NAME
    Tk::SMListbox - Sortable Multicolumn Listbox with arrows in headers
    indicating sort order.

AUTHOR
    Jim Turner

    (c) 2015-2022, Jim Turner under the same license that Perl 5 itself is.
    All rights reserved.

    Tk::MListbox authors: Hans Jorgen Helgesen, hans_helgesen@hotmail.com
    (from March 2000: hans.helgesen@novit.no)

SYNOPSIS
    use Tk::SMListbox;

    $ml = $parent->SMListbox (<options>);

DESCRIPTION
    Tk::SMListbox is a derivitive of Tk::MListbox that adds optional tiny up
    and down arrow graphics to columns in the SMListbox that the data is
    currently sorted on indicating ascending and/or descending order.

    Sorting is done by clicking on one of the column headings in the widget.
    The first click will sort the data with the selected column as key, a
    new click will reverse the sort order.

EXAMPLES
    my $table = $w->Scrolled('SMListbox'

            -scrollbars => 'se', 

            -height => 12,

            -relief => 'sunken',

            -sortable => 1,   #USER CAN SORT BY COLUMN BY CLICKING ON THE COLUMN HEADER BUTTON.

            -selectmode => 'extended',

            -showallsortcolumns => 1,  #SHOW SORT DIRECTION ARROW ON ALL SORTED COLUMNS.

            -takefocus => 1,

            -borderwidth => 1,

            -fillcolumn => 1,   #IF WINDOW RESIZED, EXPAND COLUMN 1 ("Name") TO FILL THE EXTRA SPACE.

            -columns => [    #COLUMN WIDTH, SORT FUNCTIONS, HEADER BUTTON INFORMATION, ETC.:

                [-text => '~D', -width => 3, -comparecommand => sub { $_[1] cmp $_[0] } ],

                [-text => '~Name', -width => 25 ],

                [-text => '~Perm.', -width => 10 ],

                [-text => '~Owner:Group', -width => 14 ],

                [-text => '~Size', -width => 8, -comparecommand => sub { $_[1] <=> $_[0] } ],

                [-text => 'Date/~Time', -width => 15, -reversearrow => 1, -comparecommand => sub { $_[1] cmp $_[0] }],

            ]

            )->pack(

                    -expand => 'yes',

            );

STANDARD OPTIONS
    -background -foreground -relief -takefocus -borderwidth -heigh
    -selectbackground -cursor -highlightbackground -selectborderwidth
    -xscrollcommand -exportselection -highlightcolor -selectforeground
    -yscrollcommand -font -highlightthickness -setgrid

WIDGET SPECIFIC OPTIONS
    -columns => *list*
        Defines the columns in the widget. Each element in the list
        describes a column. See the COLUMNS section below.

    -configurecommand => *callback*
        The -configurecommand callback will be called whenever the layout of
        the widget has changed due to user interaction. That is, the user
        changes the width of a column by dragging the separator, or moves a
        column by dragging the column header.

        This option is useful if the application wants to store the widget
        layout for later retrieval. The widget layout can be obtained by the
        callback by calling the method columnPackInfo().

    -fillcolumn => *index*
        Specify the index number of a column that will expand to fill any
        new space opened up by dragging the window to a larger size. All
        other columns maintain their current widths unless changed by the
        user dragging a column separator. Otherwise all columns maintain
        their sizes and the extra space is unused (if no column specified
        here). Default: -1 (no column expands horizontally). All columns
        always expand vertically though. The same column keeps it's
        expansion privilege even if user rearranges their positions.

    -focuscolumn => *index*
        Specify the column to receive the input focus when the SMListbox
        receives focus. This is useful if the first column is not the one of
        primary interest to the user, since only one column will show the
        active row cursor because the underlying Tk::Listbox widgets only
        show the active row cursor when they have the focus.

        NOTE: none of this applies if -nocolumnfocus is set, which also has
        the side effect of disabling most keyboard bindings on the
        SMListbox. Default: *0* (The first column will get the focus and
        show the active row cursor (usually an *underline*).

