The Tk Toolkit

SCCS: @(#) README 1.37 97/01/29 13:24:34

1. Introduction

---------------

This directory and its descendants contain the sources and documentation

for Tk, an X11 toolkit implemented with the Tcl scripting language. The

information here corresponds to Tk 4.2, patch level 2 for Tk 4.2. This

is actually the first official patch release for Tk 4.2: patch level 1

was only released for the Macintosh. Tk 4.2 is designed to work with

Tcl 7.6 and may not work with any other version of Tcl.

Tk 4.2 is a minor release. The main changes are a revision of the

gridder, a new set of standard dialog boxes, and a new virtual event

mechanism. See below for details. There should be no backward

incompatibilities in Tk 4.2 except for two small changes related to the

gridder.

2. Documentation

----------------

The best way to get started with Tk is to read one of the introductory

books on Tcl and Tk:

Tcl and the Tk Toolkit, by John Ousterhout,

Addison-Wesley, 1994, ISBN 0-201-63337-X

Practical Programming in Tcl and Tk, by Brent Welch,

Prentice-Hall, 1995, ISBN 0-13-182007-9

Exploring Expect, by Don Libes,

O'Reilly and Associates, 1995, ISBN 1-56592-090-2

The "doc" subdirectory in this release contains a complete set of

reference manual entries for Tk. Files with extension ".1" are for

programs such as wish; files with extension ".3" are for C library

procedures; and files with extension ".n" describe Tcl commands. To

print any of the manual entries, cd to the "doc" directory and invoke

your favorite variant of troff using the normal -man macros, for example

ditroff -man wish.1

to print wish.1. If Tk has been installed correctly and your "man"

program supports it, you should be able to access the Tcl manual entries

using the normal "man" mechanisms, such as

man wish

If you are porting Tk 3.6 scripts to Tk 4.0 or later releases, you may

find the Postscript file doc/tk4.0.ps useful. It is a porting guide

that summarizes the new features and discusses how to deal with the

changes in Tk 4.0 that are not backwards compatible.

There is also an official home for Tcl and Tk on the Web:

http://www.smli.com/research/tcl

These Web pages include release updates, reports on bug fixes and porting

issues, HTML versions of the manual pages, and pointers to many other

Tcl/Tk Web pages at other sites. Check them out!

3. Compiling and installing Tk

------------------------------

This release contains everything you should need to compile and run

Tk under UNIX, Macintoshes, and PCs (either Windows NT, Windows 95,

or Win 3.1 with Win32s).

Before trying to compile Tk you should do the following things:

(a) Check for a binary release. Pre-compiled binary releases are

available now for PCs and Macintoshes, and several flavors of

UNIX. Binary releases are much easier to install than source

releases. To find out whether a binary release is available for

your platform, check the home page for the Sun Tcl/Tk project

(http://www.sunlabs.com/research/tcl) and also check in the FTP

directory from which you retrieved the base distribution.

(b) Make sure you have the most recent patch release. Look in the

FTP directory from which you retrieved this distribution to see

if it has been updated with patches. Patch releases fix bugs

without changing any features, so you should normally use the

latest patch release for the version of Tk that you want.

Patch releases are available in two forms. A file like

tk4.2p2.tar.Z is a complete release for patch level 2 of Tk

version 4.2. If there is a file with a higher patch level than

this release, just fetch the file with the highest patch level

and use it.

Patches are also available in the form of patch files that just

contain the changes from one patch level to another. These

files have names like tk4.2p2.patch, tk4.2p3.patch, etc. They

may also have .gz or .Z extensions to indicate compression. To

use one of these files, you apply it to an existing release with

the "patch" program. Patches must be applied in order,

except that there is no patch level 1 for Tcl 7.6:

tk4.2p2.patch must be applied to an unpatched Tk 4.2 release

to produce a Tk 4.2p2 release; tk4.2p3.patch can then be

applied to Tk 4.2p2 to produce Tk 4.2p3, and so on. To apply an

uncompressed patch file such as tk4.2p2.patch, invoke a shell

command like the following from the directory containing this

file:

patch -p < tk4.2p2.patch

If the patch file has a .gz extension, it was compressed with

gzip. To apply it, invoke a command like the following:

gunzip -c tk4.2p2.patch.gz | patch -p

If the patch file has a .Z extension, it was compressed with

compress. To apply it, invoke a command like the following:

zcat tk4.2p2.patch.Z | patch -p

If you're applying a patch to a release that has already been

compiled, then before applying the patch you should cd to the

"unix" subdirectory and type "make distclean" to restore the

directory to a pristine state.

Once you've done this, change to the "unix" subdirectory if you're

compiling under UNIX, "win" if you're compiling under Windows, or

"mac" if you're compiling on a Macintosh. Then follow the instructions

in the README file in that directory for compiling Tk, installing it,

and running the test suite.

4. Getting started

------------------

The best way to get started with Tk is by reading one of the introductory

books.

The subdirectory library/demos contains a number of pre-canned scripts

that demonstrate various features of Tk. See the README file in the

directory for a description of what's available. The file

library/demos/widget is a script that you can use to invoke many individual

demonstrations of Tk's facilities, see the code that produced the demos,

and modify the code to try out alternatives.

5. Summary of changes in Tk 4.2

-------------------------------

Here are the new features in Tk 4.2. The release also includes several

bug fixes. See the "changes" file for a complete list of all changes.

