source: trunk/gui/scripts/combobox.tcl @ 16

# ----------------------------------------------------------------------
#  COMPONENT: combobox - entry widget with a drop-down list of values
#
#  This widget is a typical combobox, an entry widget with a drop-down
#  list of values.  If the -editable option is turned off, then the
#  value can be set only from the drop-down list.  Otherwise, the
#  drop-down is treated as a list of preset choices, but the user can
#  type anything in the entry area.
# ======================================================================
#  AUTHOR:  Michael McLennan, Purdue University
#  Copyright (c) 2004-2005
#  Purdue Research Foundation, West Lafayette, IN
# ======================================================================
package require Itk
package require BLT

option add *Combobox.borderWidth 2 widgetDefault
option add *Combobox.relief sunken widgetDefault
option add *Combobox.width 10 widgetDefault
option add *Combobox.editable yes widgetDefault
option add *Combobox.textBackground white widgetDefault
option add *Combobox.textForeground black widgetDefault
option add *Combobox.font -*-helvetica-medium-r-normal-*-*-120-* widgetDefault

itcl::class Rappture::Combobox {
    inherit itk::Widget

    itk_option define -editable editable Editable ""
    itk_option define -width width Width 0

    constructor {args} { # defined below }

    public method value {args}
    public method translate {value}
    public method choices {option args}

    protected method _entry {option}
    protected method _dropdown {option}

    blt::bitmap define ComboboxArrow {
        #define arrow_width 8
        #define arrow_height 4
        static unsigned char arrow_bits[] = {
           0xfe, 0x7c, 0x38, 0x10};
    }
}
                                                                                
itk::usual Combobox {
    keep -cursor -font
    keep -foreground -background
    keep -textforeground -textbackground
    keep -selectbackground -selectforeground -selectborderwidth
}

# ----------------------------------------------------------------------
# CONSTRUCTOR
# ----------------------------------------------------------------------
itcl::body Rappture::Combobox::constructor {args} {
    itk_option add hull.borderwidth hull.relief

    itk_component add button {
        button $itk_interior.btn -bitmap ComboboxArrow -padx 0 \
            -borderwidth 1 -relief raised -highlightthickness 0
    } {
        usual
        ignore -highlightthickness -highlightbackground -highlightcolor
        ignore -borderwidth -relief
    }
    pack $itk_component(button) -side right -fill y

    itk_component add entry {
        entry $itk_interior.entry -borderwidth 0 -relief flat
    } {
        usual
        keep -width
        rename -highlightbackground -textbackground textBackground Background
        rename -background -textbackground textBackground Background
        rename -foreground -textforeground textForeground Foreground
        rename -disabledbackground -textbackground textBackground Background
        rename -disabledforeground -textforeground textForeground Foreground
        ignore -borderwidth -relief
    }
    pack $itk_component(entry) -side left -expand yes -fill both

    bind $itk_component(entry) <KeyPress-Return> \
        [itcl::code $this _entry apply]
    bind $itk_component(entry) <ButtonPress> \
        [itcl::code $this _entry click]

    itk_component add ddlist {
        Rappture::Dropdownlist $itk_component(button).ddlist \
            -postcommand [itcl::code $this _dropdown post] \
            -unpostcommand [itcl::code $this _dropdown unpost] \
    }

    bind $itk_component(ddlist) <<DropdownlistSelect>> \
        [itcl::code $this _dropdown select]

    $itk_component(button) configure -command \
        [list $itk_component(ddlist) post $itk_component(hull) left]

    eval itk_initialize $args
}

# ----------------------------------------------------------------------
# USAGE: value ?<newval>?
#
# Clients use this to query/set the value for this widget.  With
# no args, it returns the current value for the widget.  If the
# <newval> is specified, it sets the value of the widget and
# sends a <<Value>> event.
# ----------------------------------------------------------------------
itcl::body Rappture::Combobox::value {args} {
    if {[llength $args] == 1} {
        set newval [lindex $args 0]

