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The HTML Viewer
The help viewer windows provide access to the help system topics, and
can display general HTML and image files.
There are three colored buttons in the menu bar of the viewer. The
left-facing arrow button (back) will return to the previous topic
shown in the window. The right-facing arrow button (forward) will
advance to the next topic, if the back button has been used. The Stop button will stop HTTP transfers in progress.
There are four drop-down menus in the menu bar: File, which
contains basic commands for loading and printing, Options, which
contains commands for setting display attributes, Bookmarks,
which allows saving frequently used references, and Help which
The File menu contains the following command buttons.
The Open button in the File menu pops up a dialog into
which a new keyword, URL, or file name can be entered.
- Open File
The Open File button brings up the File Selection panel.
The Ok button (green octagon) on the File Selection panel
will load the selected file into the viewer (the file should be a
viewable file). The file can also be dragged into the viewer from the
File Selection panel.
The Save button in the File menu allows the text of the
current window to be saved in a file. This functionality is also
provided by the Print button. The saved text is pure ASCII.
The Print button brings up a pop-up which allows the user to
send the help text to a printer, or to a file. The format of the text
is set by the drop-down menu, with the current setting indicated on
the menu button. The choices are PostScript in four fonts (Times,
Helvetica, New Century Schoolbook, and Lucida Bright), HTML, or plain
text. If the To File button is active, output goes to that
file, otherwise the command string is executed to send output to a
printer. If the characters ``%s'' appear in the command
string, they are replaced with the temporary print file name,
otherwise the temporary file name is appended to the string, separated
by a space character.
The Reload button in the File menu will re-read the input
file and redisplay the contents. This can be useful when writing new
help text or HTML files, as it will show changes made to the input
file. However, if you edit a ``.hlp'' file, the internally
cached offsets for the topics below the editing point will be wrong,
and will not display correctly. When developing a help text topic,
placing it in a separate file will avoid this problem. One can also
use the !helpreset command to update the file offset table. If
the displayed object is a web page, the page will be redisplayed from
the disk cache if it is enabled, rather than being downloaded again.
- Old Charset
The help viewer uses the UTF-8 character set, which is the current
standard international character set. However, older input sources
may assume another character set, such as ISO-8859, that will display
some characters incorrectly. If the user observes that some
characters are missing or wrong in the display, setting this mode
- Make FIFO
This controls an obscure but unique feature. When the button is
pressed, a named pipe, or FIFO, is created in the user's home
directory. The name is ``mozyfifo'', or if this name is in use,
an integer suffix is added to make the name unique. This is a special
type of file, that has the property in this case that text written to
this ``file'' will be parsed and displayed on the viewer screen.
The feature was developed for use in the stand-alone mozy
program, for use as a HTML viewer for the mutt mail client. If
an HTML MIME attachment is ``saved'' to the FIFO file, it will be
displayed in the viewer.
The FIFO will be destroyed if this toggle button is pressed a second
time, or when the help window exist normally. If the program crashes,
the FIFO may be left behind and require manual removal.
The Quit button in the File menu removes the help window.
This will exit help mode (where clicking on a command button brings up
help) if there are no other help windows visible. Pressing the Help button in the Help Menu a second time or pressing the Esc key also exits help mode, though the help windows remain visible.
The Options menu presents a number of configuration and visual
attribute choices to the user. These are described below.
- Save Config
The Save Config button in the Options will save a
configuration file in the user's home directory, named ``.mozyrc''. This file is read whenever a new help window appears, and
sets various parameters, defaults, etc. This provides persistence of
the options selected in the Options menu. Without an existing
.mozyrc file, changes are discarded. If the file exists, it
will be updated whenever a help window is dismissed.
- Search Database
The Search Database button in the Options menu brings up a
dialog which solicits a regular expression to use as a search key into
the help database. The regular expression syntax follows POSIX 1003.2
extended format (roughly that used by the Unix egrep command).
The search is case-insensitive. When the search is complete, a new
display appears, with the database entries which contained a match
listed in the ``References'' field. The library functions which
implement the regular expression evaluation differ slightly between
systems. Further information can be found in the Unix manual pages
- Find Text
The Find Text command enables searching for text in the window.
A dialog window appears, into which a regular expression is entered.
Text matching the regular expression, if any, is selected and scrolled
into view, on pressing one of the blue up/down arrow buttons. The
down arrow searches from the text shown at the top of the window to
the end of the document, and will highlight the first match found, and
bring it into view if necessary. The up button will search the text
starting with that shown at the bottom of the window to the start of
the document, in reverse order. Similarly, it will highlight and
possibly scroll to the first match found. The buttons can be pressed
repeatedly to visit all matches.
- Default Colors
The Default Colors button in the Options menu brings up
the Default Colors panel, from which the default colors used in
the display may be set. The entries provide defaults which are used
when the document being displayed does not provide alternative values
(in a <body> tag). The defaults apply in general to help text.
The color entries can take a color name, as listed in the listing
brought up with the Colors button, or a numerical RGB entry in
any common format. The entries are the following:
- Background color
Set the default background color used.
- Background image
If set to a path to an image file in any standard image format, the
image is used to tile the background.
- Text color
The default color to use for text.
- Link color
The default color to use for un-visited links.
- Visited link color
The default color to use for visited links.
- Activated link color
The default color to use for a link over which the user presses a
- Select color
The color to use as the background of selected text. This color can
not be set from the document.
