                                Chimera 1.70
                      X11/Athena World-Wide Web Client
                    Originally developed by John Kilburg

   Chimera is an X/Athena Web client for UNIX-based workstations.  If you do
not know about the Web then try to grab a FAQ from rtfm.mit.edu using ftp.
Chimera does not require Motif.

* Installation:
    See ./INSTALL for installation and configuration instructions.
    See ./INSTALL.hints for tips on getting it to work in special cases.

* What are all these files:
    A description of the structure of the files in this distribution appears
    near the end of this file.

* Chimera support and announcements:
    + For announcements of new versions and patches, join the
        chimera-announce@cs.unlv.edu mailing list by sending a request to
        join to chimera-announce-request@cs.unlv.edu.

    + To report bugs, send email to bug-chimera@cs.unlv.edu

    + If you want to receive the bug reports sent to bug-chimera, join the
        list by sending a request to join to bug-chimera-request@cs.unlv.edu.
        This will also keep you abreast with the Chimera-2.* development.



WHAT'S NEW IN CHIMERA 1.70
--------------------------

SUMMARY:

   If you're using any prior version of Chimera 1, you definitely want to
switch to this version!

Chimera 1.70 contains many new features compared to 1.65p1+1:
    1) Table support has been vastly improved.
    2) mailto:user@host URLs are now supported  (via an external Perl script).
    3) Display refresh has been substantially optimized.
    4) Image handling improvements speed up rendering, a lot in some cases.
    5) DNS caching cuts domain name lookup calls by about 90%.
    6) Connection progress is displayed in the Title area.
    7) The "Host:" HTTP request header has been added.
    8) A new toggle button, DeferPix, has been added that turns delayed image
        loading on and off  (or you can type 'i' if you prefer).
    9) If serious HTML command errors are encountered on a visited page, a
        small message saying so will appear at the bottom of the page.

Chimera 1.70 also contains a long list of bug fixes, including these:
    * Some 20 different memory leaks have been fixed, including all the
        major ones.
    * Handling of excess "../"s in a relative URL has been fixed, and URL
        parsing in general has been greatly improved.
    * The bug that a JPEG image in a file named *.gif would not only fail,
        but prevent ALL further image display has been fixed.
    * A page's Title and URL are now restored in many cases where before they
        weren't.

All the Chimera 1.65 patches up through 1.65p1  (plus one stray)  are included.

   The source code differences between 1.65p1+1 and 1.70 are so extensive
that patches against 1.65 or 1.65p1 will not be provided.

   For details of the numerous changes included in 1.65p0 and 1.65p1, see
"http://hasse.mathematik.tu-muenchen.de/~nikl/chimera-1.65p/index.html".
A Web page for Chimera 1.70 is then just one click away;  notes about known
problems and fixes will be put there as the opportunity arises.



DETAILS OF THE NEW FEATURES  (see ./CHANGES for the real nitty-gritty):

1. Tables

   The table support in 1.70 includes: 
        * arbitrarily nested tables,
        * arbitrary number of columns and rows per table,
        * multi-line table items,
        * support for "width="  (including widths of "w%"),
        * support for "colspan=",
        * support for "cellpadding=",
        * implicit table tags  (for bad/broken HTML that leaves out tags),
        * captions, and
        * handling of quotes around integer values in table tag parameters.

   Table formatting uses a "1 pass with retroactive fixups" algorithm.  This
is not as good as a good 2-pass system, but it does quite well in most of the
cases I've seen.  The main case where it does less well is with long
sentences in non-fixed-width cells in left-side table columns.  In that
case, it can give "too much" space to the one column, at the "expense" of
columns to its right.

   The Print, Pretty Print, select  (via mouse),  and anchor locate routines
have all been updated to work with Web pages containing tables.  The output
usually even comes out in columns.  Note, however, that lines of text in
different columns of a multi-column Web page are likely to be offset by a
fraction of a line and may resolve to different lines in the ASCII output.

   Deficiencies: There is no support for "rowspan=".


2. mailto:user@domain now supported

   Chimera now allows you to reply to mailto: URLs.  The support is provided
via a helper program and requires Perl  (4.036 will do, as well as 5.003 or
later -- if you don't already have it, consider getting it, it's cool ;).  The
helper script for mailto:user@domain URLs ought to work out of the box.
Clicking on the URL brings up a fill-in form.  Click on the "Mail" button to
send the message, which will then also be shown with most of its headers
in the Chimera window so you can then save it to a file if you wish.

   See the text of the script for some ideas how to bring up your favorite
mail client instead and pass the address to it.


