mapboxgl-control-minimap.js

function Minimap ( options )
{
	Object.assign(this.options, options);

	this._ticking = false;
	this._lastMouseMoveEvent = null;
	this._parentMap = null;
	this._isDragging = false;
	this._isCursorOverFeature = false;
	this._previousPoint = [0, 0];
	this._currentPoint = [0, 0];
	this._trackingRectCoordinates = [[[], [], [], [], []]];
}

Minimap.prototype = Object.assign({}, mapboxgl.NavigationControl.prototype, {

	options: {
		id: "mapboxgl-minimap",
		width: "320px",
		height: "180px",
		style: "mapbox://styles/mapbox/streets-v8",
		center: [0, 0],
		zoom: 6,

		// should be a function; will be bound to Minimap
		zoomAdjust: null,

		// if parent map zoom >= 18 and minimap zoom >= 14, set minimap zoom to 16
		zoomLevels: [
			[18, 14, 16],
			[16, 12, 14],
			[14, 10, 12],
			[12, 8, 10],
			[10, 6, 8]
		],

		lineColor: "#08F",
		lineWidth: 1,
		lineOpacity: 1,

		fillColor: "#F80",
		fillOpacity: 0.25,

		dragPan: false,
		scrollZoom: false,
		boxZoom: false,
		dragRotate: false,
		keyboard: false,
		doubleClickZoom: false,
		touchZoomRotate: false
	},

	onAdd: function ( parentMap )
	{
		this._parentMap = parentMap;

		var opts = this.options;
		var container = this._container = this._createContainer(parentMap);
		var miniMap = this._miniMap = new mapboxgl.Map({
			attributionControl: false,
			container: container,
			style: opts.style,
			zoom: opts.zoom,
			center: opts.center
		});

		if (opts.maxBounds) miniMap.setMaxBounds(opts.maxBounds);

		miniMap.on("load", this._load.bind(this));

		return this._container;
	},

	_load: function ()
	{
		var opts = this.options;
		var parentMap = this._parentMap;
		var miniMap = this._miniMap;
		var interactions = [
			"dragPan", "scrollZoom", "boxZoom", "dragRotate",
			"keyboard", "doubleClickZoom", "touchZoomRotate"
		];

		interactions.forEach(function(i){
			if( opts[i] !== true ) {
				miniMap[i].disable();
			}
		});

		if( typeof opts.zoomAdjust === "function" ) {
			this.options.zoomAdjust = opts.zoomAdjust.bind(this);
		} else if( opts.zoomAdjust === null ) {
			this.options.zoomAdjust = this._zoomAdjust.bind(this);
		}

		var bounds = miniMap.getBounds();

		this._convertBoundsToPoints(bounds);

		miniMap.addSource("trackingRect", {
			"type": "geojson",
			"data": {
				"type": "Feature",
				"properties": {
					"name": "trackingRect"
				},
				"geometry": {
					"type": "Polygon",
					"coordinates": this._trackingRectCoordinates
				}
			}
		});

		miniMap.addLayer({
			"id": "trackingRectOutline",
			"type": "line",
			"source": "trackingRect",
			"layout": {},
			"paint": {
				"line-color": opts.lineColor,
				"line-width": opts.lineWidth,
				"line-opacity": opts.lineOpacity
			}
		});

		// needed for dragging
		miniMap.addLayer({
			"id": "trackingRectFill",
			"type": "fill",
			"source": "trackingRect",
			"layout": {},
			"paint": {
				"fill-color": opts.fillColor,
				"fill-opacity": opts.fillOpacity
			}
		});

		this._trackingRect = this._miniMap.getSource("trackingRect");

		this._update();

		parentMap.on("move", this._update.bind(this));

		miniMap.on("mousemove", this._mouseMove.bind(this));
		miniMap.on("mousedown", this._mouseDown.bind(this));
		miniMap.on("mouseup", this._mouseUp.bind(this));

		miniMap.on("touchmove", this._mouseMove.bind(this));
		miniMap.on("touchstart", this._mouseDown.bind(this));
		miniMap.on("touchend", this._mouseUp.bind(this));

		this._miniMapCanvas = miniMap.getCanvasContainer();
		this._miniMapCanvas.addEventListener("wheel", this._preventDefault);
		this._miniMapCanvas.addEventListener("mousewheel", this._preventDefault);
	},

