VGA display. This only applies for a VGA
display. For 1/4 VGA, calculation takes place using lines and columns.
#include
#include #include "visapi.h" #define T_SIZE 192 /* VGA 40x40 pixel array
from 640x480*/ UINT _LOCAL ready; TouchAction _GLOBAL touch; UDINT _GLOBAL x_position; UDINT
_GLOBAL y_position; USINT _GLOBAL touch_status; _GLOBAL unsigned char KeyMatrix[T_SIZE]; _GLOBAL
unsigned long VC_HANDLE; _CYCLIC void Cyclic(void) { int lines; int columns; int offset; if (!ready) {
VC_HANDLE = VA_Setup(1 , "display"); /* VC project name */ if (VC_HANDLE) ready = 1; } if (ready) {
if (!VA_Saccess(1,VC_HANDLE)) { VA_GetTouchAction (1,VC_HANDLE,&touch); VA_Srelease(1,VC_HANDLE);
x_position = touch.x + 1; y_position = touch.y + 1; touch_status = touch.status; if(touch_status ==
2) /* Nothing pressed */ memset(KeyMatrix,0,T_SIZE); else { /* Columns */ columns = (x_position /
40); /* Lines */ lines = (y_position / 40); offset = (columns + (lines*16)); /* Since 16 columns per
line (640/40)*/ if(offset < T_SIZE) KeyMatrix[offset] = 1; /* Current touch field */ else
memset(KeyMatrix,0,T_SIZE); /* Error */ } } } }
Tip:
This new VISAPI function permits an exact pixel evaluation of the pressed coordinates.
4.14.2.2 Calculating the Key Matrix 447