Context Managers for CoreGraphics

The CoreGraphics bindings for PyObjC introduce a couple of context manager for use with the with statement. These are simple wrappers around the basic CoreGraphics/Quartz API’s that make using the API more convenient and allow you to write easier to understand code.

Note that you’ll have to use from __future__ import with_statement to use the with-statement in Python 2.5.

• CGSavedGState(context)

  This wraps a block of code between CGContextSaveGState and CGContextRestoreGState.

  Usage:

  with CGSavedGState(context):
     # Change context and use changed context
     pass
  
  # Context is restored to before the with-statement at this point.
  

• CGTransparencyLayer(context, info, rect=None)

  This wraps a block of code between CGContextBeginTransparencyLayer (or CGContextBeginTransparencyLayerWithRect if rect is not None) and CGContextEndTransparencyLayer.

  Usage:

  with CGTransparancyLayer(context, None):
     pass
  

  Or:

  with CGTransparancyLayer(context, None, myRect):
     pass
  

• CGContextPage

This wraps a block of code between calls to CGContextBeginPage and CGContextEndPage).

Usage:

    with CGContextPage(context [, mediaBox]):
       pass

__all__ = ('CGSavedGState', 'CGTransparencyLayer',  'CGContextPage')