Skip to content

Commit 4673dc2

Browse files
Update susp-ignored.csv line numbers
1 parent e479510 commit 4673dc2

File tree

2 files changed

+181
-144
lines changed

2 files changed

+181
-144
lines changed

Doc/library/tkinter.rst

Lines changed: 175 additions & 144 deletions
Original file line numberDiff line numberDiff line change
@@ -207,210 +207,241 @@ Additional modules:
207207
Tkinter Life Preserver
208208
----------------------
209209

210-
.. sectionauthor:: Matt Conway
210+
This section is not designed to be an exhaustive tutorial on either Tk or
211+
Tkinter. For that, refer to one of the external resources noted earlier.
212+
Instead, this section provides a very quick orientation to what a Tkinter
213+
application looks like, identifies foundational Tk concepts, and
214+
explains how the Tkinter wrapper is structured.
211215

216+
The remainder of this section will help you to identify the classes,
217+
methods, and options you'll need in your Tkinter application, and where to
218+
find more detailed documentation on them, including in the official Tcl/Tk
219+
reference manual.
212220

213-
This section is not designed to be an exhaustive tutorial on either Tk or
214-
Tkinter. Rather, it is intended as a stop gap, providing some introductory
215-
orientation on the system.
216221

217-
Credits:
222+
A Hello World Program
223+
^^^^^^^^^^^^^^^^^^^^^
218224

219-
* Tk was written by John Ousterhout while at Berkeley.
225+
We'll start by walking through a "Hello World" application in Tkinter. This
226+
isn't the smallest one we could write, but has enough to illustrate some
227+
key concepts you'll need to know.
220228

221-
* Tkinter was written by Steen Lumholt and Guido van Rossum.
229+
::
222230

223-
* This Life Preserver was written by Matt Conway at the University of Virginia.
231+
from tkinter import *
232+
from tkinter import ttk
233+
root = Tk()
234+
frm = ttk.Frame(root, padding=10)
235+
frm.grid()
236+
ttk.Label(frm, text="Hello World!").grid(column=0, row=0)
237+
ttk.Button(frm, text="Quit", command=root.destroy).grid(column=1, row=0)
238+
root.mainloop()
224239

225-
* The HTML rendering, and some liberal editing, was produced from a FrameMaker
226-
version by Ken Manheimer.
227240

228-
* Fredrik Lundh elaborated and revised the class interface descriptions, to get
229-
them current with Tk 4.2.
241+
After the imports, the next line creates an instance of the :class:`Tk` class,
242+
which initializes Tk and creates its associated Tcl interpreter. It also
243+
creates a toplevel window, known as the root window, which serves as the main
244+
window of the application.
230245

231-
* Mike Clarkson converted the documentation to LaTeX, and compiled the User
232-
Interface chapter of the reference manual.
246+
The following line creates a frame widget, which in this case will contain
247+
a label and a button we'll create next. The frame is fit inside the root
248+
window.
233249

250+
The next line creates a label widget holding a static text string. The
251+
:meth:`grid` method is used to specify the relative layout (position) of the
252+
label within its containing frame widget, similar to how tables in HTML work.
234253

235-
How To Use This Section
236-
^^^^^^^^^^^^^^^^^^^^^^^
254+
A button widget is then created, and placed to the right of the label. When
255+
pressed, it will call the :meth:`destroy` method of the root window.
237256

238-
This section is designed in two parts: the first half (roughly) covers
239-
background material, while the second half can be taken to the keyboard as a
240-
handy reference.
257+
Finally, the :meth:`mainloop` method puts everything on the display, and
258+
responds to user input until the program terminates.
241259

242-
When trying to answer questions of the form "how do I do blah", it is often best
243-
to find out how to do "blah" in straight Tk, and then convert this back into the
244-
corresponding :mod:`tkinter` call. Python programmers can often guess at the
245-
correct Python command by looking at the Tk documentation. This means that in
246-
order to use Tkinter, you will have to know a little bit about Tk. This document
247-
can't fulfill that role, so the best we can do is point you to the best
248-
documentation that exists. Here are some hints:
249260

250-
* The authors strongly suggest getting a copy of the Tk man pages.
251-
Specifically, the man pages in the ``manN`` directory are most useful.
252-
The ``man3`` man pages describe the C interface to the Tk library and thus
253-
are not especially helpful for script writers.
254261

255-
* Addison-Wesley publishes a book called Tcl and the Tk Toolkit by John
256-
Ousterhout (ISBN 0-201-63337-X) which is a good introduction to Tcl and Tk for
257-
the novice. The book is not exhaustive, and for many details it defers to the
258-
man pages.
262+
Important Tk Concepts
263+
^^^^^^^^^^^^^^^^^^^^^
259264

