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diff --git a/doc/Source.htm b/doc/Source.htm deleted file mode 100644 index 82b03bee..00000000 --- a/doc/Source.htm +++ /dev/null @@ -1,430 +0,0 @@ -<!doctype html> -<html lang="en"> -<head> - <meta http-equiv="content-type" content="text/html; charset=utf-8"> - <meta name="viewport" content="user-scalable=yes, initial-scale=1, width=device-width"> - <link href="https://fonts.googleapis.com/css?family=Source+Sans+Pro:200,200i,300,300i,400,400i,600,600i,700,700i,900,900i" rel="stylesheet"> - <link rel="shortcut icon" href="images/favicon.svg"> - <title>Guide to Ghostscript Source Code</title> - <link href="default.css" rel="stylesheet" type="text/css"> -</head> - -<body> - <header><div class="title"><a href="index.html"><h1 aria-label="title">Ghostscript documentation</h1><h2 aria-label="version"></h2></a></div><a href="Search.htm" aria-label="Search" id="searchSite"><div class="search"></div></a></header> - <main> - <article> - <div class="outer"> - - <div class="inner"> -<!--START EDITING HERE--> - -<h1>Guide to Ghostscript Source Code</h1> - -<h2><a name="toc"></a>Table of contents</h2> -<ul class="toc"> - <li><a href="#Overview">Conceptual overview</a></li> - <li><a href="#PostScript_interpreter">PostScript Interpreter</a></li> - <li><a href="#PDF_interpreter">PDF interpreter</a></li> - <li><a href="#Graphics_library">Graphics library</a></li> - <li> - <ul> - <li><a href="#Drivers">Device drivers</a></li> - <li><a href="#Platform_specific_code">Platform-specific code</a></li> - </ul> - </li> - <li><a href="#Makefiles">Makefiles</a></li> -</ul> - -<!-- [1.2 end table of contents] =========================================== --> - -<!-- [1.3 begin hint] ====================================================== --> - -<p>For other information, see the <a href="Readme.htm">Ghostscript -overview</a> and the documents on <a href="Make.htm">how to build -Ghostscript</a> from source, <a href="C-style.htm">Ghostscript C coding -guidelines</a>, <a href="Drivers.htm">drivers</a>, the -<a href="Lib.htm">Ghostscript library</a> and <a href="Install.htm">how to -install Ghostscript</a>. - -<!-- [1.3 end hint] ======================================================== --> - -<hr> - -<!-- [1.0 end visible header] ============================================== --> - -<!-- [2.0 begin contents] ================================================== --> - -<h2><a name="Overview"></a>Conceptual overview</h2> - -<p> -The Ghostscript source code is divided conceptually as follows: - -<blockquote><table> -<tr> - <th align="left" colspan="2">PostScript interpreter:</th> - </tr> -<tr> - - <td>PostScript operators</td> - - <td><code>z</code>*<code>.h</code> and <code>z</code>*<code>.c</code></td> - </tr> -<tr> - - <td>Other interpreter code</td> - - <td><code>i</code>*<code>.h</code> and <code>i</code>*<code>.c</code></td> - </tr> -<tr> - - <td>PostScript code</td> - - <td><code>gs_</code>*<code>.ps</code></td> - </tr> -<tr> - <th align="left" colspan="2">PDF interpreter:</th> - </tr> -<tr> - - <td>PostScript code</td> - - <td><code>pdf_</code>*<code>.ps</code></td> - </tr> -<tr> - <th align="left" colspan="2">Graphics library:</th> - </tr> -<tr> - - <td>Main library code</td> - - <td><code>g</code>*<code>.h</code> and <code>g</code>*<code>.c</code></td> - </tr> -<tr> - - <td>Streams</td> - - <td><code>s</code>*<code>.h</code> and <code>s</code>*<code>.c</code></td> - </tr> -<tr> - - <td><a href="#Drivers">Device drivers</a></td> - - <td><code>gdev</code>*<code>.h</code> and <code>gdev</code>*<code>.c</code></td> - </tr> -<tr> - - <td><a href="#Platform_specific_code">Platform-specific code</a></td> - - <td><code>gp</code>*<code>.h</code> and <code>gp</code>*<code>.c</code></td> - </tr> -</table></blockquote> - -<hr> - -<h2><a name="PostScript_interpreter"></a>PostScript Interpreter</h2> - -<p> -<code>gs.c</code> is the main program for the interactive language -interpreter; <code>gserver.c</code> is an alternative main program that -is a rudimentary server. If you configure Ghostscript as a server rather -than an interactive program, you will use <code>gserver.c</code> instead -of <code>gs.c</code>. - -<p> -Files named <code>z</code>*<code>.c</code> are Ghostscript operator -files. The names of the files generally follow the section headings of the -operator summary in section 6.2 (Second Edition) or 8.2 (Third Edition) of -the PostScript Language Reference Manual. Each operator XXX is implemented -by a procedure named <code>z</code>XXX, for example, -<code>zfill</code> and <code>zarray</code>. - -<p> -Files