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June 2005
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2005.06.20 15:52 "Re: Invert-problem", by Bob Friesenhahn
On Mon, 20 Jun 2005, Matthias Lach wrote: > > ist me again - and i have still a problem saving my file. > > i opend a fax g-3 tiff with LibTif for Delphi (D7). > > I open it as 32 bit bitmap and can work and manipulate it > if i like ot save it i need to convert it back into > 1-bit because all other formats make the outputfile looks > jolted. > > But - no matter what bit-format i choose, all output > is invertet - and i cant find the reason why. The problem is likely with using the wrong photometric. The choices available are PHOTOMETRIC_MINISBLACK and PHOTOMETRIC_MINISWHITE. Grayscale images will usually be PHOTOMETRIC_MINISBLACK since this is how computer display systems work, but since paper is white, FAX uses PHOTOMETRIC_MINISWHITE. So you should set the photometric to PHOTOMETRIC_MINISWHITE and make sure that the sense of the bits is inverted to reflect that. In other words, a set bit indicates a black pixel when the photometric is PHOTOMETRIC_MINISWHITE. Bob ====================================== Bob Friesenhahn bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/