react-native-mock-tmp-build/build/api/PanResponder.js

A fully mocked and test-friendly version of react native

var _TouchHistoryMath=require('./TouchHistoryMath');var _TouchHistoryMath2=_interopRequireDefault(_TouchHistoryMath);function _interopRequireDefault(obj){return obj&&obj.__esModule?obj:{'default':obj};}

var currentCentroidXOfTouchesChangedAfter=
_TouchHistoryMath2['default'].currentCentroidXOfTouchesChangedAfter;
var currentCentroidYOfTouchesChangedAfter=
_TouchHistoryMath2['default'].currentCentroidYOfTouchesChangedAfter;
var previousCentroidXOfTouchesChangedAfter=
_TouchHistoryMath2['default'].previousCentroidXOfTouchesChangedAfter;
var previousCentroidYOfTouchesChangedAfter=
_TouchHistoryMath2['default'].previousCentroidYOfTouchesChangedAfter;
var currentCentroidX=_TouchHistoryMath2['default'].currentCentroidX;
var currentCentroidY=_TouchHistoryMath2['default'].currentCentroidY;

/**
 * `PanResponder` reconciles several touches into a single gesture. It makes
 * single-touch gestures resilient to extra touches, and can be used to
 * recognize simple multi-touch gestures.
 *
 * It provides a predictable wrapper of the responder handlers provided by the
 * [gesture responder system](/react-native/docs/gesture-responder-system.html).
 * For each handler, it provides a new `gestureState` object alongside the
 * native event object:
 *
 * ```
 * onPanResponderMove: (event, gestureState) => {}
 * ```
 *
 * A native event is a synthetic touch event with the following form:
 *
 *  - `nativeEvent`
 *      + `changedTouches` - Array of all touch events that have changed since the last event
 *      + `identifier` - The ID of the touch
 *      + `locationX` - The X position of the touch, relative to the element
 *      + `locationY` - The Y position of the touch, relative to the element
 *      + `pageX` - The X position of the touch, relative to the root element
 *      + `pageY` - The Y position of the touch, relative to the root element
 *      + `target` - The node id of the element receiving the touch event
 *      + `timestamp` - A time identifier for the touch, useful for velocity calculation
 *      + `touches` - Array of all current touches on the screen
 *
 * A `gestureState` object has the following:
 *
 *  - `stateID` - ID of the gestureState- persisted as long as there at least
 *     one touch on screen
 *  - `moveX` - the latest screen coordinates of the recently-moved touch
 *  - `moveY` - the latest screen coordinates of the recently-moved touch
 *  - `x0` - the screen coordinates of the responder grant
 *  - `y0` - the screen coordinates of the responder grant
 *  - `dx` - accumulated distance of the gesture since the touch started
 *  - `dy` - accumulated distance of the gesture since the touch started
 *  - `vx` - current velocity of the gesture
 *  - `vy` - current velocity of the gesture
 *  - `numberActiveTouches` - Number of touches currently on screen
 *
 * ### Basic Usage
 *
 * ```
 *   componentWillMount: function() {
 *     this._panResponder = PanResponder.create({
 *       // Ask to be the responder:
 *       onStartShouldSetPanResponder: (evt, gestureState) => true,
 *       onStartShouldSetPanResponderCapture: (evt, gestureState) => true,
 *       onMoveShouldSetPanResponder: (evt, gestureState) => true,
 *       onMoveShouldSetPanResponderCapture: (evt, gestureState) => true,
 *
 *       onPanResponderGrant: (evt, gestureState) => {
 *         // The guesture has started. Show visual feedback so the user knows
 *         // what is happening!
 *
 *         // gestureState.{x,y}0 will be set to zero now
 *       },
 *       onPanResponderMove: (evt, gestureState) => {
 *         // The most recent move distance is gestureState.move{X,Y}
 *
 *         // The accumulated gesture distance since becoming responder is
 *         // gestureState.d{x,y}
 *       },
 *       onPanResponderTerminationRequest: (evt, gestureState) => true,
 *       onPanResponderRelease: (evt, gestureState) => {
 *         // The user has released all touches while this view is the
 *         // responder. This typically means a gesture has succeeded
 *       },
 *       onPanResponderTerminate: (evt, gestureState) => {
 *         // Another component has become the responder, so this gesture
 *         // should be cancelled
 *       },
 *       onShouldBlockNativeResponder: (evt, gestureState) => {
 *         // Returns whether this component should block native components from becoming the JS
 *         // responder. Returns true by default. Is currently only supported on android.
 *         return true;
 *       },
 *     });
 *   },
 *
 *   render: function() {
 *     return (
 *       <View {...this._panResponder.panHandlers} />
 *     );
 *   },
 *
 * ```
 *
 * ### Working Example
 *
 * To see it in action, try the
 * [PanResponder example in UIExplorer](https://github.com/facebook/react-native/blob/master/Examples/UIExplorer/PanResponderExample.js)
 */

