[devel] Revise libpng*.txt

about calling png_set_IHDR() multiple times and about the order
of color samples in the tRNS chunk.

CHANGES

@@ -2147,10 +2147,13 @@ version 1.4.0beta62 [June 2, 2009]
   Added "#define PNG_NO_WRITE_SWAP" to contrib/pngminim/encoder/pngusr.h
     and "define PNG_NO_READ_SWAP" to decoder/pngusr.h and preader/pngusr.h
   Reformatted several remaining "else statement" into two lines.
-  Added a section about using png_get_io_ptr() in configure scripts to detect
-    the presence of libpng.
+  Added a section to the libpng documentation about using png_get_io_ptr()
+    in configure scripts to detect the presence of libpng.
 
-version 1.4.0beta63 [June 5, 2009]
+version 1.4.0beta63 [June 8, 2009]
+  Revised libpng*.txt and libpng.3 to mention calling png_set_IHDR()
+    multiple times and to specify the sample order in the tRNS chunk,
+    because the ISO PNG specification has a typo in the tRNS table.
 
 version 1.4.0betaN [future]
   Build shared libraries with -lz and sometimes -lm.

libpng-1.4.0beta63.txt

 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.4.0beta63 - June 5, 2009
+ libpng version 1.4.0beta63 - June 8, 2009
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2009 Glenn Randers-Pehrson
@@ -9,7 +9,7 @@ libpng.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.4.0beta63 - June 5, 2009
+ libpng versions 0.97, January 1998, through 1.4.0beta63 - June 8, 2009
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2009 Glenn Randers-Pehrson
 
@@ -1839,8 +1839,9 @@ other png_set_*() functions, which might require access to some of
 the IHDR settings.  The remaining png_set_*() functions can be called
 in any order.
 
-If you wish, you can reset the compression_type, interlace_type,
-or filter_method later.
+If you wish, you can reset the compression_type, interlace_type, or
+filter_method later by calling png_set_IHDR() again; if you do this, the
+width, height, bit_depth, and color_type must be the same in each call.
 
     png_set_PLTE(png_ptr, info_ptr, palette,
        num_palette);
@@ -1903,8 +1904,9 @@ or filter_method later.
        trans_color);
     trans          - array of transparent entries for
                      palette (PNG_INFO_tRNS)
-    trans_color    - graylevel or color sample values of
-                     the single transparent color for
+    trans_color    - graylevel or color sample values
+                     (in order red, green, blue) of the
+                     single transparent color for
                      non-paletted images (PNG_INFO_tRNS)
     num_trans      - number of transparent entries
                      (PNG_INFO_tRNS)
@@ -3117,7 +3119,7 @@ We don't use C++ style ("//") comments. We have, however,
 used them in the past in some now-abandoned MMX assembler
 code.
 
-Functions and their curly brackets are not indented, and
+Functions and their curly braces are not indented, and
 exported functions are marked with PNGAPI:
 
  /* This is a public function that is visible to
@@ -3161,7 +3163,7 @@ source.
 
 XIII. Y2K Compliance in libpng
 
-June 5, 2009
+June 8, 2009
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.