gopatterns/pkg/util/point_list.go

package util

import (
	"fmt"
	"strconv"

	svg "github.com/ajstarks/svgo/float"
)

type PointMap map[int]Point

func (pm PointMap) Scale(s float64) PointMap {
	pointMap := make(PointMap, len(pm))

	for i, p := range pm {
		pointMap[i] = p.Multiply(s)
	}

	return pointMap

}

func (pm PointMap) Box() (Point, Point) {
	min := Point{}
	max := Point{}

	for _, p := range pm {
		min = min.Min(p)
		max = max.Max(p)
	}

	return min, max
}

func (pm PointMap) Offset(point Point) PointMap {
	pointMap := make(PointMap, len(pm))

	for i, p := range pm {
		pointMap[i] = p.Subtract(point)
	}

	return pointMap
}

func (pm PointMap) Normalize() PointMap {
	min, _ := pm.Box()
	return pm.Offset(min)
}

func (pm PointMap) Draw(canvas *svg.SVG) {
	for i, point := range pm.Normalize() {
		canvas.Circle(point.X, point.Y, 2.0, "stroke:black;fill:black")
		canvas.Text(point.X+2, point.Y+2, strconv.Itoa(i))
	}
}

func (pm PointMap) Line(canvas *svg.SVG, lines ...int) {
	for i := 0; i < len(lines)-1; i++ {
		start := lines[i]
		end := lines[i+1]
		canvas.Line(pm[start].X, pm[start].Y, pm[end].X, pm[end].Y, "stroke:black;stroke-width:3")
	}
}

func (pm PointMap) Bezier(canvas *svg.SVG, lines ...int) error {
	if len(lines) != 4 {
		return fmt.Errorf("expected 4 line definitons, got %d instead", len(lines))
	}

	canvas.Bezier(pm[lines[0]].X, pm[lines[0]].Y, pm[lines[1]].X, pm[lines[1]].Y, pm[lines[2]].X, pm[lines[2]].Y, pm[lines[3]].X, pm[lines[3]].Y, "stroke:black;fill:none")

	return nil
}