chartx/dist/utils/intersect.js

Data Visualization Chart Library

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");
Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.lineLine = lineLine;
exports.lineRect = lineRect;
var _vec = _interopRequireDefault(require("vec2"));
/**
 * !#en Test line and line
 * !#zh 测试线段与线段是否相交
 * @method lineLine
 * @param {Vec2} a1 - The start point of the first line
 * @param {Vec2} a2 - The end point of the first line
 * @param {Vec2} b1 - The start point of the second line
 * @param {Vec2} b2 - The end point of the second line
 * @return {boolean}
 */
function lineLine(a1, a2, b1, b2) {
  // b1->b2向量 与 a1->b1向量的向量积
  var ua_t = (b2.x - b1.x) * (a1.y - b1.y) - (b2.y - b1.y) * (a1.x - b1.x);
  // a1->a2向量 与 a1->b1向量的向量积
  var ub_t = (a2.x - a1.x) * (a1.y - b1.y) - (a2.y - a1.y) * (a1.x - b1.x);
  // a1->a2向量 与 b1->b2向量的向量积
  var u_b = (b2.y - b1.y) * (a2.x - a1.x) - (b2.x - b1.x) * (a2.y - a1.y);
  // u_b == 0时，角度为0或者180 平行或者共线不属于相交
  if (u_b !== 0) {
    var ua = ua_t / u_b;
    var ub = ub_t / u_b;
    if (0 <= ua && ua <= 1 && 0 <= ub && ub <= 1) {
      return true;
    }
  }
  return false;
}

/**
 * !#en Test line and rect
 * !#zh 测试线段与矩形是否相交
 * @method lineRect
 * @param {Vec2} a1 - The start point of the line
 * @param {Vec2} a2 - The end point of the line
 * @param {Rect} b - The rect
 * @return {boolean}
 */
function lineRect(a1, a2, b) {
  var r0 = new _vec.default(b.x, b.y);
  var r1 = new _vec.default(b.x, b.yMax);
  var r2 = new _vec.default(b.xMax, b.yMax);
  var r3 = new _vec.default(b.xMax, b.y);
  if (lineLine(a1, a2, r0, r1)) return true;
  if (lineLine(a1, a2, r1, r2)) return true;
  if (lineLine(a1, a2, r2, r3)) return true;
  if (lineLine(a1, a2, r3, r0)) return true;
  return false;
}