From: James_Hastings-Trew@telepro.UUCP (James Hastings-Trew)
Newsgroups: comp.sys.amiga.graphics
Subject: Re: Converting Structured Graphics Formats
Date: 23 Aug 92 17:33:48 GMT
Organization: TelePro Technologies

In a message dated Sun 23 Aug 92 10:04, Ladyhawke@cup.portal.com (classic -
wrote:

 L> Vector graphics conversion utilities?  YES, please.  And if PostScript
 L> is to be one of the formats, then I would love to see a flag or option
 L> for the format.  Most developers have implemented PostScript files 
 L> without the accompanying bitmap which PostScript allows so you can see
 L> the image on the screen (instead of that annoying shaded box).  I'd

There is no point in Amiga programs putting a preview on the end of the EPS
files if the Amiga DTP programs won't use them. They are the people
responsible for the lack of preview support.

 L> like to see it implemented in a flexible way so you can select the
 L> target platform for the PostScript file and attach the appropriate
 L> bitmap.
 L> For example, I think some of the Mac programs use TIFF as the bitmap
 L> format to accompany a PostScript file.  Haven't investigated what

Mac EPS files use either a Black and White or 8 bit colour PICT bitmap.
PICT is a bitmap graphic format that is based on QuickDraw routines built
into the Mac ROMS. IBM EPS files use a 1 bit TIFF format -- it is important
to know that the IBM TIFF format is different from the Mac TIFF format
because the byte-order in 16 bit words is different on Intel CPUs than it
is on Motorolla CPUs. So far, only PageStream makes any attempt to use Mac
EPS files (from Adobe Illustrator) to show a preview or to convert the file
to its own internal structured graphic format.

MacDraw files are structured PICT files. These again are dependent upon
code in the Mac ROMS, and so would not be an easy thing to convert to an
Amiga format without a LOT of work. EPS files from Illustrator or Freehand
on the other hand are PostScript code. To convert these to a bitmap format
would "only" require the creation of a Postscript interpreter engine.

If Black Belt wants to include a Postcript interpreter into Imagemaster, I
suggest that they take the approach that Adobe did with their Photoshop
product -- support only one format (Illustrator) and fine-tune the
rendering engine for that format only. Their converstion is great. You have
the options of setting the size, resolution, colouration, and anti-aliasing
of the final bitmapped representation. The anti-aliasing is incredible - a
near perfect rendering of the PostScript file in whatever resolution you
choose.

 L> others
 L> use.  There's no reason why an image processor couldn't be set up to
 L> convert just the bitmap portion and leave the PostScript code alone.

Except that the bitmap on EPS graphics are usually of very low quality,
compared to the Postscript code itself.

If people want to convert EPS graphics to bitmap format they can do so
RIGHT NOW, for FREE. Just get POST 1.7 from the Fred Fish disks. It does
not anti-alias, but it is a complete Postscript engine that can read just
about any Postscript file and create a bitmap from it. The limitation is
that it will not create a 24 bit representation of the EPS graphic - it
only produces a 3 or 4 bitplane version of the Postscript file.

If you want it to anti-alias, just make the bitmap 2x or 4x larger than you
need it, and scale it down to size in Imagemaster (or ADPro!). It won't be
as good as the Adobe Photoshop rendering, but it will be close.

If Black Belt wants to make a general purpose structured graphics
conversion utility, I would like to see it as a seperate product from
Imagemaster. It should use plug-in conversion modules (a la Interchange)
and central "engine" that uses the read/write modules to do all the dirty
work. It will be difficult to convert Postscript's bezier curves to other
formats that don't use them - cubic splines or many many little
straight-line segments? It should be EASY to convert an EPS file to ProDraw
clip format. The only problematic part (aside from getting the clip file
specs from Gold Disk) would be what to do with features in one program that
are not supported in another (compound objects, etc.) If done well, it
would be a great product -- one that I would pay up to $250 for.


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Newsgroups: comp.sys.amiga.graphics