openlayers/src/ol/control/OverviewMap.js

/**
 * @module ol/control/OverviewMap
 */
import {inherits} from '../util.js';
import Collection from '../Collection.js';
import Map from '../Map.js';
import MapEventType from '../MapEventType.js';
import MapProperty from '../MapProperty.js';
import {getChangeEventType} from '../Object.js';
import ObjectEventType from '../ObjectEventType.js';
import Overlay from '../Overlay.js';
import OverlayPositioning from '../OverlayPositioning.js';
import ViewProperty from '../ViewProperty.js';
import Control from '../control/Control.js';
import {rotate as rotateCoordinate, add as addCoordinate} from '../coordinate.js';
import {CLASS_CONTROL, CLASS_UNSELECTABLE, CLASS_COLLAPSED} from '../css.js';
import {replaceNode} from '../dom.js';
import {listen, listenOnce, unlisten} from '../events.js';
import EventType from '../events/EventType.js';
import {containsExtent, getBottomLeft, getBottomRight, getTopLeft, getTopRight, scaleFromCenter} from '../extent.js';


/**
 * Maximum width and/or height extent ratio that determines when the overview
 * map should be zoomed out.
 * @type {number}
 */
const MAX_RATIO = 0.75;


/**
 * Minimum width and/or height extent ratio that determines when the overview
 * map should be zoomed in.
 * @type {number}
 */
const MIN_RATIO = 0.1;


/**
 * @typedef {Object} Options
 * @property {string} [className='ol-overviewmap'] CSS class name.
 * @property {boolean} [collapsed=true] Whether the control should start collapsed or not (expanded).
 * @property {string|Element} [collapseLabel='«'] Text label to use for the
 * expanded overviewmap button. Instead of text, also an element (e.g. a `span` element) can be used.
 * @property {boolean} [collapsible=true] Whether the control can be collapsed or not.
 * @property {string|Element} [label='»'] Text label to use for the collapsed
 * overviewmap button. Instead of text, also an element (e.g. a `span` element) can be used.
 * @property {Array.<module:ol/layer/Layer>|module:ol/Collection.<module:ol/layer/Layer>} [layers]
 * Layers for the overview map. If not set, then all main map layers are used
 * instead.
 * @property {function(module:ol/MapEvent)} [render] Function called when the control
 * should be re-rendered. This is called in a `requestAnimationFrame` callback.
 * @property {Element|string} [target] Specify a target if you want the control
 * to be rendered outside of the map's viewport.
 * @property {string} [tipLabel='Overview map'] Text label to use for the button tip.
 * @property {module:ol/View} [view] Custom view for the overview map. If not provided,
 * a default view with an EPSG:3857 projection will be used.
 */


/**
 * Create a new control with a map acting as an overview map for an other
 * defined map.
 * @constructor
 * @extends {module:ol/control/Control}
 * @param {module:ol/control/OverviewMap~Options=} opt_options OverviewMap options.
 * @api
 */
const OverviewMap = function(opt_options) {

  const options = opt_options ? opt_options : {};

  /**
   * @type {boolean}
   * @private
   */
  this.collapsed_ = options.collapsed !== undefined ? options.collapsed : true;

  /**
   * @private
   * @type {boolean}
   */
  this.collapsible_ = options.collapsible !== undefined ?
    options.collapsible : true;

  if (!this.collapsible_) {
    this.collapsed_ = false;
  }

  const className = options.className !== undefined ? options.className : 'ol-overviewmap';

  const tipLabel = options.tipLabel !== undefined ? options.tipLabel : 'Overview map';

  const collapseLabel = options.collapseLabel !== undefined ? options.collapseLabel : '\u00AB';

  if (typeof collapseLabel === 'string') {
    /**
     * @private
     * @type {Element}
     */
    this.collapseLabel_ = document.createElement('span');
    this.collapseLabel_.textContent = collapseLabel;
  } else {
    this.collapseLabel_ = collapseLabel;
  }

  const label = options.label !== undefined ? options.label : '\u00BB';


  if (typeof label === 'string') {
    /**
     * @private
     * @type {Element}
     */
    this.label_ = document.createElement('span');
    this.label_.textContent = label;
  } else {
    this.label_ = label;
  }

  const activeLabel = (this.collapsible_ && !this.collapsed_) ?
    this.collapseLabel_ : this.label_;
  const button = document.createElement('button');
  button.setAttribute('type', 'button');
  button.title = tipLabel;
  button.appendChild(activeLabel);

  listen(button, EventType.CLICK,
    this.handleClick_, this);

