react-map-gl/src/components/interactive-map.js

import * as React from 'react';
import {useContext, useRef, useMemo, useEffect, useLayoutEffect, forwardRef} from 'react';
import * as PropTypes from 'prop-types';

import StaticMap from './static-map';
import {MAPBOX_LIMITS} from '../utils/map-state';
import WebMercatorViewport from 'viewport-mercator-project';

import TransitionManager from '../utils/transition-manager';
import MapContext, {MapContextProvider} from './map-context';

import {EventManager} from 'mjolnir.js';
import MapController from '../utils/map-controller';

const propTypes = Object.assign({}, StaticMap.propTypes, {
  // Additional props on top of StaticMap

  /** Viewport constraints */
  // Max zoom level
  maxZoom: PropTypes.number,
  // Min zoom level
  minZoom: PropTypes.number,
  // Max pitch in degrees
  maxPitch: PropTypes.number,
  // Min pitch in degrees
  minPitch: PropTypes.number,

  // Callbacks fired when the user interacted with the map. The object passed to the callbacks
  // contains viewport properties such as `longitude`, `latitude`, `zoom` etc.
  onViewStateChange: PropTypes.func,
  onViewportChange: PropTypes.func,
  onInteractionStateChange: PropTypes.func,

  /** Viewport transition **/
  // transition duration for viewport change
  transitionDuration: PropTypes.oneOfType([PropTypes.number, PropTypes.string]),
  // TransitionInterpolator instance, can be used to perform custom transitions.
  transitionInterpolator: PropTypes.object,
  // type of interruption of current transition on update.
  transitionInterruption: PropTypes.number,
  // easing function
  transitionEasing: PropTypes.func,
  // transition status update functions
  onTransitionStart: PropTypes.func,
  onTransitionInterrupt: PropTypes.func,
  onTransitionEnd: PropTypes.func,

  /** Enables control event handling */
  // Scroll to zoom
  scrollZoom: PropTypes.bool,
  // Drag to pan
  dragPan: PropTypes.bool,
  // Drag to rotate
  dragRotate: PropTypes.bool,
  // Double click to zoom
  doubleClickZoom: PropTypes.bool,
  // Multitouch zoom
  touchZoom: PropTypes.bool,
  // Multitouch rotate
  touchRotate: PropTypes.bool,
  // Keyboard
  keyboard: PropTypes.bool,

  /** Event callbacks */
  onHover: PropTypes.func,
  onClick: PropTypes.func,
  onDblClick: PropTypes.func,
  onContextMenu: PropTypes.func,
  onMouseDown: PropTypes.func,
  onMouseMove: PropTypes.func,
  onMouseUp: PropTypes.func,
  onTouchStart: PropTypes.func,
  onTouchMove: PropTypes.func,
  onTouchEnd: PropTypes.func,
  onMouseEnter: PropTypes.func,
  onMouseLeave: PropTypes.func,
  onMouseOut: PropTypes.func,
  onWheel: PropTypes.func,

  /** Custom touch-action CSS for the event canvas. Defaults to 'none' */
  touchAction: PropTypes.string,

  /** Custom hammer.js recognizer options */
  eventRecognizerOptions: PropTypes.object,

  /** Radius to detect features around a clicked point. Defaults to 0. */
  clickRadius: PropTypes.number,

  /** List of layers that are interactive */
  interactiveLayerIds: PropTypes.array,

  /** Accessor that returns a cursor style to show interactive state */
  getCursor: PropTypes.func,

  // A map control instance to replace the default map controller
  // The object must expose a method: `setOptions(opts)`
  controller: PropTypes.instanceOf(MapController)
});

const getDefaultCursor = ({isDragging, isHovering}) =>
  isDragging ? 'grabbing' : isHovering ? 'pointer' : 'grab';

const defaultProps = Object.assign(
  {},
  StaticMap.defaultProps,
  MAPBOX_LIMITS,
  TransitionManager.defaultProps,
  {
    onViewStateChange: null,
    onViewportChange: null,
    onClick: null,
    onNativeClick: null,
    onHover: null,
    onContextMenu: event => event.preventDefault(),

    scrollZoom: true,
    dragPan: true,
    dragRotate: true,
    doubleClickZoom: true,
    touchZoom: true,
    touchRotate: false,
    keyboard: true,

    touchAction: 'none',
    eventRecognizerOptions: {},
    clickRadius: 0,
    getCursor: getDefaultCursor
  }
);

