defs.h doubled include fixed.

[wxWidgets.git] / src / png / libpng.txt

diff --git a/src/png/libpng.txt b/src/png/libpng.txt
index 0324715bb29293ef2c3e7246a690428d56f0252a..4dec2dd3aed76729e1878994a108765ff55b43fc 100644 (file)
--- a/src/png/libpng.txt
+++ b/src/png/libpng.txt
@@ -1,6 +1,6 @@
 libpng.txt - A description on how to use and modify libpng
 
 libpng.txt - A description on how to use and modify libpng
 

- libpng version 1.2.6 - August 15, 2004
+ libpng version 1.2.7 - September 12, 2004

  Updated and distributed by Glenn Randers-Pehrson
  <glennrp@users.sourceforge.net>
  Copyright (c) 1998-2004 Glenn Randers-Pehrson
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp@users.sourceforge.net>
  Copyright (c) 1998-2004 Glenn Randers-Pehrson


@@ -37,19 +37,23 @@ Libpng was written as a companion to the PNG specification, as a way
 of reducing the amount of time and effort it takes to support the PNG
 file format in application programs.
 
 of reducing the amount of time and effort it takes to support the PNG
 file format in application programs.
 

-The PNG-1.2 specification is available at <http://www.libpng.org/pub/png>
-and at <ftp://ftp.uu.net/graphics/png/documents/>.
+The PNG specification (second edition), November 2003, is available as
+a W3C Recommendation and as an ISO Standard (ISO/IEC 15948:2003 (E)) at
+<http://www.w3.org/TR/2003/REC-PNG-20031110/
+The W3C and ISO documents have identical technical content.
+
+The PNG-1.2 specification is available at
+<http://www.libpng.org/pub/png/documents/>

 
 The PNG-1.0 specification is available
 
 The PNG-1.0 specification is available

-as RFC 2083 <ftp://ftp.uu.net/graphics/png/documents/> and as a
+as RFC 2083 <http://www.libpng.org/pub/png/documents/> and as a

 W3C Recommendation <http://www.w3.org/TR/REC.png.html>. Some
 additional chunks are described in the special-purpose public chunks
 W3C Recommendation <http://www.w3.org/TR/REC.png.html>. Some
 additional chunks are described in the special-purpose public chunks

-documents at <ftp://ftp.uu.net/graphics/png/documents/>.
+documents at <http://www.libpng.org/pub/png/documents/>.

 
 Other information
 about PNG, and the latest version of libpng, can be found at the PNG home
 
 Other information
 about PNG, and the latest version of libpng, can be found at the PNG home

-page, <http://www.libpng.org/pub/png/>
-and at <ftp://ftp.uu.net/graphics/png/>.
+page, <http://www.libpng.org/pub/png/>.

 
 Most users will not have to modify the library significantly; advanced
 users may want to modify it more.  All attempts were made to make it as
 
 Most users will not have to modify the library significantly; advanced
 users may want to modify it more.  All attempts were made to make it as


@@ -82,7 +86,6 @@ 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.
 
 by use of some of the MMX assembler code in pnggccrd.c, which is only
 compiled when the user defines PNG_THREAD_UNSAFE_OK.
 

-

 II. Structures
 
 There are two main structures that are important to libpng, png_struct
 II. Structures
 
 There are two main structures that are important to libpng, png_struct


@@ -397,6 +400,9 @@ then png_read_image(), and finally png_read_end().
 (The final parameter of this call is not yet used.  Someday it might point
 to transformation parameters required by some future input transform.)
 
 (The final parameter of this call is not yet used.  Someday it might point
 to transformation parameters required by some future input transform.)
 

+You must use png_transforms and not call any png_set_transform() functions
+when you use png_read_png().
+

 After you have called png_read_png(), you can retrieve the image data
 with
 
 After you have called png_read_png(), you can retrieve the image data
 with
 


@@ -761,14 +767,14 @@ unless the library has been told to transform it into another format.
 For example, 4 bit/pixel paletted or grayscale data will be returned
 2 pixels/byte with the leftmost pixel in the high-order bits of the
 byte, unless png_set_packing() is called.  8-bit RGB data will be stored
 For example, 4 bit/pixel paletted or grayscale data will be returned
 2 pixels/byte with the leftmost pixel in the high-order bits of the
 byte, unless png_set_packing() is called.  8-bit RGB data will be stored

