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86 lines
1.8 KiB
86 lines
1.8 KiB
export interface Pos {
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x: number
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y: number
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}
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export function equals(a: Pos, b: Pos): boolean {
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return a.x === b.x && a.y === b.y
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}
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export const NULL_POS: Pos = { x: 0, y: 0 }
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/**
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* Returns position of a relative to b
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* @param a
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* @param b
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*/
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export function relativeTo(a: Pos, b: Pos): Pos {
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return { x: a.x - b.x, y: a.y - b.y }
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}
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/**
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* Returns the middle position of the given rectangle
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* @param rect
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*/
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export function middlePos(rect: DOMRect): Pos {
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return { x: rect.x + rect.width / 2, y: rect.y + rect.height / 2 }
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}
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export function add(a: Pos, b: Pos): Pos {
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return { x: a.x + b.x, y: a.y + b.y }
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}
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export function minus(a: Pos, b: Pos): Pos {
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return { x: a.x - b.x, y: a.y - b.y }
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}
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export function mul(a: Pos, t: number): Pos {
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return { x: a.x * t, y: a.y * t }
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}
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export function distance(a: Pos, b: Pos): number {
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return Math.sqrt((a.x - b.x) ** 2 + (a.y - b.y) ** 2)
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}
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export function norm(vector: Pos): number {
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return distance(NULL_POS, vector)
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}
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/**
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* Returns the angle in radian between the two points
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* @param a
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* @param b
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*/
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export function angle(a: Pos, b: Pos): number {
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const r = relativeTo(a, b)
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return Math.atan2(r.x, r.y)
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}
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export function ratioWithinBase(pos: Pos, base: DOMRect): Pos {
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return {
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x: (pos.x - base.x) / base.width,
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y: (pos.y - base.y) / base.height,
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}
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}
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export function posWithinBase(ratio: Pos, base: DOMRect): Pos {
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return {
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x: ratio.x * base.width,
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y: ratio.y * base.height,
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}
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}
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export function middle(a: Pos, b: Pos): Pos {
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return {
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x: a.x / 2 + b.x / 2,
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y: a.y / 2 + b.y / 2,
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}
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}
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export function rotate(vec: Pos, rad: number): Pos {
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return {
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x: Math.cos(rad) * vec.x - Math.sin(rad) * vec.y,
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y: Math.sin(rad) * vec.x + Math.cos(rad) * vec.y,
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}
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}
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