var PanResponder={

/**
   *
   * A graphical explanation of the touch data flow:
   *
   * +----------------------------+             +--------------------------------+
   * | ResponderTouchHistoryStore |             |TouchHistoryMath                |
   * +----------------------------+             +----------+---------------------+
   * |Global store of touchHistory|             |Allocation-less math util       |
   * |including activeness, start |             |on touch history (centroids     |
   * |position, prev/cur position.|             |and multitouch movement etc)    |
   * |                            |             |                                |
   * +----^-----------------------+             +----^---------------------------+
   *      |                                          |
   *      | (records relevant history                |
   *      |  of touches relevant for                 |
   *      |  implementing higher level               |
   *      |  gestures)                               |
   *      |                                          |
   * +----+-----------------------+             +----|---------------------------+
   * | ResponderEventPlugin       |             |    |   Your App/Component      |
   * +----------------------------+             +----|---------------------------+
   * |Negotiates which view gets  | Low level   |    |             High level    |
   * |onResponderMove events.     | events w/   |  +-+-------+     events w/     |
   * |Also records history into   | touchHistory|  |   Pan   |     multitouch +  |
   * |ResponderTouchHistoryStore. +---------------->Responder+-----> accumulative|
   * +----------------------------+ attached to |  |         |     distance and  |
   *                                 each event |  +---------+     velocity.     |
   *                                            |                                |
   *                                            |                                |
   *                                            +--------------------------------+
   *
   *
   *
   * Gesture that calculates cumulative movement over time in a way that just
   * "does the right thing" for multiple touches. The "right thing" is very
   * nuanced. When moving two touches in opposite directions, the cumulative
   * distance is zero in each dimension. When two touches move in parallel five
   * pixels in the same direction, the cumulative distance is five, not ten. If
   * two touches start, one moves five in a direction, then stops and the other
   * touch moves fives in the same direction, the cumulative distance is ten.
   *
   * This logic requires a kind of processing of time "clusters" of touch events
   * so that two touch moves that essentially occur in parallel but move every
   * other frame respectively, are considered part of the same movement.
   *
   * Explanation of some of the non-obvious fields:
   *
   * - moveX/moveY: If no move event has been observed, then `(moveX, moveY)` is
   *   invalid. If a move event has been observed, `(moveX, moveY)` is the
   *   centroid of the most recently moved "cluster" of active touches.
   *   (Currently all move have the same timeStamp, but later we should add some
   *   threshold for what is considered to be "moving"). If a palm is
   *   accidentally counted as a touch, but a finger is moving greatly, the palm
   *   will move slightly, but we only want to count the single moving touch.
   * - x0/y0: Centroid location (non-cumulative) at the time of becoming
   *   responder.
   * - dx/dy: Cumulative touch distance - not the same thing as sum of each touch
   *   distance. Accounts for touch moves that are clustered together in time,
   *   moving the same direction. Only valid when currently responder (otherwise,
   *   it only represents the drag distance below the threshold).
   * - vx/vy: Velocity.
   */

_initializeGestureState:function(){function _initializeGestureState(gestureState){
var newGestureState=gestureState;
newGestureState.moveX=0;
newGestureState.moveY=0;
newGestureState.x0=0;
newGestureState.y0=0;
newGestureState.dx=0;
newGestureState.dy=0;
newGestureState.vx=0;
newGestureState.vy=0;
newGestureState.numberActiveTouches=0;
newGestureState._accountsForMovesUpTo=0;
}return _initializeGestureState;}(),

