perl-tk 1:804.031-1build1 / usr / lib / perl5 / Tk / Spinbox.pod

#  Copyright (c) 2000 Jeffrey Hobbs.
#  Copyright (c) 2000 Ajuba Solutions.
#  See the file "license.terms" for information on usage and redistribution
#  of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#  RCS: @(#) $Id: spinbox.n,v 1.3 2001/12/18 23:02:35 hobbs Exp $

=head1 NAME

Tk::Spinbox - Create and manipulate Spinbox widgets

=for category  Tk Generic Methods

=head1 SYNOPSIS

I<$spinbox> =  I<$parent>-E<gt>Spinbox(?I<options>?);

 -activebackground    -highlightthickness -repeatinterval
 -background          -insertbackground   -selectbackground
 -borderwidth         -insertborderwidth  -selectborderwidth
 -cursor              -insertontime       -selectforeground
 -exportselection     -insertwidth        -takefocus
 -font                -insertofftime      -textvariable
 -foreground          -justify            -xscrollcommand
 -highlightbackground -relief
 -highlightcolor      -repeatdelay

=head1 WIDGET-SPECIFIC OPTIONS

=over 4

=item Option:	B<-buttonbackground>

=item Name:	B<buttonBackground>

=item Class:	B<Background>

The background color to be used for the spin buttons.

=item Option:	B<-buttoncursor>

=item Name:	B<buttonCursor>

=item Class:	B<Cursor>

The cursor to be used when over the spin buttons.  If this is empty
(the default), a default cursor will be used.

=item Option:	B<-buttondownrelief>

=item Name:	B<buttonDownRelief>

=item Class:	B<Relief>

The relief to be used for the upper spin button.

=item Option:	B<-buttonuprelief>

=item Name:	B<buttonUpRelief>

=item Class:	B<Relief>

The relief to be used for the lower spin button.

=item Option:	B<-command>

=item Name:	B<command>

=item Class:	B<Command>

Specifies a Perl/Tk callback to invoke whenever a Spinbutton is invoked.
The callback has these two arguments I<appended> to any existing callback
arguments: the current value of the widget and the direction of the button
press (B<up> or B<down>).

=item Option:	B<-disabledbackground>

=item Name:	B<disabledBackground>

=item Class:	B<DisabledBackground>

Specifies the background color to use when the Spinbox is disabled.  If
this option is the empty string, the normal background color is used.

=item Option:	B<-disabledforeground>

=item Name:	B<disabledForeground>

=item Class:	B<DisabledForeground>

Specifies the foreground color to use when the Spinbox is disabled.  If
this option is the empty string, the normal foreground color is used.

=item Option:	B<-format>

=item Name:	B<format>

=item Class:	B<Format>

Specifies an alternate format to use when setting the string value
when using the B<-from> and B<-to> range.
This must be a format specifier of the form B<%E<lt>padE<gt>.E<lt>padE<gt>f>,
as it will format a floating-point number.

=item Option:	B<-from>

=item Name:	B<from>

=item Class:	B<From>

A floating-point value corresponding to the lowest value for a Spinbox, to
be used in conjunction with B<-to> and B<-increment>.  When all
are specified correctly, the Spinbox will use these values to control its
contents.  This value must be less than the B<-to> option.
If B<-values> is specified, it supercedes this option.

=item Option:	B<-invalidcommand>

=item Alias:	B<-invcmd>

=item Name:	B<invalidCommand>

=item Class:	B<InvalidCommand>

Specifies a script to eval when B<validateCommand> returns 0.  Setting
it to an empty string disables this feature (the default).  The best use of
this option is to set it to I<bell>.  See B<Validation> below for
more information.

=item Option:	B<-increment>

=item Name:	B<increment>

=item Class:	B<Increment>

A floating-point value specifying the increment.  When used with
B<-from> and B<-to>, the value in the widget will be adjusted by
B<-increment> when a spin button is pressed (up adds the value,
down subtracts the value).

