gopatterns/pkg/pattern/point/relative_point.go

package point

import (
	"math"

	"git.wtrh.nl/patterns/gopatterns/pkg/position"
	"git.wtrh.nl/patterns/gopatterns/pkg/vector"
	"github.com/tdewolff/canvas"
)

// RelativePoint implements Point and defines a position that is relative to a different Point.
type RelativePoint struct {
	draw           bool
	name           string
	point          Point
	relativeOffset position.Position
	id             ID
	hide           bool
}

// Name returns the name of a point.
func (r *RelativePoint) Name() string {
	return r.name
}

// Done returns the relativePoint as interface.
func (r *RelativePoint) Done() Point { //nolint:ireturn
	return r
}

// MarkWith sets the ID of the point.
func (r *RelativePoint) MarkWith(n ID) *RelativePoint {
	r.id = n

	if r.name == "" {
		r.name = string(n)
	}

	return r
}

// Position calculates and returns the absolute [position.Position].
func (r *RelativePoint) Position() position.Position {
	p := r.point.Position()
	return p.Add(r.relativeOffset)
}

// Matrix calculates and returns the [canvas.Matrix] of a point.
func (r *RelativePoint) Matrix() canvas.Matrix {
	return r.point.Matrix().Translate(r.relativeOffset.Vector.Values()).Rotate(r.relativeOffset.Rotation / math.Pi * 180)
}

// Vector calculates and returns the absolute [vector.Vector].
func (r *RelativePoint) Vector() vector.Vector {
	return r.Position().Vector
}

// ID returns the point ID.
func (r *RelativePoint) ID() ID {
	return r.id
}

// NewRelativePointWithVector returns a new RelativePoint.
func NewRelativePointWithVector(point Point, p vector.Vector, id ID) *RelativePoint {
	return &RelativePoint{
		point:          point,
		relativeOffset: position.Position{Vector: p},
		id:             id,
		name:           string(id),
	}
}

// NewRelativePoint returns a new RelativePoint.
func NewRelativePoint(point Point) *RelativePoint {
	return &RelativePoint{
		point: point,
	}
}

// NewRotationPoint returns a new RelativePoint with a specific rotation.
func NewRotationPoint(point Point, a float64, id ID) *RelativePoint {
	p := &RelativePoint{
		point: point,
		relativeOffset: position.Position{
			Vector:   vector.Vector{},
			Rotation: a,
		},

		name: string(id),
		id:   id,
	}

	return p
}

// WithXOffset sets the x value for the relative offset.
func (r *RelativePoint) WithXOffset(value float64) *RelativePoint {
	r.relativeOffset.Vector.X = value

	return r
}

// WithYOffset sets the y value for the relative offset.
func (r *RelativePoint) WithYOffset(value float64) *RelativePoint {
	r.relativeOffset.Vector.Y = value

	return r
}

// WithRotationOffset sets the angle for the relative offset.
func (r *RelativePoint) WithRotationOffset(value float64) *RelativePoint {
	r.relativeOffset.Rotation = value

	return r
}

// NewRelativePointBelow returns a RelativePoint distance f below another Point.
func NewRelativePointBelow(point Point, f float64, id ID) *RelativePoint {
	return NewRelativePointWithVector(point, vector.Vector{X: 0, Y: -f}, id)
}

// NewRelativePointAbove returns a RelativePoint distance f above another Point.
func NewRelativePointAbove(point Point, f float64, id ID) *RelativePoint {
	return NewRelativePointWithVector(point, vector.Vector{X: 0, Y: f}, id)
}

// NewRelativePointLeft returns a RelativePoint distance f left of another Point.
func NewRelativePointLeft(point Point, f float64, id ID) *RelativePoint {
	return NewRelativePointWithVector(point, vector.Vector{X: -f, Y: 0}, id)
}

// NewRelativePointRight returns a RelativePoint distance f right of another Point.
func NewRelativePointRight(point Point, f float64, id ID) *RelativePoint {
	return NewRelativePointWithVector(point, vector.Vector{X: f, Y: 0}, id)
}

// Draw returns if the point should be drawn.
func (r *RelativePoint) Draw() bool {
	return r.draw
}

// SetDraw indicates that the point should be drawn.
func (r *RelativePoint) SetDraw() {
	r.draw = true
}

// UnsetDraw indicates that the point should not be drawn.
func (r *RelativePoint) UnsetDraw() {
	r.draw = true
}

// Hide returns if the point must remain hidden.
func (r *RelativePoint) Hide() bool {
	return r.hide
}

// SetHide indicates that the must be hidden.
func (r *RelativePoint) SetHide() {
	r.hide = true
}