This appendix explains four configuration variables that determine how colors are displayed.
You need to read this appendix only if you want to understand the exact effects of the various COLOR-MODEL settings, or want to experiment with its component settings. COLOR-MODEL is a composite variable; it combines the effects of the variables described in this appendix.
For most sites, COLOR-MODEL and COLOR-TABLE will be adequate for color control. For details on these two variables, see Chapter 9, "Color Mapping" in Book 2, "User Interface Programming."
This appendix describes these four configuration variables:
For each character position on the screen, ACUCOBOL-GT assigns four values: the foreground color, the background color, the foreground intensity, and the background intensity. Your COBOL application may directly control three of these attributes with various ACCEPT and DISPLAY options. The attributes you control are the foreground and background colors, and the foreground intensity. You do not have direct control of the background intensity from the ACCEPT or DISPLAY verbs.
When the runtime system displays screen data, it performs a series of steps to transform the colors and intensities specified by your program, to the actual colors and intensities shown. You can use a variety of configuration options to affect these transformations. By doing so, you can alter the appearance of your program without changing any of the program's code.
In order to explain the available configuration options, we will walk through the steps taken by the runtime system. At each point where an option can affect the results, that option will be described.
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Step 1 - Assign Initial Colors