Imported from libpng-1.0.5q.tar
This commit is contained in:
parent
166c5a397e
commit
61c32d9e66
65
ANNOUNCE
65
ANNOUNCE
@ -1,5 +1,5 @@
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Libpng 1.0.5h - December 10, 1999
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Libpng 1.0.5q - February 5, 2000
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This is not intended to be a public release. It will be replaced
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within a few weeks by a public version or by another test version.
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@ -73,13 +73,72 @@ version libpng-1.0.5g December 7, 1999
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Moved PNG_CHNK string macro definitions outside of PNG_NO_EXTERN block
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Added "translated_key" to png_text structure and png_write_iTXt().
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Added code in pngwrite.c to work around a newly discovered zlib bug.
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version 1.0.5h [December 10, 1999]
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NOTE: regarding the not for version 1.0.5e, the following must also
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version libpng-1.0.5h December 10, 1999
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NOTE: regarding the note for version 1.0.5e, the following must also
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be included in your code:
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png_text[i].translated_key = NULL;
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Unknown chunk handling is now supported.
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Option to eliminate all floating point support was added. Some new
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fixed-point functions such as png_set_gAMA_fixed() were added.
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version libpng-1.0.5i December 13, 1999
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Added some type casts to silence compiler warnings.
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Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
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Removed leading blanks from a #define in pngvcrd.c
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Added some parameters to the new png_set_keep_unknown_chunks() function,
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and relocated it in pngset.c
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Added a test for up->location != 0 in the first instance of writing
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unknown chunks in pngwrite.c
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Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
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prevent recursion.
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Added png_free_hIST() function.
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Various patches to fix bugs in the sCAL and integer cHRM processing,
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and to add some convenience macros for use with sCAL.
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version libpng-1.0.5j December 21, 1999
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Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
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around buggy compilers.
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Added new type "png_fixed_point" for integers that hold float*100000 values
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Restored backward compatibility of tEXt/zTXt chunk processing:
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Added members "lang_key" and "itxt_length" to png_text struct. Set
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text_length=0 when "text" contains iTXt data. Use the "compression"
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member to distinguish among tEXt/zTXt/iTXt types. Restored the first
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four members of png_text to the same order as v.1.0.5d. The "Note" above,
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about backward incompatibility of libpng-1.0.5e, no longer applies.
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Added PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
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Fixed png_read|write_iTXt() to read|write parameters in the right order.
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and to write the iTXt chunk after IDAT if it appears in the end_ptr.
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Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
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Reversed the order of trying to write floating-point and fixed-point gAMA.
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version libpng-1.0.5k December 27, 1999
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Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
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Added png_handle_as_unknown()
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Added png_free_chunk_list() function and chunk_list and num_chunk_list members
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of png_ptr.
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Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
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Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
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about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
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Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
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Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
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Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
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version libpng-1.0.5l January 1, 2000
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Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
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for setting a callback function to handle unknown chunks and for
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retrieving the associated user pointer (Glenn).
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version 1.0.5m [January 7, 2000]
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Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
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version 1.0.5n [January 9, 2000]
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Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
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own memory for info_ptr->palette. This makes it safe for the calling
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application to free its copy of the palette any time after it calls
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png_set_PLTE().
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version 1.0.5o [January 20, 2000]
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Cosmetic changes only (removed some trailing blanks and TABs)
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version 1.0.5p [January 31, 2000]
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Renamed pngdll.mak to makefile.bd32
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Cosmetic changes in pngtest.c
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version 1.0.5q [February 5, 2000]
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Relocated the makefile.solaris warning about PATH problems.
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Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
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Revised makefile.gcmmx
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Send comments/corrections/commendations to
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png-implement@ccrc.wustl.edu or to randeg@alum.rpi.edu
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65
CHANGES
65
CHANGES
@ -517,7 +517,7 @@ version 1.0.5e [November 30, 1999]
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with trailing compressed parts easier in the future, and added new functions
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png_free_iCCP, png_free_pCAL, png_free_sPLT, png_free_text, png_get_iCCP,
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png_get_spalettes, png_set_iCCP, png_set_spalettes (Eric S. Raymond).
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NOTE: Applications that write text chunks MUST define png_text->lang and
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NOTE: Applications that write text chunks MUST define png_text->lang
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before calling png_set_text(). It must be set to NULL if you want to
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write tEXt or zTXt chunks. If you want your application to be able to
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run with older versions of libpng, use
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@ -544,9 +544,70 @@ version 1.0.5g [December 7, 1999]
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Added "translated_key" to png_text structure and png_write_iTXt().
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Added code in pngwrite.c to work around a newly discovered zlib bug.
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version 1.0.5h [December 10, 1999]
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NOTE: regarding the not for version 1.0.5e, the following must also
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NOTE: regarding the note for version 1.0.5e, the following must also
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be included in your code:
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png_text[i].translated_key = NULL;
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Unknown chunk handling is now supported.
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Option to eliminate all floating point support was added. Some new
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fixed-point functions such as png_set_gAMA_fixed() were added.
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Expanded tabs and removed trailing blanks in source files.
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version 1.0.5i [December 13, 1999]
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Added some type casts to silence compiler warnings.
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Renamed "png_free_spalette" to "png_free_spalettes" for consistency.
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Removed leading blanks from a #define in pngvcrd.c
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Added some parameters to the new png_set_keep_unknown_chunks() function.
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Added a test for up->location != 0 in the first instance of writing
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unknown chunks in pngwrite.c
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Changed "num" to "i" in png_free_spalettes() and png_free_unknowns() to
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prevent recursion.
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Added png_free_hIST() function.
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Various patches to fix bugs in the sCAL and integer cHRM processing,
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and to add some convenience macros for use with sCAL.
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version 1.0.5j [December 21, 1999]
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Changed "unit" parameter of png_write_sCAL from png_byte to int, to work
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around buggy compilers.
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Added new type "png_fixed_point" for integers that hold float*100000 values
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Restored backward compatibility of tEXt/zTXt chunk processing:
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Restored the first four members of png_text to the same order as v.1.0.5d.
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Added members "lang_key" and "itxt_length" to png_text struct. Set
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text_length=0 when "text" contains iTXt data. Use the "compression"
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member to distinguish among tEXt/zTXt/iTXt types. Added
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PNG_ITXT_COMPRESSION_NONE (1) and PNG_ITXT_COMPRESSION_zTXt(2) macros.
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The "Note" above, about backward incompatibility of libpng-1.0.5e, no
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longer applies.
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Fixed png_read|write_iTXt() to read|write parameters in the right order,
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and to write the iTXt chunk after IDAT if it appears in the end_ptr.
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Added pnggccrd.c, version of pngvcrd.c Intel assembler for gcc (Greg Roelofs)
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Reversed the order of trying to write floating-point and fixed-point gAMA.
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version 1.0.5k [December 27, 1999]
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Added many parentheses, e.g., "if (a && b & c)" becomes "if (a && (b & c))"
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Added png_handle_as_unknown() function (Glenn)
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Added png_free_chunk_list() function and chunk_list and num_chunk_list members
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of png_ptr.
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Eliminated erroneous warnings about multiple sPLT chunks and sPLT-after-PLTE.
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Fixed a libpng-1.0.5h bug in pngrutil.c that was issuing erroneous warnings
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about ignoring incorrect gAMA with sRGB (gAMA was in fact not ignored)
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Added png_free_tRNS(); png_set_tRNS() now malloc's its own trans array (ESR).
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Define png_get_int_32 when oFFs chunk is supported as well as when pCAL is.
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Changed type of proflen from png_int_32 to png_uint_32 in png_get_iCCP().
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version 1.0.5l [January 1, 2000]
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Added functions png_set_read_user_chunk_fn() and png_get_user_chunk_ptr()
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for setting a callback function to handle unknown chunks and for
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retrieving the associated user pointer (Glenn).
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version 1.0.5m [January 7, 2000]
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Added high-level functions png_read_png(), png_write_png(), png_free_pixels().
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version 1.0.5n [January 9, 2000]
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Added png_free_PLTE() function, and modified png_set_PLTE() to malloc its
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own memory for info_ptr->palette. This makes it safe for the calling
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application to free its copy of the palette any time after it calls
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png_set_PLTE().
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version 1.0.5o [January 20, 2000]
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Cosmetic changes only (removed some trailing blanks and TABs)
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version 1.0.5p [January 31, 2000]
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Renamed pngdll.mak to makefile.bd32
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Cosmetic changes in pngtest.c
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version 1.0.5q [February 5, 2000]
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Relocated the makefile.solaris warning about PATH problems.
