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Source code:Lib/tkinter/__init__.py

The tkinter package ('Tk interface') is the standard Python interface tothe Tk GUI toolkit. Both Tk and tkinter are available on most Unixplatforms, as well as on Windows systems. (Tk itself is not part of Python; itis maintained at ActiveState.)

Running python-mtkinter from the command line should open a windowdemonstrating a simple Tk interface, letting you know that tkinter isproperly installed on your system, and also showing what version of Tcl/Tk isinstalled, so you can read the Tcl/Tk documentation specific to that version.

See also

Tkinter documentation:

The Python Tkinter Topic Guide provides a great deal of information on using Tkfrom Python and links to other sources of information on Tk.

Extensive tutorial plus friendlier widget pages for some of the widgets.

On-line reference material.

Online reference for tkinter supported by effbot.org.

Book by Mark Lutz, has excellent coverage of Tkinter.

Book by Mark Roseman about building attractive and modern graphical user interfaces with Python and Tkinter.

Book by John Grayson (ISBN 1-884777-81-3).

Tcl/Tk documentation:

Most commands are available as tkinter or tkinter.ttk classes.Change ‘8.6' to match the version of your Tcl/Tk installation.

Recent Tcl/Tk manuals on www.tcl.tk.

The Tk/Tcl development is largely taking place at ActiveState.

Book by John Ousterhout, the inventor of Tcl.

Brent Welch's encyclopedic book.

Tkinter Modules¶

Most of the time, tkinter is all you really need, but a number ofadditional modules are available as well. The Tk interface is located in abinary module named _tkinter. This module contains the low-levelinterface to Tk, and should never be used directly by application programmers.It is usually a shared library (or DLL), but might in some cases be staticallylinked with the Python interpreter.

In addition to the Tk interface module, tkinter includes a number ofPython modules, tkinter.constants being one of the most important.Importing tkinter will automatically import tkinter.constants,so, usually, to use Tkinter all you need is a simple import statement:

Or, more often:

The Tk class is instantiated without arguments. This creates a toplevelwidget of Tk which usually is the main window of an application. Each instancehas its own associated Tcl interpreter.

The Tcl() function is a factory function which creates an object much likethat created by the Tk class, except that it does not initialize the Tksubsystem. This is most often useful when driving the Tcl interpreter in anenvironment where one doesn't want to create extraneous toplevel windows, orwhere one cannot (such as Unix/Linux systems without an X server). An objectcreated by the Tcl() object can have a Toplevel window created (and the Tksubsystem initialized) by calling its loadtk() method.

Other modules that provide Tk support include:

Dialog to let the user choose a color.

Base class for the dialogs defined in the other modules listed here.

Common dialogs to allow the user to specify a file to open or save.

Utilities to help work with fonts.

Access to standard Tk dialog boxes.

Text widget with a vertical scroll bar built in.

Basic dialogs and convenience functions.

Drag-and-drop support for tkinter. This is experimental and shouldbecome deprecated when it is replaced with the Tk DND.

Turtle graphics in a Tk window.

Tkinter Life Preserver¶

This section is not designed to be an exhaustive tutorial on either Tk orTkinter. Rather, it is intended as a stop gap, providing some introductoryorientation on the system.

Credits:

• Tk was written by John Ousterhout while at Berkeley.

• Tkinter was written by Steen Lumholt and Guido van Rossum.

• This Life Preserver was written by Matt Conway at the University of Virginia.

• The HTML rendering, and some liberal editing, was produced from a FrameMakerversion by Ken Manheimer.

• Fredrik Lundh elaborated and revised the class interface descriptions, to getthem current with Tk 4.2.

• Mike Clarkson converted the documentation to LaTeX, and compiled the UserInterface chapter of the reference manual. Cities skyline industries dlc.

How To Use This Section¶

This section is designed in two parts: the first half (roughly) coversbackground material, while the second half can be taken to the keyboard as ahandy reference.

