Chapter 5 - Creating Groups and Applications

A group is a collection of modules that serve a common purpose, sharing a single control panel and having some of the parameters of the constituent modules raised to the group level. From the viewpoint of the operating system, the constituent modules are still separate processes: from the user's point of view, however, they behave as a single entity.

You create groups of modules that are frequently used in combination, or that together form a unit of computation. For example, you might want to create a map that processes an image using four different parameters, each of which resides in a different module. When you wire all the modules into the map, you get the parameters you want as well as several others you don't need.

In this case, you can simplify the map by creating a group for the four image-processing modules. This reduces the apparent number of modules, and thus wires, on screen, as well as reducing the number of control panels and widgets.

To complete the new group control panel, select these parameters in the Group Editor:

• Sharpness from SharpenImg
• Bias from SobelEdgeImg
• Blend from BlendImg

Some ports may not be required by an individual module, but must be promoted once the module is part of a group, because there are connections to other modules in the map outside the group at the time of creating the group.

Suppose you select ReadLat, Contour, and WireFrame to make a group. The group has one outside connection, a hookup from GenerateColormap to Contour. The Colormap - - Lattice input port on Contour is not intrinsically a required port, but in the context of the new group, it becomes required because of its link to GenerateColormap. Hence, it is automatically promoted to a group-level port.

This principle also holds true for output ports. If a connection exists downstream of the group, the port with that connection is automatically promoted and indicated as selected in the Group Editor.

You cannot promote loop controller capability from the loop controller to a group module. If you want to link a grouped loop into another loop, you must include a separate loop controller module in the new loop.

Use the Group Editor to create a default layout.

To do this, click on the OK button at the bottom of the Group Editor window after you have selected the ports and parameters you want. This dismisses the Group Editor, applies the changes, and updates the Map Editor. In the process, it creates a default control panel for the group.

This is useful if the group does not have any parameters for which widgets are required, or if you can use all the default settings and layouts for selected parameters.

To display the full-scale control panel, click on the Maximize button, just as you would an ordinary module.

To open a group again, select Open from the Group menu. The original modules reappear with each module outlined in red.

While a group is opened you can interact with any of the widgets of the constituent modules to change their parameter settings.

If you have a nested hierarchy of groups, you may open all groups in the hierarchy. However you can use Edit only on a top level group, you cannot edit a group within a group. Therefore you should have finalised selecting promoted ports before including it within another group.

Click on the background to deselect the open group. To select one or more modules in the group hold down the <Shift> key and click on each module to toggle selection on and off. To select one module in the group, deselecting all other modules currently selected, hold down the <Alt> key and click on the module.

To close the group and display the group control panel again, select Close from the Group menu.

You can create and destroy connections within the opened group, those between modules belonging to the group. Use the port menus to create and destroy a connection as usual. When creating a connection you will see that compatible ports are highlighted only on modules within the group.

If you use the Disconnect and Reconnect options on these modules, only those connections between modules within the group are broken with Disconnect and recreated with Reconnect. Using Disconnect and Reconnect on a closed group breaks and recreates the connections from the promoted ports of the group, but not the connections internal to the group.

You cannot create a connection from inside the group to outside. You should promote the inside port to the group, using Edit on the closed group, and then connect selecting from the port menu of the closed group.

You will see when disconnecting to ports of modules within a group that the name of the module is preceeded by the name of the group to further identify the connection.

The control panel of the original group is retained, except that widgets corresponding to parameters from omitted modules are removed.

Settings for promoted ports and alias names are also retained. There may be additional required ports that are promoted from the new modules within the group. Note that it is possible for a port that was required for the original group to no longer be so. For example, by adding a module into the group that has a connection to an originally required port, removes the need for that port to be promoted to the group. This port will still be marked as promoted in the Group Editor, but can now be deselected.

When you are building an application, special attention should be given to the values of parameters in the application map.

When you run an application, only the application control panel is displayed on the screen. The IRIS Explorer window, the Map Editor window, and the Librarian are not displayed.

to change the default behavior of the main window so that double-clicking on the control panel for my-module quits the application. The user will be asked to confirm the quit operation.

To run an application so you can check its development and do debugging tasks, at the shell prompt, type:

explorer -map applicationname.map
    

When you run IRIS Explorer with this command, the application is displayed, along with the IRIS Explorer window. The IRIS Explorer window gives you access to the Map Editor and the Module Librarian if you require it.