image-js/lib/utils/geometry/getCirclePoints.js

Image processing and manipulation in JavaScript

import { circle, line } from 'bresenham-zingl';
import { deleteDuplicates } from '../../draw/utils/deleteDuplicates.js';
import { sortByColumnRow } from './points.js';
/**
 * Get the coordinates of the points on a circle. The reference is the center of the circle.
 * The first point is the right one and they are then sorted clockwise.
 * @param radius - Radius of the circle.
 * @returns The coordinates of the points on a circle of given diameter.
 */
export function getCirclePoints(radius) {
    const circlePoints = [];
    circle(radius, radius, radius, (column, row) => {
        circlePoints.push({ row: row - radius, column: column - radius });
    });
    const firstQuarter = [];
    const secondQuarter = [];
    const thirdQuarter = [];
    const fourthQuarter = [];
    for (let i = 0; i < circlePoints.length; i = i + 4) {
        firstQuarter.push(circlePoints[i % circlePoints.length]);
        secondQuarter.push(circlePoints[(i + 1) % circlePoints.length]);
        thirdQuarter.push(circlePoints[(i + 2) % circlePoints.length]);
        fourthQuarter.push(circlePoints[(i + 3) % circlePoints.length]);
    }
    return firstQuarter.concat(secondQuarter, thirdQuarter, fourthQuarter);
}
const zeroPoint = { row: 0, column: 0 };
/**
 * Get the coordinates of the points in a circle of given radius. The points are sorted by column then row.
 * @param radius - Radius of the circle.
 * @param center - Center of the circle.
 * @returns The coordinates of the points in a circle of given radius.
 */
export function getFilledCirclePoints(radius, center = zeroPoint) {
    const circlePoints = [];
    if (radius === 0) {
        return [center];
    }
    if (radius === 1) {
        circlePoints.push(center);
    }
    circle(center.column, center.row, radius, (column, row) => {
        circlePoints.push({ row, column });
        if (column - 1 > center.column) {
            circlePoints.push(...getLinePoints({ row, column: column - 1 }, { row, column: center.column }));
        }
        else if (column + 1 < center.column) {
            circlePoints.push(...getLinePoints({ row, column: column + 1 }, { row, column: center.column }));
        }
    });
    const sorted = sortByColumnRow(circlePoints);
    return deleteDuplicates(sorted);
}
/**
 * Get the coordinates of the points on a line.
 * @param from - Starting point.
 * @param to - End point.
 * @returns The coordinates of the points on the line.
 */
export function getLinePoints(from, to) {
    const linePoints = [];
    line(from.column, from.row, to.column, to.row, (column, row) => {
        linePoints.push({
            row,
            column,
        });
    });
    return linePoints;
}
/**
 * Get the coordinates of the points that are on right, bottom, left and top at a given radius. The reference is the origin of the circle.
 * First point is the most on the right, then points are in clockwise order.
 * @param radius - Radius of the circle.
 * @returns The coordinates of the compass points.
 */
export function getCompassPoints(radius) {
    const circlePoints = [];
    circle(radius, radius, radius, (column, row) => {
        circlePoints.push({ row: row - radius, column: column - radius });
    });
    return [
        { row: 0, column: radius },
        { row: radius, column: 0 },
        { row: 0, column: -radius },
        { row: -radius, column: 0 },
    ];
}
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