You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: stroker.go
    path of file: ./repos/go-chart/drawing
    
    the code of the file until where you have to start completion: // Copyright 2010 The draw2d Authors. All rights reserved.
// created: 13/12/2010 by Laurent Le Goff

package drawing

// NewLineStroker creates a new line stroker.
func NewLineStroker(c LineCap, j LineJoin, flattener Flat
    
func (l *LineStroker) End() {
	if len(l.vertices) > 1 {
		l.Flattener.MoveTo(l.vertices[0], l.vertices[1])
		for i, j := 2, 3; j < len(l.vertices); i, j = i+2, j+2 {
			l.Flattener.LineTo(l.vertices[i], l.vertices[j])
		}
	}
	for i, j := len(l.rewind)-2, len(l.rewind)-1; j > 0; i, j = i-2, j-2 {
		l.Flattener.LineTo(l.rewind[i], l.rewind[j])
	}
	if len(l.vertices) > 1 {
		l.Flattener.LineTo(l.vertices[0], l.vertices[1])
	}
	l.Flattener.End()
	// reinit vertices
	l.vertices = l.vertices[0:0]
	l.rewind = l.rewind[0:0]
	l.x, l.y, l.nx, l.ny = 0, 0, 0, 0

}