@mapbox/react-map-gl/dist/esm/utils/transition/linear-interpolator.js

A React wrapper for MapboxGL-js and overlay API.

import _slicedToArray from "@babel/runtime/helpers/esm/slicedToArray";
import _classCallCheck from "@babel/runtime/helpers/esm/classCallCheck";
import _createClass from "@babel/runtime/helpers/esm/createClass";
import _possibleConstructorReturn from "@babel/runtime/helpers/esm/possibleConstructorReturn";
import _getPrototypeOf from "@babel/runtime/helpers/esm/getPrototypeOf";
import _assertThisInitialized from "@babel/runtime/helpers/esm/assertThisInitialized";
import _inherits from "@babel/runtime/helpers/esm/inherits";
import _defineProperty from "@babel/runtime/helpers/esm/defineProperty";
import WebMercatorViewport from 'viewport-mercator-project';
import assert from '../assert';
import TransitionInterpolator from './transition-interpolator';
import { isValid, getEndValueByShortestPath } from './transition-utils';
import { lerp } from '../math-utils';
var VIEWPORT_TRANSITION_PROPS = ['longitude', 'latitude', 'zoom', 'bearing', 'pitch'];

/**
 * Performs linear interpolation of two viewports.
*/
var LinearInterpolator =
/*#__PURE__*/
function (_TransitionInterpolat) {
  _inherits(LinearInterpolator, _TransitionInterpolat);

  /**
   * @param opts {Object}
   *  - opts.transitionProps {Array}] - list of props to apply linear transition to.
   *  - opts.around {Array} - a screen point to zoom/rotate around
   */
  function LinearInterpolator() {
    var _this;

    var opts = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};

    _classCallCheck(this, LinearInterpolator);

    _this = _possibleConstructorReturn(this, _getPrototypeOf(LinearInterpolator).call(this));

    _defineProperty(_assertThisInitialized(_this), "around", void 0);

    if (Array.isArray(opts)) {
      // backward compatibility
      opts = {
        transitionProps: opts
      };
    }

    _this.propNames = opts.transitionProps || VIEWPORT_TRANSITION_PROPS;

    if (opts.around) {
      _this.around = opts.around;
    }

    return _this;
  }

  _createClass(LinearInterpolator, [{
    key: "initializeProps",
    value: function initializeProps(startProps, endProps) {
      var startViewportProps = {};
      var endViewportProps = {};

      if (this.around) {
        // anchor point in origin screen coordinates
        startViewportProps.around = this.around; // anchor point in spherical coordinates

        var aroundLngLat = new WebMercatorViewport(startProps).unproject(this.around);
        Object.assign(endViewportProps, endProps, {
          // anchor point in destination screen coordinates
          around: new WebMercatorViewport(endProps).project(aroundLngLat),
          aroundLngLat: aroundLngLat
        });
      }

      var _iteratorNormalCompletion = true;
      var _didIteratorError = false;
      var _iteratorError = undefined;

      try {
        for (var _iterator = this.propNames[Symbol.iterator](), _step; !(_iteratorNormalCompletion = (_step = _iterator.next()).done); _iteratorNormalCompletion = true) {
          var key = _step.value;
          var startValue = startProps[key];
          var endValue = endProps[key];
          assert(isValid(startValue) && isValid(endValue), "".concat(key, " must be supplied for transition"));
          startViewportProps[key] = startValue;
          endViewportProps[key] = getEndValueByShortestPath(key, startValue, endValue);
        }
      } catch (err) {
        _didIteratorError = true;
        _iteratorError = err;
      } finally {
        try {
          if (!_iteratorNormalCompletion && _iterator["return"] != null) {
            _iterator["return"]();
          }
        } finally {
          if (_didIteratorError) {
            throw _iteratorError;
          }
        }
      }

      return {
        start: startViewportProps,
        end: endViewportProps
      };
    }
  }, {
    key: "interpolateProps",
    value: function interpolateProps(startProps, endProps, t) {
      var viewport = {};
      var _iteratorNormalCompletion2 = true;
      var _didIteratorError2 = false;
      var _iteratorError2 = undefined;

      try {
        for (var _iterator2 = this.propNames[Symbol.iterator](), _step2; !(_iteratorNormalCompletion2 = (_step2 = _iterator2.next()).done); _iteratorNormalCompletion2 = true) {
          var key = _step2.value;
          viewport[key] = lerp(startProps[key], endProps[key], t);
        }
      } catch (err) {
        _didIteratorError2 = true;
        _iteratorError2 = err;
      } finally {
        try {
          if (!_iteratorNormalCompletion2 && _iterator2["return"] != null) {
            _iterator2["return"]();
          }
        } finally {
          if (_didIteratorError2) {
            throw _iteratorError2;
          }
        }
      }

      if (endProps.around) {
        // zoom around provided point
        var _getMapCenterByLngLat = new WebMercatorViewport(Object.assign({}, endProps, viewport)).getMapCenterByLngLatPosition({
          lngLat: endProps.aroundLngLat,
          // anchor point in current screen coordinates
          pos: lerp(startProps.around, endProps.around, t)
        }),
            _getMapCenterByLngLat2 = _slicedToArray(_getMapCenterByLngLat, 2),
            longitude = _getMapCenterByLngLat2[0],
            latitude = _getMapCenterByLngLat2[1];

        viewport.longitude = longitude;
        viewport.latitude = latitude;
      }

      return viewport;
    }
  }]);

  return LinearInterpolator;
}(TransitionInterpolator);

export { LinearInterpolator as default };
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