/**
   * This is nuanced and is necessary. It is incorrect to continuously take all
   * active *and* recently moved touches, find the centroid, and track how that
   * result changes over time. Instead, we must take all recently moved
   * touches, and calculate how the centroid has changed just for those
   * recently moved touches, and append that change to an accumulator. This is
   * to (at least) handle the case where the user is moving three fingers, and
   * then one of the fingers stops but the other two continue.
   *
   * This is very different than taking all of the recently moved touches and
   * storing their centroid as `dx/dy`. For correctness, we must *accumulate
   * changes* in the centroid of recently moved touches.
   *
   * There is also some nuance with how we handle multiple moved touches in a
   * single event. With the way `ReactNativeEventEmitter` dispatches touches as
   * individual events, multiple touches generate two 'move' events, each of
   * them triggering `onResponderMove`. But with the way `PanResponder` works,
   * all of the gesture inference is performed on the first dispatch, since it
   * looks at all of the touches (even the ones for which there hasn't been a
   * native dispatch yet). Therefore, `PanResponder` does not call
   * `onResponderMove` passed the first dispatch. This diverges from the
   * typical responder callback pattern (without using `PanResponder`), but
   * avoids more dispatches than necessary.
   */
_updateGestureStateOnMove:function(){function _updateGestureStateOnMove(gestureState,touchHistory){
var newGestureState=gestureState;
newGestureState.numberActiveTouches=touchHistory.numberActiveTouches;
newGestureState.moveX=currentCentroidXOfTouchesChangedAfter(
touchHistory,
newGestureState._accountsForMovesUpTo);

newGestureState.moveY=currentCentroidYOfTouchesChangedAfter(
touchHistory,
newGestureState._accountsForMovesUpTo);

var movedAfter=newGestureState._accountsForMovesUpTo;
var prevX=previousCentroidXOfTouchesChangedAfter(touchHistory,movedAfter);
var x=currentCentroidXOfTouchesChangedAfter(touchHistory,movedAfter);
var prevY=previousCentroidYOfTouchesChangedAfter(touchHistory,movedAfter);
var y=currentCentroidYOfTouchesChangedAfter(touchHistory,movedAfter);
var nextDX=newGestureState.dx+(x-prevX);
var nextDY=newGestureState.dy+(y-prevY);

// TODO: This must be filtered intelligently.
var dt=
touchHistory.mostRecentTimeStamp-newGestureState._accountsForMovesUpTo;
newGestureState.vx=(nextDX-newGestureState.dx)/dt;
newGestureState.vy=(nextDY-newGestureState.dy)/dt;

newGestureState.dx=nextDX;
newGestureState.dy=nextDY;
newGestureState._accountsForMovesUpTo=touchHistory.mostRecentTimeStamp;
}return _updateGestureStateOnMove;}(),

/**
   * @param {object} config Enhanced versions of all of the responder callbacks
   * that provide not only the typical `ResponderSyntheticEvent`, but also the
   * `PanResponder` gesture state.  Simply replace the word `Responder` with
   * `PanResponder` in each of the typical `onResponder*` callbacks. For
   * example, the `config` object would look like:
   *
   *  - `onMoveShouldSetPanResponder: (e, gestureState) => {...}`
   *  - `onMoveShouldSetPanResponderCapture: (e, gestureState) => {...}`
   *  - `onStartShouldSetPanResponder: (e, gestureState) => {...}`
   *  - `onStartShouldSetPanResponderCapture: (e, gestureState) => {...}`
   *  - `onPanResponderReject: (e, gestureState) => {...}`
   *  - `onPanResponderGrant: (e, gestureState) => {...}`
   *  - `onPanResponderStart: (e, gestureState) => {...}`
   *  - `onPanResponderEnd: (e, gestureState) => {...}`
   *  - `onPanResponderRelease: (e, gestureState) => {...}`
   *  - `onPanResponderMove: (e, gestureState) => {...}`
   *  - `onPanResponderTerminate: (e, gestureState) => {...}`
   *  - `onPanResponderTerminationRequest: (e, gestureState) => {...}`
   *  - `onShouldBlockNativeResponder: (e, gestureState) => {...}`
   *
   *  In general, for events that have capture equivalents, we update the
   *  gestureState once in the capture phase and can use it in the bubble phase
   *  as well.
   *
   *  Be careful with onStartShould* callbacks. They only reflect updated
   *  `gestureState` for start/end events that bubble/capture to the Node.
   *  Once the node is the responder, you can rely on every start/end event
   *  being processed by the gesture and `gestureState` being updated
   *  accordingly. (numberActiveTouches) may not be totally accurate unless you
   *  are the responder.
   */
create:function(){function create(config){
var gestureState={
// Useful for debugging
stateID:Math.random()};

