"{ Encoding: utf8 }"

"

 COPYRIGHT (c) 2008 by eXept Software AG

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

"{ Package: 'stx:libwidg2' }"

"{ NameSpace: Smalltalk }"

Object subclass:#HierarchicalDropTargetController

	instanceVariableNames:'expandBlock highlightMode receiver dropOverLine dropSelector

		canDropSelector canExpandSelector'

	classVariableNames:''

	poolDictionaries:''

	category:'Interface-DragAndDrop'

!

!HierarchicalDropTargetController class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 2008 by eXept Software AG

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

! !

!HierarchicalDropTargetController class methodsFor:'instance creation'!

receiver:aReceiver argument:anArgument dropSelector:aDropSelector canDropSelector:aCanDropSelector

    ^ self 

        receiver:aReceiver 

        argument:anArgument 

        dropSelector:aDropSelector

        canDropSelector:aCanDropSelector 

        canExpandSelector:nil

!

receiver:aReceiver argument:anArgument dropSelector:aDropSelector canDropSelector:aCanDropSelector canExpandSelector: aCanExpandSelector

    |target|

    target := self new.

    ^ target

        receiver:aReceiver 

        argument:anArgument 

        dropSelector:aDropSelector 

        canDropSelector:aCanDropSelector 

        canExpandSelector:aCanExpandSelector

!

receiver:aReceiver dropSelector:aDropSelector canDropSelector:aCanDropSelector

    ^ self

        receiver:aReceiver 

        argument:nil 

        dropSelector:aDropSelector

        canDropSelector:aCanDropSelector

        canExpandSelector:nil

!

receiver:aReceiver dropSelector:aDropSelector canDropSelector:aCanDropSelector canExpandSelector:aCanExpandSelector

    ^ self

        receiver:aReceiver 

        argument:nil 

        dropSelector:aDropSelector

        canDropSelector:aCanDropSelector

        canExpandSelector:aCanExpandSelector

! !

!HierarchicalDropTargetController class methodsFor:'constants'!

delayMilliSecondsBeforeExpand

    ^ 1000

! !

!HierarchicalDropTargetController methodsFor:'drop actions'!

canDrop:aDropContext

    "return true, if the DropContext can be dropped into the list of items"

    dropOverLine isNil ifTrue:[ ^ false ].      "/ never setup by dropEnter:

    canDropSelector isNil ifTrue:[ ^ false ].

    ^ receiver 

        perform:canDropSelector 

        withOptionalArgument:aDropContext and:dropOverLine

!

drop:aDropContext

    "drop the dropContext into the hierachical list of items

    "

    |lnNr|

    (self canDrop:aDropContext) ifFalse:[

        self dropLeave:aDropContext.

        ^ false.

    ].

    lnNr := dropOverLine.

    lnNr isNil ifTrue:[^ false ].      "/ never setup by dropEnter:

    self dropLeave:aDropContext.

    dropSelector isNil ifTrue:[ ^ false ].

    ^ receiver 

        perform:dropSelector 

        withOptionalArgument:aDropContext and:lnNr

!

dropEnter:aDropContext

    "a drop operation enters my widget; set the highlightMode in the target widget"

    |widget|

    dropOverLine := 0.

    widget := aDropContext targetWidget.

    highlightMode := widget highlightMode.

    highlightMode notNil ifTrue:[

        aDropContext saveDraw:[

            widget highlightMode: #dropMode.

            widget windowGroup processExposeEvents.

        ].

    ].

!

dropLeave:aDropContext

    "restore drop indications drawn..."

    self changeDropLineTo:nil in:aDropContext.

!

dropOver:aDropContext

    |target lineNr|

    dropOverLine isNil ifTrue:[^ self ].       "/ never setup by dropEnter:

    target := aDropContext targetWidget.

    lineNr := target yVisibleToLineNr:(aDropContext targetPointInDeviceCoordinates y).

    lineNr isNil ifTrue:[ lineNr := 0. ].

    lineNr > target size ifTrue:[

        lineNr := 0.

    ].

    self changeDropLineTo:lineNr in:aDropContext.