    -headerbackground => *color*
        Specify a different background color for the top ("header") row.
        Default: -background or parent window's background.

    -headerforeground => *color*
        Specify a different foreground color for the top ("header") row.
        Default: -foreground or parent window's foreground.

    -moveable => *boolean*
        A value of 1 indicates that it is okay for the user to move the
        columns by dragging the column headers. 0 disables this function.
        Default: 1.

    -nocolumnfocus => *boolean*
        Prevents the SMListbox widget from giving the keyboard focus to a
        specific column. The net effect of this option being set is that the
        widget itself takes focus, but many keyboard bindings will not work,
        namely selecting rows with the spacebar. Default: *0* (Take focus
        normally and give the focus to one of the column listboxes under the
        hood so that row-based keyboard bindings will all work properly). To
        have the SMListbox widget itself be skipped in the focus order, set
        -takefocus to *0*.

    -resizeable => *boolean*
        A value of 1 indicates that it is okay for the user to resize the
        columns by dragging the column separators. 0 disables this function.
        Default: 1.

        Note that you can also specify -resizeable on a column by column
        basis. See the COLUMNS section below.

    -selectmode => *string*
        Should be "single", "browse", "multiple", or "extended". Default:
        "browse". See Tk::Listbox.

    -separatorcolor => *string*
        Specifies the color of the separator lines (the vertical lines that
        separates the columns). Default: black.

        Note that you can also specify -separatorcolor on a column by column
        basis. See the COLUMNS section below.

    -separatorwidth => *integer*
        Specifies the width in pixels of the separator lines (the vertical
        lines that separates the columns). Default: 1.

        Note that you can also specify -separatorwidth on a column by column
        basis. See the COLUMNS section below.

    -sortable => *boolean*
        A value of 1 indicates that it is okay for the user to sort the data
        by clicking column headings. 0 disables this function. Default: 1.

        Note that you can also specify -sortable on a column by column
        basis. See *COLUMNS* below.

WIDGET SPECIFIC, COLUMN-SPECIFIC OPTIONS
    -comparecmd => *callback*
        Specifies a callback to use when sorting the SMListbox with this
        column as key. The callback will be called with two scalar
        arguments, each a value from this particular column. The callback
        should return an integer less than, equal to, or greater than 0,
        depending on how the tow arguments are ordered. If for example the
        column should be sorted by numerical value:

            -comparecommand => sub { $_[0] <=> $_[1]}

        Default: sub { $_[0] cmp $_[1] } #(Ascending by string)

    -reversearrow => 0 | 1
        New option (not included with the old Tk::MListbox) that causes the
        up / down direction of the sort arrow in the column header that
        shows the direction the sorted-by column is currently sorted.
        Default: 0 (zero): (Up-arrow) if sorted in ascending order,
        Down-arrow if in descending order. Setting to 1 reverses this. This
        is often necessary to show desired results, ie. if the sort function
        is reversed, such as: sub { $_[1] cmp $_[0] }

SMListbox COLUMN CONFIGURATION
    NOTE: See also the additional options described in the previous section
    "WIDGET SPECIFIC COLUMN-SPECIFIC OPTIONS".

    The SMListbox widget is a collection of *SMLColumn* widgets. Each
    SMLColumn contains a Listbox, a heading and the separator bar. The
    columns are created and maintained through the -columns option or the
    column methods of the widget. The columns are indexed from 0 and up.
    Initially, column 0 is the leftmost column of the widget. The column
    indices are not changed when the columns are moved or hidden. The only
    ways to change the column indices are to call columnInsert(),
    columnDelete() or configure(-column).

    Each column has its own set of options which might be passed to
    SMListbox::configure(-columns), SMListbox::insert(),
    SMListbox::columnConfigure() or SMLColumn::configure().

