Best way to find intersection

Scripting
1

What is the best way to find intersection coordinates of two paths via Glyphs?
Or is there something like layer.intersectionsBetweenPoints() but for path?

Upd:
I’ve found path.bezierPath.intersectionWithLine_lineStart_lineEnd_() , but what arguments are required?

2

This is not officially documented but you can get good hints by looking at the headers in /Applications/Glyphs.app/Contents/Frameworks/GlyphsCore.framework/Versions/A/Headers. I usually open the whole folder in my text editor and do a multi-file search for the method or class in question.

In this case the file NSBezierPath-OAExtensions.h contains the definition (in ObjectiveC):

- (BOOL)intersectionWithLine:(NSPoint *)result lineStart:(NSPoint)lineStart lineEnd:(NSPoint)lineEnd;

That suggests you need three NSPoints as parameters but I have not tested it. Does it work for you?

3

Thanks for help, Tim.

I can’t figure out what I need to send as (NSPoint *)result

ValueError: deponitize a pointer, received an NSPoint

4

Did you set up an NSPoint first and then pass it to the method (as opposed to constructing one in-line)?

But, to be honest, that’s beyond my PyObjC knowledge. @GeorgSeifert?

5

The (NSPoint *) means that the value is returned by reference. So in python, you normally put in a None and the result will be returned as a tuple.

What exactly are you trying to do?

6

Glyphs crashes when I run this code.

I want to find coordinates of intersection of 2 paths or path and line using Glyphs built-ins.

7

With the current build in functions, your first idea is probably the best. You can make a new layer, put a copy of both paths in it and run newLayer.intersectionsBetweenPoints().

8

Hi @GeorgSeifert, is this still the case? The function intersectionsBetweenPoints requires three parameters, the first two of which are the coordinates of a measurement line. As far as I have understood the OP, he wants to find the intersections between two paths, which may contain curves - is there a built-in function to do this?

9

I seem to have solved this myself; there is a function in NSBezierPath that does exactly this:
p1.bezierPath.intersectWithPath_(p2.bezierPath)
where p1 and p2 are of type GSPath.
Perhaps this info helps someone else.

10

I still don’t know what exactly you are trying to do.

There is a method layer.intersections() that will return a list of points that is used to draw the black intersection dots in the edit view.

11

Can I ask how to iterate over layer.intersections()?

12 
inter = Layer.intersections()
for i in range(inter.count()):
	print(i, inter.pointAtIndex_(i))
1 Like