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Fixed pngvcrd.c bug by pushing/popping registers in mmxsupport (Bruce Oberg)
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Revised makefile.gcmmx
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Added PNG_SETJMP_SUPPORTED, PNG_SETJMP_NOT_SUPPORTED, and PNG_ABORT() macros
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22
INSTALL
22
INSTALL
@ -1,5 +1,5 @@
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Installing libpng version 1.0.5h - December 10, 1999
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Installing libpng version 1.0.5q - February 5, 2000
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Before installing libpng, you must first install zlib. zlib
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can usually be found wherever you got libpng. zlib can be
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@ -10,7 +10,7 @@ zlib.h and zconf.h include files that correspond to the
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version of zlib that's installed.
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You can rename the directories that you downloaded (they
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might be called "libpng-1.0.5h" or "lpng103" and "zlib-1.1.3"
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might be called "libpng-1.0.5q" or "lpng103" and "zlib-1.1.3"
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or "zlib113") so that you have directories called "zlib" and "libpng".
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Your directory structure should look like this:
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@ -36,6 +36,10 @@ Your directory structure should look like this:
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contrib
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etc.
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If the line endings in the files look funny, you may wish to get the other
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distribution of libpng. It is available in both tar.gz (UNIX style line
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endings) and zip (DOS style line endings) formats.
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First enter the zlib directory and follow the instructions
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in zlib/README. Then come back here and choose the
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appropriate makefile.sys in the scripts directory.
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@ -51,8 +55,10 @@ include
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makefile.hpux => HPUX (10.20 and 11.00) makefile
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makefile.sgi => Silicon Graphics IRIX makefile
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makefile.sunos => Sun makefile
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makefile.solaris => Solaris 2.X makefile (gcc, creates libpng.so.2.1.0.5h)
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makefile.linux => Linux/ELF makefile (gcc, creates libpng.so.2.1.0.5h)
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makefile.solaris => Solaris 2.X makefile (gcc, creates libpng.so.2.1.0.5q)
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makefile.linux => Linux/ELF makefile (gcc, creates libpng.so.2.1.0.5q)
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makefile.gcmmx => Linux/ELF makefile (gcc, creates libpng.so.2.1.0.5q,
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uses assembler code tuned for Intel MMX platform)
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makefile.sco => For SCO OSr5 ELF and Unixware 7 with Native cc
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makefile.mips => MIPS makefile
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makefile.acorn => Acorn makefile
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@ -61,20 +67,20 @@ include
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(Requires SCOPTIONS, copied from scripts/SCOPTIONS.ppc)
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makefile.atari => Atari makefile
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makefile.beos => BEOS makefile for X86
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makefile.borland => Borland makefile
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makefile.borland => Borland makefile (uses bcc)
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makefile.bd32 => To make a png32bd.dll with Borland C++ 4.5
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makefile.turboc3 => Turbo C 3.0 makefile
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build.bat => MS-DOS batch file for Borland compiler
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makefile.dj2 => DJGPP 2 makefile
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makefile.msc => Microsoft C makefile
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makefile.vcawin32 => makefile for Microsoft Visual C++ 5.0 and later (uses
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assembler code)
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assembler code tuned for Intel MMX platform)
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makefile.vcwin32 => makefile for Microsoft Visual C++ 4.0 and later (does
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not use assembler code)
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makefile.turboc3 => Turbo C 3.0 makefile
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makefile.os2 => OS/2 Makefile (gcc and emx, requires pngos2.def)
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pngos2.def => OS/2 module definition file used by makefile.os2
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makefile.watcom => Watcom 10a+ Makefile, 32-bit flat memory model
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makevms.com => VMS build script
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pngdll.mak => To make a png32bd.dll with Borland C++ 4.5
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pngdef.pas => Defines for a png32bd.dll with Borland C++ 4.5
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SCOPTIONS.ppc => Used with smakefile.ppc
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11
KNOWNBUG
11
KNOWNBUG
@ -38,6 +38,9 @@ Known bugs and suggested enhancements in libpng-1.0.5
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for the png_set_gAMA(), png_set_cHRM(), and corresponding png_get_()
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functions will be needed.
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Much of this was completed in libpng-1.0.5h, but gamma compensation
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is not yet done in fixed-point arithmetic.
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4. October 1999 -- BUG
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pngvcrd.c is failing for interlaced PNGs that have empty passes.
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@ -64,4 +67,10 @@ Known bugs and suggested enhancements in libpng-1.0.5
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is not backward compatible (the lang member was added, and the
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translated_key member was added to libpng-1.0.5g)
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STATUS: Will be fixed before the next public release.
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STATUS: Fixed in libpng-1.0.5j/1.1.0
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7. December 1999 -- BUG
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The new pnggccrd.c has syntax errors when compiled with gcc.
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STATUS: Under investigation.
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8
LICENSE
8
LICENSE
@ -4,8 +4,8 @@ Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
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(libpng versions 0.5, May 1995, through 0.89c, May 1996)
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Copyright (c) 1996, 1997 Andreas Dilger
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(libpng versions 0.90, December 1996, through 0.96, May 1997)
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Copyright (c) 1998, 1999 Glenn Randers-Pehrson
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(libpng versions 0.97, January 1998, through 1.0.5h, December 10, 1999)
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Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
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(libpng versions 0.97, January 1998, through 1.0.5q, February 5, 2000)
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For the purposes of this copyright and license, "Contributing Authors"
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is defined as the following set of individuals:
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@ -63,9 +63,9 @@ boxes and the like:
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Also, the PNG logo (in PNG format, of course) is supplied in the
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file "pngnow.png".
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Libpng is OSI Certified Open Source Software. OSI Certified is a
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Libpng is OSI Certified Open Source Software. OSI Certified Open Source is a
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certification mark of the Open Source Initiative.
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Glenn Randers-Pehrson
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randeg@alum.rpi.edu
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December 10, 1999
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February 5, 2000
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22
README
22
README
@ -1,8 +1,12 @@
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README for libpng 1.0.5h - December 10, 1999 (shared library 2.1)
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README for libpng 1.0.5q - February 5, 2000 (shared library 2.1)
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See the note about version numbers near the top of png.h
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See INSTALL for instructions on how to install libpng.
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Libpng comes in two distribution formats. Get libpng-*.tar.gz if you
|
||||
want UNIX-style line endings in the text files, or lpng*.zip if you want
|
||||
DOS-style line endings.
|
||||
|
||||
Version 0.89 was the first official release of libpng. Don't let the
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fact that it's the first release fool you. The libpng library has been in
|
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extensive use and testing since mid-1995. By late 1997 it had
|
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@ -171,9 +175,12 @@ Files in this distribution:
|
||||
makefile.sgi => Silicon Graphics IRIX makefile
|
||||
makefile.sunos => Sun makefile
|
||||
makefile.solaris => Solaris 2.X makefile
|
||||
(gcc, creates libpng.so.2.1.0.5h)
|
||||
(gcc, creates libpng.so.2.1.0.5q)
|
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makefile.linux => Linux/ELF makefile
|
||||
(gcc, creates libpng.so.2.1.0.5h)
|
||||
(gcc, creates libpng.so.2.1.0.5q)
|
||||
makefile.gcmmx => Linux/ELF makefile (gcc, creates
|
||||
libpng.so.2.1.0.5q, uses assembler code
|
||||
tuned for Intel MMX platform)
|
||||
makefile.sco => For SCO OSr5 ELF and Unixware 7 with Native cc
|
||||
makefile.mips => MIPS makefile
|
||||
makefile.acorn => Acorn makefile
|
||||
@ -183,20 +190,21 @@ Files in this distribution:
|
||||
scripts/SCOPTIONS.ppc)
|
||||
makefile.atari => Atari makefile
|
||||
makefile.beos => BEOS makefile for X86
|
||||
makefile.borland => Borland makefile
|
||||
makefile.borland => Borland makefile (uses bcc)
|
||||
makefile.bd32 => To make a png32bd.dll with Borland C++ 4.5
|
||||
makefile.turboc3 => Turbo C 3.0 makefile
|
||||
build.bat => MS-DOS batch file for Borland compiler
|
||||
makefile.dj2 => DJGPP 2 makefile
|
||||
makefile.msc => Microsoft C makefile
|
||||
makefile.vcawin32 => makefile for Microsoft Visual C++ 5.0 and
|
||||
later (uses assembler code)
|
||||
later (uses assembler code tuned for Intel MMX
|
||||
platform)
|
||||
makefile.vcwin32 => makefile for Microsoft Visual C++ 4.0 and
|
||||
later (does not use assembler code)
|
||||
makefile.turboc3 => Turbo C 3.0 makefile
|
||||
makefile.os2 => OS/2 Makefile (gcc and emx, requires pngos2.def)
|
||||
pngos2.def => OS/2 module definition file used by makefile.os2
|
||||
makefile.watcom => Watcom 10a+ Makefile, 32-bit flat memory model
|
||||
makevms.com => VMS build script
|
||||
pngdll.mak => To make a png32bd.dll with Borland C++ 4.5
|
||||
pngdef.pas => Defines for a png32bd.dll with Borland C++ 4.5
|
||||
SCOPTIONS.ppc => Used with smakefile.ppc
|
||||
|
||||
|
7
TODO
7
TODO
@ -1,13 +1,11 @@
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TODO - list of things to do for libpng:
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||||
Final bug fixes.
