react-aim/lib/aim.js

Determine the cursor aim for triggering mouse events.

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.distance = distance;
exports.side = side;
exports.bullseye = bullseye;
exports.default = aiming;

var _corners = require('./corners');

var _corners2 = _interopRequireDefault(_corners);

var _pointInPolygon = require('./utils/pointInPolygon');

var _pointInPolygon2 = _interopRequireDefault(_pointInPolygon);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function distance(source, target) {
  var a = source.x - target.x;
  var b = source.y - target.y;
  return Math.sqrt(a * a + b * b);
}

function side(corners) {
  if (corners[0] === 'top-right' && corners[1] === 'bottom-right') return 'right';else if (corners[0] === 'top-left' && corners[1] === 'bottom-right') return 'top-right';else if (corners[0] === 'top-left' && corners[1] === 'top-right') return 'top';else if (corners[0] === 'bottom-left' && corners[1] === 'top-right') return 'top-left';else if (corners[0] === 'bottom-left' && corners[1] === 'top-left') return 'left';else if (corners[0] === 'bottom-right' && corners[1] === 'top-left') return 'bottom-left';else if (corners[0] === 'bottom-right' && corners[1] === 'bottom-left') return 'bottom';else if (corners[0] === 'top-right' && corners[1] === 'bottom-left') return 'bottom-right';
}

function bullseye(corners, boundaries, mousePosition) {
  switch (side(corners)) {
    case 'right':
      return {
        x: boundaries[0].x,
        y: mousePosition.y
      };
    case 'top-right':
      return {
        x: boundaries[1].x,
        y: boundaries[0].y
      };
    case 'top':
      return {
        x: mousePosition.x,
        y: boundaries[0].y
      };
    case 'top-left':
      return {
        x: boundaries[0].x,
        y: boundaries[1].y
      };
    case 'left':
      return {
        x: boundaries[0].x,
        y: mousePosition.y
      };
    case 'bottom-left':
      return {
        x: boundaries[1].x,
        y: boundaries[0].y
      };
    case 'bottom':
      return {
        x: mousePosition.x,
        y: boundaries[0].y
      };
    case 'bottom-right':
      return {
        x: boundaries[0].x,
        y: boundaries[1].y
      };
  }
}

function formatPoints(points) {
  var finalPoints = [];
  for (var i = 0, len = points.length; i < len; ++i) {
    finalPoints.push([points[i].x, points[i].y]);
  }
  return finalPoints;
}

function aiming(e, mousePosition, prevMousePosition, target, alreadyAiming) {
  if (!prevMousePosition) return false;else if (!alreadyAiming && mousePosition.x === prevMousePosition.x && mousePosition.y === prevMousePosition.y) {
    return false;
  }

  var corners = (0, _corners2.default)(e, target);
  var bound = (0, _corners.boundaries)(corners, prevMousePosition, target);

  if ((0, _pointInPolygon2.default)([mousePosition.x, mousePosition.y], formatPoints(bound))) {
    var dist = Math.round(distance(mousePosition, bullseye(corners, bound, mousePosition)));
    return Math.max(dist, 1);
  }
  return false;
}