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From: rjc@wookumz.ai.mit.edu (Ray Cromwell)
Newsgroups: comp.sys.amiga.programmer
Subject: Sharing layers.library with intuition
Message-ID: <1991Jan11.001055.2055@mintaka.lcs.mit.edu>
Date: 11 Jan 91 00:10:55 GMT
Sender: daemon@mintaka.lcs.mit.edu (Lucifer Maleficius)
Followup-To: comp.sys.amiga.programmer
Organization: None
Lines: 55


 Hi. I've been doing some experimenting lately and started designing
an alternative 'window' system to intuition. I don't intend it
as a replacement, or even to distribute it, so please no debates.
(although it would be nice to have a few alternative GUI's on the
Amiga, e.g. Xwindows, Motif)

 Ok, so what is the proper way to 'share' a screen with intuition? I
tried to do something like this:
  BOOL GetScreenData(&myscreen,sizeof(myscreen),WBENCHSCREEN,NULL);
  MyLayer=CreateUpfrontLayer(&myscreen.LayerInfo,&myscreen.BitMap,x,y,x1,y1,
    NULL);
  myrast=MyLayer->rp;

 This gets me a layer on the screen that I can render into, but it
doesn't open up 'on top of' the data and windows underneath. Instead it
'takes over' the data in that region. So my layer ends up stealing part
of the bitmap that was underneath belonging to my shell window. I realize
what I'm doing is probably considered voodoo, however, I'm only
experimenting. So how do I 'share' intuition's screen and let it know
about it? And what am I doing wrong in the above example?

  I was thinking of some neat looks for my 'simulated' windows once
I get past this hurdle, such as having the MenuBar/Menus pull down
from the window title(inside the window) instead of at the top of the screen.
(the menus would also support huge menu bars by making them superbitmaps, and
having a scrollup/down menuitem as standard. I also want to hack in some
window effects like masked windows, windows that explode/collaspe [like Mac],
and wipes/effects.)


I'd also like to report a bug in PDC. The last update causes a 
recoverable alert(under 1.3) on my system. The Alert is 00038005 which
has something to do with an OpenLibrary/MathLib (from exec/alerts.h)
I had to go back to the older version.
  Funny, PDC works fine standalone, but when launched from the CCX
frontend, it causes that alert.


For Commodore gurus, why is LayersBase only a LONG(APTR) I assumed it
would atleast keep a simple structure, say, to store its internal
damage lists? Why does graphics/intuition keep pointers laying around
to other library bases? (such as in IntuitionBase) Shouldn't
the system libraries abide the same rules we do, and open other
libraries to obtain their bases instead of performing inter-library 
rom-jumping? (ok, i'm making a huge assumption here since I haven't
disassembled them.)

Finally 2 more question. (cause I'm curious)
1)How do graphics library/icon library implement icons/bobs?
Are they layers, or are they implemented seperately?

2) In a rough estimate, how many lines of source code does
the entire OS take up? (1.3/2.0) and what compiler/system
is it developed on? Unix, Vax, or Amiga?