    The following code snippets are all equal:

    1. $ml=$mw->SMListbox(-columns=>[[-text=>'Heading1', -sortable=>0],
    [-text=>'Heading2']]);

    2. $ml=$mw->SMListbox; $sml->columnInsert(0,-text=>'Heading1',
    -sortable=>0); $sml->columnInsert(0,-text=>'Heading2');

    3. $ml=$mw->SMListbox; $c=$sml->columnInsert(0,-text=>'Heading1');
    $sml->columnInsert(0,-text=>'Heading2'); $c->configure(-sortable=>0);

    4. $ml=$mw->SMListbox; $sml->columnInsert(0,-text=>'Heading1');
    $sml->columnInsert(0,-text=>'Heading2');
    $sml->columnConfigure(0,-sortable=>0);

    (See the columnConfigure() method below for details on column options).

    All column methods expects one or two column indices as arguments. The
    column indices might be an integer (between 0 and the number of columns
    minus one), 'end' for the last column, or a reference to the SMLColumn
    widget (obtained by calling SMListbox->columnGet() or by storing the
    return value from SMListbox->columnInsert()).

WIDGET METHODS
    $sml->compound(*[left|right|top|bottom]*)
        Gets / sets the side of the column header that the ascending /
        descending arrow is to appear (left, right, top, bottom). Default:
        *"right"*.

    $sml->focusColumn([index])
        Gets or sets the index of the column whose listbox is to receive the
        keyboard focus when the SMListbox widget receives keyboard focus.
        This is useful so that the *"underline"* will show on the element
        the keyboard cursor is on when navigating the widget using the Up
        and Down arrow keys to make multiple selections in "Extended" mode
        using the keyboard. The first (leftmost) column listbox gets the
        focus by default, but this option allows a different column to get
        the keyboard focus, if a different column has better, ie. wider and
        easier to see text values. This is because the underline only
        appears under non-blank text, rather than the width of the column,
        and only when the underlying Tk::Listbox itself has the focus.
        Requires version 2 or higher.

        NOTE: none of this applies if -nocolumnfocus is set, which also has
        the side effect of disabling most keyboard bindings on the
        SMListbox.

    $sml->getSortOrder()
        returns an array that is in the same format accepted by the
        $smListBox->sort method. The 1st element is either true for
        descending sort, false for assending. Subsequent elements represent
        the column indices of one or more columns by which the data is
        sorted. Default (if nothing previously set): (0, 0).

    $hml->setSortOrder(*descending*, *columnindex*...)
        Sets the default sort order and columns to sort without actually
        sorting. The arguments are the same as the sort() function.

    $sml->setButtonHeight([*pady*])
        Sets (alters) the "-pady" value for the header buttons. Should be
        called AFTER all columns have been created. Requires version 2 or
        higher.

    $sml->showallsortcolumns([*1|0*])
        Gets or sets whether a sort direction arrow is to be displayed on
        each column involved in the sorting or just the 1st (primary sort).
        Default: 0 (false) - show arrow only on the primary sort column.

    $sml->bindColumns(*sequence*,*callback*)
        Adds the binding to all column headers in the widget. See the
        section BINDING EVENTS TO SMListbox below.

    $sml->bindRows(*sequence*,*callback*)
        Adds the binding to all listboxes in the widget. See the section
        BINDING EVENTS TO SMListbox below.

    $sml->bindSeparators(*sequence*,*callback*)
        Adds the binding to all separators in the widget. See the section
        BINDING EVENTS TO SMListbox below.

  COLUMN METHODS
    (Methods for accessing and manipulating individual columns in the
    SMListbox widget)

    $sml->columnConfigure(*index*,*option*=>*value*...)
        Set option values for a specific column. Equal to
        $sml->columnGet(*index*)->configure(...).

