The Tk Toolkit SCCS: @(#) README 1.32 96/07/31 16:29:10 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 4.1. This release is designed to work with Tcl 7.5 and may not work with any other version of Tcl. The main new feature in this release is support for the Mac and PC platforms. Aside from the ports, the release consists mostly of bug fixes. There are no major new features. 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 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, 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 Tcl that you want. Patch releases are available in two forms. A file like tk4.1p1.tar.Z is a complete release for patch level 1 of Tk version 4.1. 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 tk4.1p1.patch, tk4.1p2.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: tk4.1p1.patch must be applied to an unpatched Tk 4.1 release to produce a Tk 4.1p1 release; tk4.1p2.patch can then be applied to Tk 4.1p1 to produce Tk 4.1p2, and so on. To apply an uncompressed patch file such as tk4.1p1.patch, invoke a shell command like the following from the directory containing this file: patch -p < tk4.1p1.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 tk4.1p1.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 tk4.1p1.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 4.1 ------------------------------- The main change for Tk 4.1 is that Tk now runs on Macintosh and PC platforms as well as UNIX. The PC port runs under Windows 3.1 (with Win32s), Windows 95, and Windows NT. This required a lot of reorganization of the sources but it didn't require any changes to Tk's externally visible interfaces. Besides the ports and numerous bug fixes, Tk 4.1 contains the following new features. Existing scripts for Tk 4.0 should run unchanged under Tk 4.1. 1. There is a new command "grid" that implements a table style of geometry management. This will be used by future releases of the SpecTcl GUI builder. 2. The wish main program now supports -visual and -colormap command- line arguments. 3. Text widgets have been improved in several ways: - Performance when there are many tags should be much better now; tags should only be slow if there are a very large number of tags on an individual character. - There are new "dump", "mark next", "mark prev" and "tag prevrange" widget commands for extracting information out of a text widget. 4. Tk is now a first-class Tcl package (in the sense of the new Tcl "package" command). You can load Tk into a slave interpreter "foo" with the command "load {} Tk foo" if Tk is statically linked. Tk can also be compiled as a shared library using the --enable-shared switch for "configure". 5. The event loop has moved to Tcl. Many procedures and #defines have been renamed, such as the "tkerror" command (now "bgerror"), TK_READABLE (now TCL_READABLE), and Tk_DoOneEvent (now Tcl_DoOneEvent). All of the old Tk names are still supported for backwards compatibility but you should switch over ASAP to the new ones. 6. Tk_Preserve, Tk_Release, and Tk_Eventually have been moved to Tcl. There are #defines in tk.h for backward compatibility, but you should switch ASAP to the new Tcl APIs. 7. There is a new command "after info" that allows you to find out about pending "after" handlers that haven't yet fired. 8. Scrollbars and scales now have proper button 2 support as required by Motif. 9. Menus have two new options, -transient and -tearoffcommand. 10. Entries have a new "bbox" widget command. 11. When manual pages are installed, additional links are created for each of the procedures described in the manual page, so that it's easier to invoke the "man" command. 12. Wish supports a new "--" option: it will only process options up through the --; anything after that will be passed through to the application in the argc and argv variables. Although Tk 4.1 is compatible with Tk 4.0 scripts at the Tcl level, there are a few incompatible changes in Tk's C APIs. These will only affect C code, not Tcl/Tk scripts, and they are obscure enough that they probably won't affect many existing extensions. If there are any potential problems, they will be detected by an ANSI-compliant C compiler such as gcc. 1. The procedure Tk_CreateMainWindow no longer exists. Instead, Tk_Init does everything that Tk_CreateMainWindow used to do. 2. The procedures Tk_EventInit and Tk_CreateFileHandler2 have been eliminated. Tk_EventInit is no longer needed since the event loop is always available. Tk_CreateFileHandler doesn't make sense with the new notifier in Tcl, but you can get the same effect with the new "event source" mechanism (see the Notifier.3 manual entry in Tcl). 3. Tk doesn't export any global C variables anymore, because this doesn't work with Windows DLLs. The C variable tk_NumMainWindows has been replaced with the procedures Tk_GetNumMainWindows(), and the variable tk_CanvasTagsOption has been replaced with the procedures Tk_CanvasTagsParseProc and Tk_CanvasTagsPrintProc. 4. The interface to Tk_RestrictProc has changed so that the restrict procedure can ask for an event to be discarded, as well as processed or deferred. For a complete list of all the changes in this release, see the file "changes" in this directory. 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 omp.lang.tcl may be able to offer a solution. The normal turn-around time for bugs is 2-4 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.