The tsw::toggleswitch Command

Contents

• Quick Reference
• Detailed Reference
• Choosing between toggleswitch and (ttk::)checkbutton

Quick Reference

NAME

tsw::toggleswitch – Create and manipulate toggle switch widgets

SYNOPSIS

tsw::toggleswitch pathName ?options?

DESCRIPTION

STANDARD OPTIONS

-class  -cursor  -style

WIDGET-SPECIFIC OPTIONS

-command command

-offvalue value

-onvalue value

-size 1|2|3

-takefocus 0|1|""|command

-variable variable

WIDGET COMMAND

pathName attrib ?name ?value name value ...??

pathName cget option

pathName configure ?option ?value option value ...??

pathName hasattrib name

pathName identify ?element? x y

pathName instate stateSpec ?script?

pathName state ?stateSpec?

pathName style

pathName switchstate ?boolean?

pathName toggle

pathName unsetattrib name

DEFAULT BINDINGS

WIDGET STATES

STYLING OPTIONS

KEYWORDS

toggleswitch, trough, slider, widget

Detailed Reference

NAME

tsw::toggleswitch – Create and manipulate toggle switch widgets

SYNOPSIS

tsw::toggleswitch pathName ?options?

DESCRIPTION

The tsw::toggleswitch command creates a new window named pathName and makes it into a toggleswitch widget.  Additional options, described below, may be specified on the command line or in the option database to configure aspects of the toggleswitch widget, such as its size and the Tcl script to execute whenever the switch state of the widget is toggled.  The tsw::toggleswitch command returns its pathName argument.  At the time this command is invoked, there must not exist a window named pathName, but pathName's parent must exist.

A toggleswitch is a mega-widget consisting of a horizontal trough and a slider, just like a ttk::scale widget.  Actually, these elements belong to a ttk::scale contained in the widget.  The trough is a fully rounded filled rectangle, and the slider is a filled circle contained in the trough.  Both elements are rendered using scaling-aware SVG images.  Their dimensions depend on the display's scaling level, the current theme, and the value of the -size configuration option.

Just like a light switch, a toggleswitch widget can have one of two possible switch states: on or off.  In the on state the slider is placed at the end of the trough, and in the off state at its beginning.  As described in the DEFAULT BINDINGS section below, the user can toggle between these two states with the mouse or the space key.

The Tcl command associated with a toggleswitch widget has a very simple API.  You can use the switchstate subcommand to change or query the widget's switch state.  By using the -command configuration option, you can specify a script to execute whenever the widget's switch state gets toggled.  Just like the (ttk::)checkbutton, toggleswitch widgets also support the -offvalue, -onvalue, and -variable options.

The colors used when drawing the trough and slider in the various widget states (such as active, background, disabled, pressed, and selected) depend on the current theme.  The implementation creates these elements when needed with the aid of generic procedures for arbitrary themes and theme-specific ones for a few built-in themes.  Applications can add explicit support for any theme theme by providing an appropriate command of the name tsw::createElements_theme.

STANDARD OPTIONS

-class  -cursor  -style

See the ttk_widget manual entry for details on the standard options.  The default value of the -class option is Toggleswitch and that of -cursor an empty string.  The value of the -style option defaults to Toggleswitch2, corresponding to the -size option's default value 2.

WIDGET-SPECIFIC OPTIONS

Command-Line Name:	-command
Database Name:	command
Database Class:	Command

Specifies a Tcl script to be evaluated at global scope whenever the switch state of the widget is toggled (programmatically, by invoking the switchstate or toggle subcommand, or interactively).  The default is an empty string.

Command-Line Name:	-offvalue
Database Name:	offValue
Database Class:	OffValue

The value to store in the associated variable when the widget's switch state is set to off.  Defaults to 0.

Command-Line Name:	-onvalue
Database Name:	onValue
Database Class:	OnValue

The value to store in the associated variable when the widget's switch state is set to on.  Defaults to 1.

Command-Line Name:	-size
Database Name:	size
Database Class:	Size

Specifies the size identifier of the toggleswitch widget.  The supported values are the strings 1, 2 (the default), and 3.  If the current theme is aqua then these size IDs correspond to the control sizes "mini", "small", and "large" of the native toggle switches on macOS.  The value 1 stands for the trough size of 26 x 15 pixels, the value 2 for the trough size of 32 x 18 pixels, and the value 3 identifies the trough size of 38 x 22 pixels.  For all the other themes, on an unscaled screen the value 1 stands for the trough size of 32 x 16 pixels, the value 2 for the trough size of 40 x 20 pixels, and the value 3 identifies the trough size of 48 x 24 pixels, except that on Windows 10 and earlier, for the themes vista, winnative, and xpnative the unscaled trough width is 35, 44, and 53 pixels, respectively (for compatibility with the native toggle switch).

