CameraRegionController.js

var Signal = require('signals').Signal;
var clamp = require('clamp');
function Controller(opts) {
	var pointers = opts.pointers;
	var onMouseWheelSignal = opts.mouseWheel ? opts.mouseWheel.onWheelSignal : null;

	var _panning = false;
	var _pinchEnabled = true;
	var _singleFingerPanEnabled = opts.singleFingerPanEnabled !== undefined ? opts.singleFingerPanEnabled : true;
	var _wheelEnabled = true;
	var panSignal = new Signal();
	var zoomSignal = new Signal();

	var mousePosition = [0, 0];

	var activePointers = [];
	var positions = [];
	for (var i = 0; i < 100; i++) {
		positions.push(0, 0);
	}

	function onPointerDown(x, y, id) {
		if(activePointers.indexOf(id) !== -1) return;
		if(id === 0 && activePointers.length < 2) {
			mousePosition[0] = x;
			mousePosition[1] = y;
		}
		if(activePointers.length >= 2) return;
		positions[id*2] = x;
		positions[id*2+1] = y;
		_panning = true;

		activePointers.push(id);
	}

	function onPointerMove(x, y) {
		mousePosition[0] = x;
		mousePosition[1] = y;
	}

	function len(x, y) {
		return Math.sqrt(x*x+y*y);
	}

	var indexAx, indexAy, indexBx, indexBy;
	function onPointerDrag(x, y, id) {
		if(id === 0 && activePointers.length < 2) {
			mousePosition[0] = x;
			mousePosition[1] = y;
		}
		if(activePointers.indexOf(id) === -1) return;
		indexAx = id*2;
		indexAy = indexAx+1;
		var activeFingers = activePointers.length;
		if (!_pinchEnabled) {
			activeFingers = 1; // only allow panning
		}

		switch(activeFingers) {
			case 1:
				if(_singleFingerPanEnabled) {
					panSignal.dispatch(
						positions[id*2] - x,
						positions[id*2+1] - y
					);
				}
				break;
			case 2:
				indexBx = (id*2+2)%4;
				indexBy = indexBx+1;
				panSignal.dispatch(
					(positions[indexAx] - x) * 0.5,
					(positions[indexAy] - y) * 0.5
				);
				var zoom = len(
					positions[indexAx] - positions[indexBx], 
					positions[indexAy] - positions[indexBy]
				) / len(
					x - positions[indexBx], 
					y - positions[indexBy]
				);
				zoomSignal.dispatch(
					(positions[0] + positions[2]) * 0.5,
					(positions[1] + positions[3]) * 0.5,
					zoom
				);
				break;
		}
		positions[indexAx] = x;
		positions[indexAy] = y;
	}

	function onMouseOut(x, y) {
		onPointerUp(x, y, pointers.mouseID);
	}

	function onPointerUp(x, y, id) {
		positions[id*2] = x;
		positions[id*2+1] = y;
		var index = activePointers.indexOf(id);
		if(index !== -1) activePointers.splice(index);
		_panning = false;
	}

	function onMouseWheelZoom(deltaX, deltaY, event) {
		if (!_wheelEnabled) return;
		zoomSignal.dispatch(
			mousePosition[0], 
			mousePosition[1], 
			clamp((3000 + deltaY) / 3000, 0.8, 1.2),
			true
		);
	}


	var active = false;

	function setState(state) {
		if(state === active) return;
		active = state;
		var op = state ? 'add' : 'remove';
		pointers.onPointerDownSignal[op](onPointerDown);
		pointers.onPointerMoveSignal[op](onPointerMove);
		pointers.onPointerDragSignal[op](onPointerDrag);
		pointers.onPointerUpSignal[op](onPointerUp);
		pointers.mouse.onOutSignal[op](onMouseOut);
		onMouseWheelSignal[op](onMouseWheelZoom);
		if(!state) {
			_panning = false;
			while(activePointers.length > 0) activePointers.splice(0, 1);
		}
	}

	function isPanning() {
		return _panning;
	}

	function setPinchEnabled(bool) {
		_pinchEnabled = bool;
	}

	function isPinchEnabled() {
		return _pinchEnabled;
	}

	function setSingleFingerPanEnabled(bool) {
		_singleFingerPanEnabled = bool;
	}

	function isSingleFingerPanEnabled() {
		return _singleFingerPanEnabled;
	}

	function setWheelEnabled(bool) {
		_wheelEnabled = bool;
	}

	function isWheelEnabled() {
		return _wheelEnabled
	}

	this.panSignal = panSignal;
	this.zoomSignal = zoomSignal;
	this.panSignal = panSignal;
	this.zoomSignal = zoomSignal;
	this.setState = setState;
	this.onPointerDown = onPointerDown;
	this.isPanning = isPanning;
	this.setPinchEnabled = setPinchEnabled;
	this.isPinchEnabled = isPinchEnabled;
	this.setSingleFingerPanEnabled = setSingleFingerPanEnabled;
	this.isSingleFingerPanEnabled = isSingleFingerPanEnabled;
	this.setWheelEnabled = setWheelEnabled;
	this.isWheelEnabled = isWheelEnabled;
	this.activePointers = activePointers;
}
module.exports = Controller;