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Fix problem with C++ and EXTERN "C".
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||||
Finish work on the no-floating-point version (including gamma compensation)
|
||||
Better C++ wrapper/full C++ implementation?
|
||||
Keep up with public chunks.
|
||||
Fix problem with C++ and EXTERN "C".
|
||||
cHRM transformation.
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Support for application-defined chunk handlers.
|
||||
Improve setjmp/longjmp usage or remove it in favor of returning error codes.
|
||||
High-level API for reading images.
|
||||
Add "grayscale->palette" transformation and "palette->grayscale" detection.
|
||||
Improved dithering.
|
||||
Multi-lingual error and warning message support.
|
||||
@ -19,4 +17,3 @@ Better filter selection
|
||||
Histogram creation.
|
||||
Text conversion between different code pages (Latin-1 -> Mac and DOS).
|
||||
Improve API by hiding the info_ptr.
|
||||
Make a no-floating-point version.
|
||||
|
30
Y2KINFO
30
Y2KINFO
@ -1,29 +1,29 @@
|
||||
Y2K compliance in libpng:
|
||||
=========================
|
||||
|
||||
December 10, 1999
|
||||
|
||||
|
||||
February 5, 2000
|
||||
|
||||
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 1.0.5h are Y2K compliant. It is my belief that earlier
|
||||
upward through 1.0.5q 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
|
||||
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.
|
||||
|
||||
|
||||
There are seven time-related functions:
|
||||
|
||||
png_convert_to_rfc_1123() in png.c
|
||||
png_convert_to_rfc_1123() in png.c
|
||||
(formerly png_convert_to_rfc_1152() in error)
|
||||
png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
|
||||
png_convert_from_time_t() in pngwrite.c
|
||||
@ -31,8 +31,8 @@
|
||||
png_handle_tIME() in pngrutil.c, called in pngread.c
|
||||
png_set_tIME() in pngset.c
|
||||
png_write_tIME() in pngwutil.c, called in pngwrite.c
|
||||
|
||||
All appear to handle dates properly in a Y2K environment. The
|
||||
|
||||
All appear to handle dates properly in a Y2K environment. The
|
||||
png_convert_from_time_t() function calls gmtime() to convert from system
|
||||
clock time, which returns (year - 1900), which we properly convert to
|
||||
the full 4-digit year. There is a possibility that applications using
|
||||
@ -42,14 +42,14 @@
|
||||
but this is not under our control. The libpng documentation has always
|
||||
stated that it works with 4-digit years, and the APIs have been
|
||||
documented as such.
|
||||
|
||||
|
||||
The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
|
||||
integer to hold the year, and can hold years as large as 65535.
|
||||
|
||||
zlib, upon which libpng depends, is also Y2K compliant. It contains
|
||||
no date-related code.
|
||||
|
||||
|
||||
|
||||
|
||||
Glenn Randers-Pehrson
|
||||
libpng maintainer
|
||||
PNG Development Group
|
||||
|
52
contrib/pngminus/makefile
Normal file
52
contrib/pngminus/makefile
Normal file
@ -0,0 +1,52 @@
|
||||
# Makefile for PngMinus (png2pnm and pnm2png)
|
||||
# Linux / Unix
|
||||
|
||||
CC=cc -O -n32
|
||||
LD=cc -O -n32
|
||||
#CC=gcc -O
|
||||
#LD=gcc -O
|
||||
LB=ar
|
||||
RM=rm
|
||||
CP=cp
|
||||
|
||||
PNGPATH = /usr/local
|
||||
PNGINC = $(PNGPATH)/include
|
||||
PNGLIB = $(PNGPATH)/lib -lpng
|
||||
# PNGLIB = $(PNGPATH)/libpng.a
|
||||
|
||||
ZPATH = /usr/local
|
||||
ZINC = $(ZPATH)/include
|
||||
ZLIB = $(ZPATH)/lib -lz
|
||||
# ZLIB = $(ZPATH)/libz.a
|
||||
|
||||
CCFLAGS=-I$(PNGINC) -I$(ZINC)
|
||||
LDFLAGS=-L$(PNGLIB) -L$(ZLIB) -lm
|
||||
C=.c
|
||||
O=.o
|
||||
L=.a
|
||||
E=
|
||||
|
||||
# dependencies
|
||||
|
||||
all: png2pnm$(E) pnm2png$(E)
|
||||
|
||||
png2pnm$(O): png2pnm$(C)
|
||||
$(CC) -c $(CCFLAGS) png2pnm$(C)
|
||||
|
||||
png2pnm$(E): png2pnm$(O)
|
||||
$(LD) -o png2pnm$(E) png2pnm$(O) $(LDFLAGS)
|
||||
|
||||
pnm2png$(O): pnm2png$(C)
|
||||
$(CC) -c $(CCFLAGS) pnm2png$(C)
|
||||
|
||||
pnm2png$(E): pnm2png$(O)
|
||||
$(LD) -o pnm2png$(E) pnm2png$(O) $(LDFLAGS)
|
||||
|
||||
clean:
|
||||
$(RM) png2pnm$(O)
|
||||
$(RM) pnm2png$(O)
|
||||
$(RM) png2pnm$(E)
|
||||
$(RM) pnm2png$(E)
|
||||
|
||||
# End of makefile for png2pnm / pnm2png
|
||||
|
@ -77,7 +77,8 @@ int main(int argc, char *argv[])
|
||||
if ((fp_al = fopen (argv[argi], "rb")) == NULL)
|
||||
{
|
||||
fprintf (stderr, "PNM2PNG\n");
|
||||
fprintf (stderr, "Error: alpha-channel file %s does not exist\n", argv[argi]);
|
||||
fprintf (stderr, "Error: alpha-channel file %s does not exist\n",
|
||||
argv[argi]);
|
||||
exit (1);
|
||||
}
|
||||
break;
|
||||
@ -511,8 +512,8 @@ png_uint_32 get_value (FILE *pnm_file, int depth)
|
||||
for (i = 0; i < depth; i++)
|
||||
mask = (mask << 1) | 0x01;
|
||||
|
||||
get_token (pnm_file, token);
|
||||
sscanf (token, "%lu", &ret_value);
|
||||
get_token (pnm_file, (char *) token);
|
||||
sscanf ((const char *) token, "%lu", &ret_value);
|
||||
|
||||
ret_value &= mask;
|
||||
|
||||
|
49
example.c
49
example.c
@ -136,6 +136,19 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
|
||||
/* If we have already read some of the signature */
|
||||
png_set_sig_bytes(png_ptr, sig_read);
|
||||
|
||||
#ifdef hilevel
|
||||
/*
|
||||
* If you have enough memory to read in the entire image at once,
|
||||
* and you need to specify only transforms that can be controlled
|
||||
* with one of the PNG_TRANSFORM_* bits (this presently excludes
|
||||
* dithering, filling, setting background, and doing gamma
|
||||
* adjustment), then you can read the entire image (including
|
||||
* pixels) into the info structure with this call:
|
||||
*/
|
||||
png_read_png(png_ptr, info_ptr, png_transforms, NULL);
|
||||
#else
|
||||
/* OK, you're doing it the hard way, with the lower-level functions */
|
||||
|
||||
/* The call to png_read_info() gives us all of the information from the
|
||||
* PNG file before the first IDAT (image data chunk). REQUIRED
|
||||
*/
|
||||
@ -275,7 +288,7 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
|
||||
*/
|
||||
if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
|
||||
{
|
||||
png_color8p sig_bit;
|
||||
png_color_8p sig_bit;
|
||||
|
||||
png_get_sBIT(png_ptr, info_ptr, &sig_bit);
|
||||
png_set_shift(png_ptr, sig_bit);
|
||||
@ -350,6 +363,9 @@ void read_png(FILE *fp, unsigned int sig_read) /* file is already open */
|
||||
|
||||
/* read rest of file, and get additional chunks in info_ptr - REQUIRED */
|
||||
png_read_end(png_ptr, info_ptr);
|
||||
#endif hilevel
|
||||
|
||||
/* At this point you have read the entire image */
|
||||
|
||||
/* clean up after the read, and free any memory allocated - REQUIRED */
|
||||
png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
|
||||
@ -530,7 +546,7 @@ void write_png(char *file_name /* , ... other image information ... */)
|
||||
}
|
||||
|
||||
/* Set error handling. REQUIRED if you aren't supplying your own
|
||||
* error hadnling functions in the png_create_write_struct() call.
