"

 COPYRIGHT (c) 1995 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.

"

"{ Package: 'stx:libwidg' }"

"{ NameSpace: Smalltalk }"

Controller subclass:#ButtonController

	instanceVariableNames:'enableChannel pressChannel releaseChannel pressed active entered

		isTriggerOnDown autoRepeat repeatBlock initialDelay repeatDelay

		pressActionBlock releaseActionBlock isToggle isRadio buttonDown

		doubleClickActionBlock'

	classVariableNames:''

	poolDictionaries:''

	category:'Interface-Support-Controllers'

!

!ButtonController class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1995 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

"

    ButtonControllers are used with buttons and handle all user interaction.

    These are automatically created when a Button is created, therefore no manual

    action is required for creation.

    In normal applications, you don't have to care for the controller; 

    access to the controllers behavior is possible via messages to the button.

    (setting actions, controlling autorepeat etc.)

    A ButtonController supports 3 types of notifications:

        MVC change notification - as usual

        channel notifications   - through the pressChannel/releaseChannels

        action callBack         - through pressAction / releaseAction blocks.

    Notifications are made in the above order (i.e. an actionBlock sees the model

    already changed, if there is a model).

    Having multiple mechanisms here is both historic and to make the life

    of simple applications easier - most buttons don't need a model or notification

    channels and simply perform some action.

    In general: actionBlocks are useful, if there is a single subject which

    needs to be told about the press (i.e. actionButtons); 

    models should be used when the button represents some value in some other

    object.

    Channels are much like the MVC approach, however, these are useful if

    press/release/label etc. may come from different objects, and a single 

    (synthetic) model does not make sense or is not appropriate.

    Actually, the channels are the most general - and the other mechanism could

    (and will, maybe) based upon them; after all, an actionBlock is a channel,

    whcih sends #value to its block ....

    See examples in the Button class.

    [Instance variables:]

      enableChannel           <ValueHolder    pressing is allowed (default: true)

                               on Boolean>    

      pressed                 <Boolean>       true if currently pressed (read-only)

      entered                 <Boolean>       true if the cursor is currently in this view

      isTriggerOnDown         <Boolean>       controls if the action should be executed on

                                              press or on release (default: on release).

      isToggle                <Boolean>       controls if the button should show toggle

                                              behavior (as opposed to one-shot behavior)

      pressActionBlock        <Block>         block to evaluate when pressed (default: noop)

      releaseActionBlock      <Block>         block to evaluate when released (default: noop)

      autoRepeat              <Boolean>       auto-repeats when pressed long enough (default: false)

      initialDelay            <Number>        seconds till first auto-repeat (default: 0.2)

      repeatDelay             <Number>        seconds of repeat intervall (default: 0.025)

      repeatBlock             <Block>         block evaluated for auto-repeat (internal)

      active                  <Boolean>       true during action evaluation (internal)

    [author:]

        Claus Gittinger

"

! !

!ButtonController class methodsFor:'defaults'!

defaultInitialDelay

    "when autorepeat is enabled, and button is not released,

     start repeating after initialDelay seconds"

    ^ 0.2

!

defaultRepeatDelay

    "when autorepeat is enabled, and button is not released,

     repeat every repeatDelay seconds"

    ^ 0.025

! !

!ButtonController methodsFor:'accessing-behavior'!

action:aBlock

    "convenient method: depending on the setting the triggerOnDown flag,

     either set the press-action & clear any release-action or

     vice versa, set the release-action and clear the press-action."

    isTriggerOnDown ifTrue:[

        releaseActionBlock := nil.

        pressActionBlock := aBlock

    ] ifFalse:[

        releaseActionBlock := aBlock.

        pressActionBlock := nil

    ].

    "Modified: 9.2.1996 / 22:41:22 / cg"

!

autoRepeat

    "turn on autorepeat. OBSOLETE; use #autoRepeat:"

    self autoRepeat:true.

    "Modified: 9.2.1996 / 22:42:46 / cg"

!

autoRepeat:aBoolean

    "turn on/off autorepeat"

    autoRepeat := aBoolean.

    repeatBlock := MessageSend receiver:self selector:#repeat. "/ [self repeat]

    "Modified: 5.9.1995 / 22:06:00 / claus"

    "Modified: 20.3.1997 / 21:56:13 / cg"

!

beButton

    "make the receiver act like a button; that's the default, anyway"

    "/ because I will be a trigger-on-up button

    (isTriggerOnDown 

    and:[pressActionBlock notNil 

    and:[releaseActionBlock isNil]]) ifTrue:[

        pressActionBlock := releaseActionBlock.

        releaseActionBlock := nil.

    ].

    isTriggerOnDown := false.

    isToggle := false.

    isRadio := false.

    "Modified: 15.7.1996 / 13:42:15 / cg"

    "Created: 27.1.1997 / 13:30:11 / cg"

!

beRadioButton

    "make the receiver act like a radioButton;

     That is like a toggle, but do not allow turning myself off

     by buttonPress (instead, must be turned off by another button or programmatically)"

    "/ because I will be a trigger-on-down button

    (isTriggerOnDown not 

    and:[releaseActionBlock notNil 

    and:[pressActionBlock isNil]]) ifTrue:[

        pressActionBlock := releaseActionBlock.

        releaseActionBlock := nil.

    ].

    isTriggerOnDown := true.

    isToggle := false.

    isRadio := true.

!

beToggle

    "make the receiver act like a toggle"

    "/ because I will be a trigger-on-down button

    (isTriggerOnDown not 

    and:[releaseActionBlock notNil 

    and:[pressActionBlock isNil]]) ifTrue:[

        pressActionBlock := releaseActionBlock.

        releaseActionBlock := nil.

