@globalfishingwatch/react-map-gl/src/components/marker.js

A React wrapper for MapboxGL-js and overlay API.

// @flow
// Copyright (c) 2015 Uber Technologies, Inc.

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
import * as React from 'react';
import {useMemo} from 'react';
import PropTypes from 'prop-types';
import useDraggableControl, {
  draggableControlDefaultProps,
  draggableControlPropTypes
} from './draggable-control';
import {crispPixel} from '../utils/crisp-pixel';

import type {DraggableControlProps, DraggableControlRef} from './draggable-control';

const propTypes = Object.assign({}, draggableControlPropTypes, {
  // Custom className
  className: PropTypes.string,
  // Longitude of the anchor point
  longitude: PropTypes.number.isRequired,
  // Latitude of the anchor point
  latitude: PropTypes.number.isRequired
});

const defaultProps = Object.assign({}, draggableControlDefaultProps, {
  className: ''
});

export type MarkerProps = DraggableControlProps & {
  className: string,
  longitude: number,
  latitude: number
};

function getPosition({props, state, context}): [number, number] {
  const {longitude, latitude, offsetLeft, offsetTop} = props;
  const {dragPos, dragOffset} = state;

  // If dragging, just return the current drag position
  if (dragPos && dragOffset) {
    return [dragPos[0] + dragOffset[0], dragPos[1] + dragOffset[1]];
  }

  // Otherwise return the projected lat/lng with offset
  let [x, y] = context.viewport.project([longitude, latitude]);
  x += offsetLeft;
  y += offsetTop;
  return [x, y];
}

/*
 * PureComponent doesn't update when context changes.
 * The only way is to implement our own shouldComponentUpdate here. Considering
 * the parent component (StaticMap or InteractiveMap) is pure, and map re-render
 * is almost always triggered by a viewport change, we almost definitely need to
 * recalculate the marker's position when the parent re-renders.
 */
function Marker(props: MarkerProps) {
  const thisRef: DraggableControlRef = useDraggableControl(props);
  const {state, containerRef} = thisRef;

  const {draggable} = props;
  const {dragPos} = state;

  const [x, y] = getPosition(thisRef);
  const transform = `translate(${crispPixel(x)}px, ${crispPixel(y)}px)`;
  const cursor = draggable ? (dragPos ? 'grabbing' : 'grab') : 'auto';

  const control = useMemo(
    () => {
      const containerStyle = {
        position: 'absolute',
        left: 0,
        top: 0,
        transform,
        cursor
      };

      return (
        <div
          className={`mapboxgl-marker ${props.className}`}
          ref={thisRef.containerRef}
          style={containerStyle}
        >
          {props.children}
        </div>
      );
    },
    [props.className]
  );

  const container = containerRef.current;
  if (container) {
    container.style.transform = transform;
    container.style.cursor = cursor;
  }

  return control;
}

Marker.defaultProps = defaultProps;
Marker.propTypes = propTypes;

export default Marker;