[Moose-dev] Roassal draggable/droppable

Hi, Currently I don't see any way how to tell an element that another one has been dropped onto him. For example if I want to drag an element into a container (see example at the end). Unfortunately in my solution i had to change the behaviour of Trachel (RTMorph), so could this be in some (better) way incorporated into Roassal (Trachel)? My solution is making a subclass ------------------------------------- TRAbstractMouseEvent subclass: #TRMouseDragDrop ------------------------------------- And altering mouseDragEnd ------------------------------------- RTMorph>>rtMouseDragEnd: evt | ee dropEvent dropShape relativePosition | "notify the dragged element" ee := TRMouseDragEnd new. ee shape: shapeBeingPointed. ee canvas: trachelCanvas. ee morph: self. shapeBeingPointed announce: ee. "notify the element onto which was the drag performed" shapeBeingPointed = trachelCanvas ifFalse: [ shapeBeingPointed element attributes at: #rtDroppable ifPresent: [ relativePosition := self relativePositionFor: evt. dropShape := self shapeWithAction: TRMouseDragDrop forPositionInPixels: relativePosition. dropShape = shapeBeingPointed ifFalse: [ dropEvent := TRMouseDragDrop new shape: shapeBeingPointed; canvas: trachelCanvas; morph: self. dropShape announce: dropEvent ] ] ]. eventBeginingDragging := nil. shapeBeingPointed := nil ------------------------------------- Example (use case) is: ------------------------------------- view := RTView new. container := RTBox new size: 200; color: Color white; borderColor: Color black; element. group := RTGroup new. RTNest new on: container nest: group. container trachelShape size: 200. box := RTBox new size: 50; color: Color magenta; element. box translateTo: 250 @ 0. container @ RTDraggable. container @ RTResizeable. box @ RTDraggable. box attributes at: #rtDroppable put: true. container when: TRMouseDragDrop do: [ :event | | el | el := event shape element. el attributes at: #container ifPresent: [ group remove: el. ]. group add: el. el attributes at: #container put: group. ]. view canvas when: TRMouseDragDrop do: [ :event | | el | el := event shape element. el attributes at: #container ifPresent: [ :parent | parent remove: el. el attributes removeKey: #container. ]. ]. view add: container; add: box. view open. ------------------------------------- Also it would be nice to have an option to highlight the drop area. There is TRMouseEnter/TRMouseLeave but it fires only for the top level shape, perhaps it should for all? Or less invasive to add TRMouseDragEnter/TRMouseDragLeave which would work like regular Enter/Leave but on the next (on z-axis) shape. Please let me know what you think. Peter