        $itk_component(entry) configure -state normal
        $itk_component(entry) delete 0 end
        $itk_component(entry) insert 0 $newval
        if {!$itk_option(-editable)} {
            $itk_component(entry) configure -state disabled
        }

        after 10 [list event generate $itk_component(hull) <<Value>>]
    } elseif {[llength $args] != 0} {
        error "wrong # args: should be \"value ?newval?\""
    }
    return [$itk_component(entry) get]
}

# ----------------------------------------------------------------------
# USAGE: translate <value>
#
# Clients use this to translate a value from the entry part of the
# combobox to one of the underlying values in the combobox.  If the
# <value> string matches one of the labels for the choices, this
# method returns the corresponding value.  Otherwise, it returns "".
# ----------------------------------------------------------------------
itcl::body Rappture::Combobox::translate {value} {
    foreach {val label} [choices get -both] {
        if {$label == $value} {
            return $val
        }
    }
    return ""
}

# ----------------------------------------------------------------------
# USAGE: choices insert <pos> ?<value1> <label1> ...?
# USAGE: choices delete <first> ?<last>?
# USAGE: choices get ?-value|-label|-both? ?<index>?
# USAGE: choices index <value>
#
# Clients use this to manipulate the list of choices in the drop-down
# list.  Each choice is represented by a (computer-friendly) value
# and its corresponding (human-friendly) label.  The "get" option
# returns information about options on the list, including the value,
# the label, or both.
# ----------------------------------------------------------------------
itcl::body Rappture::Combobox::choices {option args} {
    eval $itk_component(ddlist) $option $args
}

# ----------------------------------------------------------------------
# USAGE: _entry apply
# USAGE: _entry click
#
# Used internally to handle the dropdown list for this combobox.  The
# post/unpost options are invoked when the list is posted or unposted
# to manage the relief of the controlling button.  The select option
# is invoked whenever there is a selection from the list, to assign
# the value back to the gauge.
# ----------------------------------------------------------------------
itcl::body Rappture::Combobox::_entry {option} {
    switch -- $option {
        apply {
            if {$itk_option(-editable)} {
                event generate $itk_component(hull) <<Value>>
            }
        }
        click {
            if {!$itk_option(-editable)} {
                $itk_component(button) configure -relief sunken
                update idletasks; after 100
                $itk_component(button) configure -relief raised

                $itk_component(ddlist) post $itk_component(hull) left
            }
        }
        default {
            error "bad option \"$option\": should be apply, click"
        }
    }
}

# ----------------------------------------------------------------------
# USAGE: _dropdown post
# USAGE: _dropdown unpost
# USAGE: _dropdown select
#
# Used internally to handle the dropdown list for this combobox.  The
# post/unpost options are invoked when the list is posted or unposted
# to manage the relief of the controlling button.  The select option
# is invoked whenever there is a selection from the list, to assign
# the value back to the gauge.
# ----------------------------------------------------------------------
itcl::body Rappture::Combobox::_dropdown {option} {
    switch -- $option {
        post {
            set value [$itk_component(entry) get]
            set i [$itk_component(ddlist) index -label $value]
            if {$i >= 0} {
                $itk_component(ddlist) select clear 0 end
                $itk_component(ddlist) select set $i
            }
        }
        unpost {
            if {$itk_option(-editable)} {
                focus $itk_component(entry)
            }
        }
        select {
            set val [$itk_component(ddlist) current -label]
            if {"" != $val} {
                value $val
            }
        }
        default {
            error "bad option \"$option\": should be post, unpost, select"
        }
    }
}

# ----------------------------------------------------------------------
# CONFIGURATION OPTION: -editable
# ----------------------------------------------------------------------
itcl::configbody Rappture::Combobox::editable {
    if {![string is boolean -strict $itk_option(-editable)]} {
        error "bad value \"$itk_option(-editable)\": should be boolean"
    }
    if {$itk_option(-editable)} {
        $itk_component(entry) configure -state normal
    } else {
        $itk_component(entry) configure -state disabled
        if {[focus] == $itk_component(entry)} {
            focus [tk_focusNext [focus]]
        }
    }
}