[change] update PanResponder implementation

Fix #171

Author: necolas

src/apis/PanResponder/index.js

@@ -1,394 +1,2 @@
-/**
- * Copyright (c) 2016-present, Nicolas Gallagher.
- * Copyright (c) 2015-present, Facebook, Inc.
- * All rights reserved.
- *
- * This source code is licensed under the BSD-style license found in the
- * LICENSE file in the root directory of this source tree.
- *
- * @providesModule PanResponder
- * @noflow
- */
-
-import TouchHistoryMath from '../../vendor/TouchHistoryMath';
-
-const currentCentroidXOfTouchesChangedAfter =
-  TouchHistoryMath.currentCentroidXOfTouchesChangedAfter;
-const currentCentroidYOfTouchesChangedAfter =
-  TouchHistoryMath.currentCentroidYOfTouchesChangedAfter;
-const previousCentroidXOfTouchesChangedAfter =
-  TouchHistoryMath.previousCentroidXOfTouchesChangedAfter;
-const previousCentroidYOfTouchesChangedAfter =
-  TouchHistoryMath.previousCentroidYOfTouchesChangedAfter;
-const currentCentroidX = TouchHistoryMath.currentCentroidX;
-const currentCentroidY = TouchHistoryMath.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](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)
- */
-
-const 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(gestureState) {
-    gestureState.moveX = 0;
-    gestureState.moveY = 0;
-    gestureState.x0 = 0;
-    gestureState.y0 = 0;
-    gestureState.dx = 0;
-    gestureState.dy = 0;
-    gestureState.vx = 0;
-    gestureState.vy = 0;
-    gestureState.numberActiveTouches = 0;
-    // All `gestureState` accounts for timeStamps up until:
-    gestureState._accountsForMovesUpTo = 0;
-  },
-
-  /**
-   * 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(gestureState, touchHistory) {
-    gestureState.numberActiveTouches = touchHistory.numberActiveTouches;
-    gestureState.moveX = currentCentroidXOfTouchesChangedAfter(
-      touchHistory,
-      gestureState._accountsForMovesUpTo
-    );
-    gestureState.moveY = currentCentroidYOfTouchesChangedAfter(
-      touchHistory,
-      gestureState._accountsForMovesUpTo
-    );
-    const movedAfter = gestureState._accountsForMovesUpTo;
-    const prevX = previousCentroidXOfTouchesChangedAfter(touchHistory, movedAfter);
-    const x = currentCentroidXOfTouchesChangedAfter(touchHistory, movedAfter);
-    const prevY = previousCentroidYOfTouchesChangedAfter(touchHistory, movedAfter);
-    const y = currentCentroidYOfTouchesChangedAfter(touchHistory, movedAfter);
-    const nextDX = gestureState.dx + (x - prevX);
-    const nextDY = gestureState.dy + (y - prevY);
-
-    // TODO: This must be filtered intelligently.
-    const dt = touchHistory.mostRecentTimeStamp - gestureState._accountsForMovesUpTo;
-    gestureState.vx = (nextDX - gestureState.dx) / dt;
-    gestureState.vy = (nextDY - gestureState.dy) / dt;
-
-    gestureState.dx = nextDX;
-    gestureState.dy = nextDY;
-    gestureState._accountsForMovesUpTo = touchHistory.mostRecentTimeStamp;
-  },
-
-  /**
-   * @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(config) {
-    const gestureState = {
-      // Useful for debugging
-      stateID: Math.random()
-    };
-    PanResponder._initializeGestureState(gestureState);
-    const panHandlers = {
-      onStartShouldSetResponder: function(e) {
-        return config.onStartShouldSetPanResponder === undefined
-          ? false
-          : config.onStartShouldSetPanResponder(e, gestureState);
-      },
-      onMoveShouldSetResponder: function(e) {
-        return config.onMoveShouldSetPanResponder === undefined
-          ? false
-          : config.onMoveShouldSetPanResponder(e, gestureState);
-      },
-      onStartShouldSetResponderCapture: function(e) {
-        // TODO: Actually, we should reinitialize the state any time
-        // touches.length increases from 0 active to > 0 active.
-        if (e.nativeEvent.touches) {
-          if (e.nativeEvent.touches.length === 1) {
-            PanResponder._initializeGestureState(gestureState);
-          }
-        } else if (
-          e.nativeEvent.originalEvent &&
-          e.nativeEvent.originalEvent.type === 'mousedown'
-        ) {
-          PanResponder._initializeGestureState(gestureState);
-        }
-        gestureState.numberActiveTouches = e.touchHistory.numberActiveTouches;
-        return config.onStartShouldSetPanResponderCapture !== undefined
-          ? config.onStartShouldSetPanResponderCapture(e, gestureState)
-          : false;
-      },
-
-      onMoveShouldSetResponderCapture: function(e) {
-        const 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;
-      },
-
-      onResponderGrant: function(e) {
-        gestureState.x0 = currentCentroidX(e.touchHistory);
-        gestureState.y0 = currentCentroidY(e.touchHistory);
-        gestureState.dx = 0;
-        gestureState.dy = 0;
-        config.onPanResponderGrant && config.onPanResponderGrant(e, gestureState);
-        // TODO: t7467124 investigate if this can be removed
-        return config.onShouldBlockNativeResponder === undefined
-          ? true
-          : config.onShouldBlockNativeResponder();
-      },
-
-      onResponderReject: function(e) {
-        config.onPanResponderReject && config.onPanResponderReject(e, gestureState);
-      },
-
-      onResponderRelease: function(e) {
-        config.onPanResponderRelease && config.onPanResponderRelease(e, gestureState);
-        PanResponder._initializeGestureState(gestureState);
-      },
-
-      onResponderStart: function(e) {
-        const touchHistory = e.touchHistory;
-        gestureState.numberActiveTouches = touchHistory.numberActiveTouches;
-        config.onPanResponderStart && config.onPanResponderStart(e, gestureState);
-      },
-
-      onResponderMove: function(e) {
-        const 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);
-        config.onPanResponderMove && config.onPanResponderMove(e, gestureState);
-      },
-
-      onResponderEnd: function(e) {
-        const touchHistory = e.touchHistory;
-        gestureState.numberActiveTouches = touchHistory.numberActiveTouches;
-        config.onPanResponderEnd && config.onPanResponderEnd(e, gestureState);
-      },
-
-      onResponderTerminate: function(e) {
-        config.onPanResponderTerminate && config.onPanResponderTerminate(e, gestureState);
-        PanResponder._initializeGestureState(gestureState);
-      },
-
-      onResponderTerminationRequest: function(e) {
-        return config.onPanResponderTerminationRequest === undefined
-          ? true
-          : config.onPanResponderTerminationRequest(e, gestureState);
-      }
-    };
-    return { panHandlers: panHandlers };
-  }
-};
-
+import PanResponder from '../../vendor/PanResponder';
 export default PanResponder;

src/vendor/PanResponder/SHA

@@ -0,0 +1 @@
+facebook/react-native@71006f74cdafdae7212c8a10603fb972c6ee338c