"

 COPYRIGHT (c) 1992 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.

"

GraphicsContext subclass:#DeviceGraphicsContext

	instanceVariableNames:'drawableId gcId deviceFont foreground background'

	classVariableNames:'CachedScaledForms CachedScales Lobby'

	poolDictionaries:''

	category:'Graphics-Support'

!

!DeviceGraphicsContext class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1992 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

"

    I provide the common protocol for a graphicsContext which is associated with a particular

    device (i.e. Bitmaps, Pixmaps, RootWindow and Windows in Xs world, but also postscript 

    printer pages or fax pages).

    My instance variables are mainly caching device-related stuff (such as font- and color-Ids)

    to avoid needless message traffic. This class is abstract, no direct instances of it

    exist in the system.

    All real work is done by my device, which is accessed via the device instance variable.

    Most drawing requests are simply forwarded to it, others are simulated by using more basic 

    drawing functions (see GraphicsContext drawing vs. basic drawing category).

    The added variables foreground/background are the drawing colors actually 

    used; these are the real (i.e. non dithered) colors supported by the device.

    Direct access to fg/bg is discouraged, since in the future, these may be 

    totally replaced by paint/bgPaint 

    (there are some operations and special cases, for which a direct access to 

     fg/bg makes sense)

    [Instance variables:]

	drawableId      <SmallInteger>  my drawableId on the device (a device handle)

	gcId            <SmallInteger>  my gc's ID on the device (a device handle)

	deviceFont      <Font>          the actual font, currently set in the device

	foreground      <Color>         the device foreground color used for drawing

	background      <Color>         the device background color used for drawing

    [see also:]

	DeviceWorkstation

	Color Font Cursor

    [author:]

	Claus Gittinger

"

! !

!DeviceGraphicsContext class methodsFor:'initialization'!

initialize

    Lobby isNil ifTrue:[

	Lobby := Registry new.

    ]

! !

!DeviceGraphicsContext class methodsFor:'instance creation'!

new

    "create a new drawable - take the current display as

     its device (for now, this may be changed until the view is

     physically created)"

"

    'Warning: DeviceGraphicsContext (' print. self name print. ') should not be created with new' printNL.

"

    ^ self onDevice:Screen current "Display"

!

on:aDevice

    "create a new drawable on aDevice"

    ^ self onDevice:aDevice

!

onDevice:aDevice

    "create a new drawable on aDevice"

    |newDrawable|

    newDrawable := self basicNew.

    "

     set display before its initialized 

     - so it can do something useful (i.e. get font sizes etc.) in its

     intitialize method(s)

    "

    newDrawable device:aDevice.

    newDrawable initialize.

    Lobby register:newDrawable.

    ^ newDrawable

! !

!DeviceGraphicsContext class methodsFor:'cleanup'!

lowSpaceCleanup

    CachedScaledForms := CachedScales := nil

!

releaseResourcesOnDevice:aDevice

    "this is sent when a display connection is closed,

     to release all cached bitmap/window objects from that device"

    Lobby unregisterAllForWhich:[:aDrawable | aDrawable graphicsDevice == aDevice]

    "Created: 16.1.1997 / 16:43:52 / cg"

! !

!DeviceGraphicsContext methodsFor:'accessing'!

at:aPoint

    "return the pixel at the coordinate given by aPoint"

    ^ device

	getPixelX:(aPoint x)

		y:(aPoint y)

	     from:drawableId

!

at:aPoint put:aPixel

    "set a pixel"

    |oldFg|

    oldFg := foreground.

    self foreground:aPixel.

    self displayPointX:(aPoint x) y:(aPoint y).

    self foreground:oldFg

!

atX:x y:y

    "return the pixel at the coordinate given by x/y"

    ^ device getPixelX:x y:y from:drawableId

!

atX:x y:y put:aPixel

    "set a pixel"

    |oldFg|

    oldFg := foreground.

    self foreground:aPixel.

    self displayPointX:x y:y.

    self foreground:oldFg

!

backgroundPaint:aColor

    "set the background-paint color; this is used in opaque-draw

     operations"

    (aColor ~~ bgPaint) ifTrue:[

	aColor notNil ifTrue:[

	    bgPaint := aColor.

	    gcId notNil ifTrue:[

		bgPaint isColor ifTrue:[

		    bgPaint := aColor on:device.

		    bgPaint colorId notNil ifTrue:[

			background := bgPaint.

			device setBackground:(bgPaint colorId) in:drawableId.

