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<!-- REMEMBER TO EDIT index.html.source --><head><TITLE>gd 2.0.33</TITLE></head><body bgcolor="#FFFFFF"><!-- BANNER HERE --><H2>gd 2.0.33</H2><H3>A graphics library for fast image creation</H3><H3>Follow this link to the<A HREF="http://www.boutell.com/gd/">latest versionof this document</A>.</H3><blockquote><strong>UPGRADING UNIX USERS: READ THIS FIRST!</strong>Modern versions of gd install by default to /usr/local/lib and/usr/local/include. If you already have an older version of gdin /usr/lib and /usr/include, you may wish to use:<pre>./configure --prefix=/usr</pre> To ensure that yournew installation overwrites the old.<p><strong>GIF support has been restored in gd 2.0.28 and above.</strong>The well-known patents on LZW compression held by Unisyshave expired in all countries. British Telecom and IBM may hold relatedpatents but have never chosen to require royalties for GIF applications,to the best of my knowledge. I am not a lawyer and cannot givelegal advice regarding this issue. PNG remains a superior format especiallyif lossless truecolor images are needed.<p>When building from soruce, gd 2.0.33 <strong>requires</strong> that the following libraries also be installed, in order to produce the related image formats. The win32 binary release (bgd) already contains theappropriate libraries.You may skip libraries associated with formats you do not use:<p>libpng (see the <a href="http://www.libpng.org/pub/png/">libpng home page</a>), if you want PNG<p>zlib (see the <a href="http://www.info-zip.org/pub/infozip/zlib/">info-zip home page</a>), if you want PNG<p>jpeg-6b or later, if desired (see the <a href="http://www.ijg.org/">Independent JPEG Group home page</a>), if you want JPEG<p>If you want to use the TrueType font support, you must alsoinstall the <strong>FreeType 2.x library</strong>, includingthe header files. See the <a href="http://www.freetype.org/">Freetype Home Page</a>, or <a href="http://freetype.sourceforge.net/">SourceForge</a>. No, I cannot explain why that site is down on a particular day, and no, I can't send you a copy.<p>If you want to use the Xpm color bitmap loading support, you must alsohave the X Window System and the Xpm library installed (Xpm is oftenincluded in modern X distributions). Most of the time you won'tneed Xpm.<p>Please read the documentation and install the required libraries.Do not send email asking why <code>png.h</code> is not found. Do not send email asking why <code>libgd.so</code> is not found, either.See the <a href="#required">requirements section</a> for moreinformation. Thank you!</blockquote><H3>Table of Contents</H3><UL><LI><A HREF="#notice">Credits and license terms</A><LI><A HREF="#whatsnew2.0.33">What's new in version "XYZ" of GD?</A><LI><A HREF="#whatis">What is gd?</A><LI><A HREF="#gdother">What if I want to use another programming language?</A><LI><A HREF="#required">What else do I need to use gd?</A><LI><A HREF="#getgd">How do I get gd?</A><LI><A HREF="#buildgd">How do I build gd?</A><LI><A HREF="#basics">gd basics: using gd in your program</A><LI><A HREF="#webpng">webpng: a useful example</A><LI><A HREF="#reference">Function and type reference by category</A><LI><A HREF="#gdformat">About the additional .gd image file format</A><LI><A HREF="#informing"><strong>Please</strong> tell us you're using gd!</A><LI><A HREF="#support">How do I get support?</A><LI><A HREF="#index">Alphabetical quick index</A></UL><P><A HREF="http://www.boutell.com/">Up to the <EM>Boutell.Com, Inc. Home Page</EM></A><A NAME="notice"><H3>Credits and license terms</A></H3><P>In order to resolve any possible confusion regarding the authorshipof gd, the following copyright statement covers all of the authorswho have required such a statement. <strong>If you are aware of any oversightsin this copyright notice, please contact<a href="http://www.boutell.com/contact">Thomas Boutell</a> who will bepleased to correct them.