Question

Has anybody an idea in which case this can happen?

GDB output:

0 .. 8:  kill, abort, objc_exception_throw etc.
9:  0x00007fff87ea21f4 in +[NSException raise:format:] ()
10: 0x00007fff8694e9e2 in -[NSBezierPath currentPoint] ()
11: 0x00007fff869e3b3b in __NSAppendBezierPathWithGlyphs ()
12: 0x00007fff869e5baf in -[NSBezierPath appendBezierPathWithGlyphs:count:inFont:]()
13: 0x00007fff869e2e2d in -[NSBezierPath appendBezierPathWithGlyph:inFont:] ()

Answer 1

objc_exception_throw is the function to throw an exception. There are two things to look at in this circumstance: The Console log, which will identify the exception itself, and the call stack leading to objc_exception_throw.

In this case, I can guess what the exception was from the call stack alone: currentPoint will throw if the path has no current point. This is backed up by the documentation for the appendBezierPathWithGlyphs:count:inFont: method (as well as for the method you’re directly calling):

You must set the path’s current point (using the moveToPoint: method or through the creation of a preceding line or curve segment) before you invoke this method.