src/ngTouch/swipe.js
'use strict';
/* global ngTouch: false */
/**
* @ngdoc service
* @name $swipe
*
* @deprecated
* sinceVersion="1.7.0"
*
* See the {@link ngTouch module} documentation for more information.
*
* @description
* The `$swipe` service is a service that abstracts the messier details of hold-and-drag swipe
* behavior, to make implementing swipe-related directives more convenient.
*
* Requires the {@link ngTouch `ngTouch`} module to be installed.
*
* `$swipe` is used by the `ngSwipeLeft` and `ngSwipeRight` directives in `ngTouch`.
*
* # Usage
* The `$swipe` service is an object with a single method: `bind`. `bind` takes an element
* which is to be watched for swipes, and an object with four handler functions. See the
* documentation for `bind` below.
*/
ngTouch.factory('$swipe', [function() {
// The total distance in any direction before we make the call on swipe vs. scroll.
var MOVE_BUFFER_RADIUS = 10;
var POINTER_EVENTS = {
'mouse': {
start: 'mousedown',
move: 'mousemove',
end: 'mouseup'
},
'touch': {
start: 'touchstart',
move: 'touchmove',
end: 'touchend',
cancel: 'touchcancel'
},
'pointer': {
start: 'pointerdown',
move: 'pointermove',
end: 'pointerup',
cancel: 'pointercancel'
}
};
function getCoordinates(event) {
var originalEvent = event.originalEvent || event;
var touches = originalEvent.touches && originalEvent.touches.length ? originalEvent.touches : [originalEvent];
var e = (originalEvent.changedTouches && originalEvent.changedTouches[0]) || touches[0];
return {
x: e.clientX,
y: e.clientY
};
}
function getEvents(pointerTypes, eventType) {
var res = [];
angular.forEach(pointerTypes, function(pointerType) {
var eventName = POINTER_EVENTS[pointerType][eventType];
if (eventName) {
res.push(eventName);
}
});
return res.join(' ');
}
return {
/**
* @ngdoc method
* @name $swipe#bind
*
* @description
* The main method of `$swipe`. It takes an element to be watched for swipe motions, and an
* object containing event handlers.
* The pointer types that should be used can be specified via the optional
* third argument, which is an array of strings `'mouse'`, `'touch'` and `'pointer'`. By default,
* `$swipe` will listen for `mouse`, `touch` and `pointer` events.
*
* The four events are `start`, `move`, `end`, and `cancel`. `start`, `move`, and `end`
* receive as a parameter a coordinates object of the form `{ x: 150, y: 310 }` and the raw
* `event`. `cancel` receives the raw `event` as its single parameter.
*
* `start` is called on either `mousedown`, `touchstart` or `pointerdown`. After this event, `$swipe` is
* watching for `touchmove`, `mousemove` or `pointermove` events. These events are ignored until the total
* distance moved in either dimension exceeds a small threshold.
*
* Once this threshold is exceeded, either the horizontal or vertical delta is greater.
* - If the horizontal distance is greater, this is a swipe and `move` and `end` events follow.
* - If the vertical distance is greater, this is a scroll, and we let the browser take over.
* A `cancel` event is sent.
*
* `move` is called on `mousemove`, `touchmove` and `pointermove` after the above logic has determined that
* a swipe is in progress.
*
* `end` is called when a swipe is successfully completed with a `touchend`, `mouseup` or `pointerup`.
*
* `cancel` is called either on a `touchcancel` or `pointercancel` from the browser, or when we begin scrolling
* as described above.
*
*/
bind: function(element, eventHandlers, pointerTypes) {
// Absolute total movement, used to control swipe vs. scroll.
var totalX, totalY;
// Coordinates of the start position.
var startCoords;
// Last event's position.
var lastPos;
// Whether a swipe is active.
var active = false;
pointerTypes = pointerTypes || ['mouse', 'touch', 'pointer'];
element.on(getEvents(pointerTypes, 'start'), function(event) {
startCoords = getCoordinates(event);
active = true;
totalX = 0;
totalY = 0;
lastPos = startCoords;
if (eventHandlers['start']) {
eventHandlers['start'](startCoords, event);
}
});
var events = getEvents(pointerTypes, 'cancel');
if (events) {
element.on(events, function(event) {
active = false;
if (eventHandlers['cancel']) {
eventHandlers['cancel'](event);
}
});
}
element.on(getEvents(pointerTypes, 'move'), function(event) {
if (!active) return;
// Android will send a touchcancel if it thinks we're starting to scroll.
// So when the total distance (+ or - or both) exceeds 10px in either direction,
// we either:
// - On totalX > totalY, we send preventDefault() and treat this as a swipe.
// - On totalY > totalX, we let the browser handle it as a scroll.
if (!startCoords) return;
var coords = getCoordinates(event);
totalX += Math.abs(coords.x - lastPos.x);
totalY += Math.abs(coords.y - lastPos.y);
lastPos = coords;
if (totalX < MOVE_BUFFER_RADIUS && totalY < MOVE_BUFFER_RADIUS) {
return;
}
// One of totalX or totalY has exceeded the buffer, so decide on swipe vs. scroll.
if (totalY > totalX) {
// Allow native scrolling to take over.
active = false;
if (eventHandlers['cancel']) {
eventHandlers['cancel'](event);
}
return;
} else {
// Prevent the browser from scrolling.
event.preventDefault();
if (eventHandlers['move']) {
eventHandlers['move'](coords, event);
}
}
});
element.on(getEvents(pointerTypes, 'end'), function(event) {
if (!active) return;
active = false;
if (eventHandlers['end']) {
eventHandlers['end'](getCoordinates(event), event);
}
});
}
};
}]);