diff options
Diffstat (limited to 'Build/source/libs/libpng/libpng.3')
-rw-r--r-- | Build/source/libs/libpng/libpng.3 | 174 |
1 files changed, 37 insertions, 137 deletions
diff --git a/Build/source/libs/libpng/libpng.3 b/Build/source/libs/libpng/libpng.3 index a94c616db7f..060cdc1426f 100644 --- a/Build/source/libs/libpng/libpng.3 +++ b/Build/source/libs/libpng/libpng.3 @@ -1,6 +1,6 @@ -.TH LIBPNG 3 "May 15, 2007" +.TH LIBPNG 3 "December 14, 2007" .SH NAME -libpng \- Portable Network Graphics (PNG) Reference Library 1.2.18 +libpng \- Portable Network Graphics (PNG) Reference Library 1.2.24 .SH SYNOPSIS \fB #include <png.h>\fP @@ -410,7 +410,7 @@ Following is a copy of the libpng.txt file that accompanies libpng. .SH LIBPNG.TXT libpng.txt - A description on how to use and modify libpng - libpng version 1.2.18 - May 15, 2007 + libpng version 1.2.24 - December 14, 2007 Updated and distributed by Glenn Randers-Pehrson <glennrp at users.sourceforge.net> Copyright (c) 1998-2007 Glenn Randers-Pehrson @@ -496,9 +496,7 @@ Libpng is thread safe, provided the threads are using different instances of the structures. Each thread should have its own png_struct and png_info instances, and thus its own image. Libpng does not protect itself against two threads using the -same instance of a structure. Note: thread safety may be defeated -by use of some of the MMX assembler code in pnggccrd.c, which is only -compiled when the user defines PNG_THREAD_UNSAFE_OK. +same instance of a structure. .SH II. Structures @@ -2765,17 +2763,13 @@ For a more compact example of writing a PNG image, see the file example.c. .SH V. Modifying/Customizing libpng: -There are three issues here. The first is changing how libpng does +There are two issues here. The first is changing how libpng does standard things like memory allocation, input/output, and error handling. The second deals with more complicated things like adding new chunks, adding new transformations, and generally changing how libpng works. Both of those are compile-time issues; that is, they are generally determined at the time the code is written, and there is rarely a need -to provide the user with a means of changing them. The third is a -run-time issue: choosing between and/or tuning one or more alternate -versions of computationally intensive routines; specifically, optimized -assembly-language (and therefore compiler- and platform-dependent) -versions. +to provide the user with a means of changing them. Memory allocation, input/output, and error handling @@ -3136,125 +3130,6 @@ When PNG_DEBUG = 1, the macros are defined, but only png_debug statements having level = 0 will be printed. There aren't any such statements in this version of libpng, but if you insert some they will be printed. -.SH VI. Runtime optimization - -A new feature in libpng 1.2.0 is the ability to dynamically switch between -standard and optimized versions of some routines. Currently these are -limited to three computationally intensive tasks when reading PNG files: -decoding row filters, expanding interlacing, and combining interlaced or -transparent row data with previous row data. Currently the optimized -versions are available only for x86 (Intel, AMD, etc.) platforms with -MMX support, though this may change in future versions. (For example, -the non-MMX assembler optimizations for zlib might become similarly -runtime-selectable in future releases, in which case libpng could be -extended to support them. Alternatively, the compile-time choice of -floating-point versus integer routines for gamma correction might become -runtime-selectable.) - -Because such optimizations tend to be very platform- and compiler-dependent, -both in how they are written and in how they perform, the new runtime code -in libpng has been written to allow programs to query, enable, and disable -either specific optimizations or all such optimizations. For example, to -enable all possible optimizations (bearing in mind that some "optimizations" -may actually run more slowly in rare cases): - - #if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200) - png_uint_32 mask, flags; - - flags = png_get_asm_flags(png_ptr); - mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE); - png_set_asm_flags(png_ptr, flags | mask); - #endif - -To enable only optimizations relevant to reading PNGs, use PNG_SELECT_READ -by itself when calling png_get_asm_flagmask(); similarly for optimizing -only writing. To disable all optimizations: - - #if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200) - flags = png_get_asm_flags(png_ptr); - mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE); - png_set_asm_flags(png_ptr, flags & ~mask); - #endif - -To enable or disable only MMX-related features, use png_get_mmx_flagmask() -in place of png_get_asm_flagmask(). The mmx version takes one additional -parameter: - - #if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200) - int selection = PNG_SELECT_READ | PNG_SELECT_WRITE; - int compilerID; - - mask = png_get_mmx_flagmask(selection, &compilerID); - #endif - -On return, compilerID will indicate which version of the MMX assembler -optimizations was compiled. Currently two flavors exist: Microsoft -Visual C++ (compilerID == 1) and GNU C (a.k.a. gcc/gas, compilerID == 2). -On non-x86 platforms or on systems compiled without MMX optimizations, a -value of -1 is used. - -Note that both png_get_asm_flagmask() and png_get_mmx_flagmask() return -all valid, settable optimization bits for the version of the library that's -currently