Note that by setting this option to a value size, the -style option's value will automatically change to Toggleswitchsize if its previous or requested value was Toggleswitch1, Toggleswitch2, or Toggleswitch3, and to prefix.Toggleswitchsize if its previous or requested value was prefix.Toggleswitch1, prefix.Toggleswitch2, or prefix.Toggleswitch3.  Conversely, by setting the -style option to a value of the form Toggleswitchsize or prefix.Toggleswitchsize (where size is one of 1, 2, or 3), the -size option will automatically be set to size.  When configuring both options -size and -style, the former will take precedence over the latter, regardless of the order in which they were specified.

For example, if you create the widget with

tsw::toggleswitch pathName -size 3 -style My.Toggleswitch3

or invoke

pathName configure -style My.Toggleswitch3

then the -style option will be set to My.Toggleswitch3 (and the -size option will have the value 3).  On the other hand, if you create the widget with

tsw::toggleswitch pathName -style My.Toggleswitch3

then the -style option will have the value My.Toggleswitch2 rather than My.Toggleswitch3, because the widget creation triggers the default  -size 2  setting, which takes precedence over  -style My.Toggleswitch3.

Command-Line Name:	-takefocus
Database Name:	takeFocus
Database Class:	TakeFocus

This option determines whether the toggleswitch widget accepts the focus during keyboard traversal.  It is almost identical to the standard option of the same name (see the options manual entry for details).  The only difference is that not the toggleswitch itself but the ttk::scale widget contained in it will receive the focus during keyboard traversal with the standard keys (Tab and Shift-Tab).  The default is "ttk::takefocus" (just like for most Tk themed widgets).

Command-Line Name:	-variable
Database Name:	variable
Database Class:	Variable

The name of a global variable whose value is linked to the toggleswitch.  The widget's switch state changes to on when this variable is set to the value specified by the -onvalue option and to off otherwise.  Defaults to the widget's pathname if not specified.

Note that, just like in the case of the (ttk::)checkbutton, toggling the widget's switch state by changing the value of this variable will not cause the script specified by the -command option to get executed.

WIDGET COMMAND

The tsw::toggleswitch command creates a new Tcl command whose name is pathName.  This command may be used to invoke various operations on the widget.  It has the following general form:

pathName option ?arg arg ...?

option and the args determine the exact behavior of the command.  The following commands are possible for toggleswitch widgets:

pathName attrib ?name ?value name value ...??

Queries or modifies the attributes of the widget.  If no name is specified, the command returns a list of pairs, each of which contains the name and the value of an attribute for pathName.  If name is specified with no value, then the command returns the value of the one named attribute, or an empty string if no corresponding value exists (you can use the hasattrib subcommand to distinguish this case from the one that the value of an existing attribute is an empty string).  If one or more name-value pairs are specified, then the command sets the given widget attribute(s) to the given value(s); in this case the return value is an empty string.  name may be an arbitrary string.

pathName cget option

Returns the current value of the configuration option given by option, which may have any of the values accepted by the tsw::toggleswitch command.

pathName configure ?option ?value option value ...??

Queries or modifies the configuration options of the widget.  If no option is specified, the command returns a list describing all of the available options for pathName (see Tk_ConfigureInfo for information on the format of this list).  If option is specified with no value, then the command returns a list describing the one named option (this list will be identical to the corresponding sublist of the value returned if no option is specified).  If one or more option-value pairs are specified, then the command modifies the given widget option(s) to have the given value(s); in this case the return value is an empty string.  option may have any of the values accepted by the tsw::toggleswitch command.

pathName hasattrib name

Returns 1 if the attribute name exists and 0 otherwise.

pathName identify ?element? x y

See the ttk_widget manual entry.

pathName instate stateSpec ?script?

See the ttk_widget manual entry.

pathName state ?stateSpec?

See the ttk_widget manual entry.

pathName style

Returns the style used by the underlying ttk::scale widget.  For Tk themed widgets this subcommand was introduced in Tk 8.7a4, but the toggleswitch widget provides it for all supported Tk versions.

pathName switchstate ?boolean?

