On Sat, Sep 17, 2005 at 06:37:37PM +0200, Florian Weimer wrote: > * Justin Pryzby: > > > I was trying to load a FITS image, and I think I caused a stack smash. > > imview should certainly protect itself against that .. it should never > > read in more data than there is in a file (reading past the end of an > > mmap, or such), and it should never write more data to a buffer than > > the buffer can store. > > Could you provide the image for reference, so that we can reproduce > the bug? You could try one of the images on my "website"; say, http://justinpryzby.com/m27.00000001.Dumbbell_Nebula.FIT [0].
I did File / Open / All Files (*.*), and got a dialog beginning with "format not recognized". So I'm apparently supposed to give it hints about where the raster image data is inside that file. I looked at the header of the file: SIMPLE = T / http://fits.gsfc.nasa.gov./ BITPIX = 16 / Bits/pixel; 2s compliment MSB (big-end) integer NAXIS1 = 765 / Length of axis NAXIS2 = 510 / Length of axis BSCALE = 1.00000 / Physical value = BZERO + pixel value * BSCALE BZERO = 32768.0 / Physical value = BZERO + pixel value * BSCALE and so entered into the X,Y,Z Dimensions fields 765,510,1, respectively. It is short/MSB type data, as per BITPIX. I don't know what "Bands/Nb" is, so I left it at its default: Nb=1. I set Skip=5760 because thats where the data begins. (Compute Header wont't work for FITS, usually, because both the header *and the data* are padded to a multiple of 2880 bytes.) Anyway, I pressed "Try" and got a new dialog: "Coult not open ?^A, No such file or directory", followed by another dialog "Read of <garbage here> failed, error=10". It occurs to me that imview is probably not sufficiently general to use FITS files. Integer FITS data is always stored as signed, and there are oftentimes keywords BSCALE and BZERO which must be used to interpret the data .. a given pixel value _a_ will have the physical value a*bscale+bzero, with units BUNITS, if specified. Maybe you can forward that upstream, and allow FITS to work with imview? Or even include full support for FITS? -- Clear skies, Justin References [0] A 20 minute exposure from a couple weeks ago, which includes a new nova alongside the popular deep-sky object M27. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