260-
* :file:`tkinter/__init__.py` is a last resort for most, but can be a good
261-
place to go when nothing else makes sense.
265+
Even this simple program illustrates the following key Tk concepts:
262266

267+
widgets
268+
A Tkinter user interface is made up of individual *widgets*. Each widget is
269+
represented as a Python object, instantiated from classes like
270+
:class:`ttk.Frame`, :class:`ttk.Label`, and :class:`ttk.Button`.
263271

264-
A Simple Hello World Program
265-
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
272+
widget hierarchy
273+
Widgets are arranged in a *hierarchy*. The label and button were contained
274+
within a frame, which in turn was contained within the root window. When
275+
creating each *child* widget, its *parent* widget is passed as the first
276+
argument to the widget constructor.
266277

267-
::
278+
configuration options
279+
Widgets have *configuration options*, which modify their appearance and
280+
behavior, such as the text to display in a label or button. Different
281+
classes of widgets will have different sets of options.
268282

269-
import tkinter as tk
283+
geometry management
284+
Widgets aren't automatically added to the user interface when they are
285+
created. A *geometry manager* like ``grid`` controls where in the
286+
user interface they are placed.
270287

271-
class Application(tk.Frame):
272-
def __init__(self, master=None):
273-
super().__init__(master)
274-
self.master = master
275-
self.pack()
276-
self.create_widgets()
288+
event loop
289+
Tkinter reacts to user input, changes from your program, and even refreshes
290+
the display only when actively running an *event loop*. If your program
291+
isn't running the event loop, your user interface won't update.
277292

278-
def create_widgets(self):
279-
self.hi_there = tk.Button(self)
280-
self.hi_there["text"] = "Hello World\n(click me)"
281-
self.hi_there["command"] = self.say_hi
282-
self.hi_there.pack(side="top")
283293

284-
self.quit = tk.Button(self, text="QUIT", fg="red",
285-
command=self.master.destroy)
286-
self.quit.pack(side="bottom")
294+
Understanding How Tkinter Wraps Tcl/Tk
295+
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
287296

288-
def say_hi(self):
289-
print("hi there, everyone!")
297+
When your application uses Tkinter's classes and methods, internally Tkinter
298+
is assembling strings representing Tcl/Tk commands, and executing those
299+
commands in the Tcl interpreter attached to your applicaton's :class:`Tk`
300+
instance.
290301

291-
root = tk.Tk()
292-
app = Application(master=root)
293-
app.mainloop()
302+
Whether it's trying to navigate reference documentation, trying to find
303+
the right method or option, adapting some existing code, or debugging your
304+
Tkinter application, there are times that it will be useful to understand
305+
what those underlying Tcl/Tk commands look like.
294306

307+
To illustrate, here is the Tcl/Tk equivalent of the main part of the Tkinter
308+
script above.
295309

296-
A (Very) Quick Look at Tcl/Tk
297-
-----------------------------
310+
::
298311

299-
The class hierarchy looks complicated, but in actual practice, application
300-
programmers almost always refer to the classes at the very bottom of the
301-
hierarchy.
312+
ttk::frame .frm -padding 10
313+
grid .frm
314+
grid [ttk::label .frm.lbl -text "Hello World!"] -column 0 -row 0
315+
grid [ttk::button .frm.btn -text "Quit" -command "destroy ."] -column 1 -row 0
302316

303-
Notes:
304317

305-
* These classes are provided for the purposes of organizing certain functions
306-
under one namespace. They aren't meant to be instantiated independently.
318+
Tcl's syntax is similar to many shell languages, where the first word is the
319+
command to be executed, with arguments to that command following it, separated
320+
by spaces. Without getting into too many details, notice the following:
307321

308-
* The :class:`Tk` class is meant to be instantiated only once in an application.
309-
Application programmers need not instantiate one explicitly, the system creates
310-
one whenever any of the other classes are instantiated.
322+
* The commands used to create widgets (like ``ttk::frame``) correspond to
323+
widget classes in Tkinter.
311324

312-
* The :class:`Widget` class is not meant to be instantiated, it is meant only
313-
for subclassing to make "real" widgets (in C++, this is called an 'abstract
314-
class').
325+
* Tcl widget options (like ``-text``) correspond to keyword arguments in
326+
Tkinter.
315327

316-
To make use of this reference material, there will be times when you will need
317-
to know how to read short passages of Tk and how to identify the various parts
318-
of a Tk command. (See section :ref:`tkinter-basic-mapping` for the
319-
:mod:`tkinter` equivalents of what's below.)
328+
* Widgets are referred to by a *pathname* in Tcl (like ``.frm.btn``),
329+
whereas Tkinter doesn't use names but object references.
320330