When trying to answer questions of the form 'how do I do blah', it is often bestto find out how to do 'blah' in straight Tk, and then convert this back into thecorresponding tkinter call. Python programmers can often guess at thecorrect Python command by looking at the Tk documentation. This means that inorder to use Tkinter, you will have to know a little bit about Tk. This documentcan't fulfill that role, so the best we can do is point you to the bestdocumentation that exists. Here are some hints:

• The authors strongly suggest getting a copy of the Tk man pages.Specifically, the man pages in the manN directory are most useful.The man3 man pages describe the C interface to the Tk library and thusare not especially helpful for script writers.

• Addison-Wesley publishes a book called Tcl and the Tk Toolkit by JohnOusterhout (ISBN 0-201-63337-X) which is a good introduction to Tcl and Tk forthe novice. The book is not exhaustive, and for many details it defers to theman pages.

• tkinter/__init__.py is a last resort for most, but can be a goodplace to go when nothing else makes sense.

A (Very) Quick Look at Tcl/Tk¶

The class hierarchy looks complicated, but in actual practice, applicationprogrammers almost always refer to the classes at the very bottom of thehierarchy.

Notes:

• These classes are provided for the purposes of organizing certain functionsunder one namespace. They aren't meant to be instantiated independently.

• The Tk class is meant to be instantiated only once in an application.Application programmers need not instantiate one explicitly, the system createsone whenever any of the other classes are instantiated.

• The Widget class is not meant to be instantiated, it is meant onlyfor subclassing to make 'real' widgets (in C++, this is called an ‘abstractclass').

To make use of this reference material, there will be times when you will needto know how to read short passages of Tk and how to identify the various partsof a Tk command. (See section Mapping Basic Tk into Tkinter for thetkinter equivalents of what's below.)

Tk scripts are Tcl programs. Like all Tcl programs, Tk scripts are just listsof tokens separated by spaces. A Tk widget is just its class, the optionsthat help configure it, and the actions that make it do useful things.

To make a widget in Tk, the command is always of the form:

denotes which kind of widget to make (a button, a label, a menu…)

is the new name for this widget. All names in Tk must be unique. To helpenforce this, widgets in Tk are named with pathnames, just like files in afile system. The top level widget, the root, is called . (period) andchildren are delimited by more periods. For example,.myApp.controlPanel.okButton might be the name of a widget.

configure the widget's appearance and in some cases, its behavior. The optionscome in the form of a list of flags and values. Flags are preceded by a ‘-‘,like Unix shell command flags, and values are put in quotes if they are morethan one word.

For example:

Once created, the pathname to the widget becomes a new command. This newwidget command is the programmer's handle for getting the new widget toperform some action. In C, you'd express this as someAction(fred,someOptions), in C++, you would express this as fred.someAction(someOptions),and in Tk, you say:

Note that the object name, .fred, starts with a dot.

As you'd expect, the legal values for someAction will depend on the widget'sclass: .freddisable works if fred is a button (fred gets greyed out), butdoes not work if fred is a label (disabling of labels is not supported in Tk).

The legal values of someOptions is action dependent. Some actions, likedisable, require no arguments, others, like a text-entry box's deletecommand, would need arguments to specify what range of text to delete.

Mapping Basic Tk into Tkinter¶

Class commands in Tk correspond to class constructors in Tkinter.

The master of an object is implicit in the new name given to it at creationtime. In Tkinter, masters are specified explicitly.

The configuration options in Tk are given in lists of hyphened tags followed byvalues. In Tkinter, options are specified as keyword-arguments in the instanceconstructor, and keyword-args for configure calls or as instance indices, indictionary style, for established instances. See sectionSetting Options on setting options.

In Tk, to perform an action on a widget, use the widget name as a command, andfollow it with an action name, possibly with arguments (options). In Tkinter,you call methods on the class instance to invoke actions on the widget. Theactions (methods) that a given widget can perform are listed intkinter/__init__.py.

To give a widget to the packer (geometry manager), you call pack with optionalarguments. In Tkinter, the Pack class holds all this functionality, and thevarious forms of the pack command are implemented as methods. All widgets intkinter are subclassed from the Packer, and so inherit all the packingmethods. See the tkinter.tix module documentation for additionalinformation on the Form geometry manager.

