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From: rsholmes@rodan.acs.syr.edu (Rich Holmes)
Newsgroups: comp.sys.handhelds
Subject: 48SX/Mac GROBer bug?
Summary: Good in, garbage out
Keywords: Macintosh GROB GROBer bug HP48SX
Message-ID: <1990Nov1.234036.1041@rodan.acs.syr.edu>
Date: 1 Nov 90 23:40:36 GMT
Organization: Syracuse University, Syracuse, NY
Lines: 47

I have the Mac interface and am having some trouble with the GROBer
software. I've converted some Mac pictures to GROBs without
difficulty.  However, recently I tried a picture (a section of a
scanned photo, about 131 x 64 pixels) and found that GROBer was
corrupting it; the rightmost 15-20% of the picture was garbage:

              PICT                                 GROB
---------------------------------   ---------------------------------
|                               |   |                          |    |
|                               |   |                          | Ga |
|<------- Good Picture -------->|-->|<----- Good Picture ----->| rb |
|                               |   |                          | ag |
|                               |   |                          | e  |
---------------------------------   ---------------------------------

I observed this after downloading to the HP48SX but by reading back
the GROB file on the Mac into GROBer I verified that the GROB was
corrupt on the Mac. That is, this corruption had nothing to do with
any problems with downloading; it was the Mac GROB file itself that
was incorrect.  Same happened whether I used ASCII or binary format
for the GROB.


Another picture was corrupted on the bottom:
 
             PICT                                 GROB
---------------------------------   ---------------------------------
|              ^                |   |               ^               |
|              |                |   |          Good Picture         |
|         Good Picture          |-->|               V               |
|              |                |   |-------------------------------|
|              V                |   |             Garbage           |
---------------------------------   ---------------------------------

This seems to occur at the same place relative to the content of each
picture, regardless of the size of the picture: e.g. if I select and
convert only the bottom half of the second picture, it gets corrupted
close to the top.  So it appears to be the local content of the
picture, not its size or complexity, that is triggering the problem.

This is on a Mac SE running System 6.0.2.  I could upload a PICT
document showing exactly what is happening if that would help.

-- 
 - Rich Holmes                                  rich@suhep.bitnet
   Syracuse U. Physics Dept.                    rich@suhep.phy.syr.edu
                                or if you must: rsholmes@rodan.acs.syr.edu