321-
Tk scripts are Tcl programs. Like all Tcl programs, Tk scripts are just lists
322-
of tokens separated by spaces. A Tk widget is just its *class*, the *options*
323-
that help configure it, and the *actions* that make it do useful things.
331+
* A widget's place in the widget hierarchy is encoded in its (hierarchical)
332+
pathname, which uses a ``.`` (dot) as a path separator. The pathname for
333+
the root window is just ``.`` (dot). In Tkinter, the hierarchy is defined
334+
not by pathname but by specifying the parent widget when creating each
335+
child widget.
324336

325-
To make a widget in Tk, the command is always of the form::
337+
* Operations which are implemented as separate *commands* in Tcl (like
338+
``grid`` or ``destroy``) are represented as *methods* on Tkinter widget
339+
objects. As you'll see shortly, at other times Tcl uses what appear to be
340+
method calls on widget objects, which more closely mirror what would is
341+
used in Tkinter.
326342

327-
classCommand newPathname options
328343

329-
*classCommand*
330-
denotes which kind of widget to make (a button, a label, a menu...)
344+
How do I...? What option does...?
345+
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
331346

332-
.. index:: single: . (dot); in Tkinter
347+
If you're not sure how to do something in Tkinter, and you can't immediately
348+
find it in the tutorial or reference documentation you're using, there are a
349+
few strategies that can be helpful.
333350

334-
*newPathname*
335-
is the new name for this widget. All names in Tk must be unique. To help
336-
enforce this, widgets in Tk are named with *pathnames*, just like files in a
337-
file system. The top level widget, the *root*, is called ``.`` (period) and
338-
children are delimited by more periods. For example,
339-
``.myApp.controlPanel.okButton`` might be the name of a widget.
351+
First, remember that the details of how individual widgets work may vary
352+
across different versions of both Tkinter and Tcl/Tk. If you're searching
353+
documentation, make sure it corresponds to the Python and Tcl/Tk versions
354+
installed on your system.
340355

341-
*options*
342-
configure the widget's appearance and in some cases, its behavior. The options
343-
come in the form of a list of flags and values. Flags are preceded by a '-',
344-
like Unix shell command flags, and values are put in quotes if they are more
345-
than one word.
356+
When searching for how to use an API, it helps to know the exact name of the
357+
class, option, or method that you're using. Introspection, either in an
358+
interactive Python shell or with :func:`print`, can help you identify what
359+
you need.
346360

347-
For example::
361+
To find out what configuration options are available on any widget, call its
362+
:meth:`configure` method, which returns a dictionary containing a variety of
363+
information about each object, including its default and current values. Use
364+
:meth:`keys` to get just the names of each option.
348365

349-
button .fred -fg red -text "hi there"
350-
^ ^ \______________________/
351-
| | |
352-
class new options
353-
command widget (-opt val -opt val ...)
366+
::
354367

355-
Once created, the pathname to the widget becomes a new command. This new
356-
*widget command* is the programmer's handle for getting the new widget to
357-
perform some *action*. In C, you'd express this as someAction(fred,
358-
someOptions), in C++, you would express this as fred.someAction(someOptions),
359-
and in Tk, you say::
368+
btn = ttk.Button(frm, ...)
369+
print(btn.configure().keys())
360370

361-
.fred someAction someOptions
371+
As most widgets have many configuration options in common, it can be useful
372+
to find out which are specific to a particular widget class. Comparing the
373+
list of options to that of a simpler widget, like a frame, is one way to
374+
do that.
362375

363-
Note that the object name, ``.fred``, starts with a dot.
376+
::
364377

365-
As you'd expect, the legal values for *someAction* will depend on the widget's
366-
class: ``.fred disable`` works if fred is a button (fred gets greyed out), but
367-
does not work if fred is a label (disabling of labels is not supported in Tk).
378+
print(set(btn.configure().keys()) - set(frm.configure().keys()))
368379

369-
The legal values of *someOptions* is action dependent. Some actions, like
370-
``disable``, require no arguments, others, like a text-entry box's ``delete``
371-
command, would need arguments to specify what range of text to delete.
380+
Similarly, you can find the available methods for a widget object using the
381+
standard :func:`dir` function. If you try it, you'll see there are over 200
382+
common widget methods, so again identifying those specific to a widget class
383+
is helpful.
372384

385+
::
386+
387+
print(dir(btn))
388+
print(set(dir(btn)) - set(dir(frm)))
373389

374-
.. _tkinter-basic-mapping:
375390

376-
Mapping Basic Tk into Tkinter
377-
-----------------------------
391+
Navigating the Tcl/Tk Reference Manual
392+
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
378393

379-
Class commands in Tk correspond to class constructors in Tkinter. ::
394+
As noted, the official `Tk commands <https://www.tcl.tk/man/tcl8.6/TkCmd/contents.htm>`_
395+
reference manual (man pages) is often the most accurate description of what
396+
specific operations on widgets do. Even when you know the name of the option
397+
or method that you need, you may still have a few places to look.
380398

