Wrong line Cap style for closed shapes.

[setanarut]

There is an unwanted blemish on the default circle shape. line start and end points overlap.

package main

import (
	"github.com/fogleman/gg"
)

func main() {
	d := gg.NewContext(200, 200)
	d.SetHexColor("000")
	d.Clear()
	d.SetHexColor("FFF")
	d.DrawCircle(100, 100, 50)
	// d.SetLineCapButt() <- this should be the default style and belong to the circle.
	d.Stroke()
	d.SavePNG("canvas.png")
}