/* Event handlers */
function normalizeEvent(event) {
  if (event.lngLat || !event.offsetCenter) {
    return event;
  }

  const {
    offsetCenter: {x, y}
  } = event;
  const pos = [x, y];

  const viewport = new WebMercatorViewport(
    Object.assign({}, this.props, {
      width: this.width,
      height: this.height
    })
  );

  event.point = pos;
  event.lngLat = viewport.unproject(pos);

  return event;
}

function getFeatures(pos) {
  const {map} = this;

  if (!map || !pos) {
    return null;
  }

  const queryParams = {};
  const size = this.props.clickRadius;

  if (this.props.interactiveLayerIds) {
    queryParams.layers = this.props.interactiveLayerIds;
  }

  try {
    // This may fail if map is still loading
    return map.queryRenderedFeatures(
      size
        ? // Radius enables point features, like marker symbols, to be clicked.
          [
            [pos[0] - size, pos[1] + size],
            [pos[0] + size, pos[1] - size]
          ]
        : pos,
      queryParams
    );
  } catch {
    return null;
  }
}

function onEvent(callbackName, event) {
  const func = this.props[callbackName];
  if (func) {
    func(normalizeEvent.call(this, event));
  }
}

function onPointerDown(event) {
  onEvent.call(this, event.pointerType === 'touch' ? 'onTouchStart' : 'onMouseDown', event);
}

function onPointerUp(event) {
  onEvent.call(this, event.pointerType === 'touch' ? 'onTouchEnd' : 'onMouseUp', event);
}

// eslint-disable-next-line complexity
function onPointerMove(event) {
  onEvent.call(this, event.pointerType === 'touch' ? 'onTouchMove' : 'onMouseMove', event);

  if (!this.state.isDragging) {
    const {onHover, interactiveLayerIds} = this.props;
    let features;
    event = normalizeEvent.call(this, event);
    if (interactiveLayerIds || onHover) {
      features = getFeatures.call(this, event.point);
    }
    if (onHover) {
      // backward compatibility: v3 `onHover` interface
      event.features = features;
      onHover(event);
    }

    const isHovering = Boolean(interactiveLayerIds && features && features.length > 0);
    const isEntering = isHovering && !this.state.isHovering;
    const isExiting = !isHovering && this.state.isHovering;

    if (isEntering) {
      onEvent.call(this, 'onMouseEnter', event);
    }
    if (isExiting) {
      onEvent.call(this, 'onMouseLeave', event);
    }
    if (isEntering || isExiting) {
      this.setState({isHovering});
    }
  }
}

function onPointerClick(event) {
  const {onClick, onNativeClick, onDblClick, doubleClickZoom} = this.props;
  let callbacks = [];
  const isDoubleClickEnabled = onDblClick || doubleClickZoom;

  // `click` is only fired on single click. `anyclick` is fired twice if double clicking.
  // `click` has a delay period after pointer up that prevents it from firing when
  // double clicking. `anyclick` is always fired immediately after pointer up.
  // If double click is turned off by the user, we want to immediately fire the
  // onClick event. Otherwise, we wait to make sure it's a single click.
  switch (event.type) {
    case 'anyclick':
      callbacks.push(onNativeClick);
      if (!isDoubleClickEnabled) {
        callbacks.push(onClick);
      }
      break;

    case 'click':
      if (isDoubleClickEnabled) {
        callbacks.push(onClick);
      }
      break;

    default:
  }

  callbacks = callbacks.filter(Boolean);

  if (callbacks.length) {
    event = normalizeEvent.call(this, event);
    // backward compatibility: v3 `onClick` interface
    event.features = getFeatures.call(this, event.point);
    callbacks.forEach(cb => cb(event));
  }
}
/* End of event handers */

/* eslint-disable max-statements */
const InteractiveMap = forwardRef((props, ref) => {
  const parentContext = useContext(MapContext);
  const controller = useMemo(() => props.controller || new MapController(), []);
  const eventManager = useMemo(
    () =>
      new EventManager(null, {
        touchAction: props.touchAction,
        recognizerOptions: props.eventRecognizerOptions
      }),
    []
  );
  const eventCanvasRef = useRef(null);
  const staticMapRef = ref || useRef(null);