			^ self

		    ]

		].

		self paint:paint on:aColor

	    ]

	]

    ].

!

basicFont

    "return set the font for drawing"

    ^ font

    "Created: 12.5.1996 / 11:17:59 / cg"

!

basicFont:aFont

    "set the font for drawing if it has changed.

     This is a low level entry, which is not to be redefined

     (i.e. it must not imply a redraw operation)"

    |id|

    (aFont ~~ font) ifTrue:[

	aFont notNil ifTrue:[

	    font := aFont.

	    gcId notNil ifTrue:[

		font := font on:device.

		id := font fontId.

		id notNil ifTrue:[

		    device setFont:id in:gcId

		]

	    ]

	]

    ]

    "Modified: 23.2.1996 / 17:01:06 / cg"

    "Created: 23.2.1996 / 17:16:51 / cg"

!

capStyle:aSymbol

    "set the style in which the endpoints of lines

     are drawn - aSymbol may be #notLast, #butt, #round, #projecting"

    |s|

    (s := aSymbol) isNil ifTrue:[

	s := #butt.

    ].

    (s ~~ capStyle) ifTrue:[

	capStyle := s.

	gcId notNil ifTrue:[

	    device setLineWidth:lineWidth 

			  style:lineStyle

			    cap:s

			   join:joinStyle

			     in:gcId

	]

    ]

    "Modified: 12.5.1996 / 22:23:03 / cg"

!

clipByChildren

    "drawing shall be done into my view only (default)"

    ^ self clippedByChildren:true

    "Created: 17.7.1996 / 13:25:55 / cg"

!

clipRect

    "return the clipping rectangle for drawing. If there is currently no clipRect,

     a dummy is created."

    |rect|

    clipRect isNil ifTrue:[

	rect := 0@0 extent:(self extent).

	transformation notNil ifTrue:[

	    rect := transformation applyInverseTo:rect.

	].

	^ rect

    ].

    ^ clipRect

    "Modified: 10.4.1996 / 14:32:22 / cg"

!

clippedByChildren:aBoolean

    "turn on/off drawing over children.

     If on, a superview may draw 'over' its children.

     If off (the default), drawing is 'under' its children.

     Only useful for the rootView, to draw over any visible views.

     (for example, when dragging a rubber-line)"

    gcId isNil ifTrue:[

	self initGC

    ].

    device setClipByChildren:aBoolean in:gcId

    "Created: 17.7.1996 / 13:25:16 / cg"

!

clippingRectangle:aRectangleOrNil

    "set the clipping rectangle for drawing (in logical coordinates);

     a nil argument turn off clipping (i.e. whole view is drawable)"

    |x y w h|

    aRectangleOrNil isNil ifTrue:[

	clipRect isNil ifTrue:[^ self].

	gcId notNil ifTrue:[

	    device noClipIn:gcId

	]

    ] ifFalse:[

	clipRect notNil ifTrue:[

	    (clipRect = aRectangleOrNil) ifTrue:[^ self]

	].

	gcId notNil ifTrue:[

	    x := aRectangleOrNil left.

	    y := aRectangleOrNil top.

	    w := aRectangleOrNil width.

	    h := aRectangleOrNil height.

	    transformation notNil ifTrue:[

		x := transformation applyToX:x.

		y := transformation applyToY:y.

		w := transformation applyScaleX:w.

		h := transformation applyScaleY:h.

	    ].

	    (x class == SmallInteger) ifFalse:[

		w := w + (x - x truncated).

		x := x truncated

	    ].

	    (y class == SmallInteger) ifFalse:[

		h := h + (y - y truncated).

		y := y truncated

	    ].

	    (w class == SmallInteger) ifFalse:[

		w := w truncated + 1

	    ].

