fix(sliding): much better UX + performance

- sliding should behave exactly like a native one
- much better performance

references ionic-team#7049
references ionic-team#7116
closes ionic-team#6913
closes ionic-team#6958

src/components/item/item-reorder-gesture.ts

@@ -27,10 +27,12 @@ export class ItemReorderGesture {
 
   constructor(public list: ItemReorder) {
     let element = this.list.getNativeElement();
-    this.events.pointerEvents(element,
-      this.onDragStart.bind(this),
-      this.onDragMove.bind(this),
-      this.onDragEnd.bind(this));
+    this.events.pointerEvents({
+      element: element,
+      pointerDown: this.onDragStart.bind(this),
+      pointerMove: this.onDragMove.bind(this),
+      pointerUp: this.onDragEnd.bind(this)
+    });
   }
 
   private onDragStart(ev: any): boolean {

src/components/item/item-sliding-gesture.ts

@@ -1,93 +1,105 @@
-import {DragGesture} from '../../gestures/drag-gesture';
-import {ItemSliding} from './item-sliding';
-import {List} from '../list/list';
+import { ItemSliding } from './item-sliding';
+import { List } from '../list/list';
 
-import {closest} from '../../util/dom';
+import { closest, Coordinates, pointerCoord } from '../../util/dom';
+import { PointerEvents, UIEventManager } from '../../util/ui-event-manager';
 
-const DRAG_THRESHOLD = 20;
+const DRAG_THRESHOLD = 10;
 const MAX_ATTACK_ANGLE = 20;
 
-export class ItemSlidingGesture extends DragGesture {
-  onTap: any;
-  selectedContainer: ItemSliding = null;
-  openContainer: ItemSliding = null;
+export class ItemSlidingGesture {
+  private preSelectedContainer: ItemSliding = null;
+  private selectedContainer: ItemSliding = null;
+  private openContainer: ItemSliding = null;
+  private events: UIEventManager = new UIEventManager(false);
+  private panDetector: PanXRecognizer = new PanXRecognizer(DRAG_THRESHOLD, MAX_ATTACK_ANGLE);
+  private pointerEvents: PointerEvents;
+  private firstCoordX: number;
+  private firstTimestamp: number;
 
   constructor(public list: List) {
-    super(list.getNativeElement(), {
-      direction: 'x',
-      threshold: DRAG_THRESHOLD
+    this.pointerEvents = this.events.pointerEvents({
+      element: list.getNativeElement(),
+      pointerDown: this.pointerStart.bind(this),
+      pointerMove: this.pointerMove.bind(this),
+      pointerUp: this.pointerEnd.bind(this),
     });
-    this.listen();
   }
 
-  onTapCallback(ev: any) {
-    if (isFromOptionButtons(ev)) {
-      return;
+  private pointerStart(ev: any): boolean {
+    if (this.selectedContainer) {
+      return false;
+    }
+    // Get swiped sliding container
+    let container = getContainer(ev);
+    if (!container) {
+      this.closeOpened();
+      return false;
     }
-    let didClose = this.closeOpened();
-    if (didClose) {
-      console.debug('tap close sliding item, preventDefault');
-      ev.preventDefault();
+    // Close open container if it is not the selected one.
+    if (container !== this.openContainer && this.closeOpened()) {
+      return false;
     }
+
+    let coord = pointerCoord(ev);
+    this.preSelectedContainer = container;
+    this.panDetector.start(coord);
+    this.firstCoordX = coord.x;
+    this.firstTimestamp = Date.now();
+    return true;
   }
 
-  onDragStart(ev: any): boolean {
-    let angle = Math.abs(ev.angle);
-    if (angle > MAX_ATTACK_ANGLE && Math.abs(angle - 180) > MAX_ATTACK_ANGLE) {
-      this.closeOpened();
-      return false;
+  private pointerMove(ev: any) {
+    if (this.selectedContainer) {
+      this.onDragMove(ev);
+      return;
     }
+    let coord = pointerCoord(ev);
+    if (this.panDetector.detect(coord)) {
+      if (!this.panDetector.isPanX()) {
+        this.pointerEvents.stop();
+        this.closeOpened();
+      } else {
+        this.onDragStart(ev, coord);
+      }
+    }
+  }
 