PanResponder._initializeGestureState(gestureState);
var panHandlers={
onStartShouldSetResponder:function(){function onStartShouldSetResponder(e){
return config.onStartShouldSetPanResponder===undefined?false:
config.onStartShouldSetPanResponder(e,gestureState);
}return onStartShouldSetResponder;}(),
onMoveShouldSetResponder:function(){function onMoveShouldSetResponder(e){
return config.onMoveShouldSetPanResponder===undefined?false:
config.onMoveShouldSetPanResponder(e,gestureState);
}return onMoveShouldSetResponder;}(),
onStartShouldSetResponderCapture:function(){function onStartShouldSetResponderCapture(e){
// TODO: Actually, we should reinitialize the state any time
// touches.length increases from 0 active to > 0 active.
if(e.nativeEvent.touches.length===1){
PanResponder._initializeGestureState(gestureState);
}
gestureState.numberActiveTouches=e.touchHistory.numberActiveTouches;
return config.onStartShouldSetPanResponderCapture!==undefined?
config.onStartShouldSetPanResponderCapture(e,gestureState):false;
}return onStartShouldSetResponderCapture;}(),

onMoveShouldSetResponderCapture:function(){function onMoveShouldSetResponderCapture(e){
var touchHistory=e.touchHistory;
// Responder system incorrectly dispatches should* to current responder
// Filter out any touch moves past the first one - we would have
// already processed multi-touch geometry during the first event.
if(gestureState._accountsForMovesUpTo===touchHistory.mostRecentTimeStamp){
return false;
}
PanResponder._updateGestureStateOnMove(gestureState,touchHistory);
return config.onMoveShouldSetPanResponderCapture?
config.onMoveShouldSetPanResponderCapture(e,gestureState):false;
}return onMoveShouldSetResponderCapture;}(),

onResponderGrant:function(){function onResponderGrant(e){
gestureState.x0=currentCentroidX(e.touchHistory);
gestureState.y0=currentCentroidY(e.touchHistory);
gestureState.dx=0;
gestureState.dy=0;
if(config.onPanResponderGrant){
config.onPanResponderGrant(e,gestureState);
}
// TODO: t7467124 investigate if this can be removed
return config.onShouldBlockNativeResponder===undefined?true:
config.onShouldBlockNativeResponder();
}return onResponderGrant;}(),

onResponderReject:function(){function onResponderReject(e){
if(config.onPanResponderReject){
config.onPanResponderReject(e,gestureState);
}
}return onResponderReject;}(),

onResponderRelease:function(){function onResponderRelease(e){
if(config.onPanResponderRelease){
config.onPanResponderRelease(e,gestureState);
}
PanResponder._initializeGestureState(gestureState);
}return onResponderRelease;}(),

onResponderStart:function(){function onResponderStart(e){
var touchHistory=e.touchHistory;
gestureState.numberActiveTouches=touchHistory.numberActiveTouches;
if(config.onPanResponderStart){
config.onPanResponderStart(e,gestureState);
}
}return onResponderStart;}(),

onResponderMove:function(){function onResponderMove(e){
var touchHistory=e.touchHistory;
// Guard against the dispatch of two touch moves when there are two
// simultaneously changed touches.
if(gestureState._accountsForMovesUpTo===touchHistory.mostRecentTimeStamp){
return;
}
// Filter out any touch moves past the first one - we would have
// already processed multi-touch geometry during the first event.
PanResponder._updateGestureStateOnMove(gestureState,touchHistory);
if(config.onPanResponderMove){
config.onPanResponderMove(e,gestureState);
}
}return onResponderMove;}(),

onResponderEnd:function(){function onResponderEnd(e){
var touchHistory=e.touchHistory;
gestureState.numberActiveTouches=touchHistory.numberActiveTouches;
if(config.onPanResponderEnd){
config.onPanResponderEnd(e,gestureState);
}
}return onResponderEnd;}(),

onResponderTerminate:function(){function onResponderTerminate(e){
if(config.onPanResponderTerminate){
config.onPanResponderTerminate(e,gestureState);
}
PanResponder._initializeGestureState(gestureState);
}return onResponderTerminate;}(),

onResponderTerminationRequest:function(){function onResponderTerminationRequest(e){
return config.onPanResponderTerminationRequest===undefined?true:
config.onPanResponderTerminationRequest(e,gestureState);
}return onResponderTerminationRequest;}()};

return{panHandlers:panHandlers};
}return create;}()};


module.exports=PanResponder;