|
||||
* error handling functions in the png_create_write_struct() call.
|
||||
*/
|
||||
if (setjmp(png_ptr->jmpbuf))
|
||||
{
|
||||
@ -552,6 +568,15 @@ void write_png(char *file_name /* , ... other image information ... */)
|
||||
/* where user_io_ptr is a structure you want available to the callbacks */
|
||||
#endif no_streams /* only use one initialization method */
|
||||
|
||||
#ifdef hilevel
|
||||
/* This is the easy way. Use it if you already have all the
|
||||
* image info living info in the structure. You could "|" many
|
||||
* PNG_TRANSFORM flags into the png_transforms integer here.
|
||||
*/
|
||||
png_write_png(png_ptr, info_ptr, png_transforms, NULL);
|
||||
#else
|
||||
/* This is the hard way */
|
||||
|
||||
/* Set the image information here. Width and height are up to 2^31,
|
||||
* bit_depth is one of 1, 2, 4, 8, or 16, but valid values also depend on
|
||||
* the color_type selected. color_type is one of PNG_COLOR_TYPE_GRAY,
|
||||
@ -567,6 +592,11 @@ void write_png(char *file_name /* , ... other image information ... */)
|
||||
palette = (png_colorp)png_malloc(png_ptr, 256 * sizeof (png_color));
|
||||
/* ... set palette colors ... */
|
||||
png_set_PLTE(png_ptr, info_ptr, palette, 256);
|
||||
/* You can free the palette here if you like, since libpng has made its
|
||||
own copy. In versions of libpng earlier than version 1.0.5n, it was
|
||||
necessary to keep the palette until after png_write_end(), because
|
||||
libpng was using the caller's copy. */
|
||||
free(palette);
|
||||
|
||||
/* optional significant bit chunk */
|
||||
/* if we are dealing with a grayscale image then */
|
||||
@ -615,6 +645,9 @@ void write_png(char *file_name /* , ... other image information ... */)
|
||||
* png_write_info_before_PLTE(write_ptr, write_info_ptr);
|
||||
* write_my_chunk();
|
||||
* png_write_info(png_ptr, info_ptr);
|
||||
*
|
||||
* However, given the level of known- and unknown-chunk support in 1.1.0
|
||||
* and up, this should no longer be necessary.
|
||||
*/
|
||||
|
||||
/* Once we write out the header, the compression type on the text
|
||||
@ -695,14 +728,20 @@ void write_png(char *file_name /* , ... other image information ... */)
|
||||
#endif no_entire /* use only one output method */
|
||||
|
||||
/* You can write optional chunks like tEXt, zTXt, and tIME at the end
|
||||
* as well.
|
||||
* as well. Shouldn't be necessary in 1.1.0 and up as all the public
|
||||
* chunks are supported and you can use png_set_unknown_chunks() to
|
||||
* register unknown chunks into the info structure to be written out.
|
||||
*/
|
||||
|
||||
/* It is REQUIRED to call this to finish writing the rest of the file */
|
||||
png_write_end(png_ptr, info_ptr);
|
||||
#endif hilevel
|
||||
|
||||
/* if you malloced the palette, free it here */
|
||||
free(info_ptr->palette);
|
||||
/* if you malloced a palette and have not already freed it, free it
|
||||
here (do *not* free libpng's copy of the palette in info_ptr->palette,
|
||||
as recommended in versions 1.0.5m and earlier of this example; libpng
|
||||
now takes care of that automatically). */
|
||||
free(palette);
|
||||
|
||||
/* clean up after the write, and free any memory allocated */
|
||||
png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
|
||||
|
470
libpng.3
470
libpng.3
@ -1,6 +1,6 @@
|
||||
.TH LIBPNG 3 "December 10, 1999"
|
||||
.TH LIBPNG 3 "February 5, 2000"
|
||||
.SH NAME
|
||||
libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5q
|
||||
.SH SYNOPSIS
|
||||
\fI\fB
|
||||
|
||||
@ -84,10 +84,18 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_free_chunk_list (png_structp \fIpng_ptr\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_free_default(png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fIptr\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_free_hIST (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fI\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_free_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fI\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
@ -96,11 +104,19 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_free_pixels (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_free_PLTE (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_free_sCAL (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_free_spalette (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum_text\fP\fB);\fP
|
||||
\fBvoid png_free_spalettes (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum_text\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
@ -112,6 +128,14 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_free_tRNS (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_free_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fInum_unknowns\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBpng_byte png_get_bit_depth (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fIinfo_ptr\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
@ -172,7 +196,7 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBpng_uint_32 png_get_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charpp \fP\fIname\fP\fB, int \fP\fI*compression_type\fP\fB, png_charpp \fP\fIprofile\fP\fB, int \fI*proflen\fP\fB);\fP
|
||||
\fBpng_uint_32 png_get_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charpp \fP\fIname\fP\fB, int \fP\fI*compression_type\fP\fB, png_charpp \fP\fIprofile\fP\fB, png_uint_32 \fI*proflen\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
@ -270,6 +294,10 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBpng_voidp png_get_user_chunk_ptr (png_structp \fIpng_ptr\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBpng_voidp png_get_user_transform_ptr (png_structp \fIpng_ptr\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
@ -362,6 +390,10 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_read_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, voidp \fIparams\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_read_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fP\fIrow\fP\fB, png_bytep \fIdisplay_row\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
@ -470,7 +502,7 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_set_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_charp \fP\fIprofile\fP\fB, int \fIproflen\fP\fB);\fP
|
||||
\fBvoid png_set_iCCP (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_charp \fP\fIname\fP\fB, int \fP\fIcompression_type\fP\fB, png_charp \fP\fIprofile\fP\fB, png_uint_32 \fIproflen\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
@ -490,7 +522,7 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_set_keep_unknown_chunks (png_structp \fIpng_ptr\fP\fB);\fP
|
||||
\fBvoid png_set_keep_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, int \fP\fIkeep\fP\fB, png_bytep \fP\fIchunk_list\fP\fB, int \fInum_chunks\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
@ -606,7 +638,11 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBpng_uint_32 png_set_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkp \fP\fIunknowns\fP\fB, int \fInum\fP\fB);\fP
|
||||
\fBpng_uint_32 png_set_unknown_chunks (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, png_unknown_chunkp \fP\fIunknowns\fP\fB, int \fP\fInum\fP\fB, int \fIlocation\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_set_read_user_chunk_fn (png_structp \fP\fIpng_ptr\fP\fB, png_voidp \fP\fIuser_chunk_ptr\fP\fB, png_user_chunk_ptr \fIread_user_chunk_fn\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
@ -682,6 +718,10 @@ libpng \- Portable Network Graphics (PNG) Reference Library 1.0.5h
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_write_png (png_structp \fP\fIpng_ptr\fP\fB, png_infop \fP\fIinfo_ptr\fP\fB, int \fP\fItransforms\fP\fB, voidp \fIparams\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
|
||||
\fBvoid png_write_row (png_structp \fP\fIpng_ptr\fP\fB, png_bytep \fIrow\fP\fB);\fP
|
||||
|
||||
\fI\fB
|
||||
@ -701,10 +741,10 @@ 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 1.0.5h - December 10, 1999
|
||||
libpng version 1.0.5q - February 5, 2000
|
||||
Updated and distributed by Glenn Randers-Pehrson
|
||||
<randeg@alum.rpi.edu>
|
||||
Copyright (c) 1998, 1999 Glenn Randers-Pehrson
|
||||
Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson
|
||||
For conditions of distribution and use, see copyright
|
||||
notice in png.h.
|
||||
|
||||
@ -720,10 +760,9 @@ libpng.txt - A description on how to use and modify libpng
|
||||
Schalnat, Group 42, Inc.
|
||||
|
||||
Updated/rewritten per request in the libpng FAQ
|
||||
Copyright (c) 1995 Frank J. T. Wojcik
|
||||
December 18, 1995 && January 20, 1996
|
||||
Copyright (c) 1995, 1996 Frank J. T. Wojcik
|
||||
December 18, 1995 & January 20, 1996
|
||||
|
||||
*
|
||||
.SH I. Introduction
|
||||
|
||||
This file describes how to use and modify the PNG reference library
|
||||
@ -803,13 +842,14 @@ And while I'm on the topic, make sure you include the libpng header file:
|
||||
|
||||
.SH III. Reading
|
||||
|
||||
Reading PNG files:
|
||||
|
||||
We'll now walk you through the possible functions to call when reading
|
||||
in a PNG file, briefly explaining the syntax and purpose of each one.
