CompuServe Thread

With the graphics library we're firmly entering areas where I have _no_ experience, except my eyes of course. I did give it a quick skim a couple of years ago to familiarize myself with what the Amiga is doing/can do, and to know a graphics structure name when I see one, but no more. I've always read it that way, you have to set up the image for display before you can print it. This doesn't mean you have to display it, but the image has to be display-ready before you can print it. I have no idea what the mechanics are to do this to/from disk. Hopefully somebody else will jump in with that. Back to the Exec devices, I suspect we're getting a bit confused over what's what (function call, command, parameter, etc.), so I'll go over the interface mechanism in a bit more detail. IORequest is the name of the data structure (actually an instance of that structure) used to interface with an Exec device. It has some fields that are required for all devices and some that are device specific. You (a user task) allocate the memory needed for the target device's IORequest and OpenDevice() (an Exec function call) with that request and other parameters. The function call will init some fields in the IORequest. One of the required fields is the Command field, the code in the field tells the device what to do (no, really?). The device will use the rest of the fields in the request as is necessary to process the command. <continued…>