fabric/extensions/aligning_guidelines/util/basic.ts

Object model for HTML5 canvas, and SVG-to-canvas parser. Backed by jsdom and node-canvas.

import type { FabricObject, Point } from 'fabric';
import type { PointMap } from '../typedefs';

export function getDistance(a: number, b: number) {
  return Math.abs(a - b);
}

export function getDistanceList(point: Point, list: Point[], type: 'x' | 'y') {
  let dis = Infinity;
  let arr: Point[] = [];
  for (const item of list) {
    const v = getDistance(point[type], item[type]);
    if (dis > v) {
      arr = [];
      dis = v;
    }
    if (dis == v) {
      arr.push(item);
    }
  }
  return { dis, arr };
}

export function getPointMap(target: FabricObject): PointMap {
  const coords = target.getCoords();
  return {
    tl: coords[0],
    tr: coords[1],
    br: coords[2],
    bl: coords[3],
    mt: coords[0].add(coords[1]).scalarDivide(2),
    mr: coords[1].add(coords[2]).scalarDivide(2),
    mb: coords[2].add(coords[3]).scalarDivide(2),
    ml: coords[3].add(coords[0]).scalarDivide(2),
  };
}

export function getContraryMap(target: FabricObject): PointMap {
  const aCoords = target.aCoords ?? target.calcACoords();
  return {
    tl: aCoords.br,
    tr: aCoords.bl,
    br: aCoords.tl,
    bl: aCoords.tr,
    mt: aCoords.br.add(aCoords.bl).scalarDivide(2),
    mr: aCoords.bl.add(aCoords.tl).scalarDivide(2),
    mb: aCoords.tl.add(aCoords.tr).scalarDivide(2),
    ml: aCoords.tr.add(aCoords.br).scalarDivide(2),
  };
}