2 Visual Components Manuals

Introduction to Visual Components 2.3
4.11.12 General/Drawing − VISAPI
This is an example of a small VISAPI program in the B&R Automation Basic programming language, followed by
an explanation:
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(* cyclic program *)
x1 = 100
y1 = 150
x2 = 250
y2 = 250
height = 40
width = 80
fill = 255 ; Transparent
color = 0 ; Black
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_Rect (1,VC_HANDLE,x1,y1,x2,y2,fill,color)
VA_Line (1,VC_HANDLE,x1,y1,x2,y2,color)
;Draws a rectangle
;Draws a line
VA_Ellipse(1,VC_HANDLE,x2,y2,heigth,width,fill,color) ;Draws an ellipse
VA_Textout (1,VC_HANDLE,1,100,100,color,fill,"a rectangle, a line and an ellipse");Outputs a te
VA_Srelease(1,VC_HANDLE)
EndIf
EndIf
This program draws a rectangle, a line, an ellipse, and outputs text. The following steps are required to do this:
Line(s) Description
3 − 10 Initializes variables
12 This flag stores whether the VISAPI has already been successfully initialized.
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Initializes the VISAPI and establishes the connection to the specifed project ('vga' in this example). If
the project name is valid and the VISAPI library is initialized, then a handle is returned which is stored
in the VC_HANDLE variable.
VC_HANDLE is valid, since it is 0. Therefore, the initialization flag can be set to 1 to prevent
repeated initializations and let the rest of the task continue.
19 Checks whether the VISAPI is initialized.
20 Calls VA_Saccess since drawing should now begin.
21 − 27 VA_Saccess did not return any errors, therefore drawing can take place.
29 After a successful VA_Saccess(...) call, VA_Srelease absolutely has to be called.
4.12 Tips and Tricks
Many functions are tightly integrated in Visual Components and can be used right away. This section gives more
information about additional Visual Components options.
Usually, only a few lines of code are necessary to implement striking effects and completely new functions.
4.12.1 A Few Tips
• Configuring a Help Picture
• Input Field Cursor Navigation
• Blinking Text (or Button)
4.11.12 General/Drawing − VISAPI 425