From: bacchus!eric (Eric Bloom)
Subject: Re: color eps => TIFF with high resolution?? (long)
Keywords: Graphics Rasterize PixelMagician
Reply-To: eric@bacchus.com
Organization: Bacchus, Inc.
Date: Sat, 25 Jul 1992 23:26:10 GMT


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

Newsgroups: comp.sys.next.misc