        The following column options are supported:

        -comparecommand => *callback*
            Specifies a callback to use when sorting the SMListbox with this
            column as key. The callback will be called with two scalar
            arguments, each a value from this particular column. The
            callback should return an integer less than, equal to, or
            greater than 0, depending on how the tow arguments are ordered.
            If for example the column should be sorted by numerical value:

                -comparecommand => sub { $_[0] <=> $_[1]}

            The default is to sort the columns alphabetically.

        -text => *string*
            Specifies the text to be used in the heading button of the
            column.

        -resizeable => *boolean*
            A value of 1 indicates that it is okay for the user to resize
            this column by dragging the separator. 0 disables this function.
            Default: 1.

        -separatorcolor => *string*
            Specifies the color of the separator line. Default: black.

        -separatorwidth => *integer*
            Specifies the width of the separator line in pixels. Default: 1.

        -sortable => *boolean*
            A value of 1 indicates that it is okay for the user to sort the
            data by clicking this column's heading. 0 disables this
            function. Default: 1.

        -reversearrow => 0 | 1
            New option (not included with the old Tk::MListbox) that causes
            the up / down direction of the sort arrow in the column header
            that shows the direction the sorted-by column is currently
            sorted. Default: 0 (zero) - (Up-arrow if sorted in ascending
            order, Down-arrow if in descending order. Setting to 1 reverses
            this. This is often necessary to show desired results, ie. if
            the sort function is reversed, such as: sub { $_[1] cmp $_[0] }

    $sml->columnDelete(*first*,*last*)
        If *last* is omitted, deletes column *first*. If *last* is
        specified, deletes all columns from *first* to *last*, inclusive.

        All previous column indices greater than *last* (or *first* if
        *last* is omitted) are decremented by the number of columns deleted.

    $sml->columnGet(*first*,*last*)
        If *last* is not specified, returns the SMLColumn widget specified
        by *first*. If both *first* and *last* are specified, returns an
        array containing all columns from *first* to *last*.

    $sml->columnHide(*first*,*last*)
        If *last* is omitted, hides column *first*. If *last* is specified,
        hides all columns from *first* to *last*, inclusive.

        Hiding a column is equal to calling
        $sml->columnGet(*index*)->packForget. The column is not deleted, all
        data are still available, and the column indices remain the same.

        See also the columnShow() method below.

    $sml->columnIndex(*index*)
        Returns an integer index for the column specifed by *index*.

    $sml->columnInsert(*index*,*option*=>*value*...)
        Creates a new column in the SMListbox widget. The column will get
        the index specified by *index*. If *index* is 'end', the new
        column's index will be one more than the previous highest column
        index.

        If column *index* exists, the new column will be placed to the left
        of this column. All previous column indices equal to or greater than
        *index* will be incremented by one.

        Returns the newly created SMLColumn widget.

        (See the columnConfigure() method above for details on column
        options).

    $sml->columnPack(*array*)
        Repacks all columns in the SMListbox widget according to the
        specification in *array*. Each element in *array* is a string on the
        format index:width. *index* is a column index, *width* defines the
        columns width in pixels (may be omitted). The columns are packed
        left to right in the order specified by by *array*. Columns not
        specified in *array* will be hidden.

        This method is most useful if used together with the
        columnPackInfo() method.

    $sml->columnPackInfo()
        Returns an array describing the current layout of the SMListbox
        widget. Each element of the array is a string on the format
        index:width (see columnPack() above). Only indices of columns that
        are currently shown (not hidden) will be returned. The first element
        in the returned array represents the leftmost column.

        This method may be used in conjunction with columnPack() to save and
        restore the column configuration.

    $sml->columnShow(*index*,*option*=>*value*)
        Shows a hidden column (see the columnHide() method above). The
        column to show is specified by *index*.

        By default, the column is pack'ed at the rigthmost end of the
        SMListbox widget. This might be overridden by specifying one of the
        following options:

    -after => *index*
        Place the column after (to the right of) the column specified by
        *index*.

    -before => *index*
        Place the column before (to the left of) the column specified by
        *index*.

