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Editorial Team
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Asked: 2026-06-03T08:28:09+00:00

For my Cocoa app I need to know whether a given CGContextRef is a

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For my Cocoa app I need to know whether a given CGContextRef is a PDF context (as opposed to a bitmap or screen context) in order to take a different rendering path in my CALayer’s drawInContext implementation. With the iOS SDK, I can do this with:

BOOL isPDF = !CGRectIsEmpty(UIGraphicsGetPDFContextBounds());

But UIGraphics* functions aren’t available in the OS X SDK. I was hoping to be able to use:

BOOL isPDf = CFGetTypeID(currentContext) != CGContextGetTypeID();

But it doesn’t seem to hold true, and there is no CGPDFContextGetTypeID() function that returns a type ID specific to PDFs.

Is there any way to identify the type of a given CGContextRef without doing anything nasty like setting static variables?

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1 Answer

  1. Editorial Team

    There is no public API for getting the type of a CGContextRef, so you will have to keep this information outside of the context ref itself.

    There is an undocumented CGContextGetType() function that returns the type of the context, see the CGContextType enum for a list of possible values. But you should really not use this.

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