Re: [BLACKBOX] Program freezes when window loses focus

From: [at]} <Bob>
Date: Wed, 30 Mar 2011 22:31:55 +0100

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> I see. That's fine. I don't really care how one gets the
> keystroke, but there must be a simple way of reading keys.

No, not really.

> BB reads
> keystrokes SOMEHOW (I don't know, maybe it's complicated).

In the Kernel module there's a process called KeyboardWatcher which appears
to capture Window keyboard events (key press, key release) but I haven't
studied it and I can't see what it does with the key at a quick glance, but
you might want to study that. However I think you'd be better off
understanding the principles underlying BB and working within its model
rather than fighting against it.
 
> Is there a
> SIMPLE way of handling the following three cases, for example?
>
> 1. REPEAT
> (* I don't know how long this loop will take. If it takes a
> month, I might want to
> interrupt it *)
> UNTIL something happens (* message from windows that a key is pressed?
> *)

I wouldn't do that with a keystroke. I'd use a button in a dialog and get it
to set a variable that the loop checks periodically.

>
> 2. I'm doing a delicate visual, graphical manipulation and I want to
> nudge an image around with keystrokes.
>
> 3. Suppose you want to write a specialized editor. You need to read a
> keystroke and (optionally) display it. How does the BB environment
> read a keystroke?
>
> Any hints?
>

For your 2nd & 3rd examples you need to use a model-viewer-controller
design. In Mossenbock's book "Object-Oriented Programming in Oberon-2" he
gives examples of a text editor and a graphics editor. Although he's not
using Blackbox he does do a good job of explaining the principles that
underlie it, and that might help you understand why your questions are so
difficult to answer in an email.

> Rex Couture
>
>

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Received on Wed Mar 30 2011 - 23:31:55 UTC