"
 COPYRIGHT (c) 1993 by Claus Gittinger
	      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.
"

Object subclass:#WindowEvent
	 instanceVariableNames:'view type arguments'
	 classVariableNames:''
	 poolDictionaries:''
	 category:'Interface-Support'
!

!WindowEvent class methodsFor:'documentation'!

copyright
"
 COPYRIGHT (c) 1993 by Claus Gittinger
	      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.
"
!

documentation
"
    Instances of WindowEvent are created for every event coming from
    the graphics device. 
    Usually, they are enqueued by the event dispatcher process into
    a sensors input queue, and dequeued & processed by a windowGroup process
    in its event loop.

    WindowEvents hold the event type and additional information (such as key,
    x/y coordinates etc). Also, windowEvents know how to send themself to some
    destination. To provide a common (single) place where event dispatching is
    implemented, this forwarding is done by a clas method here (i.e. not by the
    window group itself).

    The algorithm for event dispatching is:

	- if the destination view has a keyboard focus set,
	  AND the event is a keyboard event,
	  THEN recursively invoke the event dispatching method,
	       sending the event to the focus view (or its delegate, as below)

	- if the destination view has a delegate,
	  AND its a keyboard, button or pointer event,
	  AND the delegate is interrested in that event 
	      (i.e. implements & responds to #handlesXXX with true)
	  THEN send the event to the delegate, passing the original view
	       as additional argument

	- if the view has a nonNil controller,
	  AND its a key, button or pointer event,
	  THEN send the event to the controller

	- otherwise send the event to the view


    If the view has a non-nil transformation, the event is sent as a
    #deviceXXX message, passing device coordinates. Typically, subclasses
    of view do not redefine this method and the inherited default method
    translates these device coordinates into logical coordinates and resends
    an XXX message.
    If the view has no transformation, the XXX message is directly sent here.

    For example, a 'buttonPress:button x:x y:y' event leads to sending of
    'aView deviceButtonPress:button x:x y:y' which resends
    'aView buttonPress:button x:(x-logical) y:(y-logical)'

    This allows views which are interrested in deviceCoordinates to get them
    (by redefining #deviceXXX) and other views to transparently get & use
    logical coordinates.

    Therefore, for a delegated keyPress messages, the flow is:

	sendEvent
	    view has delegate
		------> ask delegate via 'handlesKeyPress:key inView:view'
		<------ returns true
		------> 'delegate keyPress:key x:x y:y view:view'
			-----> delegate does whatever it wants to do
			       (typically sends the event to some other view)

    for an undelegated message:

	sendEvent
	    view has delegate
		------> ask delegate via 'handlesKeyPress:key inView:view'
		<------ returns false
	    view has controller
		------> 'controller keyPress:key x:x y:y'
	    view has no controller
		view has transformation
		    ----> 'view deviceKeyPress:key x:x y:y'
			  inverse transform x/y
			  ----> 'self keyPress:key x:xLogical y:yLogical'
		view has no transformation
		    ----> 'view keyPress:key x:x y:y'
"
!

version
    ^ '$Header: /cvs/stx/stx/libview/WindowEvent.st,v 1.21 1995-11-23 10:38:12 cg Exp $'
! !

!WindowEvent class methodsFor:'instance creation'!

damageFor:aView rectangle:aRectangle
    "create and return a new damage Event for aRectangle
     in aView"

    ^ (self new) for:aView type:#damage arguments:aRectangle

!

for:aView type:aSymbol
    "create and return a new windowEvent for sending
     aSymbol-message with no arguments to aView"

    ^ (self new) for:aView type:aSymbol arguments:#()
!

for:aView type:aSymbol arguments:argArray
    "create and return a new windowEvent for sending
     aSymbol-message with arguments to aView"

    ^ (self new) for:aView type:aSymbol arguments:argArray
! !

!WindowEvent class methodsFor:'forwarding events'!

sendEvent:type arguments:arguments view:view
    "forward the event represented by type and arguments to the views delegate,
     the views controller or the view. 

     If there is a delegate, only messages which are understood by it are 
     forwarded. Also, the delegate is asked if it is willing to handle the event
     before.
     Delegated messages get the original view as an extra argument.
     Delegation has higher priority than controller forwarding."

    ^ self 
	sendEvent:type 
	arguments:arguments 
	view:view 
	withFocusOn:nil 
	delegate:true
!

sendEvent:type arguments:argArray view:view withFocusOn:focusView
    "forward the event represented by type and arguments to the views delegate,
     the views controller or the view. 
     If focusView is nonNil, and it is a keyboard event, it is forwarded to this
     view (even if there is a delegate).

     If there is a delegate, only messages which are understood by it are 
     forwarded. Also, the delegate is asked if it is willing to handle the event
     before.
     Delegated messages get the original view as an extra argument.
     Delegation has higher priority than both controller or focusView 
     forwarding."

