HDevelop User's Manual

2.6. VARIABLE WINDOW 53
operator have to be calculated. In case the È is placed at or after the insertion position,
this operator is executed only. Before execution the operator is entered into the program
window. The È and the insertion cursor are positioned after the new operator. The
computed output parameter values are displayed in the variable window. Iconic variables
are shown in the current graphics window, if you haven’t suppressed this option (see page
24). Afterwards the operator window is cleared. If you did not specify all parameters or
if you used wrong values, an error dialog is raised and execution is canceled. In this case,
the operator window remains open to support appropriate changes.
ÒØÖ
By clicking the button ÒØÖ the program line is only transferred in the program window.
There is no operator execution, i.e., the position of the È is not changed. The insertion
cursor is positioned after the new operator.
ÔÔÐÝ
If you click ÔÔÐÝ the operator is executed with the specified parameters, but not entered
into or changed in the program. This enables you to determine the optimum parameters
of an operator rapidly since the operator dialog remains open, and hence you can change
parameters quickly. Unlike the button ÇÃ, only the single line you edit or enter is executed,
no matter where the È is located. Thus, you have to ensure that all the input variables
contain maningful values. By pressing ÔÔÐÝ, the corresponding output variables are
changed or created, if necessary, to allow you to inspect their values. If you decide to
not enter the line into the program, some unused variables may thus be created. You can
easily remove them by selecting Ð º ÐÒÙÔ.
ÒÐ
Clicking ÒÐ clears the contents of the operator window. Thus, there are neither
changes in the program nor in any variables.
ÀÐÔ
Clicking ÀÐÔ invokes an appropriate help text for the selected operator. For this the
system activates an HTML-browser (see chapter 6.3).
2.6 Variable Window
There are two kinds of variables in HALCON. This corresponds to the two parameter types of
HALCON: iconic objects (images, regions, and XLDs) and control data (numbers, strings). In
HALCON the corresponding variables are called iconic and control variables. These variables
may possess a value or be undefined. An undefined variable is created, for example, when loading
a program or after inserting an operator with a new variable that is not executed immediately
into a program. You may access these undefined variables by writing them only. If you try to
read such a variable, a runtime error occurs. If a variable obtains a value, the variable type is
specified more precisely. A control variable that contains, for example, an integer is of type
ÒØÖ. This type might change after specification of new values for this variable to ÖÐ or
a tuple of ÒØÖ. But it always remains a control variable. The more refined type is bound
to the value and not to the variable. Similarly, this is the case for iconic variables, which may
contain regions, images, or XLDs. You may assign new values as often as you want to. But you
cannot change them to the state before the first assignment (see above).
HALCON 6.0