# -*- mode: TCL; fill-column: 75; tab-width: 8; coding: iso-latin-1-unix -*-
#
# $Id: DragDrop.tcl,v 1.4 2001/12/09 05:04:02 idiscovery Exp $
#
# DragDrop.tcl ---
#
# Implements drag+drop for Tix widgets.
#
# Copyright (c) 1993-1999 Ioi Kim Lam.
# Copyright (c) 2000-2001 Tix Project Group.
#
# See the file "license.terms" for information on usage and redistribution
# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#

tixClass tixDragDropContext {
-superclass {}
-classname TixDragDropContext
-method {
cget configure drag drop set startdrag
}
-flag {
-command -source
}
-configspec {
{-command ""}
{-source ""}
}
}

proc tixDragDropContext:Constructor {w} {
upvar #0 $w data
}

#----------------------------------------------------------------------
# Private methods
#
#----------------------------------------------------------------------
proc tixDragDropContext:CallCommand {w target command X Y} {
upvar #0 $w data

set x [expr $X-[winfo rootx $target]]
set y [expr $Y-[winfo rooty $target]]

regsub %x $command $x command
regsub %y $command $y command
regsub %X $command $X command
regsub %Y $command $Y command
regsub %W $command $target command
regsub %S $command [list $data(-command)] command

eval $command
}

proc tixDragDropContext:Send {w target event X Y} {
upvar #0 $w data
global tixDrop

foreach tag [tixDropBindTags $target] {
if {[info exists tixDrop($tag,$event)]} {
tixDragDropContext:CallCommand $w $target \
$tixDrop($tag,$event) $X $Y
}
}
}

#----------------------------------------------------------------------
# set --
#
# Set the "small data" of the type supported by the source widget
#----------------------------------------------------------------------

proc tixDragDropContext:set {w type data} {

}

#----------------------------------------------------------------------
# startdrag --
#
# Start the dragging action
#----------------------------------------------------------------------
proc tixDragDropContext:startdrag {w x y} {
upvar #0 $w data

set data(oldTarget) ""

$data(-source) config -cursor "[tix getbitmap drop] black"
tixDragDropContext:drag $w $x $y
}

#----------------------------------------------------------------------
# drag --
#
# Continue the dragging action
#----------------------------------------------------------------------
proc tixDragDropContext:drag {w X Y} {
upvar #0 $w data
global tixDrop

set target [winfo containing -displayof $w $X $Y]

if {$target != $data(oldTarget)} {
if {$data(oldTarget) != ""} {
tixDragDropContext:Send $w $data(oldTarget) <Out> $X $Y
}
if {$target != ""} {
tixDragDropContext:Send $w $target <In> $X $Y
}
set data(oldTarget) $target
}
if {$target != ""} {
tixDragDropContext:Send $w $target <Over> $X $Y
}
}

proc tixDragDropContext:drop {w X Y} {
upvar #0 $w data
global tixDrop

set target [winfo containing -displayof $w $X $Y]
if {$target != ""} {
tixDragDropContext:Send $w $target <Drop> $X $Y
}

if {$data(-source) != ""} {
$data(-source) config -cursor ""
}
set data(-source) ""
}

#----------------------------------------------------------------------
# Public Procedures -- This is NOT a member of the tixDragDropContext
# class!
#
# parameters :
# $w: who wants to start dragging? (currently ignored)
#----------------------------------------------------------------------
proc tixGetDragDropContext {w} {
global tixDD
if {[info exists tixDD]} {
return tixDD
}

return [tixDragDropContext tixDD]
}

proc tixDropBind {w event command} {
global tixDrop

set tixDrop($w) 1
set tixDrop($w,$event) $command
}

proc tixDropBindTags {w args} {
global tixDropTags

if {$args == ""} {
if {[info exists tixDropTags($w)]} {
return $tixDropTags($w)
} else {
return [list [winfo class $w] $w]
}
} else {
set tixDropTags($w) $args
}
}