3. Display refresh optimization

   The display refresh optimization is the result of redisplaying only things
actually inside the refresh region.  Previously, 100% of everything remotely
associated with the region  (including items "on the same line as" the area
being refreshed)  would be redisplayed.  While the improvement was often small
in non-table documents, the improvement in table documents was significant.


4. Internal image handling improvements

   Previously, an image was loaded and converted every time it was needed,
and if the image appeared several times on a page, it was loaded and
converted several times.  Chimera 1.70 now loads and converts each image only
once per Web page and saves X-server calls for the duplicates as well.  This
speedup is particularly nice on pages that use small colored "bullet" graphic
dots for lists, and greatly reduces redisplay time in Delayed Image mode when
you have clicked and loaded a deferred image.


5. DNS caching

   The vast majority of domain name server lookups were for the same host
name several times in a row.  Chimera 1.70 caches up to two DNS lookup
results, cutting the number of DNS lookups required by about 90%  (even
more when you use an HTTP proxy).


6. Connection progress displays

   Downloading progress is displayed as before, but now you can also follow
the progress  (or lack thereof)  of each connection before any data are
forthcoming.  Connection progress is displayed in the Title area.


7. "Host:" HTTP request header added

   Joining the ranks of modern browsers, Chimera 1.70 now uses the "Host:"
header in its HTTP requests.  (It is mandatory in HTTP/1.1, and is required
to identify the desired document on multi-homed web sites.)


8. DeferPix button added

   A new button, labelled "DeferPix" has been added to allow dynamic
selection of delayed image loading.  It is a toggle button that turns light
or dark to indicate whether delayed image loading is currently selected.  The
keyboard key "i"  (for "image")  may also be used to toggle delayed image
loading.  (The keyboard key may be used even if you use a special button
configuration that does not include the DelayPix botton itself.)

   The X resource delayImageLoads now just sets the initial state.


9. HTML syntax error display

   When a document contains HTML syntax errors, the resulting display may
not be what the author intended.  Such errors include unterminated font
changes, unclosed tables, and over a dozen other causes.  When such errors
are found, a small message appears at the end of the page.

   This extra message is separate from the document itself.  It cannot be
selected with the mouse or found by Search, and it will not be included in
File, Print, or Email output.

   The default is to display the message if >0 errors are encountered.  You
may change this threshold using the new X resource *html.htmlErrorMsgCutoff.
Its default value is 0.  A negative value disables display of these messages.
A non-negative value limits these messages to pages with more errors than the
specified cutoff.



WHAT FILES ARE HERE
-------------------

The Chimera distribution is made up of several parts:

src            The source code for Chimera -- this is
               code originally written by John Kilburg.

lib            Run-time configuration files and help page for Chimera.

mxw            Miscellaneous X widgets written by various people.

libhtmlw       This is the HTML widget.  It was originally written at NCSA,
               and you could find an original version of this code in the
               Mosaic-2.4 distribution  (see libhtmlw/README for more).
               It has, however, been extensively modified by others for
               Chimera.

util           Utility programs used by chimera.  E.g., the mailto script
               lives here until it's installed.

xloadimage     Functions for handling graphics images -- this code was
               snarfed from xloadimage which is available on ftp.x.org.

compat         This directory was grabbed from the TCL 7.3 distribution.
               It contains functions used by chimera that may not exist
               on all machines.  I grabbed strcasecmp() from the BSD
               sources.

common         Stuff common to all of the above directories  (memory
               allocation, in particular).

   You should examine the files in each of these directories for copyright
and distribution information.



WHY CREATE 1.70 WHEN CHIMERA 2.XXX IS AVAILABLE?
------------------------------------------------

   This is intended as "a better Chimera 1.*" and a stopgap until Chimera 2.*
gets enough further along to be a superset of Chimera 1.*.  Unfortunately,
although Chimera 2 has lots of neat new features, it's clearly  (as ad-
vertised)  alpha software -- crashing too often to suit me, and not even
supporting &nbsp  (as of 2.164).  Also, several features of Chimera 1.65,
such as Emacs-like editing keys in text widgets and gamma correction, were
absent in Chimera 2.

   The addition of substantial table support and dynamic selection of delayed
image loading seemed like big enough changes to merit rounding the version
number up to 70.  Once Gerhard and I got going, we ended up adding a few
dozen more new features and fixed many bugs, making "70" well earned.  The
other reason for choosing "1.70" was to avoid confusion with 1.65 and
anything John might want to do.  Numbers 1.66 to 1.69 were skipped.

   Enjoy,
Winston Edmond <wbe@shore.net>
Gerhard Niklasch <nikl@mathematik.tu-muenchen.de>

Tuesday, May 6, 1997
