WEB2PNG(1)                                           WEB2PNG(1)





NAME
       web2png  -  convert  a web tree from using GIFs to using
       PNGs

SYNOPSIS
       web2png [-adnrtv] [directory...]


DESCRIPTION
       Web2png is a front end for gif2png(1) that automatically
       converts  entire web page hierarchies from using GIFs to
       using PNGs. It does image conversion and patches IMG SRC
       references in web pages.


       The  arguments  to  web2png must be directories; if none
       are given, the current directory is assumed.


       In each directory, web2png tries to convert every GIF to
       a  PNG.  It  leaves alone GIFs that have either multiple
       images or transparency, because these will  not  display
       properly  in  all  current  browsers.  It  also does not
       reconvert GIFs  that  already  have  corresponding  PNGs
       (e.g. the same name except for the .gif file extension).
       The original GIFs are left in place.


       Web2png tracks successful conversions. It then looks  at
       each  HTML,  secure  HTML,  HTML  inclusion,  PHP  page,
       JavaScript program or Cascading Style  Sheet  under  the
       argument  directories  (extensions  html,  shtml,  .inc,
       .php, .js, .css). In these pages, it fixes  each  refer-
       ence  to  each  successful converted GIF to point at the
       PNG. References in relative HREF and BACKGROUND tags are
       recognized  by  filename  and  fixed (any base directory
       declared by a BASE tag will be be prepended to the rela-
       tive  URL).  References  that  are HTTP URLs are matched
       against the list of convertible  GIFs  by  basename;  if
       there  is  such  a  match,  the  contents  of the URL is
       retrieved and compared to the convertible GIF.  If  both
       basename and data match, the HTTP reference is fixed. If
       the pages are under RCS version control, they're checked
       out  for modification before being altered; otherwise, a
       copy of the original of each modified web page  is  left
       in  the  same  directory,  with the additional extension
       .bak.


       The following options change the behavior  of  the  pro-
       gram:


       Convert all GIF files, including those with multiple images and/or transparency.


       Delete originals. Removes all GIFs with corresponding PNGs, and all .bak files.


       Make no changes. With this option, web2png reports on what needs to be done (and on GIFs that use transparency or have multiple images), but neither converts GIFs nor touches web pages.


       Reverse. Restore all HTML/SHTML/PHP pages from the .bak files created by a previous run (or, if the files were under version control, revert them). Remove PNGs with corresponding GIFs.


       Convert transparent GIFs (for use with IE 5.0+. Netscape 6.0+, and Mozilla).


       Verbose. Utter more trace information about the conversion process. Web2png can be run on a directory that has already been partly converted by previous runs; it will do the minimum necessary amount of work. The changes it makes will be fully reversible with -r until you run it in -d mode. Web2png is written in Python. Python 1.5.2 or better must be installed and accessible on your system in order for web2png to run.


NOTE
       Sometimes  it's  possible  to  convert  transparent GIFs
       without altering the appearance of the page, by  knowing
       from  context that they will always place within an area
       of fixed and solid color. Web2png can't deduce when this
       will  be,  so  it  doesn't  try; but it may be useful to
       apply gif2png with the -b option by hand.


KNOWN PROBLEMS
       The algorithm for fixing HTTP URLs is not foolproof.  It
       could  be confused into incorrectly patching an HTTP URL
       reference to a GIF into an invalid reference to a PNG if
       the  GIF matches a local target GIF by both basename and
       binary content, but actually lives on another host.


       This program does not automatically convert CGIs; you'll
       have  to  do that by hand. Other dynamic-content methods
       (such as server-side inclusions) may also require  hand-
       hacking.


       The program cannot tell converted from preexisting PNGs;
       if you have PNGs with the same stem name as  correspond-
       ing GIFs but carrying different information, the -r mode
       will clobber them.


SEE ALSO
       gif2png(1)


AUTHORS
       Eric S. Raymond <esr@thyrsus.com>, October 1999.


       Slightly  modified   for   Debian   by   Aaron   Isotton
       <aaron@isotton.com>.




                                                     WEB2PNG(1)