  /**
   * @type {Element}
   * @private
   */
  this.ovmapDiv_ = document.createElement('DIV');
  this.ovmapDiv_.className = 'ol-overviewmap-map';

  /**
   * @type {module:ol/Map}
   * @private
   */
  this.ovmap_ = new Map({
    controls: new Collection(),
    interactions: new Collection(),
    view: options.view
  });
  const ovmap = this.ovmap_;

  if (options.layers) {
    options.layers.forEach(
      /**
       * @param {module:ol/layer/Layer} layer Layer.
       */
      (function(layer) {
        ovmap.addLayer(layer);
      }).bind(this));
  }

  const box = document.createElement('DIV');
  box.className = 'ol-overviewmap-box';
  box.style.boxSizing = 'border-box';

  /**
   * @type {module:ol/Overlay}
   * @private
   */
  this.boxOverlay_ = new Overlay({
    position: [0, 0],
    positioning: OverlayPositioning.BOTTOM_LEFT,
    element: box
  });
  this.ovmap_.addOverlay(this.boxOverlay_);

  const cssClasses = className + ' ' + CLASS_UNSELECTABLE + ' ' + CLASS_CONTROL +
      (this.collapsed_ && this.collapsible_ ? ' ' + CLASS_COLLAPSED : '') +
      (this.collapsible_ ? '' : ' ol-uncollapsible');
  const element = document.createElement('div');
  element.className = cssClasses;
  element.appendChild(this.ovmapDiv_);
  element.appendChild(button);

  Control.call(this, {
    element: element,
    render: options.render || render,
    target: options.target
  });

  /* Interactive map */

  const scope = this;

  const overlay = this.boxOverlay_;
  const overlayBox = this.boxOverlay_.getElement();

  /* Functions definition */

  const computeDesiredMousePosition = function(mousePosition) {
    return {
      clientX: mousePosition.clientX - (overlayBox.offsetWidth / 2),
      clientY: mousePosition.clientY + (overlayBox.offsetHeight / 2)
    };
  };

  const move = function(event) {
    const coordinates = ovmap.getEventCoordinate(computeDesiredMousePosition(event));

    overlay.setPosition(coordinates);
  };

  const endMoving = function(event) {
    const coordinates = ovmap.getEventCoordinate(event);

    scope.getMap().getView().setCenter(coordinates);

    window.removeEventListener('mousemove', move);
    window.removeEventListener('mouseup', endMoving);
  };

  /* Binding */

  overlayBox.addEventListener('mousedown', function() {
    window.addEventListener('mousemove', move);
    window.addEventListener('mouseup', endMoving);
  });
};

inherits(OverviewMap, Control);


/**
 * @inheritDoc
 * @api
 */
OverviewMap.prototype.setMap = function(map) {
  const oldMap = this.getMap();
  if (map === oldMap) {
    return;
  }
  if (oldMap) {
    const oldView = oldMap.getView();
    if (oldView) {
      this.unbindView_(oldView);
    }
    this.ovmap_.setTarget(null);
  }
  Control.prototype.setMap.call(this, map);

  if (map) {
    this.ovmap_.setTarget(this.ovmapDiv_);
    this.listenerKeys.push(listen(
      map, ObjectEventType.PROPERTYCHANGE,
      this.handleMapPropertyChange_, this));

    // TODO: to really support map switching, this would need to be reworked
    if (this.ovmap_.getLayers().getLength() === 0) {
      this.ovmap_.setLayerGroup(map.getLayerGroup());
    }

    const view = map.getView();
    if (view) {
      this.bindView_(view);
      if (view.isDef()) {
        this.ovmap_.updateSize();
        this.resetExtent_();
      }
    }
  }
};


/**
 * Handle map property changes.  This only deals with changes to the map's view.
 * @param {module:ol/Object~ObjectEvent} event The propertychange event.
 * @private
 */
OverviewMap.prototype.handleMapPropertyChange_ = function(event) {
  if (event.key === MapProperty.VIEW) {
    const oldView = /** @type {module:ol/View} */ (event.oldValue);
    if (oldView) {
      this.unbindView_(oldView);
    }
    const newView = this.getMap().getView();
    this.bindView_(newView);
  }
};