|
||||
See example.c and png.h for more detail. While Progressive reading
|
||||
is covered in the next section, you will still need some of the
|
||||
functions discussed in this section to read a PNG file.
|
||||
in a PNG file sequentially, briefly explaining the syntax and purpose
|
||||
of each one. See example.c and png.h for more detail. While
|
||||
progressive reading is covered in the next section, you will still
|
||||
need some of the functions discussed in this section to read a PNG
|
||||
file.
|
||||
|
||||
.SS Setup
|
||||
|
||||
You will want to do the I/O initialization(*) before you get into libpng,
|
||||
so if it doesn't work, you don't have much to undo. Of course, you
|
||||
@ -909,6 +949,10 @@ free any memory.
|
||||
return;
|
||||
}
|
||||
|
||||
If you would rather avoid the complexity of setjmp/longjmp issues,
|
||||
you can compile libpng with PNG_SETJMP_NOT_SUPPORTED, in which case
|
||||
errors will result in a call to PNG_ABORT() which defaults to abort().
|
||||
|
||||
Now you need to set up the input code. The default for libpng is to
|
||||
use the C function fread(). If you use this, you will need to pass a
|
||||
valid FILE * in the function png_init_io(). Be sure that the file is
|
||||
@ -925,6 +969,42 @@ libpng know that there are some bytes missing from the start of the file.
|
||||
|
||||
png_set_sig_bytes(png_ptr, number);
|
||||
|
||||
.SS Setting up callback code
|
||||
|
||||
You can set up a callback function to handle any unknown chunks in the
|
||||
input stream. You must supply the function
|
||||
|
||||
read_chunk_callback(png_ptr ptr,
|
||||
png_unknown_chunkp chunk);
|
||||
{
|
||||
/* The unknown chunk structure contains your
|
||||
chunk data: */
|
||||
png_byte name[5];
|
||||
png_byte *data;
|
||||
png_size_t size;
|
||||
/* Note that libpng has already taken care of the
|
||||
CRC handling */
|
||||
|
||||
/* put your code here. Return one of the following: */
|
||||
|
||||
return (-n); /* chunk had an error */
|
||||
return (0); /* did not recognize */
|
||||
return (n); /* success */
|
||||
}
|
||||
|
||||
(You can give your function another name that you like instead of
|
||||
"read_chunk_callback")
|
||||
|
||||
To inform libpng about your function, use
|
||||
|
||||
png_set_read_user_chunk_fn(png_ptr, user_chunk_ptr,
|
||||
read_chunk_callback);
|
||||
|
||||
This names not only the callback function, but also a user pointer that
|
||||
you can retrieve with
|
||||
|
||||
png_get_user_chunk_ptr(png_ptr);
|
||||
|
||||
At this point, you can set up a callback function that will be
|
||||
called after each row has been read, which you can use to control
|
||||
a progress meter or the like. It's demonstrated in pngtest.c.
|
||||
@ -941,19 +1021,6 @@ To inform libpng about your function, use
|
||||
|
||||
png_set_read_status_fn(png_ptr, read_row_callback);
|
||||
|
||||
In PNG files, the alpha channel in an image is the level of opacity.
|
||||
If you need the alpha channel in an image to be the level of transparency
|
||||
instead of opacity, you can invert the alpha channel (or the tRNS chunk
|
||||
data) after it's read, so that 0 is fully opaque and 255 (in 8-bit or
|
||||
paletted images) or 65535 (in 16-bit images) is fully transparent, with
|
||||
|
||||
png_set_invert_alpha(png_ptr);
|
||||
|
||||
This has to appear here rather than later with the other transformations
|
||||
because the tRNS chunk data must be modified in the case of paletted images.
|
||||
If your image is not a paletted image, the tRNS data (which in such cases
|
||||
represents a single color to be rendered as transparent) won't be changed.
|
||||
|
||||
Finally, you can write your own transformation function if none of
|
||||
the existing ones meets your needs. This is done by setting a callback
|
||||
with
|
||||
@ -977,6 +1044,8 @@ function
|
||||
png_set_user_transform_info(png_ptr, user_ptr,
|
||||
user_depth, user_channels);
|
||||
|
||||
The user's application, not libpng, is responsible for allocating and
|
||||
freeing any memory required for the user structure.
|
||||
|
||||
You can retrieve the pointer via the function
|
||||
png_get_user_transform_ptr(). For example:
|
||||
@ -984,23 +1053,100 @@ png_get_user_transform_ptr(). For example:
|
||||
voidp read_user_transform_ptr =
|
||||
png_get_user_transform_ptr(png_ptr);
|
||||
|
||||
You are now ready to read all the file information up to the actual
|
||||
image data. You do this with a call to png_read_info().
|
||||
.SS Unknown-chunk handling
|
||||
|
||||
Now you get to set the way the library processes unknown chunks in the
|
||||
input PNG stream. Both known and unknown chunks will be read. Normal
|
||||
behavior is that known chunks will be parsed into information in
|
||||
various info_ptr members; unknown chunks will be discarded. To change
|
||||
this, you can call:
|
||||
|
||||
png_set_keep_unknown_chunks(png_ptr, info_ptr, keep,
|
||||
chunk_list, num_chunks);
|
||||
keep - 0: do not keep
|
||||
1: keep only if safe-to-copy
|
||||
2: keep even if unsafe-to-copy
|
||||
chunk_list - list of chunks affected (a byte string,
|
||||
five bytes per chunk, NULL or '\0' if
|
||||
num_chunks is 0)
|
||||
num_chunks - number of chunks affected; if 0, all
|
||||
unknown chunks are affected
|
||||
|
||||
Unknown chunks declared in this way will be saved as raw data onto a
|
||||
list of png_unknown_chunk structures. If a chunk that is normally
|
||||
known to libpng is named in the list, it will be handled as unknown,
|
||||
according to the "keep" directive. If a chunk is named in successive
|
||||
instances of png_set_keep_unknown_chunks(), the final instance will
|
||||
take precedence.
|
||||
|
||||
.SS The high-level read interface
|
||||
|
||||
At this point there are two ways to proceed; through the high-level
|
||||
read interface, or through a sequence of low-level read operations.
|
||||
You can use the high-level interface if (a) you are willing to read
|
||||
the entire image into memory, and (b) the input transformations
|
||||
you want to do are limited to the following set:
|
||||
|
||||
PNG_TRANSFORM_IDENTITY No transformation
|
||||
PNG_TRANSFORM_STRIP_16 Strip 16-bit samples to 8 bits
|
||||
PNG_TRANSFORM_STRIP_ALPHA Discard the alpha channel
|
||||
PNG_TRANSFORM_PACKING Expand 1, 2 and 4-bit samples to bytes
|
||||
PNG_TRANSFORM_PACKSWAP Change order of packed pixels to LSB first
|
||||
PNG_TRANSFORM_EXPAND Perform set_expand()
|
||||
PNG_TRANSFORM_INVERT_MONO Invert monochrome images
|
||||
PNG_TRANSFORM_SHIFT Normalize pixels to the sBIT depth
|
||||
PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA to BGRA
|
||||
PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA to AG
|
||||
PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity to transparency
|
||||
PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
|
||||
|
||||
(This excludes setting a background color, doing gamma transformation,
|
||||
dithering, and setting filler.) If this is the case, simply do this:
|
||||
|
||||
png_read_png(png_ptr, info_ptr, png_transforms, NULL)
|
||||
|
||||
where png_transforms is an integer containing the logical-or of some set of
|
||||
transformation flags. This call is equivalent to png_read_info(),
|
||||
followed the set of transformations indicated by the transform mask,
|
||||
followed by png_update_info(), followed by a read of the image bytes
|
||||
to the info member `rowpointers', followed by png_read_end().
|
||||
|
||||
(The final parameter of this call is not yet used. Someday it
|
||||
will point to transformation parameters.)
|
||||
|
||||
.SS The low-level read interface
|
||||
|
||||
If you are going the low-level route, you are now ready to read all
|
||||
the file information up to the actual image data. You do this with a
|
||||
call to png_read_info().
|
||||
|
||||
png_read_info(png_ptr, info_ptr);
|
||||
|
||||
This will read all chunks up to but not including the image data.
|
||||
Both known and unknown chunks will be read. Known chunks will be
|
||||
parsed into information in various info_ptr members; unknown chunks
|
||||
will be discarded, unless you previously called
|
||||
This will process all chunks up to but not including the image data.
