button(n) Tk Built-In Commands button(n)
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NAME
button - Create and manipulate button widgets
SYNOPSIS
button pathName ?options?
STANDARD OPTIONS
-activebackground -foreground -repeatdelay
-activeforeground -highlightbackground -repeatinterval
-anchor -highlightcolor -takefocus
-background -highlightthickness -text
-bitmap -image -textvariable
-borderwidth -justify -underline
-cursor -padx -wraplength
-disabledforeground -pady
-font -relief
See the options manual entry for details on the standard options.
WIDGET-SPECIFIC OPTIONS
Command-Line Name:-command
Database Name: command
Database Class: Command
Specifies a Tcl command to associate with the button. This command is typically invoked when
mouse button 1 is released over the button window. |
Command-Line Name:-compound |
Database Name: compound |
Database Class: Compound |
Specifies whether the button should display both an image and text, and if so, where the image |
should be placed relative to the text. Valid values for this option are bottom, center, left, |
none, right and top. The default value is none, meaning that the button will display either |
an image or text, depending on the values of the -image and -bitmap options.
Command-Line Name:-default
Database Name: default
Database Class: Default
Specifies one of three states for the default ring: normal, active, or disabled. In active |
state, the button is drawn with the platform specific appearance for a default button. In |
normal state, the button is drawn with the platform specific appearance for a non-default but- |
ton, leaving enough space to draw the default button appearance. The normal and active states |
will result in buttons of the same size. In disabled state, the button is drawn with the non- |
default button appearance without leaving space for the default appearance. The disabled |
state may result in a smaller button than the active state. ring.
Command-Line Name:-height
Database Name: height
Database Class: Height
Specifies a desired height for the button. If an image or bitmap is being displayed in the
button then the value is in screen units (i.e. any of the forms acceptable to Tk_GetPixels);
for text it is in lines of text. If this option isn't specified, the button's desired height
is computed from the size of the image or bitmap or text being displayed in it. |
Command-Line Name:-overrelief |
Database Name: overRelief |
Database Class: OverRelief |
Specifies an alternative relief for the button, to be used when the mouse cursor is over the |
widget. This option can be used to make toolbar buttons, by configuring -relief flat -overre- |
lief raised. If the value of this option is the empty string, then no alternative relief is |
used when the mouse cursor is over the button. The empty string is the default value.
Command-Line Name:-state
Database Name: state
Database Class: State
Specifies one of three states for the button: normal, active, or disabled. In normal state
the button is displayed using the foreground and background options. The active state is typ-ically typically
ically used when the pointer is over the button. In active state the button is displayed
using the activeForeground and activeBackground options. Disabled state means that the button
should be insensitive: the default bindings will refuse to activate the widget and will
ignore mouse button presses. In this state the disabledForeground and background options
determine how the button is displayed.
Command-Line Name:-width
Database Name: width
Database Class: Width
Specifies a desired width for the button. If an image or bitmap is being displayed in the
button then the value is in screen units (i.e. any of the forms acceptable to Tk_GetPixels);
for text it is in characters. If this option isn't specified, the button's desired width is
computed from the size of the image or bitmap or text being displayed in it.
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DESCRIPTION
The button command creates a new window (given by the pathName argument) and makes it into a button
widget. Additional options, described above, may be specified on the command line or in the option
database to configure aspects of the button such as its colors, font, text, and initial relief. The
button 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 button is a widget that displays a textual string, bitmap or image. If text is displayed, it must
all be in a single font, but it can occupy multiple lines on the screen (if it contains newlines or
if wrapping occurs because of the wrapLength option) and one of the characters may optionally be
underlined using the underline option. It can display itself in either of three different ways,
according to the state option; it can be made to appear raised, sunken, or flat; and it can be made
to flash. When a user invokes the button (by pressing mouse button 1 with the cursor over the but-ton), button),
ton), then the Tcl command specified in the -command option is invoked.
WIDGET COMMAND
The button 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 button widgets:
pathName cget option
Returns the current value of the configuration option given by option. Option may have any of
the values accepted by the button command.
pathName configure ?option? ?value option value ...?
Query or modify the configuration options of the widget. If no option is specified, returns a
list describing all of the available options for pathName (see Tk_ConfigureInfo for informa-tion information
tion 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 correspond-ing corresponding
ing 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 command returns an empty string. Option may have any of the val-ues values
ues accepted by the button command.
pathName flash
Flash the button. This is accomplished by redisplaying the button several times, alternating
between active and normal colors. At the end of the flash the button is left in the same nor-mal/active normal/active
mal/active state as when the command was invoked. This command is ignored if the button's
state is disabled.
pathName invoke
Invoke the Tcl command associated with the button, if there is one. The return value is the
return value from the Tcl command, or an empty string if there is no command associated with
the button. This command is ignored if the button's state is disabled.
DEFAULT BINDINGS
Tk automatically creates class bindings for buttons that give them default behavior:
[1] A button activates whenever the mouse passes over it and deactivates whenever the mouse leaves
the button. Under Windows, this binding is only active when mouse button 1 has been pressed |
over the button.
[2] A button's relief is changed to sunken whenever mouse button 1 is pressed over the button, and
the relief is restored to its original value when button 1 is later released.
[3] If mouse button 1 is pressed over a button and later released over the button, the button is
invoked. However, if the mouse is not over the button when button 1 is released, then no
invocation occurs.
[4] When a button has the input focus, the space key causes the button to be invoked.
If the button's state is disabled then none of the above actions occur: the button is completely
non-responsive.
The behavior of buttons can be changed by defining new bindings for individual widgets or by redefin-ing redefining
ing the class bindings.
KEYWORDS
button, widget
Tk 4.4 button(n)
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