/**
 * Register listeners for view property changes.
 * @param {module:ol/View} view The view.
 * @private
 */
OverviewMap.prototype.bindView_ = function(view) {
  listen(view,
    getChangeEventType(ViewProperty.ROTATION),
    this.handleRotationChanged_, this);
};


/**
 * Unregister listeners for view property changes.
 * @param {module:ol/View} view The view.
 * @private
 */
OverviewMap.prototype.unbindView_ = function(view) {
  unlisten(view,
    getChangeEventType(ViewProperty.ROTATION),
    this.handleRotationChanged_, this);
};


/**
 * Handle rotation changes to the main map.
 * TODO: This should rotate the extent rectrangle instead of the
 * overview map's view.
 * @private
 */
OverviewMap.prototype.handleRotationChanged_ = function() {
  this.ovmap_.getView().setRotation(this.getMap().getView().getRotation());
};


/**
 * Update the overview map element.
 * @param {module:ol/MapEvent} mapEvent Map event.
 * @this {module:ol/control/OverviewMap}
 * @api
 */
export function render(mapEvent) {
  this.validateExtent_();
  this.updateBox_();
}


/**
 * Reset the overview map extent if the box size (width or
 * height) is less than the size of the overview map size times minRatio
 * or is greater than the size of the overview size times maxRatio.
 *
 * If the map extent was not reset, the box size can fits in the defined
 * ratio sizes. This method then checks if is contained inside the overview
 * map current extent. If not, recenter the overview map to the current
 * main map center location.
 * @private
 */
OverviewMap.prototype.validateExtent_ = function() {
  const map = this.getMap();
  const ovmap = this.ovmap_;

  if (!map.isRendered() || !ovmap.isRendered()) {
    return;
  }

  const mapSize = /** @type {module:ol/size~Size} */ (map.getSize());

  const view = map.getView();
  const extent = view.calculateExtent(mapSize);

  const ovmapSize = /** @type {module:ol/size~Size} */ (ovmap.getSize());

  const ovview = ovmap.getView();
  const ovextent = ovview.calculateExtent(ovmapSize);

  const topLeftPixel =
      ovmap.getPixelFromCoordinate(getTopLeft(extent));
  const bottomRightPixel =
      ovmap.getPixelFromCoordinate(getBottomRight(extent));

  const boxWidth = Math.abs(topLeftPixel[0] - bottomRightPixel[0]);
  const boxHeight = Math.abs(topLeftPixel[1] - bottomRightPixel[1]);

  const ovmapWidth = ovmapSize[0];
  const ovmapHeight = ovmapSize[1];

  if (boxWidth < ovmapWidth * MIN_RATIO ||
      boxHeight < ovmapHeight * MIN_RATIO ||
      boxWidth > ovmapWidth * MAX_RATIO ||
      boxHeight > ovmapHeight * MAX_RATIO) {
    this.resetExtent_();
  } else if (!containsExtent(ovextent, extent)) {
    this.recenter_();
  }
};


/**
 * Reset the overview map extent to half calculated min and max ratio times
 * the extent of the main map.
 * @private
 */
OverviewMap.prototype.resetExtent_ = function() {
  if (MAX_RATIO === 0 || MIN_RATIO === 0) {
    return;
  }

  const map = this.getMap();
  const ovmap = this.ovmap_;

  const mapSize = /** @type {module:ol/size~Size} */ (map.getSize());

  const view = map.getView();
  const extent = view.calculateExtent(mapSize);

  const ovview = ovmap.getView();

  // get how many times the current map overview could hold different
  // box sizes using the min and max ratio, pick the step in the middle used
  // to calculate the extent from the main map to set it to the overview map,
  const steps = Math.log(
    MAX_RATIO / MIN_RATIO) / Math.LN2;
  const ratio = 1 / (Math.pow(2, steps / 2) * MIN_RATIO);
  scaleFromCenter(extent, ratio);
  ovview.fit(extent);
};


/**
 * Set the center of the overview map to the map center without changing its
 * resolution.
 * @private
 */
OverviewMap.prototype.recenter_ = function() {
  const map = this.getMap();
  const ovmap = this.ovmap_;

  const view = map.getView();

  const ovview = ovmap.getView();

  ovview.setCenter(view.getCenter());
};


