"{ Package: 'stx:libview2' }"

ActiveHelp subclass:#FlyByHelp

	instanceVariableNames:'currentFrame currentView currentHelpView showProcess closeProcess'

	classVariableNames:'DelayTime ShowTime TheOneAndOnlyHelpListener'

	poolDictionaries:''

	category:'Interface-Help'

!

!FlyByHelp class methodsFor:'initialization'!

initialize

    "set default delay & help-display times"

    ShowTime := 15.

    DelayTime := 0.25.

    "

     FlyByHelp initialize

    "

    "Modified: 27.4.1996 / 15:07:27 / cg"

! !

!FlyByHelp class methodsFor:'start & stop'!

start

    "start activeHelp for all apps"

    TheOneAndOnlyHelpListener isNil ifTrue:[

        TheOneAndOnlyHelpListener := self new.

    ].

    TheOneAndOnlyHelpListener listenForAll

    "

     FlyByHelpHelp start

    "

! !

!FlyByHelp methodsFor:'private'!

helpTextFromModel:aModel view:aView at:aPointOrNil 

    "helper: ask aModel for its helpText."

    |text|

    aPointOrNil notNil ifTrue:[

        (aModel respondsTo:#flyByHelpTextFor:at:) ifTrue:[

            text := aModel flyByHelpTextFor:aView at:aPointOrNil.

        ].

    ].

    text isNil ifTrue:[

        (aModel respondsTo:#flyByHelpTextFor:) ifTrue:[

            text := aModel flyByHelpTextFor:aView.

        ].

    ].

    ^ text

!

helpTextFromView:aView at:aPointOrNil 

    "helper: ask aView for its helpText."

    |text|

    aPointOrNil notNil ifTrue:[

        (aView respondsTo:#flyByHelpTextAt:) ifTrue:[

            text := aView flyByHelpTextAt:aPointOrNil.

        ].

    ].

    text isNil ifTrue:[

        (aView respondsTo:#flyByHelpText) ifTrue:[

            text := aView flyByHelpText.

        ].

    ].

    ^ text.

!

hideIfPointerLeft:aView

    "hide help, if the pointer is not in aView"

    |whereOnScreen|

    currentFrame notNil ifTrue:[

        whereOnScreen := aView graphicsDevice pointerPosition.

        (currentFrame notNil

        and:[(currentFrame insetBy:1@1) containsPoint:whereOnScreen]) ifFalse:[

            self hideHelp.

        ].

    ].

    "Modified: 28.5.1996 / 20:18:28 / cg"

!

initiateHelpFor:aView at:aPointOrNil now:showItNow

    "ask aView for helpText, passing x/y coordinates;

     start a timeout process to display this helpText after some delay;

     Normally used internally, but can also be used by widgets to force 

     re-negotiation of the displayed helpText 

     (for example in a menu, when the selection changes)"

    |text|

    (self interestedIn:aView) ifFalse:[

        ^ self

    ].

    text := self helpTextFor:aView at:aPointOrNil.

    lastHelpText = text ifTrue:[

        ^ self

    ].

    text size > 0 ifTrue:[

        (showItNow not and:[DelayTime > 0]) ifTrue:[

            self stopHelpDisplayProcess.

            showProcess := [

                    Delay waitForSeconds:DelayTime.

                    showProcess := nil.

                    self showHelp:text for:aView

            ] forkAt:(Processor userSchedulingPriority + 1).

        ] ifFalse:[

            self showHelp:text for:aView

        ]

    ].

!

interestedIn:aView

    "return true, if I am interested in aView (either listeningForAll,

     or in my list of apps)"

    aView isNil ifTrue:[^ false].

    aView topView == currentHelpView ifTrue:[^ false].

    ^ super interestedIn:aView

! !

!FlyByHelp methodsFor:'show / hide help'!

hideHelp

    "hide the help text"

    |p|

    self stopHelpDisplayProcess.

    currentHelpView notNil ifTrue:[

        [

            currentHelpView destroy.

            currentHelpView := nil.

            currentView := nil.

        ] valueUninterruptably

    ].

    currentFrame := nil.

    closeProcess notNil ifTrue:[

        p := closeProcess. closeProcess := nil.

        p terminate.

    ]

    "Modified: 28.6.1997 / 14:03:50 / cg"

!

showHelp:aHelpText for:view

    "show the help text for aView"

    |org p v dev|

    view == currentView ifTrue:[

        lastHelpText = aHelpText ifTrue:[

            ^ self

        ]

    ].

    lastHelpText := aHelpText.

    closeProcess notNil ifTrue:[

        p := closeProcess. closeProcess := nil.

        p terminate.

    ].

    currentHelpView notNil ifTrue:[

        self hideHelp

    ].

    org := view originRelativeTo:nil.

    currentFrame := org extent:view extent.

    org :=org + (view extent // 2).

    v := ActiveHelpView for:aHelpText withCRs.

    dev := view graphicsDevice.

    org := dev pointerPosition.

    (org x + v width) > dev width ifTrue:[

        org := (org x - v width) @ org y

    ].

    (org y + v height) > dev height ifTrue:[

        org := org x @ (org y - v height).

    ].

    v origin:org.

"/    currentHelpView open.

    v realize.

    v enableButtonMotionEvents.

    v enableMotionEvents.

    currentHelpView := v.

    currentView := view.

    closeProcess := [

        [

            (Delay forSeconds:ShowTime) wait.

            [

                currentHelpView notNil ifTrue:[

                    currentHelpView destroy.

                    currentHelpView := nil.

                ]

            ] valueUninterruptably

        ] valueOnUnwindDo:[

            closeProcess := nil.

        ].

    ] forkAt:(Processor userSchedulingPriority + 1).

    "Modified: 31.8.1995 / 19:20:45 / claus"

    "Modified: 28.6.1997 / 14:45:15 / cg"

!

stopHelpDisplayProcess

    |p|

    showProcess notNil ifTrue:[

        p := showProcess. showProcess := nil.

        p terminate.

    ].

    "Created: 28.6.1997 / 14:03:17 / cg"

! !

!FlyByHelp class methodsFor:'documentation'!

version

! !

FlyByHelp initialize!