How Tk and Tkinter are Related¶

From the top down:

A Python application makes a tkinter call.

This call (say, for example, creating a button widget), is implemented inthe tkinter package, which is written in Python. This Pythonfunction will parse the commands and the arguments and convert them into aform that makes them look as if they had come from a Tk script instead ofa Python script.

These commands and their arguments will be passed to a C function in the_tkinter - note the underscore - extension module.

This C function is able to make calls into other C modules, including the Cfunctions that make up the Tk library. Tk is implemented in C and some Tcl.The Tcl part of the Tk widgets is used to bind certain default behaviors towidgets, and is executed once at the point where the Python tkinterpackage is imported. (The user never sees this stage).

The Tk part of the Tk Widgets implement the final mapping to …

the Xlib library to draw graphics on the screen.

Handy Reference¶

Setting Options¶

Options control things like the color and border width of a widget. Options canbe set in three ways:

At object creation time, using keyword arguments

After object creation, treating the option name like a dictionary index

Use the config() method to update multiple attrs subsequent to object creation

For a complete explanation of a given option and its behavior, see the Tk manpages for the widget in question.

Note that the man pages list 'STANDARD OPTIONS' and 'WIDGET SPECIFIC OPTIONS'for each widget. The former is a list of options that are common to manywidgets, the latter are the options that are idiosyncratic to that particularwidget. The Standard Options are documented on the options(3) manpage.

No distinction between standard and widget-specific options is made in thisdocument. Some options don't apply to some kinds of widgets. Whether a givenwidget responds to a particular option depends on the class of the widget;buttons have a command option, labels do not.

The options supported by a given widget are listed in that widget's man page, orcan be queried at runtime by calling the config() method withoutarguments, or by calling the keys() method on that widget. The returnvalue of these calls is a dictionary whose key is the name of the option as astring (for example, 'relief') and whose values are 5-tuples.

Some options, like bg are synonyms for common options with long names(bg is shorthand for 'background'). Passing the config() method the nameof a shorthand option will return a 2-tuple, not 5-tuple. The 2-tuple passedback will contain the name of the synonym and the 'real' option (such as('bg','background')).

Example:

Of course, the dictionary printed will include all the options available andtheir values. This is meant only as an example.

The Packer¶

The packer is one of Tk's geometry-management mechanisms. Geometry managersare used to specify the relative positioning of widgets within their container -their mutual master. In contrast to the more cumbersome placer (which isused less commonly, and we do not cover here), the packer takes qualitativerelationship specification - above, to the left of, filling, etc - andworks everything out to determine the exact placement coordinates for you.

The size of any master widget is determined by the size of the 'slave widgets'inside. The packer is used to control where slave widgets appear inside themaster into which they are packed. You can pack widgets into frames, and framesinto other frames, in order to achieve the kind of layout you desire.Additionally, the arrangement is dynamically adjusted to accommodate incrementalchanges to the configuration, once it is packed.

Note that widgets do not appear until they have had their geometry specifiedwith a geometry manager. It's a common early mistake to leave out the geometryspecification, and then be surprised when the widget is created but nothingappears. A widget will appear only after it has had, for example, the packer'spack() method applied to it.

The pack() method can be called with keyword-option/value pairs that controlwhere the widget is to appear within its container, and how it is to behave whenthe main application window is resized. Here are some examples:

Packer Options¶

For more extensive information on the packer and the options that it can take,see the man pages and page 183 of John Ousterhout's book.

Anchor type. Denotes where the packer is to place each slave in its parcel.

Boolean, 0 or 1.

Legal values: 'x', 'y', 'both', 'none'.

A distance - designating internal padding on each side of the slave widget.

A distance - designating external padding on each side of the slave widget.

Legal values are: 'left', 'right', 'top', 'bottom'.