in use. In the case of shared (dynamically linked) libraries, -this may include optimizations that did not exist at the time the code was -written and compiled. It is also possible, of course, to enable only known, -specific optimizations; for example: - - #if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200) - flags = PNG_ASM_FLAG_MMX_READ_COMBINE_ROW \ - | PNG_ASM_FLAG_MMX_READ_INTERLACE \ - | PNG_ASM_FLAG_MMX_READ_FILTER_SUB \ - | PNG_ASM_FLAG_MMX_READ_FILTER_UP \ - | PNG_ASM_FLAG_MMX_READ_FILTER_AVG \ - | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ; - png_set_asm_flags(png_ptr, flags); - #endif - -This method would enable only the MMX read-optimizations available at the -time of libpng 1.2.0's release, regardless of whether a later version of -the DLL were actually being used. (Also note that these functions did not -exist in versions older than 1.2.0, so any attempt to run a dynamically -linked app on such an older version would fail.) - -To determine whether the processor supports MMX instructions at all, use -the png_mmx_support() function: - - #if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200) - mmxsupport = png_mmx_support(); - #endif - -It returns -1 if MMX support is not compiled into libpng, 0 if MMX code -is compiled but MMX is not supported by the processor, or 1 if MMX support -is fully available. Note that png_mmx_support(), png_get_mmx_flagmask(), -and png_get_asm_flagmask() all may be called without allocating and ini- -tializing any PNG structures (for example, as part of a usage screen or -"about" box). - -The following code can be used to prevent an application from using the -thread_unsafe features, even if libpng was built with PNG_THREAD_UNSAFE_OK -defined: - -#if defined(PNG_USE_PNGGCCRD) && defined(PNG_ASSEMBLER_CODE_SUPPORTED) \ - && defined(PNG_THREAD_UNSAFE_OK) - /* Disable thread-unsafe features of pnggccrd */ - if (png_access_version_number() >= 10200) - { - png_uint_32 mmx_disable_mask = 0; - png_uint_32 asm_flags; - - mmx_disable_mask |= ( PNG_ASM_FLAG_MMX_READ_COMBINE_ROW \ - | PNG_ASM_FLAG_MMX_READ_FILTER_SUB \ - | PNG_ASM_FLAG_MMX_READ_FILTER_AVG \ - | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ); - asm_flags = png_get_asm_flags(png_ptr); - png_set_asm_flags(png_ptr, asm_flags & ~mmx_disable_mask); - } -#endif - -For more extensive examples of runtime querying, enabling and disabling -of optimized features, see contrib/gregbook/readpng2.c in the libpng -source-code distribution. - .SH VII. MNG support The MNG specification (available at http://www.libpng.org/pub/mng) allows @@ -3331,13 +3206,13 @@ application: .SH IX. Y2K Compliance in libpng -May 15, 2007 +December 14, 2007 Since the PNG Development group is an ad-hoc body, we can't make an official declaration. This is your unofficial assurance that libpng from version 0.71 and -upward through 1.2.18 are Y2K compliant. It is my belief that earlier +upward through 1.2.24 are Y2K compliant. It is my belief that earlier versions were also Y2K compliant. Libpng only has three year fields. One is a 2-byte unsigned integer that @@ -3526,6 +3401,31 @@ the first widely used release: 1.2.17 13 10217 12.so.0.17[.0] 1.0.26 10 10026 10.so.0.26[.0] 1.2.18 13 10218 12.so.0.18[.0] + 1.2.19beta1-31 13 10219 12.so.0.19[.0] + 1.0.27rc1-6 10 10027 10.so.0.27[.0] + 1.2.19rc1-6 13 10219 12.so.0.19[.0] + 1.0.27 10 10027 10.so.0.27[.0] + 1.2.19 13 10219 12.so.0.19[.0] + 1.2.20beta01-04 13 10220 12.so.0.20[.0] + 1.0.28rc1-6 10 10028 10.so.0.28[.0] + 1.2.20rc1-6 13 10220 12.so.0.20[.0] + 1.0.28 10 10028 10.so.0.28[.0] + 1.2.20 13 10220 12.so.0.20[.0] + 1.2.21beta1-2 13 10221 12.so.0.21[.0] + 1.2.21rc1-3 13 10221 12.so.0.21[.0] + 1.0.29 10 10029 10.so.0.29[.0] + 1.2.21 13 10221 12.so.0.21[.0] + 1.2.22beta1-4 13 10222 12.so.0.22[.0] + 1.0.30rc1 13 10030 10.so.0.30[.0] + 1.2.22rc1 13 10222 12.so.0.22[.0] + 1.0.30 10 10030 10.so.0.30[.0] + 1.2.22 13 10222 12.so.0.22[.0] + 1.2.23beta01-05 13 10223 12.so.0.23[.0] + 1.2.23rc01 13 10223 12.so.0.23[.0] + 1.2.23 13 10223 12.so.0.23[.0] + 1.2.24beta01-02 13 10224 12.so.0.24[.0] + 1.2.24rc01 13 10224 12.so.0.24[.0] + 1.2.24 13 10224 12.so.0.24[.0] Henceforth the source version will match the shared-library minor and patch numbers; the shared-library major version number will be @@ -3538,7 +3438,7 @@ version 1.0.6j; from then on they were given the upcoming public release number plus "betaNN" or "rcN". .SH "SEE ALSO" -libpngpf(3), png(5) +.IR libpngpf(3) ", " png(5) .LP .IR libpng : .IP @@ -3581,7 +3481,7 @@ possible without all of you. Thanks to Frank J. T. Wojcik for helping with the documentation. -Libpng version 1.2.18 - May 15, 2007: +Libpng version 1.2.24 - December 14, 2007: Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc. Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net). @@ -3602,7 +3502,7 @@ included in the libpng distribution, the latter shall prevail.) If you modify libpng you may insert additional notices immediately following this sentence. -libpng versions 1.2.6, August 15, 2004, through 1.2.18, May 15, 2007, are +libpng versions 1.2.6, August 15, 2004, through 1.2.24, December 14, 2007, are Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are distributed according to the same disclaimer and license as libpng-1.2.5 with the following individual added to the list of Contributing Authors @@ -3701,7 +3601,7 @@ certification mark of the Open Source Initiative. Glenn Randers-Pehrson glennrp at users.sourceforge.net -May 15, 2007 +December 14, 2007 .\" end of man page |