gopatterns/pkg/path/path.go

// Package path provides objects to define lines on a sewing pattern.
package path

import (
	"git.wtrh.nl/patterns/gopatterns/pkg/point"
	"git.wtrh.nl/patterns/gopatterns/pkg/util"
	"github.com/tdewolff/canvas"
)

// Polygon defines a set of straight lines through points.
type Polygon struct {
	points []point.Point
	style  Style
	id     util.ID
}

func (p *Polygon) Through() []point.Point {
	return p.points
}

// NewPolygon returns a new [Polygon].
func NewPolygon(points []point.Point, style Style, id util.ID) *Polygon {
	return &Polygon{points: points, style: style, id: id}
}

// WithStyle updates the style of the Polygon.
func (p *Polygon) WithStyle(Style Style) *Polygon {
	p.style = Style
	return p
}

// Draw the path to the provided [canvas.Canvas].
func (p *Polygon) Draw(c *canvas.Canvas) error {
	polyline := canvas.Polyline{}
	for _, next := range p.points {
		polyline.Add(next.Vector().Values())
	}

	c.RenderPath(polyline.ToPath(), p.style.ToCanvas(), canvas.Identity)

	return nil
}

func (p *Polygon) Length() (float64, error) {
	length := 0.0

	for i := range p.points[1:] {
		length += p.points[i].Position().Distance(p.points[i+1].Position())
	}

	return length, nil
}

func (p *Polygon) ID() util.ID {
	return p.id
}

type Path interface {
	Draw(c *canvas.Canvas) error
	Length() (float64, error)
	Through() []point.Point
}