history2.txt

实现并行算法

Procedures
----------

Changes the distribution script so that it stores all text files in the
main source archive with Unix end-of-line conventions, but with DOS
end-of-line conventions in the MS-DOS-specific archive.

Changes the MS-DOS, MS Windows, and OS/2 makefiles so that 486SX and 486DX
processors are different CPU_TYPEs.  (The former, designated by
CPU_TYPE=485, does not include an on-chip FPU.)

Adds a line to gs_init.ps which can be uncommented to select A4 as
the default paper size.

Adds a definable CFLAGS macro to the makefiles, allowing -DA4 to
select A4 as the default paper size.

Adds the H-P printer drivers to the standard Unix configurations.

Utilities
---------

Fixes bugs:
	- If there were no unencoded characters, prfont.ps would get
an error.

Changes ansi2knr to accept a wider range of function declaration syntax,
and to not depend on any Ghostscript header files.

Drivers
-------

Fixes bugs:
	- Several drivers (DigiFax, Epson LQ-2550, NEC P6) didn't handle
A4 paper width.
	- The IBM ProPrinter wasn't being initialized properly.
	- The Epson driver didn't work properly with compilers that
insisted on 'char' being a signed type.
	- The Epson driver ignored its end_string argument, producing
incorrect end-of-page behavior on some printers.

Adds new drivers:
	- User-contributed drivers for Bellcore MGR (a window manager most
commonly used with OS-9) devices.
	- A user-contributed driver for the CIF file format.
	- A user-contributed driver for the HP 2563B line printer.

Changes the LaserJet 2p, 3, and 4 drivers so they set the initial position
to (0,0) rather than (0,0.25").  (I don't remember why it was the other
way.)

Implements the PageCount property in all drivers, not just printer
drivers.

Introduces a new gx_tile_bitmap type, and changes the tile_rectangle
device procedure to take it in place of gx_bitmap.  THIS IS A
NON-BACKWARD-COMPATIBLE CHANGE.  However, it only affects devices that
implement their own tile_rectangle procedures, of which there aren't very
many.

Platforms
---------

Fixes bugs:
	- The VMS module lists referred to SDCTD and SDCTE instead of
SDCT.
	- The Unix install script tried to install the non-existent file
readme.doc.
	- Microsoft C does something bizarre with empty macro parameters,
which caused a problem with the gs_struct_type_... macros.
	- The Unix platforms didn't automatically handle the presence
or absence of <dirent.h>.
	- The DEC Alpha OSF/1 1.3 library lacks `const' in the prototype
for popen, which requires a workaround.
	- The DEC Alpha OSF/1 1.3 X Windows library uses `private' as a
member name.

Splits off gp_unifs.c, containing code common to "Unix-like" file systems.

Adds a user-contributed OS-9 platform.

Interpreter
-----------

Fixes bugs:
	- The currentfile cache wasn't updated properly if an executable
file appeared in the middle of a procedure.  In particular, eexec-encoded
.PFB fonts often didn't work.
	- There was an extraneous `goto top' in scfd.c.
	- An integer constant overflowed in iname.c.
	- -2147483648 (i.e., -1 << 31) was converted to a float.
	- eexec didn't skip the first 4 characters correctly if they were
split across a buffer boundary.
	- The font/matrix pair cache didn't properly free entries with only
an XUID that was being deallocated.

Implements additional Level 2 features:
	- Patterns, makepattern, setpattern.
	- IODevice resource, setdevparams, currentdevparams.
	- OutputDevice resource, setpagedevice, currentpagedevice.
	(Partially implemented.)

Adds a new type t_struct to handle miscellaneous types that are allocated
as objects and that the interpreter doesn't handle specially, and changes
condition, fontID, gstate, lock, and save types to use t_struct.  (This is
an internal change, not visible at the language level.)

Moves the maxlength of a dictionary to its own ref, eliminating the "size
of integer" hack.  (This is an internal change, not visible at the
language level.)