- Imagemap border color
The color to use for the border drawn around imagemaps. This color
can not be set from the document.
The Colors button brings up a panel which lists available named
colors. Clicking on a name in this panel selects it, and enters the
name into the system clipboard. The ``paste'' operation can then be
used to enter the color name into an entry area. This may vary
between systems, typically clicking on an entry area with the middle
mouse button will paste text from the clipboard.
Pressing the Apply button will apply the new colors to the
viewer window. Pressing Dismiss or otherwise retiring the panel
without pressing Apply will discard changes. Changes made will
not be persistent unless the Save Config button has been
used to create a .mozyrc file, as mentioned above.
- Set Font
The Set Font button in the Options menu will bring up a
font selection pop-up. One can choose a typeface from among those
listed in the left panel. The base size can be selected in the right
panel. There are two separate font families used by the viewer: the
normal, proportional-spaced font, and a fixed-pitch font for
preformatted and ``typewriter'' text. Pressing Apply will set
the currently selected font. The display will be redrawn using the
In Xic, there are commands to set the font families:
The format of the family-size argument depends upon the version
of the GTK toolkit employed.
- Cache group
A disk cache of downloaded pages and images is maintained. The cache
is located in the user's home directory under a subdirectory named
``.wr_cache''. The cache files are named ``wr_cacheN''" where N is an integer. A file named ``directory''
in this directory contains a human-readable listing of the cache files
and the original URLs. The listing consists of a line with internal
data, followed by data for the cache files. Each such line has three
columns. The first column indicates the file number N. The
second column is 0 if the wr_cacheN file exists and is
complete, 1 otherwise. The third column is the source URL for the
file. The number of files saved is limited, defaulting to 64. The
cache only pertains to files obtained through HTTP transfer. This
directory may also contain a file named ``cookies'' which
contains a list of cookies received from web sites.
A page will not be downloaded if it exists in the cache, unless the
modification time of the page is newer than the modification time of
the cache file.
The Don't Cache button in the Options menu will disable
caching of downloaded pages and images.
The Clear Cache button in the Options menu will clear the
internal references to the cache. The files, however, are not cleared.
The Reload Cache button in the Options menu will clear and
reload the internal cache references from the files that presently
exist in the cache directory.
The Show Cache button in the Options menu brings up a
listing of the URLs in the internal cache. Clicking on one of the
URLs in the listing will load that page or image into the viewer.
This is particularly useful on a system that is not continuously
on-line. One can access the pages while on-line, then read them
later, from cache, without being on-line.
- No Cookies
Support is provided for Netscape-style cookies. Cookies are small
fragments if information stored by the browser and transmitted to or
received from the web site. The No Cookies button in the Options menu will disable sending and receiving cookies. With
cookies, it is possible to view certain web sites that require
registration (for example). It is also possible to view some commerce
sites that require cookies. There is no encryption, so it is not a
good idea to send sensitive information such as credit card numbers.
- Images group
Image support is provided for gif, jpeg, png, tiff, xbm, and xpm.
Animated gifs are supported as well. Images found on the local file
system are always displayed immediately (unless debugging options are
set in the startup file). The treatment of images that must be
downloaded is set by this button group in the Options menu. One
and only one of these choices is active. If No Images is
chosen, images that aren't local will not be displayed at all. If
Sync Images is chosen, images are downloaded as they are
encountered. All downloading will be complete before the page is
displayed. If Delayed Images is chosen, images are downloaded
after the page is displayed. The display will be updated as the
images are received. If Progressive Images is chosen, images
are downloaded after the page is displayed, and images are displayed
in sections as downloading progresses.
- Anchor group
There are choices as to how anchors (the clickable references) are
displayed. If the Anchor Plain button in the Options menu
is selected, anchors will be displayed with standard blue text. If
Anchor Buttons is selected, a button metaphor will be used to
display the anchors. If Anchor Underline is selected, the
anchor will consist of underlined blue text. The underlining style
can be changed in the ``mozyrc'' startup file. One and only
one of these three choices is active. In addition, if Anchor
Highlight is selected, the anchors are highlighted when the pointer
passes over them.
- Bad HTML Warnings
If the Bad HTML Warnings button in the Options menu is
active, messages about incorrect HTML format are emitted to standard
- Freeze Animations
If the Freeze Animations button in the Options menu is
active, active animations are frozen at the current frame. New
animations will stop after the first frame is shown. This is for
users who find animations distracting.
- Log Transactions
If the Log Transactions button in the Options menu is
active, the header text emitted and received during HTTP transactions
is printed on the terminal screen. This is for debugging and hacking.
The Bookmarks menu contains entries to add and delete entries,
plus a list of entries. The entries, previously added by the user,
are help keywords, file names, or URLs that can be accessed by
selecting the entry. Thus, frequently accessed pages can be saved for
convenient access. Pressing the Add button will add the page
currently displayed in the viewer to the list. The next time the Bookmarks menu is displayed, the topic should appear in the menu. To
remove a topic, the Delete button is pressed. Then, the menu is
brought up again, and the item to delete is selected. This will
remove the item from the menu. Selecting any of the other items in
the menu will display the item in the viewer. The bookmark entries
are saved in a file named ``bookmarks'' which is located in the
same directory containing the cache files.
Next: The Help Database
Up: The Help Button: Obtain
Previous: The Help Button: Obtain
Stephen R. Whiteley