CGPathRef encoding

Question

Is it possible to encode CGPathRef variables? I mean is there an encodeObject:forKey like method for CGPathRef variables?

score 2 · Answer 1 · answered Apr 26 '11 at 00:20

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yes, there is - I have done this: https://github.com/mro/MROGeometry/blob/master/NSCoder_MROCGPath.m

answered Apr 26 '11 at 00:20

Marcus Rohrmoser

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Thank you so much for this. Life saver! – anna Aug 09 '12 at 03:28
Oh no, the only link that was about to save my life is broken now. – 0xNSHuman Oct 13 '14 at 22:14
here it is: https://github.com/mro/MROGeometry/blob/master/MROGeometry/NSCoder_MROCGPath.m – Marcus Rohrmoser Jul 30 '15 at 10:09
It seems as though it won't handle all paths yet? There's a comment that it doesn't support "eliptical arcs". – Glenn Howes Oct 15 '15 at 13:52
Also, the license is fairly political. – Glenn Howes Oct 15 '15 at 13:57

score 1 · Answer 2 · answered Sep 15 '09 at 21:22

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CGPaths are objects, but I don't think you can encode them—at least, if you can, it's not documented. You'll need to generate a saveable representation of the path yourself, and encode that, and then, when you decode that representation, reincarnate the path from it yourself.

answered Sep 15 '09 at 21:22

Peter Hosey

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Is there any relationship between `CGPathRef` and `NSBezierPath`? `NSBezierPath` should be serializable, and if there's a way to convert one to the other, you could encode the `NSBezierPath` and convert to a CGPath as needed. `NSBezierPath` strikes me as a bit less opaque than CGPath. – Alex Sep 16 '09 at 13:17
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No, there is none. You would have to convert manually using an applier function. This is usually not that hard, but if the CGPath contains a quadratic curve (one with one control point), you'd have to convert that to a cubic curve (two control points). – Peter Hosey Sep 16 '09 at 13:40
On iOS, you can `UIBezierPath`, which is `NSCoding` compliant and which implements a class method `bezierPathWithCGPath:`. See http://stackoverflow.com/questions/9938864/encode-and-decode-cgmutablepathref-with-arc/23548794#23548794 – algal May 08 '14 at 17:36

score 1 · Answer 3 · answered Oct 15 '15 at 14:01

This header on Github has two utility strings to interchange CGPaths with NSStrings:

+(nullable NSString*) svgPathFromCGPath:(CGPathRef)aPath;
+(nullable CGPathRef) newCGPathFromSVGPath:(NSString*)anSVGPath whileApplyingTransform:(CGAffineTransform)aTransform;

You can use those strings with NSCoders to store things away. Be warned that anytime you convert between paths and strings you might lose significant digits because of the conversion.

I wrote these routines and they are under MIT license.

CGPathRef encoding

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