    "Modified: / 15-06-2018 / 02:25:37 / Claus Gittinger"

! !

!HierarchicalDropTargetController methodsFor:'instance creation'!

receiver:aReceiver argument:anArgument dropSelector:aDropSelector canDropSelector:aCanDropSelector canExpandSelector:aCanExpandSelector

    |target|

    receiver        := aReceiver.

    dropSelector    := aDropSelector.

    canDropSelector := aCanDropSelector.

    canExpandSelector := aCanExpandSelector.

    target := DropTarget

        receiver:self

        argument:anArgument

        dropSelector:#drop:

        canDropSelector:#canDrop:.

    target enterSelector:#dropEnter:.

    target leaveSelector:#dropLeave:.

    target overSelector:#dropOver:.

    ^ target

! !

!HierarchicalDropTargetController methodsFor:'private'!

changeDropLineTo:aLineOrNil in:aDropContext

    |x0 y0 y1 view item bgColor fgColor processEvents|

    aLineOrNil == dropOverLine ifTrue:[ ^ self ]. "/ nothing changed

    view := aDropContext targetWidget.

    expandBlock notNil ifTrue:[

        Processor removeTimedBlock:expandBlock.

        expandBlock := nil.

    ].

    processEvents := aLineOrNil isNil.

    aDropContext contentsWillChange.

    (aLineOrNil isNil and:[highlightMode notNil]) ifTrue:[

        "/ resore the selection mode

        view highlightMode: highlightMode.

        highlightMode := nil.

        processEvents := true.

    ].

    (dropOverLine notNil and:[dropOverLine ~~ 0]) ifTrue:[

        "/ invalidate old line

        view invalidateLineAt:dropOverLine.

        processEvents := true.

    ].

    processEvents ifTrue:[

        view windowGroup processExposeEvents.

    ].

    dropOverLine := aLineOrNil.

    (dropOverLine isNil or:[dropOverLine == 0]) ifTrue:[

        ^ self

    ].

    item := view at:dropOverLine ifAbsent:nil.

    item isNil ifTrue:[ ^ self ].

    y0 := view yVisibleOfLine:dropOverLine.

    y1 := view yVisibleOfLine:(dropOverLine + 1).

    x0 := view xVisibleOfTextAtLevel:item level.

    bgColor := view hilightBackgroundColor.

    fgColor := view hilightForegroundColor.

    view paint: bgColor.

    view fillRectangle:(Rectangle left:(x0 - 2) top:y0 width:(item widthOn:view) + 4 height:(y1 - y0)).

    view paint:fgColor on:bgColor.

    item displayOn:view x:x0 y:y0 h:(y1 - y0) isHighlightedAsSelected:false.

    view device isX11Platform ifTrue:[

        "work around X11 draw problems"

        Delay waitForMilliseconds:20.

    ].

    item isExpanded ifTrue:[ ^ self ].

    item canExpand ifFalse:[ ^ self ].

    canExpandSelector notNil ifTrue:[

        (receiver 

            perform:canExpandSelector 

            withOptionalArgument:aDropContext and:dropOverLine) 

        ifFalse:[

            ^ self

        ].

    ].

    expandBlock := [self expandForDrop:aDropContext at:aLineOrNil].

    Processor 

        addTimedBlock:expandBlock

        afterMilliseconds:(self class delayMilliSecondsBeforeExpand).

!

expandForDrop:aDropContext at:aLnNr

    |item view|

    expandBlock := nil.

    aLnNr == dropOverLine ifFalse:[ ^ self].

    view := aDropContext targetWidget.

    item := view at:aLnNr ifAbsent:nil.

    item isNil ifTrue:[^ self].

    aDropContext saveDraw:[

        item expand.

        view windowGroup processExposeEvents.

        view device isX11Platform ifTrue:[

            "work around X11 draw problems"

            Delay waitForMilliseconds:20.

        ].

    ].

! !

!HierarchicalDropTargetController class methodsFor:'documentation'!

version

    ^ '$Header$'

!

version_CVS

    ^ '$Header$'

! !