32-bit BMP problems.

Martin McClure martin at hand2mouse.com
Mon Mar 18 22:43:36 UTC 2002


This may well be the problem that I posted a fix for last summer. My 
fix made it to the harvesters' list, but a few weeks ago was still on 
the list to be reviewed, so I think it's been forgotten.

Check the squeak fix or squeak-dev list archives for a BMP fix I 
posted sometime in June-August of 2001, and let me know if that fixes 
your problem. If you can't find it, email me and I'll dig it out and 
repost it within a few days.

-Martin

At 10:42 AM -0500 3/18/02, Mark Guzdial wrote:
>I'm posting this for one of the GaTech users working with MPEGs and 
>the Display.
>
>Mark
>
>>Date: Sun, 17 Mar 2002 02:19:25 -0500 (EST)
>>From: Yisrael Lowenstein <gte356h at prism.gatech.edu>
>>To: <squeakers at cc.gatech.edu>
>>Cc: <squeak at cs.uiuc.edu>
>>Subject: [squeakers] 32-bit BMP problems.
>>Sender: owner-squeakers at cc.gatech.edu
>>Reply-To: squeakers at cc.gatech.edu
>>
>>I have been working with loading bitmaps in squeak to do Digital Video
>>Special Effects for SqueakEnd and have come across a problem:
>>
>>here's my test code:
>>
>>aform := Form fromBMPFileNamed: 32bitbitmap.BMP.
>>Transcript show: (aform colorAt: 1 at 1).
>>
>>this will return "Color transparent" even though it is clearly not!
>>
>>I have narrowed the problem down to the fact that these are represented
>>differently internally than other 32 bit forms.  if you explore the bitmap
>>of aform, you will se a bunch of SmallIntegers.  If you grap a 32 bit
>>bitmap from the screen (using "anotherForm := Form fromUser." while you
>>are in a 32-bit display depth) and explore that form's bitmap, you will
>>see that it is made up of LargePositiveIntegers.  Consequently, colorAt:
>>works just great on anotherForm...
>>
>>So, event though both of these (the fromUser form and the bmp-file form)
>>claim to be 32-bit forms, they are represented differently internally.  Is
>>this a bug?  or some sort of limitation?  how can I get around it?
>>
>>Any help would be GREATLY appreciated.
>>
>>	Lushi
>>
>>  o      |Yisrael Lowenstein: Computer Science Master's Student & Squeaker
>>    ()  o|lushi at bigfoot.com; gte356h at prism.gatech.edu; lushi at cc.gatech.edu
>>o_/||\/ |"Before you criticize a man, walk a mile in his shoes. That way
>>    ||   | when you do criticize him, you'll be a mile away and have his
>>   _/\_  | shoes." - Unknown                    AIM: YisraelL  ICQ: 1037061
>>   Class Schedule: http://www.prism.gatech.edu/~gte356h/schedule/
>
>
>--
>--------------------------
>Mark Guzdial : Georgia Tech : College of Computing : Atlanta, GA 30332-0280
>Associate Professor - Learning Sciences & Technologies.
>Collaborative Software Lab - http://coweb.cc.gatech.edu/csl/
>(404) 894-5618 : Fax (404) 894-0673 : guzdial at cc.gatech.edu
>http://www.cc.gatech.edu/gvu/people/Faculty/Mark.Guzdial.html




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