	_mouseDown: function ( e )
	{
		if( this._isCursorOverFeature )
		{
			this._isDragging = true;
			this._previousPoint = this._currentPoint;
			this._currentPoint = [e.lngLat.lng, e.lngLat.lat];
		}
	},

	_mouseMove: function (e)
	{
		this._ticking = false;

		var miniMap = this._miniMap;
		var features = miniMap.queryRenderedFeatures(e.point, {
			layers: ["trackingRectFill"]
		});

		// don't update if we're still hovering the area
		if( ! (this._isCursorOverFeature && features.length > 0) )
		{
			this._isCursorOverFeature = features.length > 0;
			this._miniMapCanvas.style.cursor = this._isCursorOverFeature ? "move" : "";
		}

		if( this._isDragging )
		{
			this._previousPoint = this._currentPoint;
			this._currentPoint = [e.lngLat.lng, e.lngLat.lat];

			var offset = [
				this._previousPoint[0] - this._currentPoint[0],
				this._previousPoint[1] - this._currentPoint[1]
			];

			var newBounds = this._moveTrackingRect(offset);

			this._parentMap.fitBounds(newBounds, {
				duration: 80,
				noMoveStart: true
			});
		}
	},

	_mouseUp: function ()
	{
		this._isDragging = false;
		this._ticking = false;
	},

	_moveTrackingRect: function ( offset )
	{
		var source = this._trackingRect;
		var data = source._data;
		var bounds = data.properties.bounds;

		bounds._ne.lat -= offset[1];
		bounds._ne.lng -= offset[0];
		bounds._sw.lat -= offset[1];
		bounds._sw.lng -= offset[0];

		this._convertBoundsToPoints(bounds);
		source.setData(data);

		return bounds;
	},

	_setTrackingRectBounds: function ( bounds )
	{
		var source = this._trackingRect;
		var data = source._data;

		data.properties.bounds = bounds;
		this._convertBoundsToPoints(bounds);
		source.setData(data);
	},

	_convertBoundsToPoints: function ( bounds )
	{
		var ne = bounds._ne;
		var sw = bounds._sw;
		var trc = this._trackingRectCoordinates;

		trc[0][0][0] = ne.lng;
		trc[0][0][1] = ne.lat;
		trc[0][1][0] = sw.lng;
		trc[0][1][1] = ne.lat;
		trc[0][2][0] = sw.lng;
		trc[0][2][1] = sw.lat;
		trc[0][3][0] = ne.lng;
		trc[0][3][1] = sw.lat;
		trc[0][4][0] = ne.lng;
		trc[0][4][1] = ne.lat;
	},

	_update: function ( e )
	{
		if( this._isDragging  ) {
			return;
		}

		var parentBounds = this._parentMap.getBounds();

		this._setTrackingRectBounds(parentBounds);

		if( typeof this.options.zoomAdjust === "function" ) {
			this.options.zoomAdjust();
		}
	},

	_zoomAdjust: function ()
	{
		var miniMap = this._miniMap;
		var parentMap = this._parentMap;
		var miniZoom = parseInt(miniMap.getZoom(), 10);
		var parentZoom = parseInt(parentMap.getZoom(), 10);
		var levels = this.options.zoomLevels;
		var found = false;

		levels.forEach(function(zoom)
		{
			if( ! found && parentZoom >= zoom[0] )
			{
				if( miniZoom >= zoom[1] ) {
					miniMap.setZoom(zoom[2]);
				}

				miniMap.setCenter(parentMap.getCenter());
				found = true;
			}
		});

		if( ! found && miniZoom !== this.options.zoom )
		{
			if( typeof this.options.bounds === "object" ) {
				miniMap.fitBounds(this.options.bounds, {duration: 50});
			}

			miniMap.setZoom(this.options.zoom)
		}
	},

	_createContainer: function ( parentMap )
	{
		var opts = this.options;
		var container = document.createElement("div");

		container.className = "mapboxgl-ctrl-minimap mapboxgl-ctrl";
		container.setAttribute('style', 'width: ' + opts.width + '; height: ' + opts.height + ';');
		container.addEventListener("contextmenu", this._preventDefault);

		parentMap.getContainer().appendChild(container);

		if( opts.id !== "" ) {
			container.id = opts.id;
		}

		return container;
	},

	_preventDefault: function ( e ) {
		e.preventDefault();
	}
});

mapboxgl.Minimap = Minimap;