TK(2) TK(2)
NAME
Tk - graphics toolkit
SYNOPSIS
include "tk.m";
tk := load Tk Tk->PATH;
Tki: type ref Draw->Image;
Toplevel: adt
{
id: int;
image: ref Draw->Image;
};
toplevel: fn(screen: ref Draw->Screen, arg: string): ref Toplevel;
namechan: fn(t: ref Toplevel, c: chan of string, n: string): string;
cmd: fn(t: ref Toplevel, arg: string): string;
mouse: fn(screen: ref Draw->Screen, x, y, button: int);
keyboard: fn(screen: ref Draw->Screen, key: int);
windows: fn(screen: ref Draw->Screen): list of ref Toplevel;
intop: fn(screen: ref Draw->Screen, x, y: int): ref Toplevel;
imageget: fn(t: ref Toplevel, name: string): (Tki, Tki, string);
imageput: fn(t: ref Toplevel, name: string, i: Tki, m: Tki): string;
DESCRIPTION
The Tk module provides primitives for building user inter-
faces, based on Ousterhout's Tcl/TK. The interface to the
toolkit itself is primarily the passing of strings to and
from the elements of the toolkit using the cmd function; see
section 9 of this manual for more information about the syn-
tax of those strings.
Toplevel creates a new window called a Toplevel, which is
under the control of the Tk toolkit, on an existing screen,
usually one inherited from the graphics Context (see draw-
context(2)). The Toplevel is passed to cmd and namechan
(q.v.) to drive the widgets in the window. Arg is a string
containing creation options (such as -borderwidth 2) that
are applied when creating the toplevel window.
Cmd passes command strings to the widgets in the Toplevel t
and returns the string resulting from their execution. For
example, given a canvas .c in the Toplevel t,
x := int tk->cmd(t, ".c cget -actx");
returns the integer x coordinate of the canvas.
Bindings can be created in a Toplevel that trigger strings
to be sent on Limbo channels. Such channels must be
declared to the Tk module using namechan. For example, to
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TK(2) TK(2)
create a button that sends the word Ouch when it is pressed:
hitchannel := chan of string;
tk->namechan(t, hitchannel, "channel");
tk->cmd(t,
"button .b.Hit -text Hit -command {send channel Ouch}");
expl := <-hitchannel; # will see Ouch when button pressed
Mouse and keyboard pass mouse and keyboard events to Tk, for
delivery to widgets; they are usually called only by a win-
dow manager.
Windows returns a list of windows on the given screen. Intop
returns a reference to the window under point (x,y) on the
given screen, returning nil if none is found.
Imageget returns copies of the image and mask of the Tk bit-
map or Tk widget with the given name associated with
Toplevel t; either Image could be nil. Imageput replaces
the image (i) and mask (m) of the Tk bitmap image name in t.
Both functions return strings that are nil if the operation
was successful, but contain a diagnostic on error (eg,
invalid top level or name).
SOURCE
/interp/tk.c
/tk/*.c
SEE ALSO
intro(9), tkcmd(1), sh-tk(1), draw-context(2), wmlib(2),
`An Overview of Limbo/Tk', this manual, Volume 2.
BUGS
Because Tk input is handled globally per Screen, there can
be only one instance of a Tk implementation on a given
machine, a restriction that will be lifted.
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