What is the difference between closing the bezier path using closePath function and closing it manually?

Question

I am trying to make a rectangle using UIBezierPath. I adopted two different ways to draw it. Also, I increased the stroke width to 25 px.

First method : Usin

Answer 1

The difference is that the [closePath] method actually adds an additional path element to the underlying CGPath that backs the UIBezierPath.

If you use [closePath], then an additional CGPathElement with a type of kCGPathElementCloseSubpath will be appended to the end of the path immediately after that last line segment.

This is particularly important when using the [containsPoint:] method of a UIBezierPath from the docs:

A point is not considered to be enclosed by the path if it is inside an open subpath, regardless of whether that area would be painted during a fill operation. Therefore, to determine mouse hits on open paths, you must create a copy of the path object and explicitly close any subpaths (using the closePath method) before calling this method.

Answer 2

I tried your example and indeed this happens with both UIBezierPath and with simple drawing on context with CGContextAddLineToPoint.

Can't answer your question, but it seems that adding

bpath.lineCapStyle = kCGLineCapSquare;

solves this exact issue. ( or the CGcontext... alternative ).

Probably closePath takes into account the lineWidth and other line parameters to form a properly closed polygon and adjusts the path itself to be closed nicely. This becomes more probable as you delete your upper right corner ( to make it a triangle ) and notice the linecapstyle won't work anymore, only the closePath gives you a nice triangle.