  ROW METHODS
    (Methods for accessing and manipulating rows of data)

    Many of the methods for SMListbox take one or more indices as arguments.
    See Tk::Listbox for a description of row indices.

    $sml->delete(*first*,*last*)
        Deletes one or more row elements of the SMListbox. *First* and
        *last* are indices specifying the first and last elements in the
        range to delete. If *last* isn't specified it defaults to *first*,
        i.e. a single element is deleted.

    $sml->get(*first*,*last*)
        If *last* is omitted, returns the content of the SMListbox row
        indicated by *first*. If *last* is specified, the command returns a
        list whose elements are all of the listbox rows between *first* and
        *last*.

        The returned elements are all array references. The referenced
        arrays contains one element for each column of the SMListbox.

    $sml->getRow(*index*)
        In scalar context, returns the value of column 0 in the SMListbox
        row specified by *index*. In list context, returns the content of
        all columns in the row as an array.

        This method is provided for convenience, since retrieving a single
        row with the get() method might produce some ugly code.

        The following two code snippets are equal:

           1. @row=$sml->getRow(0);

           2. @row=@{($sml->get(0))[0]};

    $sml->sort(*descending*, *columnindex*...)
        Sorts the content of the SMListbox. If *descending* is a true value,
        the sort order will be descending. Default is 0 - ascending sort on
        first column (0).

        If *columnindex* is specified, the sort will be done with the
        specified column as key. You can specify as many *columnindex*
        arguments as you wish. Sorting is done on the first column, then on
        the second, etc...

        The default is to sort the data on all columns of the listbox, with
        column 0 as the first sort key, column 1 as the second, etc.

OTHER LISTBOX METHODS
    Most other Tk::Listbox methods works for the SMListbox widget. This
    includes the methods activate, cget, curselection, index, nearest, see,
    selectionXXX, size, xview, yview.

    See Tk::Listbox

BINDING EVENTS TO SMLISTBOX
    Calling $sml->bind(...) probably makes little sense, since the call does
    not specify whether the binding should apply to the listbox, the header
    button or the separator line between each column.

    In stead of the ordinary bind, the following methods should be used:

    $sml->bind(*sequence*,*callback*)
        Synonym for $sml->bindRows(*sequence*,*callback*).

    $sml->bindRows(*sequence*,*callback*)
        Synonym for $sml->bindSubwidgets('listbox',*sequence*,*callback*)

    $sml->bindColumns(*sequence*,*callback*)
        Synonym for $sml->bindSubwidgets('heading',*sequence*,*callback*)

    $sml->bindSeparators(*sequence*,*callback*)
        Synonym for $sml->bindSubwidgets('separator',*sequence*,*callback*)

    $sml->bindSubwidgets(*subwidget*,*sequence*,*callback*)
        Adds the binding specified by *sequence* and *callback* to all
        subwidgets of the given type (should be 'listbox', 'heading' or
        'separator').

        The binding is stored in the widget, and if you create a new column
        by calling $sml->columnInsert(), all bindings created by
        $sml->bindSubwidgets() are automatically copied to the new column.

        The callback is called with the SMListbox widget as first argument,
        and the index of the column where the event occured as the second
        argument.

        NOTE that $sml->bindSubwidgets() does not support all of Tk's
        callback formats. The following are supported:

             \&subname
             sub { code }
             [ \&subname, arguments...]
             [ sub { code }, arguments...]

        If *sequence* is undefined, then the return value is a list whose
        elements are all the sequences for which there exist bindings for
        *subwidget*.

        If *sequence* is specified without *callback*, then the callback
        currently bound to sequence is returned, or an empty string is
        returned if there is no binding for sequence.

        If *sequence* is specified, and *callback* is an empty string, then
        the current binding for sequence is destroyed, leaving sequence
        unbound. An empty string is returned.

        An empty string is returned in all other cases.

KEYWORDS
    smlistbox, mlistbox, listbox, widget

SEE ALSO
    Tk::MListbox Tk::Listbox

