add comments

	"github.com/taironas/tinygraphs/draw"

)

// Hexa builds an image with 10x10 grids of half diagonals

// Hexa builds an image with lines x lines grids of half diagonals in the form of an hexagon

func Hexa(w http.ResponseWriter, key string, colors []color.RGBA, size, lines int) {

	canvas := svg.New(w)

	canvas.Start(size, size)

	fringeSize := size / lines

	log.Println(fringeSize)

	// distance of center of vector to third point of equilateral triangles

	// ABC triangle, O is the center of AB vector

	// OC = SQRT(AC^2 - AO^2)

	distance := int(math.Ceil(math.Sqrt((float64(fringeSize) * float64(fringeSize)) - (float64(fringeSize)/float64(2))*(float64(fringeSize)/float64(2)))))

	fringeSize = distance

	lines = size / fringeSize

	offset := size - fringeSize*lines

	log.Println(offset)

	for xL := 0; xL < lines/2; xL++ {

		for yL := 0; yL < lines; yL++ {

			fill1 := fillWhite()

			fill2 := fillWhite()

			if isFill1InHexagon(xL, yL, lines) {

				fill1 = draw.FillFromRGBA(draw.PickColor(key, colors, (xL+3*yL+lines)%15))

			}

	return false

}

// mirrorCoordinates returns an array of coordinates mirrored with respect to x.

func mirrorCoordinates(xs []int, lines, fringeSize, offset int) (xsMirror []int) {

	xsMirror = make([]int, len(xs))

	return

}

// rightUpTriangle computes a right oriented triangle '>'

// right1stTriangle computes a right oriented triangle '>'

func right1stTriangle(xL, yL, fringeSize, distance int) (x1, y1, x2, y2, x3, y3 int) {

	x1 = xL * fringeSize

	x2 = xL*fringeSize + distance

	return

}

// leftUpTriangle computes the coordinates of a left oriented triangle '<'

// left1stTriangle computes the coordinates of a left oriented triangle '<'

func left1stTriangle(xL, yL, fringeSize, distance int) (x1, y1, x2, y2, x3, y3 int) {

	x1 = xL*fringeSize + distance

	x2 = xL * fringeSize

	return

}

// leftDownTriangle computes the coordinates of a left oriented triangle '<'

// left2ndTriangle computes the coordinates of a left oriented triangle '<'

func left2ndTriangle(xL, yL, fringeSize, distance int) (x1, y1, x2, y2, x3, y3 int) {

	x1 = xL*fringeSize + distance

	x2 = xL * fringeSize

	return

}

// rightDownTriangle computes the coordinates of a right oriented triangle '>'

// right2ndTriangle computes the coordinates of a right oriented triangle '>'

func right2ndTriangle(xL, yL, fringeSize, distance int) (x1, y1, x2, y2, x3, y3 int) {

	x1 = xL * fringeSize

	x2 = xL*fringeSize + distance

	y3 = yL*fringeSize + fringeSize/2 + distance

	return

}

// fillWhite returns the svg style to paint an object white.

func fillWhite() string {

	return "fill:rgb(255,255,255)"