=item Option:	B<-readonlybackground>

=item Name:	B<readonlyBackground>

=item Class:	B<ReadonlyBackground>

Specifies the background color to use when the Spinbox is readonly.  If
this option is the empty string, the normal background color is used.

=item Option:	B<-state>

=item Name:	B<state>

=item Class:	B<State>

Specifies one of three states for the Spinbox:  B<normal>,
B<disabled>, or B<readonly>.  If the Spinbox is readonly, then the
value may not be changed using methods and no insertion cursor
will be displayed, even if the input focus is in the widget; the
contents of the widget may still be selected.  If the Spinbox is
disabled, the value may not be changed, no insertion cursor will be
displayed, the contents will not be selectable, and the Spinbox may
be displayed in a different color, depending on the values of the
B<-disabledforeground> and B<-disabledbackground> options.

=item Option:	B<-to>

=item Name:	B<to>

=item Class:	B<To>

A floating-point value corresponding to the highest value for the Spinbox,
to be used in conjunction with B<-from> and B<-increment>.  When
all are specified correctly, the Spinbox will use these values to control
its contents.  This value must be greater than the B<-from> option.
If B<-values> is specified, it supercedes this option.

=item Option:	B<-validate>

=item Name:	B<validate>

=item Class:	B<Validate>

Specifies the mode in which validation should operate: B<none>,
B<focus>, B<focusin>, B<focusout>, B<key>, or B<all>.
It defaults to B<none>.  When you want validation, you must explicitly
state which mode you wish to use.  See B<Validation> below for more.

=item Option:	B<-validatecommand>

=item Alias:	B<-vcmd>

=item Name:	B<validateCommand>

=item Class:	B<ValidateCommand>

Specifies a script to evaluate when you want to validate the input in the
widget.  Setting it to an empty string disables this feature (the default).
Validation occurs according to the value of B<-validate>.
This command must return a valid boolean value.  If it returns 0 (or
the valid boolean equivalent) then the value of the widget will not
change and the B<invalidCommand> will be evaluated if it is set.  If it
returns 1, then value will be changed.
See B<Validation> below for more information.

=item Option:	B<-values>

=item Name:	B<values>

=item Class:	B<Values>

Must be a proper list value.  If specified, the Spinbox will use these
values as to control its contents, starting with the first value.  This
option has precedence over the B<-from> and B<-to> range.

=item Option:	B<-width>

=item Name:	B<width>

=item Class:	B<Width>

Specifies an integer value indicating the desired width of the Spinbox window,
in average-size characters of the widget's font.
If the value is less than or equal to zero, the widget picks a
size just large enough to hold its current text.

=item Option:	B<-wrap>

=item Name:	B<wrap>

=item Class:	B<Wrap>

Must be a proper boolean value.  If on, the Spinbox will wrap around the
values of data in the widget.

=back

=head1 DESCRIPTION

The B<Spinbox> method creates a new window (given by the
$spinbox argument) and makes it into a Spinbox widget.
Additional options, described above, may be specified on the
command line or in the option database
to configure aspects of the Spinbox such as its colors, font,
and relief. 

A B<Spinbox> is an extended B<Entry> widget that allows he user
to move, or spin, through a fixed set of ascending or descending values
such as times or dates in addition to editing the value as in an
B<entry>.  When first created, a Spinbox's string is empty.
A portion of the Spinbox may be selected as described below.
If a Spinbox is exporting its selection (see the B<exportSelection>
option), then it will observe the standard protocols for handling the
selection;  Spinbox selections are available as type B<STRING>.
Spinboxes also observe the standard Tk rules for dealing with the
input focus.  When a Spinbox has the input focus it displays an
I<insertion cursor> to indicate where new characters will be
inserted.

Spinboxes are capable of displaying strings that are too long to
fit entirely within the widget's window.  In this case, only a
portion of the string will be displayed; commands described below
may be used to change the view in the window.  Spinboxes use
the standard B<-xscrollcommand> mechanism for interacting with
scrollbars (see the description of the B<-xscrollcommand> option
for details).  They also support scanning, as described below.

