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Class: DeviceHandle


Inheritance:

   Object
   |
   +--DeviceHandle
      |
      +--DeviceGraphicsContext::DevicePixmapGCHandle
      |
      +--DeviceGraphicsContext::DeviceWindowGCHandle

Package:
stx:libview
Category:
Graphics-Support
Version:
rev: 1.18 date: 2017/02/10 10:17:50
user: cg
file: DeviceHandle.st directory: libview
module: stx stc-classLibrary: libview
Author:
Claus Gittinger

Description:


This is an abstract class for device handles which are responsible
for finalization i.e. to destroy underlying system resources, when the GC
frees an object which has created some system object.
Currently, these are forms and views (streams, cursors, colors and
fonts could also make use of this class - however, for historical reasons,
they continue to use their own private finalization machanisms. This may
change in future versions).


Related information:

    DeviceDrawable

Class protocol:

queries
o  isAbstract
Return if this class is an abstract class.
True is returned here for myself only; false for subclasses.
Abstract subclasses must redefine this again.


Instance protocol:

accessing
o  device

o  id
return the id of the dravable

finalization
o  finalize
I am abstract

** This method raises an error - it must be redefined in concrete classes **

private-accessing
o  setDevice: aDevice id: aDrawableId gcId: aGCId
set the handles contents



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