The first time you run Backdrop, it detaches itself from the CLI and hangs around in memory until you tell it to quit. You can change the current settings by running Backdrop again with different options. Only those options you specify will be altered, all the others will remain unchanged.
The following options can be specified:
-a followed by a number sets the foreground colour used to plot the pattern to the pen number specified (normally 0 to 3). Similarly, -b sets the background colour.
-f and -s select the window type used by Backdrop. -f uses a SMART_REFRESH window, which results in fast updating of the screen, but can use up to 64K of chip memory (in interlace mode). -s uses a SIMPLE_REFRESH window, which gives slower updating of the screen but doesn't use up any chip memory. If you can afford the memory, -f looks much more professional.
-p followed by a number selects one of the built in patterns for display. Pattern 0 is the default pattern. Numbers from 1 upwards select other patterns. If you try to select a non-existant pattern, you get the default pattern.
-q tells any copy of Backdrop already resident in memory to remove itself, and restore the screen back to normality. If Backdrop isn't already resident, then this option has no effect.
Finally, you can define your own unique pattern by giving a list of 16 hex digits. These are interpreted as 8 bytes, with each byte corresponding to one row of an 8x8 grid. This grid is then replicated over the entire screen to form the pattern. Try experimenting with random values to generate some unique patterns.
Any or all of these options may be present on the command line, and order is not important. You can get a summary of these options by invoking Backdrop with -h (or any other invalid option).
EMAIL: ecarroll@@cs.tcd.ie