named <code>i</code>*<code>.c</code>, and *<code>.h</code> -other than <code>g</code>*<code>.h</code>, are the rest of the -interpreter. See the makefile for a little more information on how the -files are divided functionally. - -<p> -The main loop of the PostScript interpreter is the <code>interp</code> -procedure in <code>interp.c</code>. When the interpreter is reading -from an input file, it calls the token scanner in -<code>iscan</code>*<code>.c</code>. - -<p> -<code>idebug.c</code> contains a lot of debugger-callable routines -useful for printing PostScript objects when debugging. - -<hr> - -<h2><a name="PDF_interpreter"></a>PDF interpreter</h2> - -<p> -The PDF interpreter is written entirely in PostScript. Its main loop is -the <code>.pdfrun</code> procedure in <code>pdf_base.ps</code>. When -the PDF interpreter is configured into the build, it redefines the -"<code>run</code>" operator to test whether the file is a PDF file. -This redefinition is near the beginning of <code>pdf_main.ps</code>. - -<hr> - -<h2><a name="Graphics_library"></a>Graphics library</h2> - -<p> -Files beginning with <code>gs</code>, <code>gx</code>, or -<code>gz</code> (both <code>.c</code> and <code>.h</code>), other -than <code>gs.c</code> and <code>gserver.c</code>, are the -Ghostscript library. Files beginning with <code>gdev</code> are device -drivers or related code, also part of the library. Other files beginning -with <code>g</code> are library files that don't fall neatly into either -the kernel or the driver category. - -<p> -Files named <code>s</code>*<code>.c</code> and -<code>s</code>*<code>.h</code> are a flexible stream package, -including the Level 2 PostScript "filters" supported by Ghostscript. See -<code>stream.h</code>, <code>scommon.h</code>, and -<code>strimpl.h</code> for all the details. - -<h3><a name="Drivers"></a>Device drivers</h3> - -<p> -The interface between the graphics library and device drivers is the only -really well documented one in all of Ghostscript: see the -<a href="Drivers.htm">documentation on drivers</a>. - -<p> -In addition to many real device and file format drivers listed in -<code>devs.mak</code> and <code>contrib.mak</code>, a number of -drivers are used for internal purposes. You can search -<code>lib.mak</code> for files named -<code>gdev</code>*<code>.c</code> to find almost all of them. - -<p> -Drivers are divided into "printer" drivers, which support banding, and -non-printer drivers, which don't. The decision whether banding is -required is made (by default on the basis of how much memory is available) -in the procedure <code>gdev_prn_alloc</code> in -<code>gdevprn.c</code>: it implements this decision by filling the -virtual procedure table for the printer device in one of two different -ways. - -<p> -A good simple "printer" (bandable) driver to read is -<code>gdevmiff.c</code>: it's less than 100 lines, of which much is -boilerplate. There are no simple non-printer drivers that actually drive -devices: probably the simplest non-printer driver for reading is -<code>gdevm8.c</code>, which implements 8-bit-deep devices that only -store the bits in memory. - -<h3><a name="Platform_specific_code"></a>Platform-specific code</h3> - -<p> -There are very few platform dependencies in Ghostscript. Ghostscript deals -with them in three ways: - -<ul> -<li>Files named *<code>_.h</code> substitute for the corresponding -<code><</code>*<code>.h></code> file by adding conditionals -that provide a uniform set of system interfaces on all platforms. - -<li>The file <code>arch.h</code> contains a set of -mechanically-discovered platform properties like byte order, size of -<code>int</code>, etc. These properties, <b>not</b> the names of -specific platforms, are used to select between different algorithms or -parameters at compile time. - -<li>Files named <code>gp</code>*<code>.h</code> define interfaces -that are intended to be implemented differently on each platform, but whose -specification is common to all platforms. -</ul> - -<p> -The platform-specific implementations of the -<code>gp</code>*<code>.h</code> interfaces have names of the form -"<code>gp_</code><em>{platform}</em><code>.c</code>, specifically -(this list may be out of date): - -<blockquote><table> -<tr> - <th colspan="2">Platform-specific interfaces</th> - </tr> -<tr> - <th align="left">Routine</th> - <th align="left">Platform</th> - </tr> -<tr> - <td><code>gp_dosfb.c</code></td> - <td>DOS</td> - </tr> -<tr> - <td><code>gp_dosfs.c</code></td> - <td>DOS and MS Windows</td> - </tr> -<tr> - <td><code>gp_itbc.c</code></td> - <td>DOS, Borland