transcend-charts/lib/charts/Geometry.js

Transcend is a charting and graph library for NUVI

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = {
  doLinesCross: function doLinesCross(line1, line2) {

    // the coordinates where the lines intersect
    var x = undefined;
    var y = undefined;

    // special case for vertical line1
    if (line1.x2 - line1.x1 === 0) {
      if (line2.x2 - line2.x1 === 0) {
        if (line1.x1 === line2.x1) {
          return true; // colinear verticals
        }
        return false;
      }

      var m2 = (line2.y2 - line2.y1) / (line2.x2 - line2.x1);
      var b2 = line2.y1 - m2 * line2.x1;
      x = line1.x1;
      y = m2 * x + b2;
    } else if (line2.x2 - line2.x1 === 0) {
      var m1 = (line1.y2 - line1.y1) / (line1.x2 - line1.x1);
      var b1 = line1.y1 - m1 * line1.x1;
      x = line2.x1;
      y = m1 * x + b1;
    } else {
      // get slope and y-intercept for line 1
      var m1 = (line1.y2 - line1.y1) / (line1.x2 - line1.x1);
      var b1 = line1.y1 - m1 * line1.x1;

      // get slope and y-intercept for line 2
      var m2 = (line2.y2 - line2.y1) / (line2.x2 - line2.x1);
      var b2 = line2.y1 - m2 * line2.x1;

      // are the lines parallel?
      if (m1 === m2) {
        if (b1 === b2) {
          return true; // colinear - they cross
        } else {
          return false; // parallel - never going to touch
        }
      }

      // find where the lines cross
      x = (b2 - b1) / (m1 - m2);
      y = m1 * x + b1;
    }

    if (x === undefined || y === undefined) {
      // parallel case that should never happen because it's handled above
      return false;
    }

    // find out which ones are the min and max coordinates
    line1.minX = Number((line1.x1 < line1.x2 ? line1.x1 : line1.x2).toPrecision(12));
    line1.maxX = Number((line1.x1 > line1.x2 ? line1.x1 : line1.x2).toPrecision(12));
    line1.minY = Number((line1.y1 < line1.y2 ? line1.y1 : line1.y2).toPrecision(12));
    line1.maxY = Number((line1.y1 > line1.y2 ? line1.y1 : line1.y2).toPrecision(12));

    line2.minX = Number((line2.x1 < line2.x2 ? line2.x1 : line2.x2).toPrecision(12));
    line2.maxX = Number((line2.x1 > line2.x2 ? line2.x1 : line2.x2).toPrecision(12));
    line2.minY = Number((line2.y1 < line2.y2 ? line2.y1 : line2.y2).toPrecision(12));
    line2.maxY = Number((line2.y1 > line2.y2 ? line2.y1 : line2.y2).toPrecision(12));

    x = Number(x.toPrecision(12));
    y = Number(y.toPrecision(12));

    // test whether the point x,y is within the bounds of the defined line segments
    if (x >= line1.minX && x <= line1.maxX && y >= line1.minY && y <= line1.maxY && x >= line2.minX && x <= line2.maxX && y >= line2.minY && y <= line2.maxY) {
      return true;
    }

    return false;
  }
};