diff options
Diffstat (limited to 'libpng.3')
| -rw-r--r-- | libpng.3 | 62 |
1 files changed, 35 insertions, 27 deletions
@@ -1,6 +1,6 @@ -.TH LIBPNG 3 "March 29, 2012" +.TH LIBPNG 3 "June 14, 2012" .SH NAME -libpng \- Portable Network Graphics (PNG) Reference Library 1.5.10 +libpng \- Portable Network Graphics (PNG) Reference Library 1.5.11 .SH SYNOPSIS \fI\fB @@ -979,9 +979,9 @@ the Portable Network Graphics (PNG) format image files. It uses the compression library. Following is a copy of the libpng-manual.txt file that accompanies libpng. .SH LIBPNG.TXT -libpng-manual.txt - A description on how to use and modify libpng +Libpng-manual.txt - A description on how to use and modify libpng - libpng version 1.5.10 - March 29, 2012 + libpng version 1.5.11 - June 14, 2012 Updated and distributed by Glenn Randers-Pehrson <glennrp at users.sourceforge.net> Copyright (c) 1998-2011 Glenn Randers-Pehrson @@ -992,7 +992,7 @@ libpng-manual.txt - A description on how to use and modify libpng Based on: - libpng versions 0.97, January 1998, through 1.5.10 - March 29, 2012 + libpng versions 0.97, January 1998, through 1.5.11 - June 14, 2012 Updated and distributed by Glenn Randers-Pehrson Copyright (c) 1998-2011 Glenn Randers-Pehrson @@ -1122,8 +1122,8 @@ APIs. Most of these are fairly obvious; for example types corresponding to integers of particular sizes and types for passing color values. One exception is how non-integral numbers are handled. For application -convenience most APIs that take such numbers have C (double) arguments, -however internally PNG, and libpng, use 32 bit signed integers and encode +convenience most APIs that take such numbers have C (double) arguments; +however, internally PNG, and libpng, use 32 bit signed integers and encode the value by multiplying by 100,000. As of libpng 1.5.0 a convenience macro PNG_FP_1 is defined in png.h along with a type (png_fixed_point) which is simply (png_int_32). @@ -1780,7 +1780,7 @@ the screen_gamma value. Pixels with alpha less than 1.0 will still have linear components. Use this format if you have control over your -compositing software and do don't do other arithmetic +compositing software and so don't do other arithmetic (such as scaling) on the data you get from libpng. Your compositing software can simply copy opaque pixels to the output but still has linear values for the @@ -2111,6 +2111,11 @@ data has been read, or zero if it is missing. The parameters to the png_get_<chunk> are set directly if they are simple data types, or a pointer into the info_ptr is returned for any complex types. +The colorspace data from gAMA, cHRM, sRGB, iCCP, and sBIT chunks +is simply returned to give the application information about how the +image was encoded. Libpng itself only does transformations using the file +gamma when combining semitransparent pixels with the background color. + png_get_PLTE(png_ptr, info_ptr, &palette, &num_palette); @@ -2122,7 +2127,7 @@ pointer into the info_ptr is returned for any complex types. png_get_gAMA(png_ptr, info_ptr, &file_gamma); png_get_gAMA_fixed(png_ptr, info_ptr, &int_file_gamma); - file_gamma - the gamma at which the file is + file_gamma - the gamma at which the file was written (PNG_INFO_gAMA) int_file_gamma - 100,000 times the gamma at which the @@ -2714,7 +2719,7 @@ the current display (e.g., the background color from a web page). You need to tell libpng how the color is represented, both the format of the component values in the color (the number of bits) and the gamma encoding of the color. The function takes two arguments, background_gamma_mode and need_expand -to convey this information, however only two combinations are likely to be +to convey this information; however, only two combinations are likely to be useful: png_color_16 my_background; @@ -3008,7 +3013,7 @@ the second parameter NULL. If you don't want libpng to handle the interlacing details, just call png_read_rows() PNG_INTERLACE_ADAM7_PASSES times to read in all the images. -Each of the images is a valid image by itself, however you will almost +Each of the images is a valid image by itself; however, you will almost certainly need to distribute the pixels from each sub-image to the correct place. This is where everything gets very tricky. @@ -4667,7 +4672,7 @@ available to set these separately for non-IDAT compressed chunks such as zTXt, iTXt, and iCCP: #include zlib.h - #if PNG_LIBPNG_VER <= 10504 + #if PNG_LIBPNG_VER >= 10504 png_set_text_compression_level(png_ptr, level); png_set_text_compression_mem_level(png_ptr, level); @@ -5137,7 +5142,7 @@ This is enabled by default but can be disabled in each png_ptr with A. Changes that affect users of libpng There are no substantial API changes between the non-deprecated parts of -the 1.4.5 API and the 1.5.0 API, however the ability to directly access +the 1.4.5 API and the 1.5.0 API; however, the ability to directly access the main libpng control structures, png_struct and png_info, deprecated in earlier versions of libpng, has been completely removed from libpng 1.5. @@ -5270,12 +5275,12 @@ B. Changes to the build and configuration of libpng Details of internal changes to the library code can be found in the CHANGES file and in the GIT repository logs. These will be of no concern to the vast -majority of library users or builders, however the few who configure libpng +majority of library users or builders; however, the few who configure libpng to a non-default feature set may need to change how this is done. There should be no need for library builders to alter build scripts if these use the distributed build support - configure or the makefiles - -however users of the makefiles may care to update their build scripts +however, users of the makefiles may care to update their build scripts to build pnglibconf.h where the corresponding makefile does not do so. Building libpng with a non-default configuration has changed completely. @@ -5381,7 +5386,7 @@ merely stops the function from being exported. PNG_FLOATING_ARITHMETIC_SUPPORTED chooses between the internal floating point implementation or the fixed point one. Typically the fixed point implementation is larger and slower than the floating point implementation -on a system that supports floating point, however it may be faster on a +on a system that supports floating point; however, it may be faster on a system which lacks floating point hardware and therefore uses a software emulation. @@ -5410,7 +5415,7 @@ pngconf.h no longer includes pngusr.h, therefore pngusr.h is ignored after the build of pnglibconf.h and it is never included in an application build. The rarely used alternative of adding a list of feature macros to the -CFLAGS setting in the build also still works, however the macros will be +CFLAGS setting in the build also still works; however, the macros will be copied to pnglibconf.h and this may produce macro redefinition warnings when the individual C files are compiled. @@ -5579,25 +5584,25 @@ Other rules can be inferred by inspecting the libpng source. .SH XIV. Y2K Compliance in libpng -March 29, 2012 +June 14, 2012 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 1.5.10 are Y2K compliant. It is my belief that earlier +upward through 1.5.11 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 -will hold years up to 65535. The other two hold the date in text +Libpng only has two year fields. One is a 2-byte unsigned integer that +will hold years up to 65535. The other holds the date in text format, and will hold years up to 9999. The integer is "png_uint_16 year" in png_time_struct. -The strings are - "png_charp time_buffer" in png_struct and - "near_time_buffer", which is a local character string in png.c. +The string is + "char time_buffer[29]" in png_struct. This will no +longer be used in libpng-1.6.x and will be removed from libpng-1.7.0. There are seven time-related functions: @@ -5798,6 +5803,9 @@ the first widely used release: 1.5.9 15 10509 15.so.15.9[.0] 1.5.10beta01-05 15 10510 15.so.15.10[.0] 1.5.10 15 10510 15.so.15.10[.0] + 1.5.11beta01 15 10511 15.so.15.11[.0] + 1.5.11rc01-05 15 10511 15.so.15.11[.0] + 1.5.11 15 10511 15.so.15.11[.0] Henceforth the source version will match the shared-library minor and patch numbers; the shared-library major version number will be @@ -5854,7 +5862,7 @@ possible without all of you. Thanks to Frank J. T. Wojcik for helping with the documentation. -Libpng version 1.5.10 - March 29, 2012: +Libpng version 1.5.11 - June 14, 2012: Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc. Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net). @@ -5877,7 +5885,7 @@ this sentence. This code is released under the libpng license. -libpng versions 1.2.6, August 15, 2004, through 1.5.10, March 29, 2012, are +libpng versions 1.2.6, August 15, 2004, through 1.5.11, June 14, 2012, 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 @@ -5976,7 +5984,7 @@ certification mark of the Open Source Initiative. Glenn Randers-Pehrson glennrp at users.sourceforge.net -March 29, 2012 +June 14, 2012 .\" end of man page |