=head1 VALIDATION

Validation works by setting the B<validateCommand>
option to a callback which will be evaluated according to the B<validate>
option as follows:

=over 4

=item B<none>

Default.  This means no validation will occur.

=item B<focus>

B<validateCommand> will be called when the Spinbox receives or
loses focus.

=item B<focusin>

B<validateCommand> will be called when the Spinbox receives focus.

=item B<focusout>

B<validateCommand> will be called when the Spinbox loses focus.

=item B<key>

B<validateCommand> will be called when the Spinbox is edited.

=item B<all>

B<validateCommand> will be called for all above conditions.


The B<validateCommand> and B<invalidCommand> callbacks are invoked
with at least 5 positional arguments, which are I<appended> to any already
existing callback arguments:

=over 4

=item * 1

The proposed value of the entry.  If you are configuring the
entry widget to have a new textVariable, this will be the value of that
textVariable.

=item * 2

The characters to be added (or deleted). This will be C<undef>
if validation is due to focus, explcit call to validate or if change
is due to C<-textvariable> changing.

=item * 3

The current value of entry i.e. before the proposed change.

=item * 4

The index of character string to be added/deleted, if any. Otherwise -1.

=item * 5

Type of action. 1 == INSERT, 0 == DELETE,
-1 if it's a forced validation or textVariable validation.

=back

In general, the B<textVariable> and B<validateCommand> can be
dangerous to mix.  Any problems have been overcome so that using the
B<validateCommand> will not interfere with the traditional behavior of
the Spinbox widget.  Using the B<textVariable> for read-only purposes will
never cause problems.  The danger comes when you try set the
B<textVariable> to something that the B<validateCommand> would not
accept, which causes B<validate> to become I<none> (the
B<invalidCommand> will not be triggered).  The same happens
when an error occurs evaluating the B<validateCommand>.

Primarily, an error will occur when the B<validateCommand> or
B<invalidCommand> encounters an error in its script while evaluating or
B<validateCommand> does not return a valid boolean value.  The
B<validate> option will also set itself to B<none> when you edit the
Spinbox widget from within either the B<validateCommand> or the
B<invalidCommand>.  Such editions will override the one that was being
validated.  If you wish to edit the value of the widget
during validation and still have the B<validate> option set, you should
include the command

 my $val = $spinbox->cget(-validate);
 $spinbox->configure(-validate => $val);

in the B<validateCommand> or B<invalidCommand> (whichever one you
were editing the Spinbox widget from).  It is also recommended to not set an
associated B<textVariable> during validation, as that can cause the
Spinbox widget to become out of sync with the B<textVariable>.

=back

=head1 WIDGET METHODS

The B<Spinbox> command creates a widget object whose
name is $widget.  This command may be used to invoke various
operations on the widget.  It has the following general form:

 $widget->method(?arg arg ...?);

Many of the methods for Spinboxes take one or more indices as
arguments.  An index specifies a particular character in the Spinbox's
string, in any of the following ways:

=over 4

=item I<number>

Specifies the character as a numerical index, where 0 corresponds
to the first character in the string.

=item B<anchor>

Indicates the anchor point for the selection, which is set with the
B<select from> and B<select adjust> methods.

=item B<end>

Indicates the character just after the last one in the Spinbox's string.
This is equivalent to specifying a numerical index equal to the length
of the Spinbox's string.

=item B<insert>

Indicates the character adjacent to and immediately following the
insertion cursor.

=item B<sel.first>

Indicates the first character in the selection.  It is an error to
use this form if the selection isn't in the Spinbox window.

=item B<sel.last>

Indicates the character just after the last one in the selection.
It is an error to use this form if the selection isn't in the
Spinbox window.

=item B<@>I<number>

In this form, I<number> is treated as an x-coordinate in the
Spinbox's window;  the character spanning that x-coordinate is used.
For example, ``B<@0>'' indicates the left-most character in the
window.

=back

Abbreviations may be used for any of the forms above, e.g. ``B<e>''
or ``B<sel.f>''.  In general, out-of-range indices are automatically
rounded to the nearest legal value.