Modifies or inquires the widget's switch state.  If the optional argument is present then it must be a boolean (a numeric value, where 0 is false and anything else is true, or a string such as true/yes/on or false/no/off).  If the widget's disabled state flag is set then the command returns an empty string immediately after checking the argument.  Otherwise, if the argument is true then the command sets the widget's switch state to on by setting the underlying ttk::scale widget's selected flag, moving the slider to the end of the trough, and setting the associated variable to the value specified by the -onvalue option; if the argument is false then the command sets the widget's switch state to off by clearing the selected flag, moving the slider to the beginning of the trough, and setting the associated variable to the value specified by the -offvalue option.

If the argument's value causes the widget's switch state to get toggled and the script specified as the value of the -command option is a nonempty string then the command evaluates that script at global scope and returns its result; otherwise the return value is an empty string.

If the optional argument is not present then the command returns the widget's current switch state as 0 (off) or 1 (on).  When a toggleswitch widget is created, its switch state is initialized with 0.

pathName toggle

This convenience subcommand toggles the widget's switch state.  It is logically equivalent to invoking the switchstate command with the argument 0 if the current switch state is on and with the argument 1 otherwise.

pathName unsetattrib name

Unsets the attribute name.  Returns an empty string.

DEFAULT BINDINGS

The Tsw package replaces the default bindings of the ttk::scale contained in a toggleswitch widget with its own bindings as follows:

If the current theme is aqua:

1. By pressing mouse button 1 over the slider and then dragging the mouse with button 1 down until the pointer enters the trough, the slider moves smoothly to the opposite edge of the trough and the widget's switch state gets toggled.  The same happens if mouse button 1 is pressed outside the slider and then the pointer leaves the widget horizontally with button 1 down.
2. By pressing mouse button 1 anywhere within the widget and then releasing it over the widget without previously moving the slider, the latter moves smoothly to the opposite edge of the trough and the widget's switch state gets toggled.
3. When the widget has the input focus, the space key causes its switch state to get toggled.

If the current theme is different from aqua:

1. By pressing mouse button 1 anywhere within the widget and then dragging the mouse with button 1 down, the slider moves in the same (horizontal) direction as the pointer.  By releasing the button, the switch state is set to off or on, depending on the slider's position relative to the middle of the widget.
2. By pressing mouse button 1 anywhere within the widget and then releasing it over the widget without previously dragging the mouse horizontally, the widget's switch state gets toggled.
3. When the widget has the input focus, the space key causes its switch state to get toggled.

If the widget's disabled state flag is set then none of the above actions occur.

WIDGET STATES

The widget sets the selected state whenever the switch state changes to on and clears it otherwise.  The default bindings set and clear the active and pressed state flags.

STYLING OPTIONS

The default class name for a tsw::toggleswitch is Toggleswitch.

Dynamic states: active, background, disabled, pressed, selected.

Toggleswitch1, Toggleswitch2, and Toggleswitch3 styling options configurable with ttk::style are:

-focuscolor color

The default is theme-specific.

-focussolid boolean

Defaults to true for the classic theme and false for all the others.  This option was introduced in Tk 8.6.15; in earlier Tk versions it has no effect.

-focusthickness amount

The default is 1.  The value may have any of the forms acceptable to Tk_GetPixels.

-padding padding

Defaults to 1.5p for the aqua theme (for which the three above-mentioned styles have no focus element) and 0.75p for all the other themes.

For the aqua theme only the -padding option is available, the others are simply ignored.

See the ttk_style manual page for information on how to configure ttk styles.

KEYWORDS

toggleswitch, trough, slider, widget

Choosing between toggleswitch and (ttk::)checkbutton

This section is based on the Microsoft Learn article Toggle switches.

For some actions, either a toggleswitch or a checkbutton might work.  To decide which control would work better, follow these tips:

• Use a toggleswitch for binary settings that work like actions by taking effect immediately after the user flips the switch.

  In the following example, for turning the kitchen lights on, you should use a toggleswitch rather than a checkbutton.

  

• For optional ("nice to have") items use checkbuttons.
• Use checkbuttons when the user can select multiple items that are related to a single setting or feature.
• Use a checkbutton when the user has to perform extra steps for changes to be effective.  For example, if the user must click a "Submit" or "Next" button to apply changes, use a checkbutton.