Coupling Widget Variables¶

The current-value setting of some widgets (like text entry widgets) can beconnected directly to application variables by using special options. Theseoptions are variable, textvariable, onvalue, offvalue, andvalue. This connection works both ways: if the variable changes for anyreason, the widget it's connected to will be updated to reflect the new value.

Unfortunately, in the current implementation of tkinter it is notpossible to hand over an arbitrary Python variable to a widget through avariable or textvariable option. The only kinds of variables for whichthis works are variables that are subclassed from a class called Variable,defined in tkinter.

There are many useful subclasses of Variable already defined:StringVar, IntVar, DoubleVar, andBooleanVar. To read the current value of such a variable, call theget() method on it, and to change its value you call the set()method. If you follow this protocol, the widget will always track the value ofthe variable, with no further intervention on your part.

For example:

The Window Manager¶

In Tk, there is a utility command, wm, for interacting with the windowmanager. Options to the wm command allow you to control things like titles,placement, icon bitmaps, and the like. In tkinter, these commands havebeen implemented as methods on the Wm class. Toplevel widgets aresubclassed from the Wm class, and so can call the Wm methodsdirectly.

To get at the toplevel window that contains a given widget, you can often justrefer to the widget's master. Of course if the widget has been packed inside ofa frame, the master won't represent a toplevel window. To get at the toplevelwindow that contains an arbitrary widget, you can call the _root() method.This method begins with an underscore to denote the fact that this function ispart of the implementation, and not an interface to Tk functionality.

Here are some examples of typical usage:

Tk Option Data Types¶

Legal values are points of the compass: 'n', 'ne', 'e', 'se','s', 'sw', 'w', 'nw', and also 'center'.

The Python Tkinter Topic Guide provides a great deal of information on using Tkfrom Python and links to other sources of information on Tk.

Extensive tutorial plus friendlier widget pages for some of the widgets.

On-line reference material.

Online reference for tkinter supported by effbot.org.

Book by Mark Lutz, has excellent coverage of Tkinter.

Book by Mark Roseman about building attractive and modern graphical user interfaces with Python and Tkinter.

Book by John Grayson (ISBN 1-884777-81-3).

Tcl/Tk documentation:

Most commands are available as tkinter or tkinter.ttk classes.Change ‘8.6' to match the version of your Tcl/Tk installation.

Recent Tcl/Tk manuals on www.tcl.tk.

The Tk/Tcl development is largely taking place at ActiveState.

Book by John Ousterhout, the inventor of Tcl.

Brent Welch's encyclopedic book.

Tkinter Modules¶

Most of the time, tkinter is all you really need, but a number ofadditional modules are available as well. The Tk interface is located in abinary module named _tkinter. This module contains the low-levelinterface to Tk, and should never be used directly by application programmers.It is usually a shared library (or DLL), but might in some cases be staticallylinked with the Python interpreter.

In addition to the Tk interface module, tkinter includes a number ofPython modules, tkinter.constants being one of the most important.Importing tkinter will automatically import tkinter.constants,so, usually, to use Tkinter all you need is a simple import statement:

Or, more often:

The Tk class is instantiated without arguments. This creates a toplevelwidget of Tk which usually is the main window of an application. Each instancehas its own associated Tcl interpreter.

The Tcl() function is a factory function which creates an object much likethat created by the Tk class, except that it does not initialize the Tksubsystem. This is most often useful when driving the Tcl interpreter in anenvironment where one doesn't want to create extraneous toplevel windows, orwhere one cannot (such as Unix/Linux systems without an X server). An objectcreated by the Tcl() object can have a Toplevel window created (and the Tksubsystem initialized) by calling its loadtk() method.

Other modules that provide Tk support include:

Dialog to let the user choose a color.

Base class for the dialogs defined in the other modules listed here.

Common dialogs to allow the user to specify a file to open or save.

Utilities to help work with fonts.

Access to standard Tk dialog boxes.

Text widget with a vertical scroll bar built in.

Basic dialogs and convenience functions.

Drag-and-drop support for tkinter. This is experimental and shouldbecome deprecated when it is replaced with the Tk DND.

Turtle graphics in a Tk window.