Adds the last OS error number to the error printout.

Removes the obsolete framedevice operator.

Implements resetfile (the only Level 1 operator not yet implemented!).

Changes the name of the getdevice operator to .getdevice.

Library
-------

Fixes bugs:
	- A couple of necessary casts from char * to byte * were omitted.
	- A Sun compiler required an extra cast to (void *) in the e1
macro in clip_rect_enum_ptrs in gxcpath.c.
	- The gx_dc_ procedures defined in gxdraw.c weren't marked as
'private'.
	- The number of "on" pixels in a halftone cell sometimes varied by
1 from cell to cell.
	- Mapping a gray level to CMYK didn't subtract it from 1 (to
produce the K component).
*	- charpath took hints into account.

Shuffles the order of some declarations to pacify the VMS C compiler.

Version 2.8-beta (11/10/93)
================

This version was distributed only to beta testers.  It adds Type 0 font
support.  It also includes extensive redesign of streams (to eventually
support procedure streams) and device properties (to eventually support
get/setpagedevice and get/setdevparams).

Documentation
-------------

Notes the change in X11 foreground/background handling.

Changes README so it no longer claims that Ghostscript works with X11R3.

Notes (in devs.mak) that the cdjmono driver is the best one to use for the
DeskJet 510.

Procedures
----------

Fixes bugs:
	- echogs wasn't always invoked with ./ on Unix systems.

Changes the file name unix-ansi.mak to unixansi.mak, so it can be created
on a MS-DOS system.

Adds a new "feature", ccinit.dev, which compiles and links the
initialization files (gs_*.ps) into the executable, just as ccfonts.dev
compiles and links fonts.  If ccinit and ccfonts are both selected, the
only external file needed at run time is Fontmap.  Note that you must have
a working version of Ghostscript already in order to create a version that
uses the ccinit feature, just as for ccfonts.

Utilities
---------

Fixes bugs:
	- the ps2image utility didn't put a %! on the first line of the
output.

Drivers
-------

Fixes bugs:
	- The Hercules display driver didn't include definitions for
outport2 and PAGE_HEIGHT_INCHES, which it uses.
	- The BGI driver didn't call setactivepage or setvisualpage,
which it needs to do in general.
	- The Apple DMP driver declared dmp_print_page rather than
appledmp_print_page, causing a compilation error.

Changes the X11 driver so that it doesn't use the default foreground and
background colors: you must set foreground and background explicitly for
Ghostscript if you want them to be other than black and white
respectively.

Adds new user-contributed drivers for:
	- The StarJet 48 inkjet printer;
	- The Linux VGALIB display interface.
	- OS/2 Presentation Manager.

Changes the margins of the Epson driver to 0.2, 0.0, 0.0, 0.0, which
more accurately reflect the printer's capabilities.

Changes the get_props and put_props device procedures to take property
list "objects" with a procedural interface, rather than a data structure
interface.  THIS IS A NON-BACKWARD-COMPATIBLE CHANGE.  It affects all
get_props and put_props procedures.  Fortunately, there were only a few
devices that implemented their own get_props and put_props procedures (the
H-P color printers, and the three window systems -- X Windows, MS Windows,
and OS/2 PM).

Platforms
---------

Fixes bugs:
	- The meaning of the -p switch for the Watcom compile-and-link
program was changed between Watcom C/386 versions 8.5 and 9.5, causing the
make process to malfunction.
	- The SCFTAB and SCFDTAB modules were omitted from the VMS link
list.

Adds user-contributed code for OS/2.

Removes the assumption that an 80486 CPU implies the presence of hardware
floating point, since the 486SX and Cyrix 486SLC don't have it.

