#if?0?/*?in?case?someone?actually?tries?to?compile?this?*/

/*?example.c?-?an?example?of?using?libpng
?*?Last?changed?in?libpng?1.2.35?[February?14?2009]
?*?This?file?has?been?placed?in?the?public?domain?by?the?authors.
?*?Maintained?1998-2009?Glenn?Randers-Pehrson
?*?Maintained?1996?1997?Andreas?Dilger）
?*?Written?1995?1996?Guy?Eric?Schalnat?Group?42?Inc.）
?*/

/*?This?is?an?example?of?how?to?use?libpng?to?read?and?write?PNG?files.
?*?The?file?libpng.txt?is?much?more?verbose?then?this.??If?you?have?not
?*?read?it?do?so?first.??This?was?designed?to?be?a?starting?point?of?an
?*?implementation.??This?is?not?officially?part?of?libpng?is?hereby?placed
?*?in?the?public?domain?and?therefore?does?not?require?a?copyright?notice.
?*
?*?This?file?does?not?currently?compile?because?it?is?missing?certain
?*?parts?like?allocating?memory?to?hold?an?image.??You?will?have?to
?*?supply?these?parts?to?get?it?to?compile.??For?an?example?of?a?minimal
?*?working?PNG?reader/writer?see?pngtest.c?included?in?this?distribution;
?*?see?also?the?programs?in?the?contrib?directory.
?*/

#include?“png.h“

?/*?The?png_jmpbuf（）?macro?used?in?error?handling?became?available?in
??*?libpng?version?1.0.6.??If?you?want?to?be?able?to?run?your?code?with?older
??*?versions?of?libpng?you?must?define?the?macro?yourself?（but?only?if?it
??*?is?not?already?defined?by?libpng!）.
??*/

#ifndef?png_jmpbuf
#??define?png_jmpbuf（png_ptr）?（（png_ptr）->jmpbuf）
#endif

/*?Check?to?see?if?a?file?is?a?PNG?file?using?png_sig_cmp（）.??png_sig_cmp（）
?*?returns?zero?if?the?image?is?a?PNG?and?nonzero?if?it?isn‘t?a?PNG.
?*
?*?The?function?check_if_png（）?shown?here?but?not?used?returns?nonzero?（true）
?*?if?the?file?can?be?opened?and?is?a?PNG?0?（false）?otherwise.
?*
?*?If?this?call?is?successful?and?you?are?going?to?keep?the?file?open
?*?you?should?call?png_set_sig_bytes（png_ptr?PNG_BYTES_TO_CHECK）;?once
?*?you?have?created?the?png_ptr?so?that?libpng?knows?your?application
?*?has?read?that?many?bytes?from?the?start?of?the?file.??Make?sure?you
?*?don‘t?call?png_set_sig_bytes（）?with?more?than?8?bytes?read?or?give?it
?*?an?incorrect?number?of?bytes?read?or?you?will?either?have?read?too
?*?many?bytes?（your?fault）?or?you?are?telling?libpng?to?read?the?wrong
?*?number?of?magic?bytes?（also?your?fault）.
?*
?*?Many?applications?already?read?the?first?2?or?4?bytes?from?the?start
?*?of?the?image?to?determine?the?file?type?so?it?would?be?easiest?just
?*?to?pass?the?bytes?to?png_sig_cmp（）?or?even?skip?that?if?you?know
?*?you?have?a?PNG?file?and?call?png_set_sig_bytes（）.
?*/
#define?PNG_BYTES_TO_CHECK?4
int?check_if_png（char?*file_name?FILE?**fp）
{
???char?buf[PNG_BYTES_TO_CHECK];

???/*?Open?the?prospective?PNG?file.?*/
???if?（（*fp?=?fopen（file_name?“rb“））?==?NULL）
??????return?0;

???/*?Read?in?some?of?the?signature?bytes?*/
???if?（fread（buf?1?PNG_BYTES_TO_CHECK?*fp）?!=?PNG_BYTES_TO_CHECK）
??????return?0;

???/*?Compare?the?first?PNG_BYTES_TO_CHECK?bytes?of?the?signature.
??????Return?nonzero

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件?????312725??2009-02-15?05:59??zlib+libpng\d7885b5e5873\aclocal.m4

?????文件???????1501??2009-02-15?05:59??zlib+libpng\d7885b5e5873\ANNOUNCE

?????文件????????639??2008-05-02?10:44??zlib+libpng\d7885b5e5873\autogen.sh

?????文件?????115802??2009-02-15?05:59??zlib+libpng\d7885b5e5873\CHANGES

?????文件??????44878??2008-05-02?11:50??zlib+libpng\d7885b5e5873\config.guess

?????文件???????2150??2009-02-15?05:59??zlib+libpng\d7885b5e5873\config.h.in

?????文件??????33387??2008-05-02?11:50??zlib+libpng\d7885b5e5873\config.sub

?????文件?????435168??2009-02-15?05:59??zlib+libpng\d7885b5e5873\configure

?????文件???????4266??2009-02-15?05:59??zlib+libpng\d7885b5e5873\configure.ac

?????文件??????17992??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\COPYING

?????文件???????2373??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\LICENSE

?????文件???????3905??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\Makefile.mingw32

?????文件???????2966??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\Makefile.sgi

?????文件???????4010??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\Makefile.unx

?????文件???????3335??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\Makefile.w32

?????文件???????3557??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\makevms.com

?????文件???????7801??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\README

?????文件???????9758??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\readpng.c

?????文件???????3260??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\readpng.h

?????文件??????24685??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\readpng2.c

?????文件???????3942??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\readpng2.h

?????文件???????5424??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\readppm.c

?????文件??????22911??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\rpng-win.c

?????文件??????30776??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\rpng-x.c

?????文件??????45309??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\rpng2-win.c

?????文件??????82268??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\rpng2-x.c

?????文件??????12901??1997-04-09?02:34??zlib+libpng\d7885b5e5873\contrib\gregbook\toucan.png

?????文件??????31050??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\wpng.c

?????文件??????12789??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\writepng.c

?????文件???????4237??2009-02-15?05:59??zlib+libpng\d7885b5e5873\contrib\gregbook\writepng.h

............此處省略512個文件信息