Tkinter Life Preserver¶

This section is not designed to be an exhaustive tutorial on either Tk orTkinter. Rather, it is intended as a stop gap, providing some introductoryorientation on the system.

Credits:

• Tk was written by John Ousterhout while at Berkeley.

• Tkinter was written by Steen Lumholt and Guido van Rossum.

• This Life Preserver was written by Matt Conway at the University of Virginia.

• The HTML rendering, and some liberal editing, was produced from a FrameMakerversion by Ken Manheimer.

• Fredrik Lundh elaborated and revised the class interface descriptions, to getthem current with Tk 4.2.

• Mike Clarkson converted the documentation to LaTeX, and compiled the UserInterface chapter of the reference manual. Cities skyline industries dlc.

How To Use This Section¶

This section is designed in two parts: the first half (roughly) coversbackground material, while the second half can be taken to the keyboard as ahandy reference.

When trying to answer questions of the form 'how do I do blah', it is often bestto find out how to do 'blah' in straight Tk, and then convert this back into thecorresponding tkinter call. Python programmers can often guess at thecorrect Python command by looking at the Tk documentation. This means that inorder to use Tkinter, you will have to know a little bit about Tk. This documentcan't fulfill that role, so the best we can do is point you to the bestdocumentation that exists. Here are some hints:

• The authors strongly suggest getting a copy of the Tk man pages.Specifically, the man pages in the manN directory are most useful.The man3 man pages describe the C interface to the Tk library and thusare not especially helpful for script writers.

• Addison-Wesley publishes a book called Tcl and the Tk Toolkit by JohnOusterhout (ISBN 0-201-63337-X) which is a good introduction to Tcl and Tk forthe novice. The book is not exhaustive, and for many details it defers to theman pages.

• tkinter/__init__.py is a last resort for most, but can be a goodplace to go when nothing else makes sense.

A (Very) Quick Look at Tcl/Tk¶

The class hierarchy looks complicated, but in actual practice, applicationprogrammers almost always refer to the classes at the very bottom of thehierarchy.

Notes:

• These classes are provided for the purposes of organizing certain functionsunder one namespace. They aren't meant to be instantiated independently.

• The Tk class is meant to be instantiated only once in an application.Application programmers need not instantiate one explicitly, the system createsone whenever any of the other classes are instantiated.

• The Widget class is not meant to be instantiated, it is meant onlyfor subclassing to make 'real' widgets (in C++, this is called an ‘abstractclass').

To make use of this reference material, there will be times when you will needto know how to read short passages of Tk and how to identify the various partsof a Tk command. (See section Mapping Basic Tk into Tkinter for thetkinter equivalents of what's below.)

Tk scripts are Tcl programs. Like all Tcl programs, Tk scripts are just listsof tokens separated by spaces. A Tk widget is just its class, the optionsthat help configure it, and the actions that make it do useful things.

To make a widget in Tk, the command is always of the form:

denotes which kind of widget to make (a button, a label, a menu…)

is the new name for this widget. All names in Tk must be unique. To helpenforce this, widgets in Tk are named with pathnames, just like files in afile system. The top level widget, the root, is called . (period) andchildren are delimited by more periods. For example,.myApp.controlPanel.okButton might be the name of a widget.

configure the widget's appearance and in some cases, its behavior. The optionscome in the form of a list of flags and values. Flags are preceded by a ‘-‘,like Unix shell command flags, and values are put in quotes if they are morethan one word.

For example:

Once created, the pathname to the widget becomes a new command. This newwidget command is the programmer's handle for getting the new widget toperform some action. In C, you'd express this as someAction(fred,someOptions), in C++, you would express this as fred.someAction(someOptions),and in Tk, you say:

Note that the object name, .fred, starts with a dot.

As you'd expect, the legal values for someAction will depend on the widget'sclass: .freddisable works if fred is a button (fred gets greyed out), butdoes not work if fred is a label (disabling of labels is not supported in Tk).

The legal values of someOptions is action dependent. Some actions, likedisable, require no arguments, others, like a text-entry box's deletecommand, would need arguments to specify what range of text to delete.

