Master's Thesis - Computer Graphics and Visualization - TU Delft

3.5.2 Various widgets to display a module’s parameters
In the design of the Culgi GPE, we use different types of widgets to display different parameters in a
module. The purpose is to reduce the user’s errors. This design is explained in three aspects.
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1) Using different widgets for different parameter types.
The widget type used for a parameter is determined by the data type of this parameter. There are three
advantages. First, the widget type of a parameter could hint the users what kind of value is expected in
this parameter. So the users’ understanding could be increased. Second, each widget type can have its
own bound checking function. When users make errors when typing, the system will warn the users by
showing the background in different color (pink in this prototype) or by some sound. This could reduce
some errors such as the value is out of range or the value is not of the expected type. Third, some
widget type itself can reduce typos. For example, the widget combobox generally used in single
selection is used when the data type of the parameter is “enum”. So the users can choose one valid
selection by clicking instead of typing in.
2) Use selection other than typing in some cases
One feature of the Culgi commands is that some commands take the same arguments, as pointed out as
one feature of the Culgi library in Chapter 2. So it is possible that the value of a parameter in a module
refers to the value of a parameter in another module. It will be handy if users can select the value of this
parameter instead of typing in (because the value has been defined in another module). Selection can
not only reduce typing errors, but also hint the users that what should the value be in this parameter.
Figure 3-5 shows two types of selection. As shown in Figure 3-5 (a), the value of parameter
DPDMolecules in module AddDPDMoleculesViewable, determines which molecules will be shown on
the screen. It needs the values from Parameter Name of CreateDPDMolecules. Users can choose one,
both or none of these two types of molecules to be visible. So the system just supplies checkbox for
multi selection widget. But Figure 3-5 (b) is a different case. It is a single selection Case. That is to say,
users can and only can select one. So the system just supplies a widget for single selection.
3) keep consistent automatically
Suppose, in the case of Figure 3-5 a user selected box1 first. Then the user changed the value ‘box1’
into another value like ‘box3’ in module ‘Box’. If the user forget to change the corresponding value in
Module CreateDPDMolecules, an error would happened when the program starts running.
Thus the system should keep the name consistent automatically. That is to say, the system will make
sure that if the definition is changed, the reference will also be changed. This mechanism is hidden for
users.
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