/**
 * Update the box using the main map extent
 * @private
 */
OverviewMap.prototype.updateBox_ = function() {
  const map = this.getMap();
  const ovmap = this.ovmap_;

  if (!map.isRendered() || !ovmap.isRendered()) {
    return;
  }

  const mapSize = /** @type {module:ol/size~Size} */ (map.getSize());

  const view = map.getView();

  const ovview = ovmap.getView();

  const rotation = view.getRotation();

  const overlay = this.boxOverlay_;
  const box = this.boxOverlay_.getElement();
  const extent = view.calculateExtent(mapSize);
  const ovresolution = ovview.getResolution();
  const bottomLeft = getBottomLeft(extent);
  const topRight = getTopRight(extent);

  // set position using bottom left coordinates
  const rotateBottomLeft = this.calculateCoordinateRotate_(rotation, bottomLeft);
  overlay.setPosition(rotateBottomLeft);

  // set box size calculated from map extent size and overview map resolution
  if (box) {
    box.style.width = Math.abs((bottomLeft[0] - topRight[0]) / ovresolution) + 'px';
    box.style.height = Math.abs((topRight[1] - bottomLeft[1]) / ovresolution) + 'px';
  }
};


/**
 * @param {number} rotation Target rotation.
 * @param {module:ol/coordinate~Coordinate} coordinate Coordinate.
 * @return {module:ol/coordinate~Coordinate|undefined} Coordinate for rotation and center anchor.
 * @private
 */
OverviewMap.prototype.calculateCoordinateRotate_ = function(
  rotation, coordinate) {
  let coordinateRotate;

  const map = this.getMap();
  const view = map.getView();

  const currentCenter = view.getCenter();

  if (currentCenter) {
    coordinateRotate = [
      coordinate[0] - currentCenter[0],
      coordinate[1] - currentCenter[1]
    ];
    rotateCoordinate(coordinateRotate, rotation);
    addCoordinate(coordinateRotate, currentCenter);
  }
  return coordinateRotate;
};


/**
 * @param {MouseEvent} event The event to handle
 * @private
 */
OverviewMap.prototype.handleClick_ = function(event) {
  event.preventDefault();
  this.handleToggle_();
};


/**
 * @private
 */
OverviewMap.prototype.handleToggle_ = function() {
  this.element.classList.toggle(CLASS_COLLAPSED);
  if (this.collapsed_) {
    replaceNode(this.collapseLabel_, this.label_);
  } else {
    replaceNode(this.label_, this.collapseLabel_);
  }
  this.collapsed_ = !this.collapsed_;

  // manage overview map if it had not been rendered before and control
  // is expanded
  const ovmap = this.ovmap_;
  if (!this.collapsed_ && !ovmap.isRendered()) {
    ovmap.updateSize();
    this.resetExtent_();
    listenOnce(ovmap, MapEventType.POSTRENDER,
      function(event) {
        this.updateBox_();
      },
      this);
  }
};


/**
 * Return `true` if the overview map is collapsible, `false` otherwise.
 * @return {boolean} True if the widget is collapsible.
 * @api
 */
OverviewMap.prototype.getCollapsible = function() {
  return this.collapsible_;
};


/**
 * Set whether the overview map should be collapsible.
 * @param {boolean} collapsible True if the widget is collapsible.
 * @api
 */
OverviewMap.prototype.setCollapsible = function(collapsible) {
  if (this.collapsible_ === collapsible) {
    return;
  }
  this.collapsible_ = collapsible;
  this.element.classList.toggle('ol-uncollapsible');
  if (!collapsible && this.collapsed_) {
    this.handleToggle_();
  }
};


/**
 * Collapse or expand the overview map according to the passed parameter. Will
 * not do anything if the overview map isn't collapsible or if the current
 * collapsed state is already the one requested.
 * @param {boolean} collapsed True if the widget is collapsed.
 * @api
 */
OverviewMap.prototype.setCollapsed = function(collapsed) {
  if (!this.collapsible_ || this.collapsed_ === collapsed) {
    return;
  }
  this.handleToggle_();
};


/**
 * Determine if the overview map is collapsed.
 * @return {boolean} The overview map is collapsed.
 * @api
 */
OverviewMap.prototype.getCollapsed = function() {
  return this.collapsed_;
};


/**
 * Return the overview map.
 * @return {module:ol/PluggableMap} Overview map.
 * @api
 */
OverviewMap.prototype.getOverviewMap = function() {
  return this.ovmap_;
};
export default OverviewMap;