Mapping Basic Tk into Tkinter¶

Class commands in Tk correspond to class constructors in Tkinter.

The master of an object is implicit in the new name given to it at creationtime. In Tkinter, masters are specified explicitly.

The configuration options in Tk are given in lists of hyphened tags followed byvalues. In Tkinter, options are specified as keyword-arguments in the instanceconstructor, and keyword-args for configure calls or as instance indices, indictionary style, for established instances. See sectionSetting Options on setting options.

In Tk, to perform an action on a widget, use the widget name as a command, andfollow it with an action name, possibly with arguments (options). In Tkinter,you call methods on the class instance to invoke actions on the widget. Theactions (methods) that a given widget can perform are listed intkinter/__init__.py.

To give a widget to the packer (geometry manager), you call pack with optionalarguments. In Tkinter, the Pack class holds all this functionality, and thevarious forms of the pack command are implemented as methods. All widgets intkinter are subclassed from the Packer, and so inherit all the packingmethods. See the tkinter.tix module documentation for additionalinformation on the Form geometry manager.

How Tk and Tkinter are Related¶

From the top down:

A Python application makes a tkinter call.

This call (say, for example, creating a button widget), is implemented inthe tkinter package, which is written in Python. This Pythonfunction will parse the commands and the arguments and convert them into aform that makes them look as if they had come from a Tk script instead ofa Python script.

These commands and their arguments will be passed to a C function in the_tkinter - note the underscore - extension module.

This C function is able to make calls into other C modules, including the Cfunctions that make up the Tk library. Tk is implemented in C and some Tcl.The Tcl part of the Tk widgets is used to bind certain default behaviors towidgets, and is executed once at the point where the Python tkinterpackage is imported. (The user never sees this stage).

The Tk part of the Tk Widgets implement the final mapping to …

the Xlib library to draw graphics on the screen.

Handy Reference¶

Setting Options¶

Options control things like the color and border width of a widget. Options canbe set in three ways:

At object creation time, using keyword arguments

After object creation, treating the option name like a dictionary index

Use the config() method to update multiple attrs subsequent to object creation

For a complete explanation of a given option and its behavior, see the Tk manpages for the widget in question.

Note that the man pages list 'STANDARD OPTIONS' and 'WIDGET SPECIFIC OPTIONS'for each widget. The former is a list of options that are common to manywidgets, the latter are the options that are idiosyncratic to that particularwidget. The Standard Options are documented on the options(3) manpage.

No distinction between standard and widget-specific options is made in thisdocument. Some options don't apply to some kinds of widgets. Whether a givenwidget responds to a particular option depends on the class of the widget;buttons have a command option, labels do not.

The options supported by a given widget are listed in that widget's man page, orcan be queried at runtime by calling the config() method withoutarguments, or by calling the keys() method on that widget. The returnvalue of these calls is a dictionary whose key is the name of the option as astring (for example, 'relief') and whose values are 5-tuples.

Some options, like bg are synonyms for common options with long names(bg is shorthand for 'background'). Passing the config() method the nameof a shorthand option will return a 2-tuple, not 5-tuple. The 2-tuple passedback will contain the name of the synonym and the 'real' option (such as('bg','background')).

Example:

Of course, the dictionary printed will include all the options available andtheir values. This is meant only as an example.

The Packer¶

The packer is one of Tk's geometry-management mechanisms. Geometry managersare used to specify the relative positioning of widgets within their container -their mutual master. In contrast to the more cumbersome placer (which isused less commonly, and we do not cover here), the packer takes qualitativerelationship specification - above, to the left of, filling, etc - andworks everything out to determine the exact placement coordinates for you.

The size of any master widget is determined by the size of the 'slave widgets'inside. The packer is used to control where slave widgets appear inside themaster into which they are packed. You can pack widgets into frames, and framesinto other frames, in order to achieve the kind of layout you desire.Additionally, the arrangement is dynamically adjusted to accommodate incrementalchanges to the configuration, once it is packed.