    ].

    isTriggerOnDown := true.

    isToggle := true.

    isRadio := false.

    "Modified: 15.7.1996 / 13:42:15 / cg"

!

beTriggerOnDown

    "make the receiver act on button press"

    isTriggerOnDown := true

!

beTriggerOnUp

    "make the receiver act on button release"

    isTriggerOnDown := false

!

disable

    "alternative invokation; redirected to basic mechanism"

    self enabled:false

    "Modified: / 30.3.1999 / 14:50:12 / stefan"

!

doubleClickAction

    "return the doubleClickAction; that's the block which gets evaluated

     when the button is double-clicked (if non-nil).

     Seldom used with buttons"

    ^ doubleClickActionBlock

!

doubleClickAction:aBlock

    "define the action to be performed on double click"

    doubleClickActionBlock := aBlock.

!

enable

    "alternative invokation; redirected to basic mechanism"

    self enabled:true

    "Modified: / 30.3.1999 / 14:50:01 / stefan"

!

enabled:aBoolean

    "disable the button"

    enableChannel value ~~ aBoolean ifTrue:[

        enableChannel value:aBoolean.

        "/ view redraw    - not needed; I listen to enableChannel

    ]

    "Created: / 30.3.1999 / 14:49:05 / stefan"

!

isTriggerOnDown

    "return true, if I trigger on press

     (in contrast to triggering on up, which is the default)"

    ^ isTriggerOnDown

!

pressAction

    "return the pressAction; that's the block which gets evaluated

     when the button is pressed (if non-nil)"

    ^ pressActionBlock

!

pressAction:aBlock

    "define the action to be performed on press"

    pressActionBlock := aBlock.

!

releaseAction

    "return the releaseAction; that's the block which gets evaluated

     when the button is released (if non-nil)"

    ^ releaseActionBlock

!

releaseAction:aBlock

    "define the action to be performed on release"

    releaseActionBlock := aBlock.

!

triggerOnDown:aBoolean

    "set/clear the flag which controls if the action block is to be evaluated

     on press or on release. 

     (see also ST-80 compatibility methods beTriggerOn*)"

    isTriggerOnDown := aBoolean

! !

!ButtonController methodsFor:'accessing-channels'!

enableChannel

    "return the valueHolder holding the enable boolean value"

    ^ enableChannel

    "Modified: 30.4.1996 / 15:09:30 / cg"

!

enableChannel:aValueHolder

    "set the valueHolder, which holds the enable boolean value"

    |wasEnabled|

    enableChannel notNil ifTrue:[

        wasEnabled := enableChannel value.

        enableChannel retractInterestsFor:self. 

    ] ifFalse:[

        wasEnabled := true

    ].

    enableChannel := aValueHolder.

    aValueHolder onChangeSend:#enableStateChanged to:self.

    enableChannel value ~~ wasEnabled ifTrue:[

        self enableStateChanged

    ]

    "Modified: 17.9.1995 / 19:41:18 / claus"

!

pressChannel

    ^ pressChannel

!

pressChannel:aChannel

    pressChannel := aChannel

!

releaseChannel

    ^ releaseChannel

!

releaseChannel:aChannel

    releaseChannel := aChannel

! !

!ButtonController methodsFor:'accessing-state'!

active

    "return true, if I am active; 

     that is: currently performing my action.

     This query can be used to avoid multiple redraws."

    ^ active

!

active:aBoolean

    active := aBoolean

!

enabled

    "return true, if I am enabled"

    ^ enableChannel value

!

entered

    "return true, if the mouse pointer is currently in my view"

    ^ entered

!

entered:aBoolean

    entered := aBoolean

!

pressed

    "return true, if I am pressed"

    ^ pressed

!

pressed:aBoolean

    pressed ~~ aBoolean ifTrue:[

	pressed := aBoolean.

	self performAction.

    ].

!

setPressed:aBoolean

    pressed := aBoolean.

    "Created: 14.11.1995 / 21:37:08 / cg"

!

toggle

    "toggle and perform the action"

    enableChannel value ifTrue:[

        self toggleNoAction.

        self performAction.

        view changed:#toggle with:pressed

    ]

!

toggleNoAction

    "toggle, but do NOT perform any action"

    pressed ifTrue:[

        view turnOff.

        pressed := false.

    ] ifFalse:[

        view turnOn.

        pressed := true.

    ].

    view repairDamage

    "Modified: / 4.3.1998 / 13:35:12 / cg"

! !

!ButtonController methodsFor:'event handling'!

buttonMotion:buttonState x:x y:y

    (x >= 0 and:[x < view width

    and:[y >= 0 and:[y < view height]]]) ifTrue:[

        entered ifFalse:[

            self pointerEnter:buttonState x:x y:y

        ]

    ] ifFalse:[

        entered ifTrue:[

            self pointerLeave:buttonState

        ]

    ]

!

buttonMultiPress:button x:x y:y

    doubleClickActionBlock notNil ifTrue:[

        doubleClickActionBlock valueWithOptionalArgument:view.

        ^ self.

    ].    

    ^ self buttonPress:button x:x y:y

!

buttonPress:button x:x y:y

    |wg|

    "/ simulate momentary loss of focus to force accept into models in other components

    wg := view windowGroup.

    wg notNil ifTrue:[

        wg focusMomentaryRelease.

    ].

    (button == 1) ifFalse:[

        ^ super buttonPress:button x:x y:y

    ].

    buttonDown := true.

    enableChannel value ifTrue:[

        isToggle ifTrue:[

            self toggle.

            ^ self

        ].

        isRadio ifTrue:[

            pressed ifFalse:[

                self toggle

            ].

            ^ self

        ].

        pressed ifFalse:[

            pressed := true.