The following commands are possible for Spinbox widgets:

=over 4

=item I<$widget>-E<gt>B<bbox>(I<index>);

Returns a list of four numbers describing the bounding box of the
character given by I<index>.
The first two elements of the list give the x and y coordinates of
the upper-left corner of the screen area covered by the character
(in pixels relative to the widget) and the last two elements give
the width and height of the character, in pixels.
The bounding box may refer to a region outside the visible area
of the window.

=item I<$widget>-E<gt>B<cget>(I<option>);

Returns the current value of the configuration option given
by I<option>.
I<Option> may have any of the values accepted by the B<Spinbox>
command.

=item I<$widget>-E<gt>B<configure>(?I<option>?, ?I<value, option, value, ...>?);

Query or modify the configuration options of the widget.
If no I<option> is specified, returns a list describing all of
the available options for $widget (see L<Tk::configure> for
information on the format of this list).  If I<option> is specified
with no I<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 I<option> is specified).  If
one or more I<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.
I<Option> may have any of the values accepted by the B<Spinbox>
command.

=item I<$widget>-E<gt>B<delete>(I<first, >?I<last>?);

Delete one or more elements of the Spinbox.
I<First> is the index of the first character to delete, and
I<last> is the index of the character just after the last
one to delete.
If I<last> isn't specified it defaults to I<first>+1,
i.e. a single character is deleted.
This command returns an empty string.

=item I<$widget>-E<gt>B<get>;

Returns the Spinbox's string.

=item I<$widget>-E<gt>B<icursor>(I<index>);

Arrange for the insertion cursor to be displayed just before the character
given by I<index>.  Returns an empty string.

=item I<$widget>-E<gt>B<identify>(I<x, y>);

Returns the name of the window element corresponding to coordinates
I<x> and I<y> in the Spinbox.  Return value is one of:
B<none>, B<buttondown>, B<buttonup>, B<entry>.

=item I<$widget>-E<gt>B<index>(I<index>);

Returns the numerical index corresponding to I<index>.

=item I<$widget>-E<gt>B<insert>(I<index, string>);

Insert the characters of I<string> just before the character
indicated by I<index>.  Returns an empty string.

=item I<$widget>-E<gt>B<invoke>(I<element>);

Causes the specified element, either B<buttondown> or B<buttonup>,
to be invoked, triggering the action associated with it.

=item I<$widget>-E<gt>B<scan>(I<option, args>);

This command is used to implement scanning on Spinboxes.  It has
two forms, depending on I<option>:

=over 4

=item I<$widget>-E<gt>B<scanMark>(I<x>);

Records I<x> and the current view in the Spinbox window;  used in
conjunction with later B<scan dragto> commands.  Typically this
command is associated with a mouse button press in the widget.  It
returns an empty string.

=item I<$widget>-E<gt>B<scanDragto>(I<x>);

This command computes the difference between its I<x> argument
and the I<x> argument to the last B<scan mark> command for
the widget.  It then adjusts the view left or right by 10 times the
difference in x-coordinates.  This command is typically associated
with mouse motion events in the widget, to produce the effect of
dragging the Spinbox at high speed through the window.  The return
value is an empty string.

=back

=item I<$widget>-E<gt>B<selection>(I<option, arg>);

This command is used to adjust the selection within a Spinbox.  It
has several forms, depending on I<option>:

=over 4

=item I<$widget>-E<gt>B<selectionAdjust>(I<index>);

Locate the end of the selection nearest to the character given by
I<index>, and adjust that end of the selection to be at I<index>
(i.e including but not going beyond I<index>).  The other
end of the selection is made the anchor point for future
B<select to> commands.  If the selection
isn't currently in the Spinbox, then a new selection is created to
include the characters between I<index> and the most recent
selection anchor point, inclusive.
Returns an empty string.

=item I<$widget>-E<gt>B<selectionClear>;

Clear the selection if it is currently in this widget.  If the
selection isn't in this widget then the command has no effect.
Returns an empty string.