    ^ self 
	sendEvent:type 
	arguments:argArray 
	view:view 
	withFocusOn:focusView 
	delegate:true 
!

sendEvent:type arguments:argArray view:view withFocusOn:focusView delegate:doDelegate
    "forward the event represented by type and arguments to the views delegate,
     the views controller or the view. 
     If focusView is nonNil, and it is a keyboard event, it is forwarded to this
     view (but not if there was a delegate in the first place).

     If doDelegate is true, keyboard and button events are forwarded to a
     delegate object (if non-nil). DoDelegate may be passed as true, to
     handle events which are already delegated.
     If there is a delegate, only messages which are understood by it are 
     forwarded. Also, the delegate is asked if it is willing to handle the event
     before.
     Delegated messages get the original view as an extra argument.
     Delegation has higher priority than both controller or focusView 
     forwarding."

    |delegate selector delegateMessage delegateQuery 
     eventReceiver controller deviceMessage
     isKeyEvent isButtonEvent isPointerEvent trans|

    isKeyEvent := isButtonEvent := isPointerEvent := false.

    (type == #'keyPress:x:y:') ifTrue:[
	isKeyEvent := true.
	deviceMessage := #'deviceKeyPress:x:y:'.
	delegateMessage := #'keyPress:x:y:view:'.
	delegateQuery := #'handlesKeyPress:inView:'.
    ] ifFalse:[ (type == #'keyRelease:x:y:') ifTrue:[
	isKeyEvent := true.
	deviceMessage := #'deviceKeyRelease:x:y:'.
	delegateMessage := #'keyRelease:x:y:view:'.
	delegateQuery := #'handlesKeyRelease:inView:'.
    ] ifFalse:[ (type == #'buttonMotion:x:y:') ifTrue:[
	isButtonEvent := true.
	deviceMessage := #'deviceButtonMotion:x:y:'.
	delegateMessage := #'buttonMotion:x:y:view:'.
	delegateQuery := #'handlesButtonMotion:inView:'.
    ] ifFalse:[ (type == #'buttonPress:x:y:') ifTrue:[
	isButtonEvent := true.
	deviceMessage := #'deviceButtonPress:x:y:'.
	delegateMessage := #'buttonPress:x:y:view:'.
	delegateQuery := #'handlesButtonPress:inView:'.
    ] ifFalse:[ (type == #'buttonRelease:x:y:') ifTrue:[
	isButtonEvent := true.
	deviceMessage := #'deviceButtonRelease:x:y:'.
	delegateMessage := #'buttonRelease:x:y:view:'.
	delegateQuery := #'handlesButtonRelease:inView:'.
    ] ifFalse:[ (type == #'buttonShiftPress:x:y:') ifTrue:[
	isButtonEvent := true.
	deviceMessage := #'deviceButtonShiftPress:x:y:'.
	delegateMessage := #'buttonShiftPress:x:y:view:'.
	delegateQuery := #'handlesButtonShiftPress:inView:'.
    ] ifFalse:[ (type == #'buttonMultiPress:x:y:') ifTrue:[
	isButtonEvent := true.
	deviceMessage := #'deviceButtonMultiPress:x:y:'.
	delegateMessage := #'buttonMultiPress:x:y:view:'.
	delegateQuery := #'handlesButtonMultiPress:inView:'.
    ] ifFalse:[ (type == #'pointerEnter:x:y:') ifTrue:[
	isPointerEvent := true.
	deviceMessage := #'devicePointerEnter:x:y:'.
	delegateMessage := #'pointerEnter:x:y:view:'.
	delegateQuery := #'handlesPointerEnter:inView:'.
    ] ifFalse:[ (type == #'pointerLeave:') ifTrue:[
	isPointerEvent := true.
	deviceMessage := type.
	delegateMessage := #'pointerLeave:view:'.
	delegateQuery := #'handlesPointerLeave:inView:'.
    ] ifFalse:[ (type == #'exposeX:y:width:height:') ifTrue:[
	deviceMessage := #'deviceExposeX:y:width:height:'.
    ] ifFalse:[ (type == #'graphicExposeX:y:width:height:') ifTrue:[
	deviceMessage := #'deviceGraphicExposeX:y:width:height:'.
    ]]]]]]]]]]].

    "
     if there is a focusView, and its a keyboard event, pass it
     to that view (or its controller, or its delegate). 
     In this case, a coordinate which is outside of
     the focusView (0 @ 0) is passed as x/y coordinates.
    "
    (focusView notNil 
    and:[isKeyEvent]) ifTrue:[
	self sendEvent:type 
	     arguments:(Array with:(argArray at:1) with:0 with:0)
	     view:focusView 
	     withFocusOn:nil
	     delegate:doDelegate.
	^ self
    ].

    doDelegate ifTrue:[
	"
	 handle delegated messages
	"
	(isKeyEvent 
	 or:[isButtonEvent 
	 or:[isPointerEvent]]) ifTrue:[
	    delegate := view delegate.