Note that widgets do not appear until they have had their geometry specifiedwith a geometry manager. It's a common early mistake to leave out the geometryspecification, and then be surprised when the widget is created but nothingappears. A widget will appear only after it has had, for example, the packer'spack() method applied to it.

The pack() method can be called with keyword-option/value pairs that controlwhere the widget is to appear within its container, and how it is to behave whenthe main application window is resized. Here are some examples:

Packer Options¶

For more extensive information on the packer and the options that it can take,see the man pages and page 183 of John Ousterhout's book.

Anchor type. Denotes where the packer is to place each slave in its parcel.

Boolean, 0 or 1.

Legal values: 'x', 'y', 'both', 'none'.

A distance - designating internal padding on each side of the slave widget.

A distance - designating external padding on each side of the slave widget.

Legal values are: 'left', 'right', 'top', 'bottom'.

Coupling Widget Variables¶

The current-value setting of some widgets (like text entry widgets) can beconnected directly to application variables by using special options. Theseoptions are variable, textvariable, onvalue, offvalue, andvalue. This connection works both ways: if the variable changes for anyreason, the widget it's connected to will be updated to reflect the new value.

Unfortunately, in the current implementation of tkinter it is notpossible to hand over an arbitrary Python variable to a widget through avariable or textvariable option. The only kinds of variables for whichthis works are variables that are subclassed from a class called Variable,defined in tkinter.

There are many useful subclasses of Variable already defined:StringVar, IntVar, DoubleVar, andBooleanVar. To read the current value of such a variable, call theget() method on it, and to change its value you call the set()method. If you follow this protocol, the widget will always track the value ofthe variable, with no further intervention on your part.

For example:

The Window Manager¶

In Tk, there is a utility command, wm, for interacting with the windowmanager. Options to the wm command allow you to control things like titles,placement, icon bitmaps, and the like. In tkinter, these commands havebeen implemented as methods on the Wm class. Toplevel widgets aresubclassed from the Wm class, and so can call the Wm methodsdirectly.

To get at the toplevel window that contains a given widget, you can often justrefer to the widget's master. Of course if the widget has been packed inside ofa frame, the master won't represent a toplevel window. To get at the toplevelwindow that contains an arbitrary widget, you can call the _root() method.This method begins with an underscore to denote the fact that this function ispart of the implementation, and not an interface to Tk functionality.

Here are some examples of typical usage:

Tk Option Data Types¶

Legal values are points of the compass: 'n', 'ne', 'e', 'se','s', 'sw', 'w', 'nw', and also 'center'.

There are eight built-in, named bitmaps: 'error', 'gray25','gray50', 'hourglass', 'info', 'questhead', 'question','warning'. To specify an X bitmap filename, give the full path to the file,preceded with an @, as in '@/usr/contrib/bitmap/gumby.bit'.

You can pass integers 0 or 1 or the strings 'yes' or 'no'.

This is any Python function that takes no arguments. For example:

Colors can be given as the names of X colors in the rgb.txt file, or as stringsrepresenting RGB values in 4 bit: '#RGB', 8 bit: '#RRGGBB', 12 bit''#RRRGGGBBB', or 16 bit '#RRRRGGGGBBBB' ranges, where R,G,B hererepresent any legal hex digit. See page 160 of Ousterhout's book for details.

The standard X cursor names from cursorfont.h can be used, without theXC_ prefix. For example to get a hand cursor (XC_hand2), use thestring 'hand2'. You can also specify a bitmap and mask file of your own.See page 179 of Ousterhout's book.

Screen distances can be specified in either pixels or absolute distances.Pixels are given as numbers and absolute distances as strings, with the trailingcharacter denoting units: c for centimetres, i for inches, m formillimetres, p for printer's points. For example, 3.5 inches is expressedas '3.5i'.

Tk uses a list font name format, such as {courier10bold}. Font sizes withpositive numbers are measured in points; sizes with negative numbers aremeasured in pixels.

This is a string of the form widthxheight, where width and height aremeasured in pixels for most widgets (in characters for widgets displaying text).For example: fred['geometry']='200x100'.

