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<title>Problems and new features in the current release</title>
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Problems and new features in Ghostscript 5.50
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<h2>Table of contents</h2>
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<ul>
<li><a href="#New_features">New features (since release 5.10)</a>
<li><a href="#Changes">Changes</a>
<li><a href="#Known_problems">Known problems</a>
<ul>
<li><a href="#Usage">Usage</a>
<li><a href="#Limitations">Limitations</a>
<li><a href="#Graphics_bugs">Graphics bugs</a>
<li><a href="#Non_graphics_bugs">Non-graphics bugs</a>
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<p>For other information, see the <a href="Readme.htm">Ghostscript
overview</a>.
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<h1><a name="New_features"></a>New features (since release 5.10)</h1>
<p>
(This is not a complete list of new features: see <a href="News.htm">the
news</a> for details.)
<p>
A number of PostScript LanguageLevel 3 features are implemented:
<b><tt>ImageType</tt></b> 4 images, Type 32 fonts and
<b><tt>CIDFontType</tt></b> 4 fonts, <b><tt>CIEBasedDEF[G]</tt></b> color
spaces, idiom recognition, <b><tt>shfill</tt></b> (partial support),
<b><tt>CloseSource</tt></b> and <b><tt>CloseTarget</tt></b>.
<p>
More of Display PostScript is implemented: view clipping,
<b><tt>DevicePixel</tt></b> color space, context creation with private
local VM, <b><tt>ImageType</tt></b> 2 images, compositing (NeXT extension).
<p>
The PDF interpreter now handles double-byte fonts. Ghostscript now handles
essentially all of PDF 1.2 (Acrobat 3.x compatibility).
<p>
The PDF writer now implements the xxx<b><tt>ImageFilter</tt></b>,
<b><tt>Encode</tt></b>xxx<b><tt>Image</tt></b>, and
<b><tt>ConvertCMYKImagesToRGB</tt></b> distiller parameters, which provide
the ability to compress images.
<p>
The PDF writer now recognizes nearly all varieties of pdfmark, other than
the Distiller 3.0 "named object" pdfmarks.
<p>
It is now possible (in fact, easy) to build Ghostscript with the source and
object files in different directories.
<p>
There is a new PostScript-to-PostScript distiller, <b><tt>ps2ps</tt></b>.
<h1><a name="Changes"></a>Changes</h1>
<p>
Contributed drivers now have their own makefile (<b><tt>contrib.mak</tt></b>).
<p>
The IJG JPEG library is now in a directory named <b><tt>jpeg</tt></b>
rather than <b><tt>jpeg-</tt></b>#.
<p>
The <b><tt>pdf2ps</tt></b> utility has been completely rewritten. It
should be much more reliable, at the expense of possibly producing larger,
lower-level output.
<p>
Running <b><tt>tar_cat</tt></b> after editing makefiles is no longer
necessary. Users should now edit the <b><tt>unix*.mak</tt></b> makefiles.
<h1><a name="Known_problems"></a>Known problems</h1>
<p>
On MS Windows, trying to execute <b><tt>setfileposition</tt></b> or
<b><tt>bytesavailable</tt></b> on the standard input file crashes
Ghostscript.
<p>
On 16-bit-deep X Windows systems, the <b><tt>x11cmyk</tt></b> device doesn't
work.
<p>
(This is not a complete list of known problems: see the <a href="News.htm">
release news</a> for details.)
<h2><a name="Usage"></a>Usage</h2>
<p>
On a DOS system, interrupting the interpreter by typing control-C doesn't
restore the display mode.
<h2><a name="Limitations"></a>Limitations</h2>
<p>
<b><tt>serialnumber</tt></b> returns the same value in all copies.
<p>
Some floating point exceptions terminate the interpreter, rather than
producing a <b><tt>limitcheck</tt></b> error.
<p>
The <b><tt>DCTEncode</tt></b> filter disregards the <b><tt>Blend</tt></b>
parameter, and uses different <b><tt>QuantTables</tt></b> and
<b><tt>HuffTables</tt></b> from Adobe's.
<p>
The DCT filters do not support nonintegral sample ratios. Also,
<b><tt>DCTEncode</tt></b> will not create files with Sum(HS×VS)>10
(regardless of the value of the <b><tt>Relax</tt></b> parameter) because
they violate the JPEG standard; but <b><tt>DCTDecode</tt></b> will read
such files.
<p>
The size of the execution stack cannot be changed dynamically. (However,
the sizes of the operand and dictionary stacks can be changed.)
<p>
<b><tt>Separation</tt></b> color spaces are implemented, but devices that
actually produce color separations are not supported:
<b><tt>Separation</tt></b> color spaces always use the alternate space. The
special color separations <b><tt>All</tt></b> and <b><tt>None</tt></b>, and
the primary separations (<b><tt>Red</tt></b>, <b><tt>Green</tt></b>, etc.),
are not supported.
<p>
<b><tt>execform</tt></b> and <b><tt>ucache</tt></b> are implemented, but
they do not actually do any caching; <b><tt>setucacheparams</tt></b> and
<b><tt>ucachestatus</tt></b> are dummies. (This only impacts performance,
not functionality.)
<p>
The <b><tt>image</tt></b> operator only honors the
<b><tt>Interpolate</tt></b> flag in the image dictionary if the combined
transformation (<b><tt>ImageMatrix</tt></b> + CTM) doesn't involve
rotation, skewing, or X-reflection; <b><tt>imagemask</tt></b> doesn't honor
<b><tt>Interpolate</tt></b> at all.
<p>
Some path-building operations that would generate a device coordinate
larger than +/-2^<small><sup>19</sup></small> will cause a
limitcheck. However, the common ones (<b><tt>[r]moveto</tt></b>,
<b><tt>[r]lineto</tt></b>, <b><tt>[r]curveto</tt></b>, <b><tt>closepath</tt></b>) will not.
<h2><a name="Graphics_bugs"></a>Graphics bugs</h2>
<p>
Opening more than one window device at the same time doesn't work.
This is the case for both X Windows and Microsoft Windows.
<p>
<b><tt>cshow</tt></b> doesn't work with composite fonts.
<h2><a name="Non_graphics_bugs"></a>Non-graphics bugs</h2>
<p>
The <b><tt>definefont</tt></b> operator (Subrs (type 1 fonts)) expects
arrays but won't accept packed arrays:
<p>
Syntax errors occurring within a binary token do not produce the error
message specified by the Adobe documentation.
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<font size=2>
<p>Copyright © 1996, 1997, 1998 Aladdin Enterprises. All rights reserved.
<p>This file is part of Aladdin Ghostscript. See the
<a href="Public.htm">Aladdin Free Public License</a> (the "License") for
full details of the terms of using, copying, modifying, and redistributing
Aladdin Ghostscript.
<p>
Ghostscript version 5.50, 16 September 1998
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