</strong><pre>COPYRIGHT STATEMENT FOLLOWS THIS LINE</pre><blockquote>Portions copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 by Cold SpringHarbor Laboratory. Funded under Grant P41-RR02188 by the NationalInstitutes of Health.<P>Portions copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 by Boutell.Com, Inc.<p>Portions relating to GD2 format copyright 1999, 2000, 2001, 2002, 2003, 2004 Philip Warner.<p>Portions relating to PNG copyright 1999, 2000, 2001, 2002, 2003, 2004 Greg Roelofs.<p>Portions relating to gdttf.c copyright 1999, 2000, 2001, 2002, 2003, 2004 John Ellson (ellson@graphviz.org).<p>Portions relating to gdft.c copyright 2001, 2002, 2003, 2004 John Ellson (ellson@graphviz.org).<p>Portions relating to JPEG and to color quantization copyright 2000, 2001, 2002, 2003, 2004, Doug Becker and copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Thomas G. Lane. This software is based in part on the work of the Independent JPEG Group. See the fileREADME-JPEG.TXT for more information.<p>Portions relating to GIF compression copyright 1989 by JefPoskanzer and David Rowley, with modifications for thread safetyby Thomas Boutell.<p>Portions relating to GIF decompression copyright 1990, 1991, 1993 by David Koblas, with modifications for thread safety byThomas Boutell.<p>Portions relating to WBMP copyright 2000, 2001, 2002, 2003, 2004 Maurice Szmurlo and Johan Van den Brande.<p>Portions relating to GIF animations copyright 2004 Jaakko Hyvätti (jaakko.hyvatti@iki.fi)<p><strong>Permission has been granted to copy, distribute and modify gd in anycontext without fee, including a commercial application, provided that this noticeis present in user-accessible supporting documentation.</strong><p>This does not affect your ownership of the derived work itself, and the intentis to assure proper credit for the authors of gd, not to interferewith your productive use of gd. If you have questions, ask."Derived works" includes all programs that utilize the library.Credit must be given in user-accessible documentation.<p><strong>This software is provided "AS IS."</strong>The copyright holders disclaim all warranties, either express or implied,including but not limited to implied warranties of merchantability andfitness for a particular purpose, with respect to this code and accompanyingdocumentation.<p>Although their code does not appear in the current release, the authorsalso wish to thank Hutchison Avenue Software Corporation for theirprior contributions.</blockquote><pre>END OF COPYRIGHT STATEMENT</pre><A NAME="whatis"><H3>What is gd?</H3></A><P>gd is a graphics library. It allows your code to quicklydraw images complete with lines, arcs, text, multiplecolors, cut and paste from other images, and flood fills, andwrite out the result as a PNG or JPEG file. This is particularlyuseful in World Wide Web applications, where PNG and JPEG are twoof the formats accepted for inline images by most browsers.<P>gd is not a paint program.If you are looking for a paint program, you are looking inthe wrong place. If you are not a programmer, you are lookingin the wrong place, unless you are installing a requiredlibrary in order to run an application.<P>gd does not provide for every possible desirable graphicsoperation. It is not necessary or desirable for gd to becomea kitchen-sink graphics package, but version 2.0 does includemost frequently requested features, including both truecolor andpalette images, resampling (smooth resizing of truecolor images)and so forth.<P><A NAME="gdother"><H3>What if I want to use another programminglanguage?</h3></A>Not all of these tools are necessarily up to date and fully compatiblewith 2.0.33.<h4>PHP</h4>A variant of gd 2.x is included in PHP 4.3.0. It is also possibleto patch PHP 4.2.3 for use with gd 2.0.33; see the<a href="http://www.boutell.com/gd/">gd home page</a> for a link tothat information. It would be a Good Idea to merge all of the thingsthat are better in mainstream gd and all of the things that arebetter in PHP gd at some point in the near future. <h4>Perl</h4>gd can also be used from Perl, courtesy ofLincoln Stein's<a href="http://stein.cshl.org/WWW/software/GD/">GD.pm</a> library, which uses gd as the basis for a set ofPerl 5.x classes. Highly recommended.