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4.2. CODE GENERATION FOR VISUAL BASIC
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and control variables belong to Variant. The subroutine RunHalcon() has a parameter Window
which is of type HWindowX. This is the link to the window in the panel where all output operations are passed to.
Depending on the program, additional subroutines and variables are declared.
4.2.2.1
Array Assignment
If a single value is assigned to a variant array, a special subroutine is called to ensure that the
index is valid. If the array is to small it is resized.
4.2.2.2
Expressions
All parameter expression inside HDevelop are translated into expressions based on the HALCON tuple operators. Therefore, an expression might look somewhat complex. In many cases
these expressions can be changed to simple Visual Basic expressions, like tuple sub becomes
a simple subtraction. To ensure that the exported program has the same effect in Visual Basic
this exchange is not applied automatically, because the semantic is not always identical.
4.2.2.3
Stop
The HDevelop operator stop is translated into a subroutine in Visual Basic which creates a
message box. This message box causes the program to halt until the button is pressed.
4.2.2.4
Exit
The HDevelop operator exit is translated into the Visual Basic routine End. Because this
routine has no parameter the parameters of exit are suppressed.
4.2.2.5
Used Classes
There are only six classes/types that are used: Variant for control parameters and
HUntypedObjectX for iconic data. In addition, there is the container class HTupleX which
comprises all operators of HALCON processing tuples, in this case the data type Variant.
Then, there are the classes HWindowXCtrl and its low level content HWindowX. HWindowXCtrl
is used inside the project for the output window and a variable of class HWindowX directs the
output to this window. Finally, the class HOperatorSetX is used as a container for all HALCON
operators. There is no need for other classes as long as the program has the same functionality
as in HDevelop. When editing a generated program you are free to use any of the classes of
HALCON/COM to extend the functionality.
4.2.3
Limitations and Troubleshooting
Besides the restrictions mentioned in this section and in section 4.4, please also check the description of the HDevelop operators on page 38.
HALCON 6.0.4