Modifying Device Designs › Device User Source › Visualizing Extents
Visualizing Extents
If it is not clear which attachment levels to use for a particular change, you can make a self-educating demonstration for each external function type. To do so, produce:
- A set of device user source functions, one for each attachment level. Each function contains only a PAINT command and comments defining the boundaries of the extent.
- A set of simple samples of each external function type, containing no more than one or two fields per format.
You then attach the device user source functions to your sample external functions to cause the device source comprising each extent to display in a separate color. The color indicates the attachment level to which the extent belongs.
In the future when you are attempting to attach device user source to one of your complex functions you can use these sample, painted functions as a reference to help you locate the correct attachment point for your patch within the device design of the function.
The following steps are basic recommendations for painting generated device source.
- Define DDS and SDF files of STR type. For better maintainability, keep all painting functions (see examples below) built over the two files accordingly.
- Create ‘painting’ device user source functions, one per attachment level (Device, Screen/Report, Format, and Entry) and per device language (DDS, SDF).
- Name the ‘painting’ functions to reflect the attachment level that is to be painted.
- Type in similar user source that inserts the boundary comments (<<<...>>>) and paints the entire extent in a selected color. Use unique colors for each device user source function within the scope of device language.
- Attach ‘painting’ device user source functions to all available attachment points of the selected external function. In order to cover Header/Footer entities, create a special version of the Header/Footer function in advance, and paint it as you would paint any external function.
- Generate the selected external functions and enjoy seeing the fully painted device source produced by CA 2E. This should assist you in understanding what extents are and how to use the power of the device user source feature.