<h4>OCaml</h4>gd can be used from OCaml, thanks to<a href="http://gd4o.sourceforge.net/">Matt Gushee's GD4O project</a>.<h4>Tcl</h4>gd can be used from Tcl with John Ellson's<a href=http://www.graphviz.org/pub/>Gdtclft</a>dynamically loaded extension package.<h4>Pascal</h4>Pascal enthusiasts should look into the<a href="http://www.freepascal.org/">freepascal</a> project, afree Pascal compiler that includes gd support.<h4>REXX</h4>A <a href="http://www.lightlink.com/hessling/RexxGd/index.html">gd interface for the REXX language</a> is available.<h4>Any Language</h4>The "fly" interpreter performs gd operations specified in a text file.You can output the desired commands to a simpletext file from whatever scripting language you prefer to use, theninvoke the interpreter.<p><ul><li><a href="http://martin.gleeson.com/fly/">fly</a>, by Martin Gleeson</ul><p><A NAME="whatsnew2.0.33"><h3>What's new in version 2.0.33?</h3></a><p>Version 2.0.33 restores compatibility with older releasesof Freetype 2.x in addition to the latest release. Thanks toJohn Ellson and the graphviz project.<p><A NAME="whatsnew2.0.32"><h3>What's new in version 2.0.32?</h3></a><p>Version 2.0.32 restores correct detection of Unicode character setsfor freetype fonts, which repairs a bug that prevented umlauts fromdisplaying properly. Thanks to John Ellson and the graphviz project.Also, version 2.0.32 builds all test programs smoothly in the absence of libpng. <p><A NAME="whatsnew2.0.31"><h3>What's new in version 2.0.31?</h3></a><p>A minor type naming conflict prevented bgd.dll from compiling, and itwas left out of the distribution as a result. This has been corrected.<p><A NAME="whatsnew2.0.30"><h3>What's new in version 2.0.30?</h3></a><p>2.0.29 did not compile correctly when freetype was not available.This has been corrected. Thanks to Alessandro Ranellucci.<p><A NAME="whatsnew2.0.29"><h3>What's new in version 2.0.29?</h3></a><p><ul><li>A 32-bit multiplication overflow vulnerability reported onthe Bugtraq mailing list has been corrected, along with a numberof similar issues. These bugs come into play only when attemptingto deal with images with <i>extremely large</i> dimensions.The relevant functions now fail gracefully when such extremeparameters are specified. The code in question is also correct for systems with larger bit depths. Thanks to Phil Knirsch,Alan Cox and infamous41md.Since exploits are theoretically possible, upgrading is recommended.<li>Support for the fontconfig library, when available. When fontconfig is available and gdFTUseFontConfig(1) has been invokedor the gdFTEX_FONTCONFIG flag has been set for a particular call, fontconfigpatterns can be used to fetch the best available font. For instance, "arial:bold:italic" does the right thing (or as close asthe available fonts permit). Also, standard PostScript font names can be mapped to an appropriate font by gdImageStringFTEx and relatives. When fontconfig is available <tt>gdlib-config --features</tt> will listthe GD_FONTCONFIG feature. For more information about fontconfig, see the<a href="http://freedesktop.org/software/fontconfig">fontconfig pages</a>.<p>The actual resolved font filename can be returned in the gdFTStringExtrastructure as the fontpath element if the gdFTEX_RETURNFONTPATHNAME flagis set. Also, a vector of character position advances can be retrieved if gdFTEX_XSHOW is set in the flags element. .afm files (font metrics) are now used to adjust size calculationswhen available. When fontconfig is not available, gd falls back to itsusual behavior and requires a specific font file name. One canstill fetch fonts by filename when gdFTUseFontConfig(1) is in effect, by⌨️ 快捷键说明
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