For other information, see the Development Projects list .
There are many areas that might make Ghostscript more useful or minor bugs that we would like to investigate and possibly fix, but for which we don't have enough resources. These may or may not be addressed in future releases.
If you would like to take responsibility for any of these issues, please contact us.
Additional comments on implementation approaches or project goals are in italic type like this.
This might be able to be fixed by applying a large positive translation to the bbox CTM which would be subtracted from coordinates passed to the target device as well as from the results the bbox device reports.
If coordinates for the ImagingBBox[0] and [1] values, then negative values are handled, but this is not reliable since there are places in the graphics library that depend on first quadrant coordinates.
Although technically correct many error messages are confusing for end users. Some commonly reported examples are listed below.
When pdfwrite device cannot open the output file it fails with:
**** Unable to open the initial device, quitting.When CIDFont-CMap pair required by PDF file is not available GS fails with:
/undefinedresource in --findresource--
Type 1 Stencil Mask Error: /ioerror in --fileposition--SourceForge Bug #223005, November 20, 2000.
This is an error in the test file, not GS. fileposition correctly
throws ioerror when it is used on filtered files.
The test should be written to use .fileposition when running on Ghostscript
and enclose fileposition in { } stopped when not. Also for portability to
PostScript interpreters without Ghostscript extensions, '=only' should be
defined to use '=print' or '='.
%! /x 333.33333333 def /y 666.66666666 def << /PageSize x y 2 packedarray >> setpagedevice (pached passed)== % fails %EOFfails with
Error: /configurationerror in --setpagedevice-- Additional information: [/PageSize [333.333344 666.666687]]
%!PS (%stdout) (w) file /ASCIIHexEncode filter /ASCIIHexEncode filter closefileSourceForge bug #224134, December 2, 2000.
One potential workaround is to use -dAutoFilterColorImages=false and -dColorImageFilter=/FlateEncode.
SourceForge bug #228808, Jan 15, 2000.
JPEG stream writes image dimensions in JPEG header when the stream is created. When the source data end the dimensions are not updated. There may be other problems too.
The loss happens diring PDF interpretation. GS can generate these attributes from pdfmark's.
March 25, 2001.
<> >>setpagedevice 612 1 scale /grad { gsave 0 0 1 100 rectclip << /ColorSpace [/DeviceCMYK] /Domain [0 1] /Coords [0 0 1 0] /Extend [false false] /Function << /FunctionType 3 /Domain [ 0 1] /Functions [ << /FunctionType 2 /N 1 /C0 [ 0 0.5 0 0 ] /Domain [ 0 1] /C1 [0.5 0 0 0] >> ] /Bounds [] /Encode [0 1] >> /ShadingType 2 >> shfill 0 0.5 0 0 setcmykcolor 0 0 0.1 50 rectfill grestore } def grad {1 exch 2 div sub} settransfer 0 100 translate grad showpageSourceForge Bug #232334, Feb 14, 2001.
/Font /Category findresource begin /CharterBT-Roman 255 string ResourceFileName = endGives the results:
/Resource/Font/CharterBT-RomanThis should be a valid platform specific file name and path such as:
f:/afpl/fonts/bchr.pfaSourceForge Bug #233403, Feb 21, 2001.
SourceForge Bug #406643, Mar 7, 2001.
A possible work around is to send the following postscript file to the printer prior to printing the problem file. This works but it leaves a .5" margin at the top and left which is may be ok for some uses.
%!PS-Adobe-2.0 % Reset the offset and margins. << /PageOffset [-12 -18] /Margins [0 0] /.HWMargins [0 0 0 0] >> setpagedeviceThis is an instance of the endless struggle with printer margins, especially for HP printers. The HP drivers are inconsistent as to whether the user space (0,0) should be the physical corner of the page (as it is in PostScript) or the corner of the printable area, and if the latterm whether the page should be clipped or scaled.
There is one other type of CID-keyed font that should also be loaded incrementally: CFF CIDFontType0, i.e., a CIDFontType 0 font represented using the compact binary CFF format. This is important because this is one of the two variants of Asian OpenType fonts (the other is essentially the same as TrueType). Ghostscript already supports both of these OpenType variants, but not with incremental loading.
SourceForge bug #223992, November 30, 2000.
We suggest that anyone who would like to work on this project start by looking at how CIDFontType 0 fonts do incremental loading (lib/gs_cidfn.ps and src/zfcid0.c). Probably much of this code can be also be used with CIDFontType 2 and TrueType fonts.
SourceForge bug #201955, February 14, 2000.
Since Acrobat 3 is superseded by Acrobat 4 which is available at no charge, and the file produced by Ghostscript meets published PDF specification, this will most likely be left as is.
%! currentpagedevice /Orientation known not { (This printer does _not_ support Orientation.) = } if <> setpagedevice currentpagedevice /Orientation known { (Err... wait... it does.) = } if %%EOFSourceForge bug #220967, October 31, 2000.
The handling of Orientation is a mess. The PLRM says quite explicitly that it is only supported for roll devices, where the page size alone doesn't give enough information to decide whether to rotate the page.
The reason that Ghostscript accepts it for other devices at all is twofold: displays are like roll media in that they don't have an inherent orientation, and almost none of the other Ghostscript devices actually specify their page sizes. Both of these reasons are now poorly motivated: displays should behave like portrait-orientation devices (albeit with variable page dimensions), rotating the image if the requested page width is greater than the height, and now that setpagedevice and the Resource machinery are fully implemented, all printer drivers should be updated to provide the paper size information. Once these fixes are made (which will probably have some repercussions other places in the code), Ghostscript will handle Orientation properly.
This should be addressed when the "setpagedevice in C" project is completed since part of this will require printer drivers to make page size information available to the setpagedevice logic.
(C*) { cvn findfont pop } 255 string /Font resourceforallSourceForge Bug #226462, December 20, 2000.
The 'findfont' operator and '/Font resourceforall' are very difficult to keep consistent, because the same logic algorithms must be implemented in two different ways. The problem is likely to be in lib/gs_fonts.ps, lib/gs_res.ps, and lib/gs_cidcm.ps.
This should be implemented using the (disk) file system rather than
actual RAM, at least initially, since that will be easy.
On Unix, it should be implemented with a directory /tmp/$$/ (where
$$ is the process id), which Ghostscript should delete when it exits.
pdfwrite needs to be changed to use a reasonable algorithm for deciding between JPEG and Flate compression, probably based on sharp vs. smooth color transitions in the image; in case of uncertainty, it should use Flate.
SourceForge Bug #226391, December 19, 2000.
SourceForge Bug #441959 keeps good test data for this.
%! /proc { currentfile =string readline pop dup == (%) anchorsearch { pop } if } bind def /test { //proc /ASCIIHexDecode filter 3 string readstring pop == } bind def (start) == test %31 %32 %33 %34 %35 %36 %37 %38 %39 (stop) == %%EOF
Adobe fills entire input buffer of ASCIIHexDecode with procedure's output, before passing data to ASCIIHexDecode, and without knowledge how much data does ASCIIHexDecode want. GS does know the size of data requested, so as the procedure is called exact number of times. Thus, GS is more conservative.
Anoter useful test to be made by repeating lines %31-%39 hundred times, without intermediate empty lines.
Copyright © 2000 artofocode LLC. All rights reserved.
This file is part of AFPL Ghostscript. See the Aladdin Free Public License (the "License") for full details of the terms of using, copying, modifying, and redistributing AFPL Ghostscript.
Ghostscript version 7.03, 20 October 2001