terriajs/lib/Map/DrawExtentHelper.js

Geospatial data visualization platform.

/*global require*/
"use strict";

var CallbackProperty = require('terriajs-cesium/Source/DataSources/CallbackProperty');
var CesiumMath = require('terriajs-cesium/Source/Core/Math');
var Color = require('terriajs-cesium/Source/Core/Color');
var CustomDataSource = require('terriajs-cesium/Source/DataSources/CustomDataSource');
var defaultValue = require('terriajs-cesium/Source/Core/defaultValue');
var defined = require('terriajs-cesium/Source/Core/defined');
var KeyboardEventModifier = require('terriajs-cesium/Source/Core/KeyboardEventModifier');
var Rectangle = require('terriajs-cesium/Source/Core/Rectangle');
var ScreenSpaceEventHandler = require('terriajs-cesium/Source/Core/ScreenSpaceEventHandler');
var ScreenSpaceEventType = require('terriajs-cesium/Source/Core/ScreenSpaceEventType');

// -------------------------------------------
// DrawExtentHelper from the cesium sample code
// modified to be available with a keyboard modifier
// on left-click - default is SHIFT
// -------------------------------------------
var DrawExtentHelper = function (terria, scene, handler, keyboardModifier) {
    this._terria = terria;
    this._scene = scene;
    this._ellipsoid = scene.globe.ellipsoid;
    this._finishHandler = handler;
    this._mouseHandler = new ScreenSpaceEventHandler(scene.canvas, false);
    this._stopHandler = undefined;
    this._interHandler = undefined;
    this._dataSource = undefined;
    this._click1 = undefined;
    this._click2 = undefined;
    this.active = false;
		this.keyboardModifier = defaultValue(keyboardModifier,  KeyboardEventModifier.SHIFT);
};

DrawExtentHelper.prototype.enableInput = function () {
    var controller = this._scene.screenSpaceCameraController;
    controller.enableInputs = true;
};

DrawExtentHelper.prototype.disableInput = function () {
    var controller = this._scene.screenSpaceCameraController;
    controller.enableInputs = false;
};

DrawExtentHelper.prototype.getExtent = function (mn, mx) {
    // Re-order south < north
    var south = Math.min(mn.latitude, mx.latitude);
    var north = Math.max(mn.latitude, mx.latitude);

    var west = Math.min(mn.longitude, mx.longitude);
    var east = Math.max(mn.longitude, mx.longitude);

    // If east-west is more than half the world, flip them.
    if (east - west > Math.PI) {
        west = Math.max(mn.longitude, mx.longitude);
        east = Math.min(mn.longitude, mx.longitude);
    }

    // Check for approx equal (shouldn't require abs due to re-order)
    var epsilon = CesiumMath.EPSILON6;

    if (Math.abs(east - west) < epsilon) {
        east += epsilon * 2.0;
    }

    if (Math.abs(north - south) < epsilon) {
        north += epsilon * 2.0;
    }

    return new Rectangle(west, south, east, north);
};

DrawExtentHelper.prototype.handleRegionStop = function (movement) {
    if (defined(this._dataSource)) {
        this._terria.dataSources.remove(this._dataSource, true);
        this._dataSource = undefined;
    }

    this._mouseHandler.removeInputAction(ScreenSpaceEventType.LEFT_UP, this.keyboardModifier);
    this._mouseHandler.removeInputAction(ScreenSpaceEventType.MOUSE_MOVE, this.keyboardModifier);
    this._mouseHandler.removeInputAction(ScreenSpaceEventType.LEFT_UP);
    this._mouseHandler.removeInputAction(ScreenSpaceEventType.MOUSE_MOVE);

    this.enableInput();
    var ext;
    if (movement) {
        var pickRay = this._scene.camera.getPickRay(movement.position);
        var cartesian = this._scene.globe.pick(pickRay, this._scene);
        if (cartesian) {
            this._click2 = this._ellipsoid.cartesianToCartographic(cartesian);
        }
        ext = this.getExtent(this._click1, this._click2);
    }
    this._scene.primitives.remove(this._extentPrimitive);
    this.active = false;
    this._finishHandler(ext);
};

DrawExtentHelper.prototype.handleRegionInter = function (movement) {
    var pickRay = this._scene.camera.getPickRay(movement.endPosition);
    var cartesian = this._scene.globe.pick(pickRay, this._scene);
    if (cartesian) {
        var cartographic = this._ellipsoid.cartesianToCartographic(cartesian);
        this._click2 = cartographic;
    }
};

DrawExtentHelper.prototype.handleRegionStart = function (movement) {
    var pickRay = this._scene.camera.getPickRay(movement.position);
    var cartesian = this._scene.globe.pick(pickRay, this._scene);
    if (cartesian) {
        this.disableInput();
        this.active = true;

        if (!defined(this._dataSource)) {
            var that = this;

            this._click1 = undefined;
            this._click2 = undefined;

            this._dataSource = new CustomDataSource('Draw Extent');
            this._dataSource.entities.add({
                name: 'Extent',
                rectangle: {
                    coordinates: new CallbackProperty(function(date, result) {
                        if (defined(that._click1) && defined(that._click2)) {
                            return that.getExtent(that._click1, that._click2);
                        }
                    }, false),
                    material: new Color(1.0, 1.0, 1.0, 0.5)
                }
            });
            this._terria.dataSources.add(this._dataSource);
        }

        this._click1 = this._ellipsoid.cartesianToCartographic(cartesian);

        this._mouseHandler.setInputAction(function (movement) {
            that.handleRegionStop(movement);
        }, ScreenSpaceEventType.LEFT_UP, this.keyboardModifier);
        this._mouseHandler.setInputAction(function (movement) {
            that.handleRegionInter(movement);
        }, ScreenSpaceEventType.MOUSE_MOVE, this.keyboardModifier);
        this._mouseHandler.setInputAction(function (movement) {
            that.handleRegionStop(movement);
        }, ScreenSpaceEventType.LEFT_UP);
        this._mouseHandler.setInputAction(function (movement) {
            that.handleRegionInter(movement);
        }, ScreenSpaceEventType.MOUSE_MOVE);
    }
};

DrawExtentHelper.prototype.start = function () {

    var that = this;

    // Now wait for start
    this._mouseHandler.setInputAction(function (movement) {
        that.handleRegionStart(movement);
    }, ScreenSpaceEventType.LEFT_DOWN, this.keyboardModifier);
};

DrawExtentHelper.prototype.destroy = function () {
    this._mouseHandler.destroy();
    this._scene = undefined;
};

module.exports = DrawExtentHelper;