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- Newsgroups: comp.sys.next.misc
- Path: sparky!uunet!psinntp!bacchus!eric
- From: bacchus!eric (Eric Bloom)
- Subject: Re: color eps => TIFF with high resolution?? (long)
- Message-ID: <1992Jul25.232610.19126@bacchus.com>
- Keywords: Graphics Rasterize PixelMagician
- Sender: eric@bacchus.com
- Reply-To: eric@bacchus.com
- Organization: Bacchus, Inc.
- References: <BruKuA.IoD@news.cso.uiuc.edu>
- Date: Sat, 25 Jul 1992 23:26:10 GMT
- Lines: 120
-
-
- Bacchus, Inc., has for some time had a graphics file format converter and
- utility on the market which would fit your task very nicely. I will address the
- specific points in your posting below. Please see our ads in NeXTWORLD and
- other NeXT publications for information on other features.
-
- > I need help in converting color eps files to TIFF *with high
- > resolution*, not just with 72dpi screen resolution.
-
- Pixel Magician can do this. Pixel Magician can read and write files at
- arbitrary (and possibly different) horizontal and vertical resolutions.
-
- > Let me explain my problem in more detail: we can use a slide
- > recorder (4000 lines resolution), which is unfortunately connected
- > to a Mac IIfx. The only format it accepts is Mac PICT format.
-
- Pixel Magician can produce 4000 lines of resolution. Customers have used Pixel
- Magician to produce slides and film images at up to 8192 lines of resolution.
- NeXT's cannot deal with images with more than 10,000 lines at full resolution
- (i.e., you are limited to 10,000 pixels in the cache). This limitation is
- documented, and, as of the Expo, NeXT had no intention of changing it. However,
- unless your NeXT is fully loaded (such as a Turbo system with 256 MBytes of
- RAM), these operations may take some time. On the plus side, Pixel Magician
- will allow you to queue up many jobs at once, so that you can go and have some
- coffee, or whatever. If NeXT hopes to compete seriously in the high-end
- graphics market, it will need to make installing large quantities of memory
- possible and affordable.
-
- > When I compose my presentation slide on the NeXT, all I end up with
- > is a nice color eps file (I use Adobe3, with imported eps files
- > from other machines [those files may contain pixel graphic from
- > screen dumps], to compose the graphic part, then I use LaTeX to
- > compose the page [with text and graphic], dvips makes a ps file out
- > of the one page [even with the -E option it most often not able to
- > produce eps, only ps], then I place this in a new Adobe file and
- > give it an invisible surrounding box and save it as eps with all
- > placements included).
-
- This last step may be unnecessary/undesirable with Pixel Magician since it can
- read PS files as well as EPS (unless the reason for your last step is to set a
- custom bounding box using Illustrator instead of doing it with LaTeX??). The
- reason dvips cannot produce an EPS file may be because the total image is
- larger than one page since multi-page EPS files are disallowed (although Pixel
- Magician will correctly read a multi-page PS file mislabelled as EPS). You may
- also wish to consider using LaTeX simply to produce the text and to use
- Illustrator to compose the text with the graphics. I assume, of course, you are
- using the latest version of dvips.
-
- > Now I have a high res (I can choose a high custom resolution in
- > dvips) color eps file. My problem is: I could not find an app which
- > could transform this into a *high res* PICT file. Well, once I
- > would have a high res TIFF file I would know how to convert that to
- > high res PICT, but all the apps I tested (Scene, ImageViewer, Icon,
- > Appsoft, Draw) that can convert to TIFF save the TIFF file with
- > only 72dpi, presumably the screen resolution. And this is just not
- > enough for the slide recorder.
-
- Using Pixel Magician, you can convert your EPS/PS file to a 4000 line
- intermediate, rasterized PXM file. From there, this PXM file can be converted
- directly to a PICT file at the desired resolution. This two step process is
- explained in the manual.
-
- > Also, the TeX test is very hard to read as parts of the characters
- > are simply missing (e.g. the horizontal bar of a capital H).
-
- I personally use Adobe scalable fonts (Helvetica, Times, Courier, Symbol) with
- TeX. You may wish to do the same, if the Mac can handle this. Unless you prefer
- the look of the CM fonts, there is no real advantage to using them. Using the
- standard Adobe fonts has the added advantage that these have been hand
- optimized to look good on the screen (using screen fonts) - although this means
- that the results on the screen are not quite wysiwyg.
-
- > I also looked into pbmplus, the utha raster toolkit, and the SDSC
- > image conversion utilities but none could READ eps, only write it!
- > I also looked into comp.graphics but didn't find anything in the
- > FAQ lists.
- >
- > Here my question: is eps a one way road? Once eps, eps for ever?
- > Everything on the NeXt is geared towards eps, but is there no way
- > to convert it to something else *without loosing resolution* so
- > that one could use output media available on other computers?
-
- No, you can always go from EPS (not EPSI) to PS. You can also easily convert to
- supersets of EPS/PS (such as later versions of the same - I know of no other
- formats general and powerful enough to produce everything that PostScript can).
- Other than that, you must rasterize, necessarily losing resolution in most
- cases. Except in very special cases, it is not possible to convert from a
- vector or vector+raster format (like EPS/PS) to a raster only format (like
- TIFF) without losing resolution. (Special cases include having only raster data
- or having any lines, curves, and fonts be composed entirely of vertical and
- horizontal line segments. On the NeXT, the requirements are even more stringent
- because of the limitation on the size of the images with which it can deal. For
- example, raster data must be aligned on a pixel boundary when imaged at a
- resolution which is a multiple of the resolution of the original raster image
- but small enough that this does not cause the entire image to exceed 10,000
- pixels in size. Change the second case mentioned similarly.) However, it is
- certainly possible to convert from an EPS/PS file to a raster file at the
- resolution of your slide recorder, so that the slides produced are at the
- maximum possible physical resolution (actually, one can make the results look
- even better using anti-aliasing, given a sufficient range of colors that your
- slide recorder can produce - consult a computer graphics text book on how to do
- this). This is, after all, how the NeXT's own printer works (it does not print
- EPS/PS directly, but rather converts it into an internal raster format at
- 300/400 DPI and prints that). Additionally, if your images have more colors
- than your slide recorder can produce, Pixel Magician can be used to
- error-diffuse your images to give a better overall approximation of your
- original colors (by default, your slide recorder probably thresholds its input
- or, at best, dithers it with a halftone screen - most people find the results
- of these methods inferior). On the other hand if these slides are for
- scientific purposes and every single pixel must be accurate and independent of
- the others (as a recent poster to this group required), Pixel Magician can be
- used to shut off any dithering your slide recorder may attempt to do.
-
- Respectfully yours,
- -ccwf
- _____________________________________________________________________
- Charles C. Fu |Send replies to
- System Administrator | ccwf@bacchus.com or
- Bacchus, Inc. | ccwf@antares.caltech.edu
-
-