=item I<$widget>-E<gt>B<selectionElement>(?I<element>?);

Sets or gets the currently selected element.  If a spinbutton element
is specified, it will be displayed depressed.

=item I<$widget>-E<gt>B<selectionFrom>(I<index>);

Set the selection anchor point to just before the character
given by I<index>.  Doesn't change the selection.
Returns an empty string.

=item I<$widget>-E<gt>B<selectionPresent>;

Returns 1 if there is are characters selected in the Spinbox,
0 if nothing is selected.

=item I<$widget>-E<gt>B<selectionRange>(I<start, >I<end>);

Sets the selection to include the characters starting with
the one indexed by I<start> and ending with the one just
before I<end>.
If I<end> refers to the same character as I<start> or an
earlier one, then the Spinbox's selection is cleared.

=item I<$widget>-E<gt>B<selectionTo>(I<index>);

If I<index> is before the anchor point, set the selection
to the characters from I<index> up to but not including
the anchor point.
If I<index> is the same as the anchor point, do nothing.
If I<index> is after the anchor point, set the selection
to the characters from the anchor point up to but not including
I<index>.
The anchor point is determined by the most recent B<select from>
or B<select adjust> command in this widget.
If the selection isn't in this widget then a new selection is
created using the most recent anchor point specified for the widget.
Returns an empty string.

=back

=item I<$widget>-E<gt>B<set>(?I<string>?);

If I<string> is specified, the Spinbox will try and set it to this
value, otherwise it just returns the Spinbox's string.
If validation is on, it will occur when setting the string.

=item I<$widget>-E<gt>B<validate>;

This command is used to force an evaluation of the B<validateCommand>
independent of the conditions specified by the B<validate> option.
This is done by temporarily setting the B<validate> option to B<all>.
It returns 0 or 1.

=item I<$widget>-E<gt>B<xview>(I<args>);

This command is used to query and change the horizontal position of the
text in the widget's window.  It can take any of the following
forms:

=over 4

=item I<$widget>-E<gt>B<xview>;

Returns a list containing two elements.
Each element is a real fraction between 0 and 1;  together they describe
the horizontal span that is visible in the window.
For example, if the first element is .2 and the second element is .6,
20% of the Spinbox's text is off-screen to the left, the middle 40% is visible
in the window, and 40% of the text is off-screen to the right.
These are the same values passed to scrollbars via the B<-xscrollcommand>
option.

=item I<$widget>-E<gt>B<xview>(I<index>);

Adjusts the view in the window so that the character given by I<index>
is displayed at the left edge of the window.

=item I<$widget>-E<gt>B<xviewMoveto>(I<fraction>);

Adjusts the view in the window so that the character I<fraction> of the
way through the text appears at the left edge of the window.
I<Fraction> must be a fraction between 0 and 1.

=item I<$widget>-E<gt>B<xviewScroll>(I<number, what>);

This command shifts the view in the window left or right according to
I<number> and I<what>.
I<Number> must be an integer.
I<What> must be either B<units> or B<pages> or an abbreviation
of one of these.
If I<what> is B<units>, the view adjusts left or right by
I<number> average-width characters on the display;  if it is
B<pages> then the view adjusts by I<number> screenfuls.
If I<number> is negative then characters farther to the left
become visible;  if it is positive then characters farther to the right
become visible.

=back

=back

=head1 DEFAULT BINDINGS

Tk automatically creates class bindings for Spinboxes that give them
the following default behavior.
In the descriptions below, ``word'' refers to a contiguous group
of letters, digits, or ``_'' characters, or any single character
other than these.

=over 4

=item [1]

Clicking mouse button 1 positions the insertion cursor
just before the character underneath the mouse cursor, sets the
input focus to this widget, and clears any selection in the widget.
Dragging with mouse button 1 strokes out a selection between
the insertion cursor and the character under the mouse.

=item [2]

Double-clicking with mouse button 1 selects the word under the mouse
and positions the insertion cursor at the beginning of the word.
Dragging after a double click will stroke out a selection consisting
of whole words.