381-
button .fred =====> fred = Button()
399+
While all operations in Tkinter are implemented as method calls on widget
400+
objects, you've seen that many Tcl/Tk operations appear as commands that
401+
take a widget pathname as its first parameter, followed by optional
402+
parameters, e.g.
382403

383-
The master of an object is implicit in the new name given to it at creation
384-
time. In Tkinter, masters are specified explicitly. ::
404+
::
385405

386-
button .panel.fred =====> fred = Button(panel)
406+
destroy .
407+
grid .frm.btn -column 0 -row 0
387408

388-
The configuration options in Tk are given in lists of hyphened tags followed by
389-
values. In Tkinter, options are specified as keyword-arguments in the instance
390-
constructor, and keyword-args for configure calls or as instance indices, in
391-
dictionary style, for established instances. See section
392-
:ref:`tkinter-setting-options` on setting options. ::
409+
Others, however, look more like methods called on a widget object (in fact,
410+
when you create a widget in Tcl/Tk, it creates a Tcl command with the name
411+
of the widget pathname, with the first parameter to that command being the
412+
name of a method to call).
393413

394-
button .fred -fg red =====> fred = Button(panel, fg="red")
395-
.fred configure -fg red =====> fred["fg"] = red
396-
OR ==> fred.config(fg="red")
414+
::
397415

398-
In Tk, to perform an action on a widget, use the widget name as a command, and
399-
follow it with an action name, possibly with arguments (options). In Tkinter,
400-
you call methods on the class instance to invoke actions on the widget. The
401-
actions (methods) that a given widget can perform are listed in
402-
:file:`tkinter/__init__.py`. ::
416+
.frm.btn invoke
417+
.frm.lbl configure -text "Goodbye"
403418

404-
.fred invoke =====> fred.invoke()
405419

406-
To give a widget to the packer (geometry manager), you call pack with optional
407-
arguments. In Tkinter, the Pack class holds all this functionality, and the
408-
various forms of the pack command are implemented as methods. All widgets in
409-
:mod:`tkinter` are subclassed from the Packer, and so inherit all the packing
410-
methods. See the :mod:`tkinter.tix` module documentation for additional
411-
information on the Form geometry manager. ::
420+
In the official Tcl/Tk reference documentation, you'll find most operations
421+
that look like method calls on the man page for a specific widget (e.g.,
422+
you'll find the :meth:`invoke` method on the
423+
`ttk::button <https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_button.htm>`_
424+
man page), while functions that take a widget as a parameter often have
425+
their own man page (e.g.,
426+
`grid <https://www.tcl.tk/man/tcl8.6/TkCmd/grid.htm>`_).
412427

413-
pack .fred -side left =====> fred.pack(side="left")
428+
You'll find many common options and methods in the
429+
`options <https://www.tcl.tk/man/tcl8.6/TkCmd/options.htm>`_ or
430+
`ttk::widget <https://www.tcl.tk/man/tcl8.6/TkCmd/ttk_widget.htm>`_ man
431+
pages, while others are found in the man page for a specific widget class.
432+
433+
You'll also find that many Tkinter methods have compound names, e.g.,
434+
:func:`winfo_x`, :func:`winfo_height`, :func:`winfo_viewable`. You'd find
435+
documentation for all of these in the
436+
`winfo <https://www.tcl.tk/man/tcl8.6/TkCmd/winfo.htm>`_ man page.
437+
438+
.. note::
439+
Somewhat confusingly, there are also methods on all Tkinter widgets
440+
that don't actually operate on the widget, but operate at a global
441+
scope, independent of any widget. Examples are methods for accessing
442+
the clipboard or the system bell. (They happen to be implemented as
443+
methods in the base :class:`Widget` class that all Tkinter widgets
444+
inherit from).
414445

415446

416447
Threading model

Doc/tools/susp-ignored.csv

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -233,6 +233,12 @@ library/tarfile,,:xz,'r:xz'
233233
library/tarfile,,:xz,'w:xz'
234234
library/time,,:mm,
235235
library/time,,:ss,
236+
library/tkinter,,::,ttk::frame .frm -padding 10
237+
library/tkinter,,::,"grid [ttk::label .frm.lbl -text ""Hello World!""] -column 0 -row 0"
238+
library/tkinter,,::,"grid [ttk::button .frm.btn -text ""Quit"" -command ""destroy .""] -column 1 -row 0"
239+
library/tkinter,,::,ttk::frame
240+
library/tkinter,,::,ttk::button
241+
library/tkinter,,::,ttk::widget
236242
library/tracemalloc,,:limit,"for index, stat in enumerate(top_stats[:limit], 1):"
237243
library/turtle,,::,Example::
238244
library/unittest,,:foo,"self.assertEqual(cm.output, ['INFO:foo:first message',"

0 commit comments

Comments
 (0)