|
||||
|
||||
png_set_keep_unknown_chunks();
|
||||
There is one transformation you may need to set up before doing
|
||||
png_read_info(), however. In PNG files, the alpha channel in an image
|
||||
is the level of opacity. If you need the alpha channel in an image to
|
||||
be the level of transparency instead of opacity, you can invert the
|
||||
alpha channel (or the tRNS chunk data) after it's read, so that 0 is
|
||||
fully opaque and 255 (in 8-bit or paletted images) or 65535 (in 16-bit
|
||||
images) is fully transparent, with
|
||||
|
||||
in which case they will be saved as raw data onto a list of
|
||||
png_unknown_chunk structures (and written out if you subsequently
|
||||
call png_write_info and friends).
|
||||
png_set_invert_alpha(png_ptr);
|
||||
|
||||
Functions are used to get the information from the info_ptr:
|
||||
This must appear before png_write_info() instead of later with the
|
||||
other transformations because in the case of paletted images the tRNS
|
||||
chunk data has to be inverted before the tRNS chunk is written.
|
||||
If your image is not a paletted image, the tRNS data (which in such cases
|
||||
represents a single color to be rendered as transparent) won't need to
|
||||
be changed, and you can safely do this transformation after your
|
||||
png_read_info() call.
|
||||
|
||||
.SS Querying the info structure
|
||||
|
||||
Functions are used to get the information from the info_ptr once it
|
||||
has been read. Note that these fields may not be completely filled
|
||||
in until png_read_end() has read the chunk data following the image.
|
||||
|
||||
png_get_IHDR(png_ptr, info_ptr, &width, &height,
|
||||
&bit_depth, &color_type, &interlace_type,
|
||||
@ -1140,20 +1286,28 @@ into the info_ptr is returned for any complex types.
|
||||
|
||||
png_get_bKGD(png_ptr, info_ptr, &background);
|
||||
background - background color (PNG_VALID_bKGD)
|
||||
valid 16-bit red, green and blue
|
||||
values, regardless of color_type
|
||||
|
||||
num_text = png_get_text(png_ptr, info_ptr, &text_ptr);
|
||||
text_ptr - array of png_text holding image
|
||||
comments
|
||||
text_ptr[i]->lang - language of comment (NULL for unknown).
|
||||
text_ptr[i]->compression - type of compression used
|
||||
on "text" PNG_TEXT_COMPRESSION_NONE
|
||||
PNG_TEXT_COMPRESSION_zTXt
|
||||
PNG_ITXT_COMPRESSION_NONE
|
||||
PNG_ITXT_COMPRESSION_zTXt
|
||||
text_ptr[i]->key - keyword for comment.
|
||||
text_ptr[i]->translated_keyword - keyword in UTF-8 (NULL for unknown).
|
||||
text_ptr[i]->text - text comments for current
|
||||
keyword.
|
||||
text_ptr[i]->compression - type of compression used
|
||||
on "text" PNG_TEXT_COMPRESSION_NONE
|
||||
or PNG_TEXT_COMPRESSION_zTXt
|
||||
text_ptr[i]->text_length - length of text string,
|
||||
after decompression, 0 for iTXt
|
||||
text_ptr[i]->itxt_length - length of itxt string,
|
||||
after decompression, 0 for tEXt/zTXt
|
||||
text_ptr[i]->lang - language of comment (NULL for unknown).
|
||||
text_ptr[i]->translated_keyword - keyword in UTF-8 (NULL
|
||||
for unknown).
|
||||
num_text - number of comments
|
||||
|
||||
num_spalettes = png_get_spalettes(png_ptr, info_ptr, &palette_ptr);
|
||||
palette_ptr - array of png_spalette structures holding contents
|
||||
of one or more sPLT chunks read.
|
||||
@ -1188,6 +1342,7 @@ into the info_ptr is returned for any complex types.
|
||||
unknowns[i].name - name of unknown chunk
|
||||
unknowns[i].data - data of unknown chunk
|
||||
unknowns[i].size - size of unknown chunk
|
||||
unknowns[i].location - position of chunk in file
|
||||
|
||||
The data from the pHYs chunk can be retrieved in several convenient
|
||||
forms:
|
||||
@ -1232,6 +1387,8 @@ make sure you have read all the text chunks, don't mess with these
|
||||
until after you read the stuff after the image. This will be
|
||||
mentioned again below in the discussion that goes with png_read_end().
|
||||
|
||||
.SS Input transformations
|
||||
|
||||
After you've read the header information, you can set up the library
|
||||
to handle any special transformations of the image data. The various
|
||||
ways to transform the data will be described in the order that they
|
||||
@ -1566,6 +1723,8 @@ are allocating one large chunk, you will need to build an
|
||||
array of pointers to each row, as it will be needed for some
|
||||
of the functions below.
|
||||
|
||||
.SS Reading image data
|
||||
|
||||
After you've allocated memory, you can read the image data.
|
||||
The simplest way to do this is in one function call. If you are
|
||||
allocating enough memory to hold the whole image, you can just
|
||||
@ -1674,12 +1833,14 @@ the second parameter NULL.
|
||||
png_read_rows(png_ptr, NULL, row_pointers,
|
||||
number_of_rows);
|
||||
|
||||
After you are finished reading the image, you can finish reading
|
||||
the file. If you are interested in comments or time, which may be
|
||||
stored either before or after the image data, you should pass the
|
||||
separate png_info struct if you want to keep the comments from
|
||||
before and after the image separate. If you are not interested, you
|
||||
can pass NULL.
|
||||
.SS Finishing a sequential read
|
||||
|
||||
After you are finished reading the image through either the high- or
|
||||
low-level interfaces, you can finish reading the file. If you are
|
||||
interested in comments or time, which may be stored either before or
|
||||
after the image data, you should pass the separate png_info struct if
|
||||
you want to keep the comments from before and after the image
|
||||
separate. If you are not interested, you can pass NULL.
|
||||
|
||||
png_read_end(png_ptr, end_info);
|
||||
|
||||
@ -1694,16 +1855,20 @@ point to allocated storage with the following functions:
|
||||
png_free_text(png_ptr, info_ptr, num)
|
||||
num - number of text item to be freed (-1 for all items)
|
||||
|
||||
png_free_hIST(png_ptr, info_ptr)
|
||||
|
||||
png_free_iCCP(png_ptr, info_ptr)
|
||||
|
||||
png_free_pCAL(png_ptr, info_ptr)
|
||||
|
||||
png_free_sCAL(png_ptr, info_ptr)
|
||||
|
||||
png_free_spalette(png_ptr, info_ptr, num)
|
||||
png_free_spalettes(png_ptr, info_ptr, num)
|
||||
num - number of suggested-paletted entry to be freed
|
||||
(-1 for all suggested palettes)
|
||||
|
||||
png_free_pixels(png_ptr, info_ptr)
|
||||
|
||||
png_free_unknown_chunk(png_ptr, info_ptr, num)
|
||||
num - number of unknown chunk to be freed
|
||||
(-1 for all suggested palettes)
|
||||
@ -1714,8 +1879,7 @@ case do nothing.
|
||||
|
||||
For a more compact example of reading a PNG image, see the file example.c.
|
||||
|
||||
|
||||
Reading PNG files progressively:
|
||||
.SS Reading PNG files progressively
|
||||
|
||||
The progressive reader is slightly different then the non-progressive
|
||||
reader. Instead of calling png_read_info(), png_read_rows(), and
|
||||
@ -1892,6 +2056,8 @@ Much of this is very similar to reading. However, everything of
|
||||
importance is repeated here, so you won't have to constantly look
|
||||
back up in the reading section to understand writing.
|
||||
|
||||
.SS Setup
|
||||
|
||||
You will want to do the I/O initialization before you get into libpng,
|
||||
so if it doesn't work, you don't have anything to undo. If you are not
|
||||
using the standard I/O functions, you will need to replace them with
|
||||
@ -1954,6 +2120,10 @@ section below for more information on the libpng error handling.
|
||||
...
|
||||
return;
|
||||
|
||||
If you would rather avoid the complexity of setjmp/longjmp issues,
|
||||
you can compile libpng with PNG_SETJMP_NOT_SUPPORTED, in which case
|
||||
errors will result in a call to PNG_ABORT() which defaults to abort().
|
||||
|
||||
Now you need to set up the output code. The default for libpng is to
|
||||
use the C function fwrite(). If you use this, you will need to pass a
|
||||
valid FILE * in the function png_init_io(). Be sure that the file is
|
||||
@ -1963,6 +2133,8 @@ Libpng section below.
|
||||
|
||||
png_init_io(png_ptr, fp);
|
||||
|
||||
.SS Write callbacks
|
||||
|
||||
At this point, you can set up a callback function that will be
|
||||
called after each row has been written, which you can use to control
|
||||
a progress meter or the like. It's demonstrated in pngtest.c.