=item [3]

Triple-clicking with mouse button 1 selects all of the text in the
Spinbox and positions the insertion cursor before the first character.

=item [4]

The ends of the selection can be adjusted by dragging with mouse
button 1 while the Shift key is down;  this will adjust the end
of the selection that was nearest to the mouse cursor when button
1 was pressed.
If the button is double-clicked before dragging then the selection
will be adjusted in units of whole words.

=item [5]

Clicking mouse button 1 with the Control key down will position the
insertion cursor in the Spinbox without affecting the selection.

=item [6]

If any normal printing characters are typed in a Spinbox, they are
inserted at the point of the insertion cursor.

=item [7]

The view in the Spinbox can be adjusted by dragging with mouse button 2.
If mouse button 2 is clicked without moving the mouse, the selection
is copied into the Spinbox at the position of the mouse cursor.

=item [8]

If the mouse is dragged out of the Spinbox on the left or right sides
while button 1 is pressed, the Spinbox will automatically scroll to
make more text visible (if there is more text off-screen on the side
where the mouse left the window).

=item [9]

The Left and Right keys move the insertion cursor one character to the
left or right;  they also clear any selection in the Spinbox and set
the selection anchor.
If Left or Right is typed with the Shift key down, then the insertion
cursor moves and the selection is extended to include the new character.
Control-Left and Control-Right move the insertion cursor by words, and
Control-Shift-Left and Control-Shift-Right move the insertion cursor
by words and also extend the selection.
Control-b and Control-f behave the same as Left and Right, respectively.
Meta-b and Meta-f behave the same as Control-Left and Control-Right,
respectively.

=item [10]

The Home key, or Control-a, will move the insertion cursor to the
beginning of the Spinbox and clear any selection in the Spinbox.
Shift-Home moves the insertion cursor to the beginning of the Spinbox
and also extends the selection to that point.

=item [11]

The End key, or Control-e, will move the insertion cursor to the
end of the Spinbox and clear any selection in the Spinbox.
Shift-End moves the cursor to the end and extends the selection
to that point.

=item [12]

The Select key and Control-Space set the selection anchor to the position
of the insertion cursor.  They don't affect the current selection.
Shift-Select and Control-Shift-Space adjust the selection to the
current position of the insertion cursor, selecting from the anchor
to the insertion cursor if there was not any selection previously.

=item [13]

Control-/ selects all the text in the Spinbox.

=item [14]

Control-\ clears any selection in the Spinbox.

=item [15]

The F16 key (labelled Copy on many Sun workstations) or Meta-w
copies the selection in the widget to the clipboard, if there is a selection.

=item [16]

The F20 key (labelled Cut on many Sun workstations) or Control-w
copies the selection in the widget to the clipboard and deletes
the selection.
If there is no selection in the widget then these keys have no effect.

=item [17]

The F18 key (labelled Paste on many Sun workstations) or Control-y
inserts the contents of the clipboard at the position of the
insertion cursor.

=item [18]

The Delete key deletes the selection, if there is one in the Spinbox.
If there is no selection, it deletes the character to the right of
the insertion cursor.

=item [19]

The BackSpace key and Control-h delete the selection, if there is one
in the Spinbox.
If there is no selection, it deletes the character to the left of
the insertion cursor.

=item [20]

Control-d deletes the character to the right of the insertion cursor.

=item [21]

Meta-d deletes the word to the right of the insertion cursor.

=item [22]

Control-k deletes all the characters to the right of the insertion
cursor.

=item [23]

Control-t reverses the order of the two characters to the right of
the insertion cursor.

If the Spinbox is disabled using the B<-state> option, then the Spinbox's
view can still be adjusted and text in the Spinbox can still be selected,
but no insertion cursor will be displayed and no text modifications will
take place.

The behavior of Spinboxes can be changed by defining new bindings for
individual widgets or by redefining the class bindings.

=back

=head1 KEYWORDS

Spinbox, Entry, widget