Legal values are the strings: 'left', 'center', 'right', and'fill'.

This is a string with four space-delimited elements, each of which is a legaldistance (see above). For example: '2345' and '3i2i4.5i2i' and'3c2c4c10.43c' are all legal regions.

Determines what the border style of a widget will be. Legal values are:'raised', 'sunken', 'flat', 'groove', and 'ridge'.

This is almost always the set() method of some scrollbar widget, but canbe any widget method that takes a single argument.

Must be one of: 'none', 'char', or 'word'.

Bindings and Events¶

The bind method from the widget command allows you to watch for certain eventsand to have a callback function trigger when that event type occurs. The formof the bind method is:

where:

is a string that denotes the target kind of event. (See the bind man page andpage 201 of John Ousterhout's book for details).

is a Python function, taking one argument, to be invoked when the event occurs.An Event instance will be passed as the argument. (Functions deployed this wayare commonly known as callbacks.)

is optional, either ' or '+'. Passing an empty string denotes thatthis binding is to replace any other bindings that this event is associatedwith. Passing a '+' means that this function is to be added to the listof functions bound to this event type.

For example:

Notice how the widget field of the event is being accessed in theturn_red() callback. This field contains the widget that caught the Xevent. The following table lists the other event fields you can access, and howthey are denoted in Tk, which can be useful when referring to the Tk man pages.

The index Parameter¶

A number of widgets require 'index' parameters to be passed. These are used topoint at a specific place in a Text widget, or to particular characters in anEntry widget, or to particular menu items in a Menu widget.

Entry widgets have options that refer to character positions in the text beingdisplayed. You can use these tkinter functions to access these specialpoints in text widgets:

The index notation for Text widgets is very rich and is best described in the Tkman pages.

Some options and methods for menus manipulate specific menu entries. Anytime amenu index is needed for an option or a parameter, you may pass in:

• an integer which refers to the numeric position of the entry in the widget,counted from the top, starting with 0;

• the string 'active', which refers to the menu position that is currentlyunder the cursor;

• the string 'last' which refers to the last menu item;

• An integer preceded by @, as in @6, where the integer is interpretedas a y pixel coordinate in the menu's coordinate system;

• the string 'none', which indicates no menu entry at all, most often usedwith menu.activate() to deactivate all entries, and finally,

• a text string that is pattern matched against the label of the menu entry, asscanned from the top of the menu to the bottom. Note that this index type isconsidered after all the others, which means that matches for menu itemslabelled last, active, or none may be interpreted as the aboveliterals, instead.

Images¶

Images of different formats can be created through the corresponding subclassof tkinter.Image:

• BitmapImage for images in XBM format.

• PhotoImage for images in PGM, PPM, GIF and PNG formats. The latteris supported starting with Tk 8.6.

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Either type of image is created through either the file or the dataoption (other options are available as well).

The image object can then be used wherever an image option is supported bysome widget (e.g. labels, buttons, menus). In these cases, Tk will not keep areference to the image. When the last Python reference to the image object isdeleted, the image data is deleted as well, and Tk will display an empty boxwherever the image was used.

See also

The Pillow package adds support forformats such as BMP, JPEG, TIFF, and WebP, among others. Warcraft iii for mac.

File Handlers¶

Tk allows you to register and unregister a callback function which will becalled from the Tk mainloop when I/O is possible on a file descriptor.Only one handler may be registered per file descriptor. Example code:

This feature is not available on Windows.

Since you don't know how many bytes are available for reading, you may notwant to use the BufferedIOBase or TextIOBaseread() or readline() methods,since these will insist on reading a predefined number of bytes.For sockets, the recv() orrecvfrom() methods will work fine; for other files,use raw reads or os.read(file.fileno(),maxbytecount).

Registers the file handler callback function func. The file argumentmay either be an object with a fileno() method (such asa file or socket object), or an integer file descriptor. The maskargument is an ORed combination of any of the three constants below.The callback is called as follows:

Unregisters a file handler.

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Constants used in the mask arguments.