Fonts
-----

Fixes bugs:
*	- The GS_FONTPATH scanner didn't recognize .PFB fonts beginning
with %!PS-AdobeFont.
*	- The GS_FONTPATH scanner often didn't recognize .PFB fonts at all.
	- Type 1 fonts always set the line join, line cap, and miter limit
to known values, rather than using the current values.  (Using the current
values doesn't make much sense, but it's apparently what the Adobe
implementations do.)
	- DISKFONTS didn't work, because of the change in the Ghostscript
fonts to do a systemdict begin/end (in version 2.7.1).

Interpreter
-----------

Fixes bugs:
	- == didn't produce exactly the same output as the Adobe
interpreters.  (Some automated debugging and testing programs care.)
	- The CCITTFaxEncode filter could get caught in an infinite loop,
because it failed to mask a byte datum when scanning for runs of black
pixels.
	- The write operator gave an error for values outside the range 0
to 255, rather than just using the low-order 8 bits.
	- Some applications call a statusdict procedure named
setresolution without checking first whether it is present; Ghostscript
didn't provide one.
	- Reading from a closed stream caused an error instead of
returning EOF.
	- Input streams didn't close automatically at EOF.
	- findfont was defined as an operator, not a procedure.
	- closefile on a closed file gave an error.  (It isn't obvious
that the Adobe documentation specifies that it shouldn't, but that's what
Adobe says they do.)
	- The LZWDecode filter didn't handle codes representing strings
longer than the buffer size correctly.
	- The LZWDecode filter only allowed 4095 codes to be used, rather
than 4096.
	- The rand operator produced an infinite string of zeros if
given 0 or 0x7fffffff as the seed.
	- When a CDevProc procedure was called, there was an extra
copy of the character name on the operand stack below the operands of
CDevProc.

Replaces all stream implementations with new ones designed to allow
interruption at arbitrary times.  ****** The 2-D case of CCITTFaxEncode
hasn't been converted (but it probably didn't work before, either).

Implements additional Level 2 features:
	- Type 0 (composite) fonts.

Adds an eexecEncode filter.

Implements setcolorscreen, which was accidentally omitted from 2.7.

Library
-------

Fixes bugs:
*	- In colorimage, if the color space of the image was different
from the current color space, and the first data values on a scan line
were zeros, the wrong color could result.
	- The new flatness testing algorithm could overflow, producing
straight lines or obvious polygons instead of curves.
	- Images could fail to display pixels after the first non-blank
pixel on a line if halftoned color was required.  (This bug was probably
introduced in 2.7.)
	- Interpolation between transfer map entries didn't work, because
of a rounding/truncation bug in frac2bits (bug introduced in 2.7.1.)
	- cshow did an extra grestore at the end.

* Implements a hack to slightly displace 1-bit-wide or -high images.  This
is necessary to work around a bug in TeX (or dvips?), which uses such
images to draw horizontal and vertical lines without positioning them to
ensure that they cover device pixel centers.

Adds support for composite fonts (no new client procedures).

Version 2.7.2-beta (10/11/93)
==================

This version was distributed only to alpha testers.

Utilities
---------

Fixes bugs:
	- prfont.ps didn't print unencoded characters.

Improves mergeini.ps to remove embedded comments.

Interpreter
-----------

Fixes bugs:
	- An error occurring within the scope of an internal .stopped
didn't pop the command and error name off the stack.
*	- The = and == procedures weren't re-entrant.

* Adds a .writecvs operator that does a cvs to an internal string followed
by a writestring.

Library
-------

Fixes bugs:
	- grestore freed the path and the clip path in an order that
was likely to lead to memory sandbars.
	- moveto + closepath didn't actually close the path.
	- moveto + reversepath produced an empty path (no moveto).
	- moveto + closepath + reversepath produced an extra lineto.
	- reversepath didn't set the current point to the end (i.e., the
former beginning) of the last subpath.

Adds a "planar" memory device.

Version 2.7.1-beta (10/4/93, not distributed to the public)
==================

Like 2.7, this version was created to satisfy a contractual requiremen