|
||||
@ -2017,6 +2189,8 @@ data. See the Compression Library for details on the compression levels.
|
||||
png_set_compression_window_bits(png_ptr, 15);
|
||||
png_set_compression_method(png_ptr, 8);
|
||||
|
||||
.SS Setting the contents of info for output
|
||||
|
||||
You now need to fill in the png_info structure with all the data you
|
||||
wish to write before the actual image. Note that the only thing you
|
||||
are allowed to write after the image is the text chunks and the time
|
||||
@ -2146,15 +2320,22 @@ Some of the more important parts of the png_info are:
|
||||
png_set_text(png_ptr, info_ptr, text_ptr, num_text);
|
||||
text_ptr - array of png_text holding image
|
||||
comments
|
||||
text_ptr[i]->lang - language of comment (NULL for unknown).
|
||||
text_ptr[i]->compression - type of compression used
|
||||
on "text" PNG_TEXT_COMPRESSION_NONE
|
||||
PNG_TEXT_COMPRESSION_zTXt
|
||||
PNG_ITXT_COMPRESSION_NONE
|
||||
PNG_ITXT_COMPRESSION_zTXt
|
||||
text_ptr[i]->key - keyword for comment.
|
||||
text_ptr[i]->translated_keyword - keyword in UTF-8 (NULL for unknown).
|
||||
text_ptr[i]->text - text comments for current
|
||||
keyword.
|
||||
text_ptr[i]->compression - type of compression used
|
||||
on "text" PNG_TEXT_COMPRESSION_NONE or
|
||||
PNG_TEXT_COMPRESSION_zTXt
|
||||
num_text - number of comments in text_ptr
|
||||
text_ptr[i]->text_length - length of text string,
|
||||
after decompression, 0 for iTXt
|
||||
text_ptr[i]->itxt_length - length of itxt string,
|
||||
after decompression, 0 for tEXt/zTXt
|
||||
text_ptr[i]->lang - language of comment (NULL for unknown).
|
||||
text_ptr[i]->translated_keyword - keyword in UTF-8 (NULL
|
||||
for unknown).
|
||||
num_text - number of comments
|
||||
|
||||
png_set_spalettes(png_ptr, info_ptr, &palette_ptr, num_spalettes);
|
||||
palette_ptr - array of png_spalette structures to be added to
|
||||
@ -2189,20 +2370,15 @@ Some of the more important parts of the png_info are:
|
||||
unknowns[i].name - name of unknown chunk
|
||||
unknowns[i].data - data of unknown chunk
|
||||
unknowns[i].size - size of unknown chunk
|
||||
|
||||
In PNG files, the alpha channel in an image is the level of opacity.
|
||||
If your data is supplied as a level of transparency, you can invert the
|
||||
alpha channel before you write it, so that 0 is fully transparent and 255
|
||||
(in 8-bit or paletted images) or 65535 (in 16-bit images) is fully opaque,
|
||||
with
|
||||
|
||||
png_set_invert_alpha(png_ptr);
|
||||
|
||||
This must appear here instead of later with the other transformations
|
||||
because in the case of paletted images the tRNS chunk data has to
|
||||
be inverted before the tRNS chunk is written. If your image is not a
|
||||
paletted image, the tRNS data (which in such cases represents a single
|
||||
color to be rendered as transparent) won't be changed.
|
||||
unknowns[i].location - position to write chunk in file
|
||||
0: do not write chunk
|
||||
PNG_HAVE_IHDR: before PLTE
|
||||
PNG_HAVE_PLTE: before IDAT
|
||||
PNG_AFTER_IDAT: after IDAT
|
||||
The "location" member is set automatically according to
|
||||
what part of the output file has already been written.
|
||||
You can change its value after calling png_set_unknown_chunks()
|
||||
as demonstrated in pngtest.c.
|
||||
|
||||
A quick word about text and num_text. text is an array of png_text
|
||||
structures. num_text is the number of valid structures in the array.
|
||||
@ -2284,6 +2460,8 @@ by the software. To facilitate the use of RFC 1123 dates, a function
|
||||
png_convert_to_rfc1123(png_timep) is provided to convert from PNG
|
||||
time to an RFC 1123 format string.
|
||||
|
||||
.SS Writing unknown chunks
|
||||
|
||||
You can use the png_set_unknown_chunks function to queue up chunks
|
||||
for writing. You give it a chunk name, raw data, and a size; that's
|
||||
all there is to it. The chunks will be written by the next following
|
||||
@ -2292,11 +2470,63 @@ Any chunks previously read into the info structure's unknown-chunk
|
||||
list will also be written out in a sequence that satisfies the PNG
|
||||
specification's ordering rules.
|
||||
|
||||
You are now ready to write all the file information up to the actual
|
||||
image data. You do this with a call to png_write_info().
|
||||
.SS The high-level write interface
|
||||
|
||||
At this point there are two ways to proceed; through the high-level
|
||||
write interface, or through a sequence of low-level write operations.
|
||||
You can use the high-level interface if your image data is present
|
||||
on the rowpointers member of the info structure. All defined output
|
||||
transformations are pernmitted, enabled by the following masks.
|
||||
|
||||
PNG_TRANSFORM_IDENTITY No transformation
|
||||
PNG_TRANSFORM_PACKING Pack 1, 2 and 4-bit samples
|
||||
PNG_TRANSFORM_PACKSWAP Change order of packed pixels to LSB first
|
||||
PNG_TRANSFORM_INVERT_MONO Invert monochrome images
|
||||
PNG_TRANSFORM_SHIFT Normalize pixels to the sBIT depth
|
||||
PNG_TRANSFORM_BGR Flip RGB to BGR, RGBA to BGRA
|
||||
PNG_TRANSFORM_SWAP_ALPHA Flip RGBA to ARGB or GA to AG
|
||||
PNG_TRANSFORM_INVERT_ALPHA Change alpha from opacity to transparency
|
||||
PNG_TRANSFORM_SWAP_ENDIAN Byte-swap 16-bit samples
|
||||
PNG_TRANSFORM_STRIP_FILLER Strip out filler bytes.
|
||||
|
||||
If you have valid image data on the rowpointers member, simply do this:
|
||||
|
||||
png_write_png(png_ptr, info_ptr, png_transforms, NULL)
|
||||
|
||||
where png_transforms is an integer containing the logical-or of some set of
|
||||
transformation flags. This call is equivalent to png_write_info(),
|
||||
followed by the set of transformations indicated by the transform
|
||||
mask, followed by followed by a write of the image bytes to the info
|
||||
member `rowpointers', followed by png_write_end().
|
||||
|
||||
(The final parameter of this call is not yet used. Someday it
|
||||
may point to output transformation parameters.)
|
||||
|
||||
.SS The low-level write interface
|
||||
|
||||
If you are going the low-level route instead, you are now ready to
|
||||
write all the file information up to the actual image data. You do
|
||||
this with a call to png_write_info().
|
||||
|
||||
png_write_info(png_ptr, info_ptr);
|
||||
|
||||
Note that there is one transformation you may need to do before
|
||||
png_write_info(). In PNG files, the alpha channel in an image is the
|
||||
level of opacity. If your data is supplied as a level of
|
||||
transparency, you can invert the alpha channel before you write it, so
|
||||
that 0 is fully transparent and 255 (in 8-bit or paletted images) or
|
||||
65535 (in 16-bit images) is fully opaque, with
|
||||
|
||||
png_set_invert_alpha(png_ptr);
|
||||
|
||||
This must appear before png_write_info() instead of later with the
|
||||
other transformations because in the case of paletted images the tRNS
|
||||
chunk data has to be inverted before the tRNS chunk is written. If
|
||||
your image is not a paletted image, the tRNS data (which in such cases
|
||||
represents a single color to be rendered as transparent) won't need to
|
||||
be changed, and you can safely do this transformation after your
|
||||
png_write_info() call.
|
||||
|
||||
If you need to write a private chunk that you want to appear before
|
||||
the PLTE chunk when PLTE is present, you can write the PNG info in
|
||||
two steps, and insert code to write your own chunk between them:
|
||||
@ -2437,6 +2667,8 @@ may be acceptable for real-time applications). Infrequent flushing will
|
||||
only degrade the compression performance by a few percent over images
|
||||
that do not use flushing.
|
||||
|
||||
.SS Writing the image data
|
||||
|
||||
That's it for the transformations. Now you can write the image data.