1. The grid geometry manager has been completely rewritten:

- The layout algorithm produces much better layouts than before,

particularly where rows or columns were stretchable.

- There is a new -pad option for rows and columns.

- The command "grid forget" has been renamed "grid remove",

and "grid forget" now has semantics like "pack forget".

- The "grid" command no longer accepts floating-point values

for row or column weights: integers must be used.

2. There are new commands for creating common dialog boxes:

tk_chooseColor, tk_getOpenFile, tk_getSaveFile and tk_messageBox.

These use native dialog boxes if they are available. Examples of

the dialogs are available in the widget demo.

3. There is a new virtual event mechanism for handling events in a

more portable way. See the new command "event". It also allows

events (both physical and virtual) to be generated dynamically.

The Macintosh now generates <<Cut>>, <<Copy>>, <<Paste>>, and <<Clear>>

events from the edit menu.

The only incompatible changes in this release are the last two for the

gridder ("grid forget" and integer row/column weights). Most scripts

that ran under Tk 4.1 should also work under Tk 4.2 with no changes.

6. Tcl/Tk newsgroup

-------------------

There is a network news group "comp.lang.tcl" intended for the exchange

of information about Tcl, Tk, and related applications. Feel free to use

this newsgroup both for general information questions and for bug reports.

We read the newsgroup and will attempt to fix bugs and problems reported

to it.

When using comp.lang.tcl, please be sure that your e-mail return address

is correctly set in your postings. This allows people to respond directly

to you, rather than the entire newsgroup, for answers that are not of

general interest. A bad e-mail return address may prevent you from

getting answers to your questions. You may have to reconfigure your news

reading software to ensure that it is supplying valid e-mail addresses.

7. Tcl/Tk contributed archive

--------------------------

Many people have created exciting packages and applications based on Tcl

and/or Tk and made them freely available to the Tcl community. An archive

of these contributions is kept on the machine ftp.neosoft.com. You

can access the archive using anonymous FTP; the Tcl contributed archive is

in the directory "/pub/tcl". The archive also contains several FAQ

("frequently asked questions") documents that provide solutions to problems

that are commonly encountered by TCL newcomers.

8. Support and bug fixes

------------------------

We're very interested in receiving bug reports and suggestions for

improvements. We prefer that you send this information to the

comp.lang.tcl newsgroup rather than to any of us at Sun. We'll see

anything on comp.lang.tcl, and in addition someone else who reads

comp.lang.tcl may be able to offer a solution. The normal turn-around

time for bugs is 3-6 weeks. Enhancements may take longer and may not

happen at all unless there is widespread support for them (we're

trying to slow the rate at which Tk turns into a kitchen sink). It's

very difficult to make incompatible changes to Tcl at this point, due

to the size of the installed base.

When reporting bugs, please provide a short wish script that we can

use to reproduce the bug. Make sure that the script runs with a

bare-bones wish and doesn't depend on any extensions or other

programs, particularly those that exist only at your site. Also,

please include three additional pieces of information with the

script:

(a) how do we use the script to make the problem happen (e.g.

what things do we click on, in what order)?

(b) what happens when you do these things (presumably this is

undesirable)?

(c) what did you expect to happen instead?

The Tcl/Tk community is too large for us to provide much individual

support for users. If you need help we suggest that you post questions

to comp.lang.tcl. We read the newsgroup and will attempt to answer

esoteric questions for which no-one else is likely to know the answer.

In addition, Tcl/Tk support and training are available commercially from

NeoSoft (info@neosoft.com), Computerized Processes Unlimited

(gwl@cpu.com), and Data Kinetics (education@dkl.com).

9. Release organization

------------------------

Each Tk release is identified by two numbers separated by a dot, e.g.

3.2 or 3.3. If a new release contains changes that are likely to break

existing C code or Tcl scripts then the major release number increments

and the minor number resets to zero: 3.0, 4.0, etc. If a new release

contains only bug fixes and compatible changes, then the minor number

increments without changing the major number, e.g. 3.1, 3.2, etc. If

you have C code or Tcl scripts that work with release X.Y, then they

should also work with any release X.Z as long as Z > Y.

Alpha and beta releases have an additional suffix of the form a2 or b1.

For example, Tk 3.3b1 is the first beta release of Tk version 3.3,

Tk 3.3b2 is the second beta release, and so on. A beta release is an

initial version of a new release, used to fix bugs and bad features

before declaring the release stable. An alpha release is like a beta

release, except it's likely to need even more work before it's "ready

for prime time". New releases are normally preceded by one or more

alpha and beta releases. We hope that lots of people will try out

the alpha and beta releases and report problems. We'll make new alpha/

beta releases to fix the problems, until eventually there is a beta

release that appears to be stable. Once this occurs we'll make the

final release.

We can't promise to maintain compatibility among alpha and beta releases.

For example, release 4.1b2 may not be backward compatible with 4.1b1, even

though the final 4.1 release will be backward compatible with 4.0. This

allows us to change new features as we find problems during beta testing.

We'll try to minimize incompatibilities between beta releases, but if a

major problem turns up then we'll fix it even if it introduces an

incompatibility. Once the official release is made then there won't

be any more incompatibilities until the next release with a new major

version number.

Patch releases have a suffix such as p1 or p2. These releases contain

bug fixes only. A patch release (e.g Tk 4.1p2) should be completely

compatible with the base release from which it is derived (e.g. Tk

4.1), and you should normally use the highest available patch release.