Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!mips!atha!lsuc!jimomura From: jimomura@lsuc.on.ca (Jim Omura) Newsgroups: comp.sys.atari.st Subject: Re: IMG gormat Message-ID: <1991May29.014046.24302@lsuc.on.ca> Date: 29 May 91 01:40:46 GMT References: Organization: Consultant, Toronto Lines: 55 In article blackbox@pfunk.hanse.de writes: >In , LarsErikOsterud writes: >>Does anyone have an EASY TO UNDERSTAND description of the .IMG Gem bitmap >>file format. I have written some scanner software but today I use the DEGAS > >Isn't the description of the IMG-format implementef in the monthly posted >picture-format list ? Just a moment, i take a look..... > >--------------cut---------------- > > *.IMG > >1 word version number of image file [1] >1 word length of header in words [usually 8] >1 word number of color planes [1 for monochrome] >1 word pattern length in bytes [1-8, usually 2 for screen images] I've been meaning to ask this for a while now, and this seems like a good time. What is this "pattern length" all about? It can't be the length of the data bytes. That would be 32000 rather than 2. >1 word pixel width in microns (1/1000 mm, 25400 microns per inch) >1 word pixel height in microns Does most software actually take this into account for anything or can you leaave the pixel dimension 0? >1 word line width in pixels >1 word number of lines >------- >? words header length defined in 2nd word of header > >? bytes data > >NOTES: If the image is a color image (planes > 1), the planes are stored >separately starting with plane 0. There is, however, no standard way of >storing the color palette. Some programs may save the palette in separate >files, some may extend the header. For this reason, you should never >assume the header is 8 words long, always get the header length from the >2nd word of the header. Also, the line width in the 7th word is the number This is one of the reasons I'm making IFF/ILBM my main "supported file type". No matter how you feel about the Amiga/Atari/Mac wars, the IMG "standard" just isn't sufficiently defined and has not real underlying rational. I don't know if I would embrace the whole of the IFF standard -- it's really just a mish-mash. But the ILBM part is rational and practical. -- Jim Omura, 2A King George's Drive, Toronto, (416) 652-3880 lsuc!jimomura Byte Information eXchange: jimomura