POSTGIF version 1.2 _______ Unless you have a colour PostScript printer, you might have observed that the visual splendor of GIF files on your screen is rarely matched by anything that you can arrive at on paper. Converting colour pictures to black and white by ``dithering'' them is time consuming and rarely results in really decent looking output. If you have a monochrome PostScript device you can have much more attractive black and white output from colour GIF files by halftoning your GIF files into black and white images. This will present you with printable, screened pictures which will reproduce at least as well as a screened photograph. Said images can be used as PostScript art in Ventura and other desktop publishing system chapters. In addition, they look slick. POSTGIF is a simple way of converting full colour GIF images of almost any size into encapsulated PostScript (EPS) files all set to send to your printer or suck into another program. It calculates which of two hundred and fifty six shades of grey best represents each colour in the palette of a GIF file and emits a copy of the file in the EPS format. It's dead easy to use. If you have a GIF file called CHEAPSEX.GIF, type POSTGIF CHEAPSEX and POSTGIF.EXE will write you a file called CHEAPSEX.EPS. To see what this looks like, type COPY CHEAPSEX.EPS LPT1: assuming that your PostScript printer is connected to LPT1:. After a while, a halftoned representation of your picture should rattle out of your printer. Encapsulated PostScript files created in this way include a ``preview'' image built in. If you suck one into Ventura, for example, you will see a fairly contrasty bit mapped representation of your original GIF file where the PostScript file is supposed to be. Slick, this. If you intend to print the EPS files you create directly to your printer... by copying them to LPT1, for example... you should disable the creation of the preview image. This is done with the /P option... that's P for ``plain'', not P for ``preview''. To disable the creation of the preview in the above example, you would POSTGIF CHEAPSEX /P If you TYPE an EPS file created with POSTGIF, you will see some garbage at the from of the file if the preview has been included and the line ``%!PS-Adobe-2.0'' first thing if it has not. These EPS files make great clip art for desktop publishing programs such as Ventura, since the results are very much like halftoned photographs. However, the default screen which your printer uses when you output a POSTGIF'd file may not be the ideal one if you intend to use the final results for reproduction... that is, if you expect to use 'em as art to be run through a printing press. As such, POSTGIF allows you to specify the halftone screen size. If you say POSTGIF CHEAPSEX /S60 the resulting EPS file will print with a screen of sixty dots per inch. The screen size you use will depend on what you plan to do with the EPS files you create. As a rule, everything else being equal, eighty line screens are about right for reproduction on newsprint, and something between one hundred and twenty to one hundred and forty-four lines are about right for repoduction on coated... glossy... paper. However, a three hundred dot per inch laser printer can't do anything like this. Experiment with different screen densities to find one that looks best on your printer. If you set the density too high... say eighty to a hundred lines on a three hundred dot per inch laser... the resulting pictures will get muddy and posterized. Bloody Little Details _____________________ There are several salient points worth mentioning about POSTGIF, to wit... - The EPS files it emits are mildly huge... plan on up to half a megabyte for an average size GIF file. If you want to know approximately how big the EPS file resulting from a particular GIF file will be, use the formula (image width) * (image depth) * 2 plus a couple of kilobytes They ARC very well, though. - You can translate multiple files at once. For example, the command POSTGIF CHEAPSEX CINDY DRAGNLDY BODE1 would translate four GIF files into four EPS files. It would take a while, though. - Non-interlaced GIF files are translated directly. Interlaced files are buffered in memory and translated. This being the case, an enormous interlaced GIF file might cause POSTGIF to abort with a memory allocation error. One rarely sees enormous interlaced GIF files, so this shouldn't be a problem. However, keep this in mind if you try to run POSTGIF with very little available memory, such as in a DOS shell. - POSTGIF does grey scale summing and interpolation to decide what grey shade best represents a particular colour. This usually works. However, if all of the colours in your GIF file are of rather medium intensities, the resultant black and white image might be pretty washed out. There's not much POSTGIF can do about this. For example, fifty percent blue and fifty percent red may stand out well in a colour image, but they'll both be translated into something like fifty percent grey by POSTGIF. - The EPS files which POSTGIF creates can be scaled, translated, rotated, and screened any way you... or your desktop publishing package... feel like. You can also edit them by hand to change various characteristics about them if you're versant with PostScript programming. - POSTGIF files work will with Freedom of Press. In fact, that's what we used to do the initial development of POSTGIF. For those who haven't come across it, Freedom of Press is a (large) program which runs on an AT or 80386 based PC and interprets PostScript files, outputting them to a LaserJet (and several other sorts of printers.) It's done by CAI, 5 Technology Centre, 900 Middlesex Turnpike, Billerica MA 01821 (508) 667-8585. Moral dogma ___________ If you like this program and find it useful, you are requested to send $20.00 to Alchemy Mindworks Inc. This will entitle you to telephone support, notification of updates and other good things like that. More to the point, though, it'll make you feel good. We've not infested the program with beg notices, crippled it or had it verbally insult you after ten days. We trust you to support POSTGIF if you like it. Oh yes, and if you fail to support this program and continue to use it, a leather winged demon of the night will tear itself, shrieking blood and fury, from the endless caverns of the nether world, hurl itself into the darkness with a thirst for blood on its slavering fangs and search the very threads of time for the throbbing of your heartbeat. Just thought you'd want to know that. We are Alchemy Mindworks Inc. P.O. Box 313 Markham, Ontario L3P 3J8 Canada Other programs we've done that you might like include: Scoop - MacPaint, GEM/IMG and PC Paintbrush file readers, with Epson FX-80, LaserJet and PostScript printer support. Drives CGA, EGA, VGA and Hercules cards. HP_Slash - Make LaserJet soft fonts smaller by selectively excising those characters you'll never use. Mac2Img - MacPaint to GEM/IMG file converter... just the beast for Ventura users. Mac2Pcx - MacPaint to PCX file converter. Calendar - Slick perpetual calendar that tells you when the equinoxes happen, what day Michaelmas fell on in 1705 and so on. gemCAP - Capture graphics screen in GEM/IMG paint format, suitable for inhalation into Ventura. CPM2DOS - Read CP/M formatted disks on your PC. IMGCUT - Crop GEM/IMG paint files into smaller files. ADDRESS - Memory resident envelope addresser with graphics. VFM - Ventura soft font manager deluxe with a side of fries. Adds new fonts and creates width tables with menu driven simplicity. MCOPY - Copying program which packs as many files as possible onto a floppy, pauses when the current floppy is full and asks for another one. D - A simple sorted directory program which contains neither a word processor nor a radish straightener. TCAP - A text screen capture program which generates GEM/IMG graphics that look like your text, all ready for inhalation into Ventura. ICON - Converts files between MacPaint, IMG, GIF, TIFF and PCX. Still in the Beta stage at this writing. DMCL - Dot matrix control language... macro driven effects control and printing program for dot matrix printers. If you can't find them in the public domain, they're available from us for $10.00 each. Source is available for Scoop, for $25.00. The author assumes no responsibility for any damage or loss caused by the use of these programs, however it comes down. If you can think of a way a picture program can cause you damage or loss you've a sneakier mind than mine. That's it...