Imported from libpng-1.0.1a.tar

libpng.3

@@ -1,4 +1,4 @@
-.TH LIBPNG 3 "March 15, 1998"
+.TH LIBPNG 3 "April 21, 1998"
 .SH NAME
 libpng \- Portable Network Graphics (PNG) Reference Library
 .SH SYNOPSIS
@@ -396,7 +396,7 @@ Following is a copy of the libpng.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng.txt - A description on how to use and modify libpng
 
- libpng version 1.0.1 March 15, 1998
+ libpng version 1.0.1a April 21, 1998
  Updated and distributed by Glenn Randers-Pehrson
  <randeg@alumni.rpi.edu>
  Copyright (c) 1998, Glenn Randers-Pehrson
@@ -872,11 +872,14 @@ 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
-in RGBRGBRGB format unless png_set_filler() is called to insert filler
+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 RRGGBBRRGGBB, with the most significant byte of the color
+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 RGBRGB triplets.
+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().
 
 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
@@ -952,7 +955,7 @@ into 4 bytes for windowing systems that need them in this format:
         PNG_COLOR_TYPE_RGB) png_set_filler(png_ptr,
         filler, PNG_FILLER_BEFORE);
 
-where "filler" is the number to fill with, and the location is
+where "filler" is the 8 or 16-bit number to fill with, and the location is
 either PNG_FILLER_BEFORE or PNG_FILLER_AFTER, depending upon whether
 you want the filler before the RGB or after.  This transformation
 does not affect images that already have full alpha channels.
@@ -1412,6 +1415,8 @@ png_infop info_ptr;
      */
  }
 
+
+
 .SH IV. Writing
 
 Much of this is very similar to reading.  However, everything of
@@ -1504,9 +1509,9 @@ not calling this function at all, as it has been tuned to deliver a good
 speed/compression ratio. The second parameter to png_set_filter() is
 the filter method, for which the only valid value is '0' (as of the
 October 1996 PNG specification, version 1.0).  The third parameter is a
-flag that indicates
-which filter type(s) are to be tested for each scanline.  See the
-Compression Library for details on the specific filter types.
+flag that indicates which filter type(s) are to be tested for each
+scanline.  See the Compression Library for details on the specific filter
+types.
 
     
     /* turn on or off filtering, and/or choose
@@ -1780,8 +1785,9 @@ checks to see if it has data that it can do something with, you should
 make sure to only enable a transformation if it will be valid for the
 data.  For example, don't swap red and blue on grayscale data.
 
-PNG files store RGB pixels packed into 3 bytes.  This code tells
-the library to expect input data with 4 bytes per pixel
+PNG files store RGB pixels packed into 3 or 6 bytes.  This code tells
+the library to expand the input data to 4 or 8 bytes per pixel
+(or expand 1 or 2-byte grayscale data to 2 or 4 bytes per pixel).
 
     png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
 
@@ -1899,11 +1905,11 @@ times, or any of that other stuff necessary with png_write_rows().
 
 where row_pointers is:
 
-    png_bytef *row_pointers[height];
+    png_byte *row_pointers[height];
 
 You can point to void or char or whatever you use for pixels.
 
-If you can't want to write the whole image at once, you can
+If you don't want to write the whole image at once, you can
 use png_write_rows() instead.  If the file is not interlaced,
 this is simple:
 
@@ -2366,7 +2372,7 @@ possible without all of you.
 
 Thanks to Frank J. T. Wojcik for helping with the documentation.
   
-Libpng version 1.0.1 March 15, 1998:
+Libpng version 1.0.1a April 21, 1998:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (randeg@alumni.rpi.edu).