  // Event handlers are registered once but need access to the latest props
  // This is an anti-pattern, though it maintains a persistent reference to the latest props/state of this component
  const _thisRef = useRef({
    width: 0,
    height: 0,
    state: {
      isHovering: false,
      isDragging: false
    }
  });
  const thisRef = _thisRef.current;
  thisRef.props = props;
  thisRef.map = staticMapRef.current && staticMapRef.current.getMap();
  thisRef.setState = newState => {
    thisRef.state = {...thisRef.state, ...newState};
    eventCanvasRef.current.style.cursor = props.getCursor(thisRef.state);
  };

  let inRender = true;
  let viewportUpdateRequested;
  let stateUpdateRequested;

  const handleViewportChange = (viewState, interactionState, oldViewState) => {
    if (inRender) {
      // Do not call the callbacks during render - may result in "cannot update during an existing state transition" error.
      // Defer the update until after render
      viewportUpdateRequested = [viewState, interactionState, oldViewState];
      return;
    }
    const {onViewStateChange, onViewportChange} = props;

    if (onViewStateChange) {
      onViewStateChange({viewState, interactionState, oldViewState});
    }
    if (onViewportChange) {
      onViewportChange(viewState, interactionState, oldViewState);
    }
  };

  const context = useMemo(
    () => ({
      ...parentContext,
      eventManager,
      container: parentContext.container || eventCanvasRef.current
    }),
    [parentContext, eventCanvasRef.current]
  );
  context.onViewportChange = handleViewportChange;

  const handleInteractionStateChange = interactionState => {
    const {isDragging = false} = interactionState;
    if (isDragging !== thisRef.state.isDragging) {
      thisRef.setState({isDragging});
    }

    if (inRender) {
      // Do not call the callbacks during render - may result in "cannot update during an existing state transition" error.
      // Defer the update until after render
      stateUpdateRequested = interactionState;
      return;
    }

    const {onInteractionStateChange} = props;
    if (onInteractionStateChange) {
      onInteractionStateChange(interactionState);
    }
  };

  const updateControllerOpts = () => {
    const opts = Object.assign({}, props, props.viewState, {
      isInteractive: Boolean(props.onViewStateChange || props.onViewportChange),
      onViewportChange: handleViewportChange,
      onStateChange: handleInteractionStateChange,
      eventManager,
      width: thisRef.width,
      height: thisRef.height
    });

    controller.setOptions(opts);
  };

  const onResize = ({width, height}) => {
    thisRef.width = width;
    thisRef.height = height;
    updateControllerOpts();
    props.onResize({width, height});
  };

  useEffect(() => {
    eventManager.setElement(eventCanvasRef.current);
    // Register event handlers
    eventManager.on({
      pointerdown: onPointerDown.bind(thisRef),
      pointermove: onPointerMove.bind(thisRef),
      pointerup: onPointerUp.bind(thisRef),
      pointerleave: onEvent.bind(thisRef, 'onMouseOut'),
      click: onPointerClick.bind(thisRef),
      anyclick: onPointerClick.bind(thisRef),
      dblclick: onEvent.bind(thisRef, 'onDblClick'),
      wheel: onEvent.bind(thisRef, 'onWheel'),
      contextmenu: onEvent.bind(thisRef, 'onContextMenu')
    });

    // Clean up on unmount
    return () => {
      eventManager.destroy();
    };
  }, []);

  useLayoutEffect(() => {
    if (viewportUpdateRequested) {
      // Perform deferred updates
      handleViewportChange(...viewportUpdateRequested);
    }
    if (stateUpdateRequested) {
      handleInteractionStateChange(stateUpdateRequested);
    }
  });

  updateControllerOpts();

  const {width, height, style, getCursor} = props;

  const eventCanvasStyle = useMemo(
    () => ({
      position: 'relative',
      ...style,
      width,
      height,
      cursor: getCursor(thisRef.state)
    }),
    [style, width, height, getCursor, thisRef.state]
  );

  if (!viewportUpdateRequested) {
    // Only rerender if no viewport update has been requested during render.
    // Otherwise return the last rendered child, and invoke the callback when we're done.
    thisRef._child = (
      <MapContextProvider value={context}>
        <div key="event-canvas" ref={eventCanvasRef} style={eventCanvasStyle}>
          <StaticMap
            {...props}
            width="100%"
            height="100%"
            style={null}
            onResize={onResize}
            ref={staticMapRef}
          />
        </div>
      </MapContextProvider>
    );
  }

  inRender = false;
  return thisRef._child;
});

InteractiveMap.supported = StaticMap.supported;
InteractiveMap.propTypes = propTypes;
InteractiveMap.defaultProps = defaultProps;

export default InteractiveMap;