	    (h class == SmallInteger) ifFalse:[

		h := h truncated + 1

	    ].

	    device setClipX:x y:y width:w height:h in:gcId

	]

    ].

    clipRect := aRectangleOrNil

    "Modified: 22.5.1996 / 13:12:07 / cg"

    "Created: 28.5.1996 / 19:40:20 / cg"

!

clippingRectangleOrNil

    "return the clipping rectangle for drawing, nil if there is none."

    ^ clipRect

    "Created: 10.4.1996 / 14:32:02 / cg"

!

dashStyle:aDashList offset:dashOffset

    "define dashes. Each element of the dashList specifies the length

     of a corresponding dash. For example, setting it to [4 4]

     defines 4on-4off dashing; 

     Setting it to [1 2 4 2] defines 1on-2off-4on-2off dashes.

     The dashOffset specifies where in the dashList the dashing starts.

     This may not be supported by all graphics devices."

    gcId notNil ifTrue:[

	device setDashes:(ByteArray withAll:aDashList)

	      dashOffset:dashOffset

		      in:gcId

    ]

    "Modified: 4.6.1996 / 19:03:06 / cg"

!

device

    "return the device, the receiver is associated with"

    ^ device

!

device:aDevice

    "set the device"

    device := aDevice

!

font:aFont

    "set the font for drawing if it has changed.

     This should be redefined in some widget to perform an automatic

     redraw. See also: #basicFont:"

    (aFont ~~ font) ifTrue:[

	self basicFont:aFont

    ]

    "Modified: 6.3.1996 / 18:17:40 / cg"

!

function:aSymbol

    "set the drawing function if it has changed"

    (aSymbol ~~ function) ifTrue:[

	function := aSymbol.

	gcId notNil ifTrue:[

	    device setFunction:aSymbol in:gcId

	]

    ]

!

gcId

    "return the receivers graphic context id on the device"

    ^ gcId

!

graphicsDevice

    "return the device, the receiver is associated with.

     Same as #device, for ST-80 compatibility."

    ^ device

    "Created: 9.5.1996 / 01:37:58 / cg"

!

id

    "return the id of the dravable on the device"

    ^ drawableId

!

joinStyle:aSymbol

    "set the style in which 2 lines are connected in polygons -

     aSymbol may be #miter, #bevel, #round"

    |s|

    (s := aSymbol) isNil ifTrue:[

	s := #miter

    ].

    (s ~~ joinStyle) ifTrue:[

	joinStyle := s.

	gcId notNil ifTrue:[

	    device setLineWidth:lineWidth 

			  style:lineStyle

			    cap:capStyle

			   join:s

			     in:gcId

	]

    ]

    "Modified: 12.5.1996 / 22:20:43 / cg"

!

lineStyle:aSymbol

    "set the style in which lines are drawn -

     aSymbol may be #solid, #dashed, #doubleDashed"

    |s|

    (s := aSymbol) isNil ifTrue:[

	s := #solid

    ].

    (s ~~ lineStyle) ifTrue:[

	lineStyle := s.

	gcId notNil ifTrue:[

	    device setLineWidth:lineWidth 

			  style:s

			    cap:capStyle

			   join:joinStyle

			     in:gcId

	]

    ]

    "Modified: 12.5.1996 / 22:21:25 / cg"

!

lineWidth:aNumber

    "set the line width for drawing if it has changed"

    |n|

    (aNumber ~~ lineWidth) ifTrue:[

	lineWidth := aNumber.

	transformation isNil ifTrue:[

	    n := aNumber.

	] ifFalse:[

	    n := transformation applyScaleX:aNumber.

	    n := n rounded

	].

	gcId notNil ifTrue:[

	    device setLineWidth:n 

			  style:lineStyle

			    cap:capStyle

			   join:joinStyle

			     in:gcId

	]

    ]

!

mask:aForm

    "set the mask form for drawing"

    |id|

    (aForm ~~ mask) ifTrue:[

	mask := aForm.

	gcId notNil ifTrue:[

	    (mask == nil) ifTrue:[

		device setBitmapMask:nil in:gcId

	    ] ifFalse:[

		mask := mask asFormOn:device.

		id := mask id.

		(mask depth == 1) ifTrue:[

		    device setBitmapMask:id in:gcId

		] ifFalse:[

		    device setPixmapMask:id in:gcId

		]

	    ]