-in RGB RGB RGB format unless png_set_filler() is called to insert filler
-bytes, either before or after each RGB triplet.  16-bit RGB data will
-be returned RRGGBB RRGGBB, with the most significant byte of the color
-value first, unless png_set_strip_16() is called to transform it to
-regular RGB RGB triplets, or png_set_filler() is called to insert
-filler bytes, either before or after each RRGGBB triplet.  Similarly,
-8-bit or 16-bit grayscale data can be modified with png_set_filler()
-or png_set_strip_16().
+in RGB RGB RGB format unless png_set_filler() or png_set_add_alpha()
+is called to insert filler bytes, either before or after each RGB triplet.
+16-bit RGB data will be returned RRGGBB RRGGBB, with the most significant
+byte of the color value first, unless png_set_strip_16() is called to
+transform it to regular RGB RGB triplets, or png_set_filler|add alpha()
+is called to insert filler bytes, either before or after each RRGGBB
+triplet.  Similarly, 8-bit or 16-bit grayscale data can be modified with
+png_set_filler(), png_set_add_alpha(), or png_set_strip_16().

 
 The following code transforms grayscale images of less than 8 to 8 bits,
 changes paletted images to RGB, and adds a full alpha channel if there is
 
 The following code transforms grayscale images of less than 8 to 8 bits,
 changes paletted images to RGB, and adds a full alpha channel if there is


@@ -853,6 +859,16 @@ does not affect images that already have full alpha channels.  To add an
 opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which
 will generate RGBA pixels.
 
 opaque alpha channel, use filler=0xff or 0xffff and PNG_FILLER_AFTER which
 will generate RGBA pixels.
 

+Note that png_set_filler() does not change the color type.  If you want
+to do that, you can add a true alpha channel with
+
+    if (color_type == PNG_COLOR_TYPE_RGB ||
+           color_type == PNG_COLOR_TYPE_GRAY)
+    png_set_add_alpha(png_ptr, filler, PNG_FILLER_AFTER);
+
+where "filler" contains the alpha value to assign to each pixel.
+This function became available in libpng-1.2.7.
+

 If you are reading an image with an alpha channel, and you need the
 data as ARGB instead of the normal PNG format RGBA:
 
 If you are reading an image with an alpha channel, and you need the
 data as ARGB instead of the normal PNG format RGBA:
 


@@ -1997,6 +2013,9 @@ then png_write_image(), and finally png_write_end().
 (The final parameter of this call is not yet used.  Someday it might point
 to transformation parameters required by some future output transform.)
 
 (The final parameter of this call is not yet used.  Someday it might point
 to transformation parameters required by some future output transform.)
 

+You must use png_transforms and not call any png_set_transform() functions
+when you use png_write_png().
+

 The low-level write interface
 
 If you are going the low-level route instead, you are now ready to
 The low-level write interface
 
 If you are going the low-level route instead, you are now ready to


@@ -2808,7 +2827,7 @@ For more extensive examples of runtime querying, enabling and disabling
 of optimized features, see contrib/gregbook/readpng2.c in the libpng
 source-code distribution.
 
 of optimized features, see contrib/gregbook/readpng2.c in the libpng
 source-code distribution.
 

-VI.  MNG support
+VII.  MNG support

 
 The MNG specification (available at http://www.libpng.org/pub/mng) allows
 certain extensions to PNG for PNG images that are embedded in MNG datastreams.
 
 The MNG specification (available at http://www.libpng.org/pub/mng) allows
 certain extensions to PNG for PNG images that are embedded in MNG datastreams.


@@ -2833,7 +2852,7 @@ or any other MNG chunks; your application must provide its own support for
 them.  You may wish to consider using libmng (available at
 http://www.libmng.com) instead.
 
 them.  You may wish to consider using libmng (available at
 http://www.libmng.com) instead.
 

-VII.  Changes to Libpng from version 0.88
+VIII.  Changes to Libpng from version 0.88

 
 It should be noted that versions of libpng later than 0.96 are not
 distributed by the original libpng author, Guy Schalnat, nor by
 
 It should be noted that versions of libpng later than 0.96 are not
 distributed by the original libpng author, Guy Schalnat, nor by


@@ -2882,15 +2901,15 @@ application:
 
    png_uint_32 application_vn = PNG_LIBPNG_VER;
 
 
    png_uint_32 application_vn = PNG_LIBPNG_VER;
 

-VII. Y2K Compliance in libpng
+IX. Y2K Compliance in libpng

 
 

-August 15, 2004
+September 12, 2004

 
 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
 
 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 1.2.6 are Y2K compliant.  It is my belief that earlier
+upward through 1.2.7 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
 versions were also Y2K compliant.
 
 Libpng only has three year fields.  One is a 2-byte unsigned integer that