8½(1) 8½(1)
NAME
8½, label, window, wloc - window system
SYNOPSIS
8½ [ -i 'cmd' ] [ -s ] [ -f font ]
label name
window 'minx miny maxx maxy' cmd arg ...
wloc
DESCRIPTION
8½ manages asynchronous layers of text, or windows, on a
bit-mapped display. It also serves a variety of files for
communicating with and controlling windows; these are dis-
cussed in section 8½(4).
Commands
The 8½ command starts a new instance of the window system.
Its -i option names a startup script, which typically con-
tains several window commands generated by wloc.
The -s option initializes windows so that text scrolls; the
default is not to scroll. The font argument names a font
used to display text, both in 8½'s menus and as a default
for any programs running in its windows; it also establishes
the environment variable $font. If -f is not given, 8½ uses
the imported value of $font if set; otherwise it imports the
default font from the underlying graphics server, usually
the terminal's operating system.
The label command changes a window's identifying name.
The window command creates a window. The first argument
gives the minimum and maximum screen coordinates of the win-
dow to be created (the units are pixels with the upper left
corner of the screen at (0, 0)); the rest of the arguments
are the command to be run in the window and its arguments.
The wloc command prints the coordinates and label of each
window in its instance of 8½ and is used to construct argu-
ments for window.
Window control
Each window behaves as a separate terminal with at least one
process associated with it. When a window is created, a new
process (usually a shell; see rc(1)) is established and
bound to the window as a new process group. Initially, each
window acts as a simple terminal that displays character
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text; the standard input and output of its processes are
attached to /dev/cons. Other special files, accessible to
the processes running in a window, may be used to make the
window a more general display. Some of these are mentioned
here; the complete set is discussed in 8½(4).
One window is current, and is highlighted with a heavy bor-
der; characters typed on the keyboard are available in the
/dev/cons file of the process in the current window. Char-
acters written on /dev/cons appear asynchronously in the
associated window whether or not the window is current.
Windows are created, deleted and rearranged using the mouse.
Clicking (depressing and releasing) mouse button 1 in a
non-current window makes that window current and brings it
in front of any windows that happen to be overlapping it.
When the mouse cursor points to the background area or is in
a window that has not claimed the mouse for its own use,
depressing mouse button 3 activates a menu of window opera-
tions provided by 8½. Releasing button 3 then selects an
operation. At this point, a gunsight or cross cursor indi-
cates that an operation is pending. The button 3 menu oper-
ations are:
New Create a window. Depress button 3 where one corner
of the new rectangle should appear (cross cursor),
and move the mouse, while holding down button 3, to
the diagonally opposite corner. Releasing button 3
creates the window, and makes it current. Very
small windows may not be created.
Reshape Change the size and location of a window. First
click button 3 in the window to be changed (gun-
sight cursor). Then sweep out a window as for the
New operation. The window is made current.
Move Move a window to another location. After pressing
and holding button 3 over the window to be moved
(gunsight cursor), indicate the new position by
dragging the rectangle to the new location. The
window is made current.
Delete Delete a window. Click in the window to be deleted
(gunsight cursor). Deleting a window causes a
`hangup' note to be sent to all processes in the
window's process group (see notify(2)).
Hide Hide a window. Click in the window to be hidden
(gunsight cursor); it will be moved off-screen.
Each hidden window is given a menu entry in the
button 3 menu according to the value of the file
/dev/label, which 8½ maintains (see 8½(4)).
label Restore a hidden window.
Text windows
Characters typed on the keyboard or written to /dev/cons
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collect in the window to form a long, continuous document.
There is always some selected text, a contiguous string
marked on the screen by reversing its color. If the
selected text is a null string, it is indicated by a hair-
line cursor between two characters. The selected text may
be edited by mousing and typing. Text is selected by point-
ing and clicking button 1 to make a null-string selection,
or by pointing, then sweeping with button 1 depressed. Text
may also be selected by double-clicking: just inside a
matched delimiter-pair with one of {[(<«`'" on the left and
}])>»`'" on the right, it selects all text within the pair;
at the beginning or end of a line, it selects the line;
within or at the edge of an alphanumeric word, it selects
the word.
Characters typed on the keyboard replace the selected text;
if this text is not empty, it is placed in a snarf buffer
common to all windows but distinct from that of sam(1).
Programs access the text in the window at a single point
maintained automatically by 8½. The output point is the
location in the text where the next character written by a
program to /dev/cons will appear; afterwards, the output
point is the null string beyond the new character. The out-
put point is also the location in the text of the next char-
acter that will be read (directly from the text in the win-
dow, not from an intervening buffer) by a program from
/dev/cons. When such a read will occur is, however, under
control of 8½ and the user.
