FontDescription subclass:#ScaledFont

	instanceVariableNames:'handle device extents'

	classVariableNames:'Lobby RecentlyUsedFonts'

!ScaledFont class methodsFor:'initialization'!

initialize

    "Invoked at system start or when the class is dynamically loaded."

    "/ please change as required (and remove this comment)

    Lobby := Registry new

    "Modified: / 09-01-2015 / 11:22:42 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!ScaledFont methodsFor:'finalization'!

finalization

    self destroy

    "Created: / 09-01-2015 / 10:20:47 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

finalizationLobby

    "answer a Registry used for finalization.

     Use a generic Registry for any object.

     Subclasses using their own Registry should redefine this"

    ^ Lobby

    "Created: / 09-01-2015 / 10:20:35 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!ScaledFont methodsFor:'initialize'!

destroy

    "Tell Cairo library to destroy the corresponding C object.

     Remember that object is physically destroyed only if internal

     refcounter goes to zero. However, after calling destroy,

     this instance should be treated as invalid."

    handle notNil ifTrue:[

        CPrimitives cairo_scaled_font_destroy: handle

    ].

    "Created: / 28-12-2014 / 22:10:19 / Jan Vrany <jan.vrany@fit.cvut.cz>"

    "Modified: / 09-01-2015 / 11:57:32 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

handle: anExternalAddress

    handle := anExternalAddress.

    CPrimitives cairo_scaled_font_reference: handle.

    self registerForFinalization.

    extents := FontExtents new.

    CPrimitives cairo_scaled_font_extents: handle _: extents

    "Created: / 09-01-2015 / 15:15:35 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

release

    self unregisterForFinalization.

    ^self destroy

    "Created: / 28-12-2014 / 23:49:00 / Jan Vrany <jan.vrany@fit.cvut.cz>"

    "Modified: / 09-01-2015 / 10:23:57 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!ScaledFont methodsFor:'queries-dimensions'!

ascent

    "return the ascent - the number of pixels above the baseLine."

    ^ extents ascent

    "Created: / 09-01-2015 / 15:33:01 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

descent

    "return the descent - the number of pixels below the baseLine."

    ^ extents descent

    "Created: / 09-01-2015 / 15:33:23 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

height

    "return the height - the number of pixels above plus below the baseLine."

    ^ extents height

    "Created: / 09-01-2015 / 15:33:36 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

isFixedWidth

    "return true, if this is a fixed pitch font (i.e. all characters

     are of the same width)"

    ^ false

    "Created: / 09-01-2015 / 15:35:23 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

maxAscent

    "return the fonts maximum-ascent (i.e. the maximum of all characters);

     That is the number of units (usually pixels) above the baseline."

    ^ self ascent

    "Created: / 09-01-2015 / 15:34:15 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

maxDescent

    "return the fonts maximum-descent (i.e. the maximum of all characters);

     That is the number of units (usually pixels) below the baseline."

    ^ self descent

    "Created: / 09-01-2015 / 15:34:36 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

maxWidth

    "return the fonts maximum-width character (i.e. the maximum of all characters);

     That is a number of units (usually pixels)."

    ^ extents maxXAdvance

    "Created: / 09-01-2015 / 15:35:11 / Jan Vrany <jan.vrany@fit.cvut.cz>"

!

widthOf:aString from:start to:stop

    "return the width of a sub string"

    | str extents width |

    (start == 1 and: [ stop == aString size ]) ifTrue:[ 

        str := aString

    ] ifFalse:[ 

        str := aString copyFrom: start to: stop.

    ].

    extents := TextExtents new.

    Cairo::CPrimitives cairo_scaled_font_text_extents: handle _: str utf8Encoded _: extents.

    width := extents width.

    extents free.

    ^ width

    "Created: / 09-01-2015 / 15:28:48 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

ScaledFont initialize!