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Re: Trouble with TIFF

To: REALbasic Network Users Group <realbasic-nug at lists dot realsoftware dot com>
Subject: Re: Trouble with TIFF
From: robsteely at nc dot rr dot com
Date: Sun, 30 Dec 2001 08:18:03 -0500
On Sat, 29 Dec 2001 18:24:37 +0200, Matthias Buercher wrote:

do you know which application wrote the TIFF? did you contact the writer
of this application?

I don't know who created the TIFFs or what program they used. It only happens on a dozen or so files from several thousand that I've tested thus far. I've pulled files from so many different locations on the internet that pinpointing their source could prove difficult.


it is also interesting to save the file again with graphic converter with
the same settings, look if the new file still crashes, and, if not,
analyze the difference between the two files.

GC reads the files, but can't save them with the same settings. I always end up with something different when I examine the file information after the save. This alone tells me that the original file settings were fairly obscure since GC supports so much.

I'm going to manually compare the files to other TIFFs to determine the differences. If I find a decent discriminator, I'll add code to my program to exclude those files from use.

The main thing that interests me is that Apple's "Preview" program successfully reads these files but RB crashes when trying to do so. So something in Apple's use of QT is different from the implementation in RB.

When stepping through my code in the debugger, I reconfirmed that the crash point is the OpenAsPicture function (from which it never returns). The console log shows a different thread state than I reported previously when testing with the built application. RB versions 3.5.2 thru 4.0b4 crash at the same point. I didn't test it with anything older than 3.5.2.

Thread 1:
#0   0x005c8a88 in LoadPictureFromSpec(FSSpec const &, int)
 #1   0x005c8a70 in LoadPictureFromSpec(FSSpec const &, int)
 #2   0x00539664 in FolderItemOpenImage

I'll REALbugs it.

Thanks,

Bob



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