In general there is text in the window after the output
point, usually placed there by typing but occasionally by
the editing operations described below. A pending read of
/dev/cons will block until the text after the output point
contains a newline, whereupon the read may acquire the text,
up to and including the newline. After the read, as
described above, the output point will be at the beginning
of the next line of text. In normal circumstances, there-
fore, typed text is delivered to programs a line at a time.
Changes made by typing or editing before the text is read
will not be seen by the program reading it. If the program
in the window does not read the terminal, for example if it
is a long-running computation, there may accumulate multiple
lines of text after the output point; changes made to all
this text will be seen when the text is eventually read.
This means, for example, that one may edit out newlines in
unread text to forestall the associated text being read when
the program finishes computing. This behavior is very dif-
ferent from most systems.
Even when there are newlines in the output text, 8½ will not
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honor reads if the window is in hold mode, which is indi-
cated by a white cursor and border. The ESC character tog-
gles hold mode. Some programs, such as mail(1), automati-
cally turn on hold mode to simplify the editing of multi-
line text; type ESC when done to allow mail to read the
text.
An EOT character (control-D) behaves exactly like newline
except that it is not delivered to a program when read.
Thus on an empty line an EOT serves to deliver an end-of-
file indication: the read will return zero characters. Like
newlines, unread EOTs may be successfully edited out of the
text. The BS character (control-H) erases the character
before the selected text. The ETB character (control-W)
erases any nonalphanumeric characters, then the alphanumeric
word just before the selected text. `Alphanumeric' here
means non-blanks and non-punctuation. The NAK character
(control-U) erases the text after the output point, and not
yet read by a program, but not more than one line. All
these characters are typed on the keyboard and hence replace
the selected text; for example, typing a BS with a word
selected places the word in the snarf buffer, removes it
from the screen, and erases the character before the word.
Text may be moved vertically within the window. A scroll
bar on the left of the window shows in its clear portion
what fragment of the total output text is visible on the
screen, and in its gray part what is above or below view; it
measures characters, not lines. Mousing inside the scroll
bar moves text: clicking button 1 with the mouse pointing
inside the scroll bar brings the line at the top of the win-
dow to the cursor's vertical location; button 3 takes the
line at the cursor to the top of the window; button 2,
treating the scroll bar as a ruler, jumps to the indicated
portion of the stored text. Also, a VIEW key (possibly with
a different label; see keyboard(6)) scrolls forward half a
window.
The DEL character sends an `interrupt' note to all processes
in the window's process group. Alone among characters, the
DEL and VIEW keys do not affect the selected text.
Normally, written output to a window blocks when the text
reaches the end of the screen; a button 2 menu item toggles
scrolling.
Other editing operations are selected from a menu on button
2. The cut operation deletes the selected text from the
screen and puts it in the snarf buffer; snarf copies the
selected text to the buffer without deleting it; paste
replaces the selected text with the contents of the buffer;
and send copies the snarf buffer to just after the output
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point, adding a final newline if missing. Paste will some-
times and send will always place text after the output
point; the text so placed will behave exactly as described
above. Therefore when pasting text containing newlines
after the output point, it may be prudent to turn on hold
mode first.
Raw text windows
Opening or manipulating certain files served by 8½ sup-
presses some of the services supplied to ordinary text win-
dows. While the file /dev/mouse is open, any mouse opera-
tions are the responsibility of another program running in
the window. Thus, 8½ refrains from maintaining the scroll
bar, supplying text editing or menus, interpreting the VIEW
key as a request to scroll, and also turns scrolling on.
The file /dev/consctl controls interpretation of keyboard
input. In particular, a raw mode may be set: in a raw-input
window, no typed keyboard characters are special, they are
not echoed to the screen, and all are passed to a program
immediately upon reading, instead of being gathered into
lines.
Graphics windows
A program that holds /dev/mouse and /dev/consctl open after
putting the console in raw mode has complete control of the
window: it interprets all mouse events, gets all keyboard
characters, and determines what appears on the screen.
FILES
/lib/font/bit/* font directories
/mnt/8½ Files served by 8½ (also unioned in /dev
in a window's name space, before the
terminal's real /dev files)
/srv/8½.user.pid Server end of 8½.
SOURCE
/sys/src/cmd/8½
/rc/bin/label
/rc/bin/window
/rc/bin/wloc
SEE ALSO
8½(4), rc(1), cpu(1), sam(1), mail(1), proof(1),
graphics(2), frame(2), layer(2), notify(2), cons(3), bit(3),
keyboard(6)
BUGS
Window works only on the machine running 8½.
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