compilers</td> - </tr> -<tr> - <td><code>gp_iwatc.c</code></td> - <td>DOS, Watcom or Microsoft compiler</td> - </tr> -<tr> - <td><code>gp_msdos.c</code></td> - <td>DOS and MS Windows</td> - </tr> -<tr> - <td><code>gp_ntfs.c</code></td> - <td>MS Windows NT</td> - </tr> -<tr> - <td><code>gp_os2.c</code></td> - <td>OS/2</td> - </tr> -<tr> - <td><code>gp_os9.c</code></td> - <td>OS-9</td> - </tr> -<tr> - <td><code>gp_unifs.c</code></td> - <td>Unix, OS-9, and QNX</td> - </tr> -<tr> - <td><code>gp_unix.c</code></td> - - <td>Unix and QNX</td> - </tr> -<tr> - <td><code>gp_vms.c</code></td> - - <td>VMS</td> - </tr> -<tr> - <td><code>gp_win32.c</code></td> - - <td>MS Windows NT</td> - </tr> -</table></blockquote> - -<p> -If you are going to extend Ghostscript to new machines or operating -systems, check the *<code>_.h</code> files for <code>ifdef</code> on -things other than <code>DEBUG</code>. You should probably plan to make -a new makefile and a new <code>gp_</code>XXX<code>.c</code> file. - -<hr> - -<h2><a name="Makefiles"></a>Makefiles</h2> - -<p> -This section is only for advanced developers who need to integrate -Ghostscript into a larger program at build time. - -<p> -NOTE: THIS SECTION IS INCOMPLETE. IT WILL BE IMPROVED IN A LATER REVISION. - -<p> -The Ghostscript makefiles are meant to be organized according to the -following two principles: - -<ul> - -<li>All the parameters that vary from platform to platform appear in the -top-level makefile for a given platform. ("Platform" = OS + compiler + -choice of interpreter vs. library) - -<li>All the rules and definitions that can meaningfully be shared among more -than 1 platform appear in a makefile that is "included" by a makefile -(normally the top-level makefile) for those platforms. -</ul> - -<p> -Thus, for example: - -<ul> - -<li>Rules and definitions shared by all builds are in -<code>gs.mak</code>. - -<li>Rules and definitions specific to the library (on all platforms) are in -<code>lib.mak</code>. In principle this could be merged with -<code>gs.mak</code>, but we wanted to leave open the possibility that -<code>gs.mak</code> might be useful with hypothetical interpreter-only -products. - -<li>Stuff specific to interpreters (on all platforms) is in -<code>int.mak</code>. - -<li>Stuff specific to all Unix platforms should be in a single -<code>unix.mak</code> file, but because <code>make</code> sometimes -cares about the order of definitions, and because some of it is shared with -DV/X, it got split between <code>unix-aux.mak</code>, -<code>unix-end.mak</code>, <code>unixhead.mak</code>, -<code>unixinst.mak</code>, and <code>unixlink.mak</code>. - -</ul> - -<p> -For MS-DOS and MS Windows builds, there should be: - -<ul> - -<li>A makefile for all MS OS (DOS or Windows) builds, for all - compilers and products. - -<li>Perhaps a makefile for all MS-DOS builds, for all compilers and -products, although since Watcom is the only such compiler we're likely to -support this may be overkill. - -<li>A makefile for all MS Windows builds, for all compilers and products. - -<li>A makefile for all Watcom builds (DOS or Windows), for all products. - -<li>A top-level makefile for the Watcom DOS interpreter product. - -<li>A top-level makefile for the Watcom Windows interpreter product. - -<li>A top-level makefile for the Watcom DOS library "product". - -<li>A top-level makefile for the Watcom Windows library "product". - -<li>A makefile for all Borland builds (DOS or Windows), for all - products. - -</ul> - -<p> -and so on. - -<!-- [2.0 end contents] ==================================================== --> - -<!-- [3.0 begin visible trailer] =========================================== --> -<hr> - -<p> -<small>Copyright © 2000-2022 Artifex Software, Inc. All rights reserved.</small> - -<p> -This software is provided AS-IS with no warranty, either express or -implied. - -This software is distributed under license and may not be copied, modified -or distributed except as expressly authorized under the terms of that -license. Refer to licensing information at <a href="https://www.artifex.com">https://www.artifex.com</a> -or contact Artifex Software, Inc., 1305 Grant Avenue - Suite 200, -Novato, CA 94945, U.S.A., +1(415)492-9861, for further information. - -<p> -<small>Ghostscript version 9.56.1, 4 April 2022 - -<!-- [3.0 end visible trailer] ============================================= --> - - - -<!--FINISH EDITING HERE--> - </div><!-- close inner --> - </div><!-- close outer --> - </article> - </main> - <script src="site.js"></script> -</body> -</html> |