clip() using lines or boxes does not return an output

[KCanner]

I want to clip using lines and arcs, but when I clip using lines nothing is returned.
This also seems to also be an issue when using box() but functions correctly using circle()

@draw begin
line(Point(100,0),Point(0,100))
line(Point(0,100),Point(-100,0))
line(Point(-100,0),Point(0,-100))
line(Point(0,-100),Point(100,0))
clip()
circle(O, 90, :fill)
end

[cormullion]

Hi!

A good way to see what's going on is to use fillpath() or storepath() rather than clip() to see the path before using it for clipping.

What you've made with your code is a path with four separate subpaths each with a single line, rather than a path with one subpath with four lines.

Path([
 PathMove(Point(100.0, 0.0)),
 PathLine(Point(0.0, 100.0)),
 PathMove(Point(0.0, 100.0)),
 PathLine(Point(-100.0, 0.0)),
 PathMove(Point(-100.0, 0.0)),
 PathLine(Point(0.0, -100.0)),
 PathMove(Point(0.0, -100.0)),
 PathLine(Point(100.0, 0.0))
])

and single line segments, whether on their own or stored in a sequence, can't do clipping.

What you probably want is:

    move(Point(100, 0))
    line(Point(0, 100)) 
    line(Point(-100, 0))
    line(Point(0, -100))
    closepath()

    clip()

which creates a single path with one subpath with four line segments.

Or perhaps:

    pts = [
        Point(100, 0),
        Point(0, 100),
        Point(-100, 0),
        Point(0, -100)
    ]
   poly(pts, :clip)
...

[KCanner]

Thank you for taking the time to explain this, it makes perfect sense now.