|
||||
The simplest way to do this is in one function call. If have the
|
||||
whole image in memory, you can just call png_write_image() and libpng
|
||||
@ -2470,7 +2702,7 @@ row_pointers:
|
||||
png_write_row(png_ptr, &row_pointer);
|
||||
|
||||
When the file is interlaced, things can get a good deal more
|
||||
complicated. The only currently (as of August 1999 -- PNG Specification
|
||||
complicated. The only currently (as of January 2000 -- PNG Specification
|
||||
version 1.2, dated July 1999) defined interlacing scheme for PNG files
|
||||
is the "Adam7" interlace scheme, that breaks down an
|
||||
image into seven smaller images of varying size. libpng will build
|
||||
@ -2500,6 +2732,8 @@ As some of these rows are not used, and thus return immediately,
|
||||
you may want to read about interlacing in the PNG specification,
|
||||
and only update the rows that are actually used.
|
||||
|
||||
.SS Finishing a sequential write
|
||||
|
||||
After you are finished writing the image, you should finish writing
|
||||
the file. If you are interested in writing comments or time, you should
|
||||
pass an appropriately filled png_info pointer. If you are not interested,
|
||||
@ -2517,16 +2751,20 @@ point to allocated storage with the following functions:
|
||||
png_free_text(png_ptr, info_ptr, num)
|
||||
num - number of text item to be freed (-1 for all items)
|
||||
|
||||
png_free_hIST(png_ptr, info_ptr)
|
||||
|
||||
png_free_iCCP(png_ptr, info_ptr)
|
||||
|
||||
png_free_pCAL(png_ptr, info_ptr)
|
||||
|
||||
png_free_sCAL(png_ptr, info_ptr)
|
||||
|
||||
png_free_spalette(png_ptr, info_ptr, num)
|
||||
png_free_spalettes(png_ptr, info_ptr, num)
|
||||
num - number of suggested-paletted entry to be freed
|
||||
(-1 for all suggested palettes)
|
||||
|
||||
png_free_pixels(png_ptr, info_ptr)
|
||||
|
||||
png_free_unknown_chunk(png_ptr, info_ptr, num)
|
||||
num - number of unknown chunk entry to be freed
|
||||
(-1 for all suggested palettes)
|
||||
@ -2535,8 +2773,7 @@ These functions may be safely called when the relevant storage has
|
||||
already been freed, or has not yet been allocated, and will in that
|
||||
case do nothing.
|
||||
|
||||
You must free any data you allocated for info_ptr, such as comments,
|
||||
palette, or histogram, before the call to png_destroy_write_struct();
|
||||
If you allocated palette data, you must free it before the call to png_destroy_write_struct();
|
||||
|
||||
For a more compact example of writing a PNG image, see the file example.c.
|
||||
|
||||
@ -2596,8 +2833,11 @@ a write stream, and vice versa.
|
||||
Error handling in libpng is done through png_error() and png_warning().
|
||||
Errors handled through png_error() are fatal, meaning that png_error()
|
||||
should never return to its caller. Currently, this is handled via
|
||||
setjmp() and longjmp(), but you could change this to do things like
|
||||
exit() if you should wish. On non-fatal errors, png_warning() is called
|
||||
setjmp() and longjmp() (unless you have compiled libpng with
|
||||
PNG_SETJMP_NOT_SUPPORTED, in which case it is handled via PNG_ABORT()),
|
||||
but you could change this to do things like exit() if you should wish.
|
||||
|
||||
On non-fatal errors, png_warning() is called
|
||||
to print a warning message, and then control returns to the calling code.
|
||||
By default png_error() and png_warning() print a message on stderr via
|
||||
fprintf() unless the library is compiled with PNG_NO_STDIO defined. If
|
||||
@ -2630,16 +2870,25 @@ after a longjmp, so the user may want to be careful about doing anything after
|
||||
setjmp returns non-zero besides returning itself. Consult your compiler
|
||||
documentation for more details.
|
||||
|
||||
If you need to read or write custom chunks, you will need to get deeper
|
||||
into the libpng code, as a mechanism has not yet been supplied for user
|
||||
callbacks with custom chunks. First, read the PNG specification, and have
|
||||
a first level of understanding of how it works. Pay particular attention
|
||||
to the sections that describe chunk names, and look at how other chunks
|
||||
were designed, so you can do things similarly. Second, check out the
|
||||
sections of libpng that read and write chunks. Try to find a chunk that
|
||||
is similar to yours and use it as a template. More details can be found in the
|
||||
comments inside the code. A way of handling unknown chunks in a generic
|
||||
method, potentially via callback functions, would be best.
|
||||
.SS Custom chunks
|
||||
|
||||
If you need to read or write custom chunks, you may need to get deeper
|
||||
into the libpng code. The library now has mechanisms for storing
|
||||
and writing chunks of unknown type; you can even declare callbacks
|
||||
for custom chunks. Hoewver, this may not be good enough if the
|
||||
library code itself needs to know about interactions between your
|
||||
chunk and existing `intrinsic' chunks.
|
||||
|
||||
If you need to write a new intrinsic chunk, first read the PNG
|
||||
specification. Acquire a first level of
|
||||
understanding of how it works. Pay particular attention to the
|
||||
sections that describe chunk names, and look at how other chunks were
|
||||
designed, so you can do things similarly. Second, check out the
|
||||
sections of libpng that read and write chunks. Try to find a chunk
|
||||
that is similar to yours and use it as a template. More details can
|
||||
be found in the comments inside the code. It is best to handle unknown
|
||||
chunks in a generic method, via callback functions, instead of by
|
||||
modifying libpng functions.
|
||||
|
||||
If you wish to write your own transformation for the data, look through
|
||||
the part of the code that does the transformations, and check out some of
|
||||
@ -2647,7 +2896,7 @@ the simpler ones to get an idea of how they work. Try to find a similar
|
||||
transformation to the one you want to add and copy off of it. More details
|
||||
can be found in the comments inside the code itself.
|
||||
|
||||
Configuring for 16 bit platforms:
|
||||
.SS Configuring for 16 bit platforms
|
||||
|
||||
You may need to change the png_large_malloc() and png_large_free()
|
||||
routines in pngmem.c, as these are required to allocate 64K, although
|
||||
@ -2656,13 +2905,13 @@ you will want to look into zconf.h to tell zlib (and thus libpng) that
|
||||
it cannot allocate more then 64K at a time. Even if you can, the memory
|
||||
won't be accessible. So limit zlib and libpng to 64K by defining MAXSEG_64K.
|
||||
|
||||
Configuring for DOS:
|
||||
.SS Configuring for DOS
|
||||
|
||||
For DOS users who only have access to the lower 640K, you will
|
||||
have to limit zlib's memory usage via a png_set_compression_mem_level()
|
||||
call. See zlib.h or zconf.h in the zlib library for more information.
|
||||
|
||||
Configuring for Medium Model:
|
||||
.SS Configuring for Medium Model
|
||||
|
||||
Libpng's support for medium model has been tested on most of the popular
|
||||
compilers. Make sure MAXSEG_64K gets defined, USE_FAR_KEYWORD gets
|
||||
@ -2670,10 +2919,10 @@ defined, and FAR gets defined to far in pngconf.h, and you should be
|
||||
all set. Everything in the library (except for zlib's structure) is
|
||||
expecting far data. You must use the typedefs with the p or pp on
|
||||
the end for pointers (or at least look at them and be careful). Make
|
||||
note that the row's of data are defined as png_bytepp, which is an
|
||||
note that the rows of data are defined as png_bytepp, which is an
|
||||
unsigned char far * far *.
|
||||
|
||||
Configuring for gui/windowing platforms:
|
||||
.SS Configuring for gui/windowing platforms:
|
||||
|
||||
You will need to write new error and warning functions that use the GUI
|
||||
interface, as described previously, and set them to be the error and
|
||||
@ -2682,7 +2931,7 @@ in order to have them available during the structure initialization.
|
||||
They can be changed later via png_set_error_fn(). On some compilers,
|
||||
you may also have to change the memory allocators (png_malloc, etc.).
|
||||
|
||||
Configuring for compiler xxx:
|
||||
.SS Configuring for compiler xxx:
|
||||
|
||||
All includes for libpng are in pngconf.h. If you need to add/change/delete
|
||||
an include, this is the place to do it. The includes that are not
|
||||
@ -2690,7 +2939,7 @@ needed outside libpng are protected by the PNG_INTERNAL definition,
|
||||
which is only defined for those routines inside libpng itself. The
|
||||
files in libpng proper only include png.h, which includes pngconf.h.
|
||||
|
||||
Configuring zlib:
|
||||
.SS Configuring zlib:
|
||||
|
||||
There are special functions to configure the compression. Perhaps the
|
||||
most useful one changes the compression level, which currently uses
|
||||
@ -2722,7 +2971,7 @@ zlib.h for more information on what these mean.
|
||||