Re: Jiri's Widgets
jiri babor wrote:
>Earlier Everett L.(Rett) Williams wrote:
>
>>> I do not redraw windows, I just save the rectangular image and
>>> re-display that at the new location. Simpler and faster, I thought.
>>> But, of course, off-screen pixels are undefined. Typically a bunch
>of
>>> zero, I suppose, and I finish with a black egg on my face, so to
>>> speak. I am open to any reasonable suggestion...
>>>
>> Build you a virtual window and a displayable window. All logic
>except
>> actual transfer to write buffer happens to the virtual window.
>
>I am not sure, Rett, I understand you completely. But if you mean
>every thing happens first in the virtual plane and only the final
>result is blasted on to the real screen, then I have a problem.
>Firstly, to do it properly, I would have to go back to assembly, which
>would be very stupid for a number of reasons I am reluctant to discuss
>right now. I even gave up forth, and then C, to get some distance
>between my brain and the metal buried under the grey plastic! And I am
>sure you are not suggesting peeks and pokes, or are you? Secondly, it
>is such a waste of effort to reblast the whole thing for every small
>incremental change...
>
>Thanks, guys. Good night. jiri
Ye wound me laddie, peek and poke indeed, though with the tools at
hand, it is rather hard to avoid at times 
With the ability to describe
and point to external data structures such as the write buffer for the
video card, much of the need for peek and poke would go away...but
now I'm dreaming again. I haven't examined your code closely, but
if you are managing to move windows partially off the screen now, it
can't be as hard to just move them around as complete objects with a
new set of limits...the virtual screen instead of the physical screen.
Effectively, if you set up the virtual limits of your screen properly, you
will never have to cut off an object again. On the other hand, you will
have to trim your write logic to stop displaying at the edge of the real
screen...something that you already do. The logic can't be that much
different from the logic that handles overlapping windows on the
existing screen...or do you handle that situation...I haven't tested.
Everett L.(Rett) Williams
rett at gvtc.com
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