Lazarus has the TCarbonBitmapContext class, implemented as a Quartz CGBitmapContext. User interface
objects use a CGImage as pixel cache. During profiling a Lazarus application on Mac OS X, I noticed
that the application spends a lot of time in TCarbonDeviceContext.DrawCGImage.
Apple writes
<http://developer.apple.com/mac/library/documentation/GraphicsImaging/Conceptual/drawingwithquartz2d/dq_context/dq_context.html>
Graphics Contexts
Note: If you want to perform offscreen drawing, before you use a bitmap graphics context, you
should first read “CGLayer Drawing.” CGLayer objects, introduced in Mac OS X v10.4 and available in
iPhone OS, support drawing to layers and provide a much more optimized solution for offscreen
drawing than bitmap graphics contexts provide.
and
Creating a Bitmap Graphics Context
CGLayer objects (CGLayerRef), available in Mac OS X v10.4 and later, are optimized for offscreen
drawing because, whenever possible, Quartz caches layers on the video card.
Therefore - unless someone else is working on it - I would like to add CGLayer support to the
Carbon widget, using CGLayers as pixel cache for interface objects. Is this a change that the
Lazarus team would welcome ? My work will is being sponsored by PGMusic <http://www.pgmusic.com>.
Regards,
Adriaan van Os
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