	    "
	     what a kludge - sending to delegate requires
	     another selector and an additional argument ...
	    "
	    (delegate notNil
	    and:[delegate respondsTo:delegateMessage]) ifTrue:[
		"
		 is the delegate interrested in that event ?
		 (if it does not respond to the handlesXXX message,
		  we assume: NO)
		"
		((delegate respondsTo:delegateQuery) 
		and:[delegate perform:delegateQuery with:(argArray at:1) with:view]) ifTrue:[
		    "
		     mhmh ... have to convert to logical coordinates
		    "        
		    (trans := view transformation) notNil ifTrue:[
			argArray size > 2 ifTrue:[
			    argArray at:2 put:(trans applyInverseToX:(argArray at:2)).
			    argArray at:3 put:(trans applyInverseToY:(argArray at:3)).
			].
		    ].
		    argArray isNil ifTrue:[
			delegate perform:delegateMessage with:view
		    ] ifFalse:[
			delegate perform:delegateMessage withArguments:(argArray copyWith:view)
		    ].
		    ^ self
		]
	    ].
	].
    ].

    "
     if there is a controller, that one gets all user events
    "
    eventReceiver := view.
    (controller := view controller) notNil ifTrue:[  
	(isKeyEvent 
	 or:[isButtonEvent 
	 or:[isPointerEvent
	 or:[(type == #focusIn)
	 or:[(type == #focusOut)]]]]) ifTrue:[
	    eventReceiver := controller.
	]
    ].

    "
     finally, another one:
     if the view has a transformation, edit the selector
     from #foo to #deviceFoo...
     This allows the view to handle the event either in device or
     logical coordinates. (since the deviceFoo-messages default implementation
     in PseudoView translates and resends).
     Actually, I could always send deviceXXX without speed penalty
     (event sending is no high frequency operation), but that just adds 
     another context to any debuggers walkback, making things less clear.
    "
    selector := type.

    view transformation notNil ifTrue:[
	(isKeyEvent
	 or:[isButtonEvent
	 or:[isPointerEvent
	 or:[(type == #'exposeX:y:width:height:')
	 or:[(type == #'graphicExposeX:y:width:height:')]]]]) ifTrue:[
	    selector := deviceMessage
	]        
    ].
    eventReceiver perform:selector withArguments:argArray
! !

!WindowEvent methodsFor:'accessing'!

arguments
    "return the arguments of the event"

    ^ arguments
!

arguments:anArray
    "set the arguments"

    arguments := anArray
!

key
    "return the key of the key-event. For non key-events, nil is returned."

    ((type == #keyPress:x:y:)
    or:[type == #keyRelease:x:y:]) ifTrue:[
	^ arguments at:1
    ].
    ^ nil
!

rectangle
    "return the damage rectangle"

    ^ arguments "consider this a kludge"
!

type
    "return the type of the event"

    ^ type
!

view
    "return the view, for which the event is for"

    ^ view
!

view:aView
    "set the view, for which the event is for"

    view := aView
! !

!WindowEvent methodsFor:'private accessing'!

for:aView type:aSymbol arguments:argArray
    "set the instance variables of the event"

    view := aView.
    type := aSymbol.
    arguments := argArray
! !

!WindowEvent methodsFor:'queries'!

isButtonEvent
    "return true, if this event is a button event"

    ^ (type == #buttonPress:x:y:) 
      or:[type == #buttonRelease:x:y:
      or:[type == #'buttonShiftPress:x:y:'
      or:[type == #'buttonMultiPress:x:y:'
      or:[type == #'buttonMotion:x:y:']]]]
!

isDamage
    "return true, if this is a damage event"

    ^ type == #damage
!

isKeyEvent
    "return true, if this event is a keyboard event"

    ^ (type == #keyPress:x:y:) or:[type == #keyRelease:x:y:]
!

isKeyPressEvent
    "return true, if this event is a keyboard event"

    ^ (type == #keyPress:x:y:)
! !

!WindowEvent methodsFor:'sending'!

sendEvent
    "forward the event represented by the receiver to the views delegate,
     the views controller or the view. Ignore any focusView."

    self sendEventWithFocusOn:nil
!

sendEventWithFocusOn:focusView
    "forward the event represented by the receiver to the views delegate,
     the views controller or the view. 
     If focusView is nonNil, and the receiver is a keyboard event, 
     the event will be forwarded to the focusView instead 
     (or its delegate, or its controller)."

    self class 
	sendEvent:type 
	arguments:arguments 
	view:view 
	withFocusOn:focusView
	delegate:true
! !