+  private pointerEnd(ev: any) {
     if (this.selectedContainer) {
-      console.debug('onDragStart, another container is already selected');
-      return false;
+      this.onDragEnd(ev);
+    } else {
+      this.closeOpened();
     }
+  }
 
+  private onDragStart(ev: any, coord: Coordinates): boolean {
     let container = getContainer(ev);
     if (!container) {
       console.debug('onDragStart, no itemContainerEle');
       return false;
     }
+    ev.preventDefault();
 
-    // Close open container if it is not the selected one.
-    if (container !== this.openContainer) {
-      this.closeOpened();
-    }
-
-    this.selectedContainer = container;
-    this.openContainer = container;
-    container.startSliding(ev.center.x);
-
-    return true;
+    this.selectedContainer = this.openContainer = this.preSelectedContainer;
+    container.startSliding(coord.x);
   }
 
-  onDrag(ev: any): boolean {
-    if (this.selectedContainer) {
-      this.selectedContainer.moveSliding(ev.center.x);
-      ev.preventDefault();
-    }
-    return;
+  private onDragMove(ev: any) {
+    let coordX = pointerCoord(ev).x;
+    ev.preventDefault();
+    this.selectedContainer.moveSliding(coordX);
   }
 
-  onDragEnd(ev: any) {
-    if (!this.selectedContainer) {
-      return;
-    }
+  private onDragEnd(ev: any) {
     ev.preventDefault();
+    let coordX = pointerCoord(ev).x;
+    let deltaX = (coordX - this.firstCoordX);
+    let deltaT = (Date.now() - this.firstTimestamp);
 
-    let openAmount = this.selectedContainer.endSliding(ev.velocityX);
+    let openAmount = this.selectedContainer.endSliding(deltaX / deltaT);
     this.selectedContainer = null;
-
-    // TODO: I am not sure listening for a tap event is the best idea
-    // we should try mousedown/touchstart
-    if (openAmount === 0) {
-      this.openContainer = null;
-      this.off('tap', this.onTap);
-      this.onTap = null;
-    } else if (!this.onTap) {
-      this.onTap = (event: any) => this.onTapCallback(event);
-      this.on('tap', this.onTap);
-    }
+    this.preSelectedContainer = null;
   }
 
   closeOpened(): boolean {
@@ -97,15 +109,17 @@ export class ItemSlidingGesture extends DragGesture {
     this.openContainer.close();
     this.openContainer = null;
     this.selectedContainer = null;
-    this.off('tap', this.onTap);
-    this.onTap = null;
     return true;
   }
 
   unlisten() {
     this.closeOpened();
-    super.unlisten();
+    this.events.unlistenAll();
+
     this.list = null;
+    this.preSelectedContainer = null;
+    this.selectedContainer = null;
+    this.openContainer = null;
   }
 }
 
@@ -117,10 +131,69 @@ function getContainer(ev: any): ItemSliding {
   return null;
 }
 
-function isFromOptionButtons(ev: any): boolean {
-  let button = closest(ev.target, '.button', true);
-  if (!button) {
+class AngleRecognizer {
+  private startCoord: Coordinates;
+  private sumCoord: Coordinates;
+  private dirty: boolean;
+  private _angle: any = null;
+  private threshold: number;
+
+  constructor(threshold: number) {
+    this.threshold = threshold ** 2;
+  }
+
+  start(coord: Coordinates) {
+    this.startCoord = coord;
+    this._angle = 0;
+    this.dirty = true;
+  }
+
+  angle(): any {
+    return this._angle;
+  }
+
+  detect(coord: Coordinates): boolean {
+    if (!this.dirty) {
+      return false;
+    }
+    let deltaX = (coord.x - this.startCoord.x);
+    let deltaY = (coord.y - this.startCoord.y);
+    let distance = deltaX * deltaX + deltaY * deltaY;
+    if (distance >= this.threshold) {
+      this._angle = Math.atan2(deltaY, deltaX);
+      this.dirty = false;
+      return true;
+    }
+    return false;
+  }
+}
+
+const degresToRadians = Math.PI / 180;
+
+class PanXRecognizer extends AngleRecognizer {
+  private _isPanX: boolean;
+  private maxAngle: number;
+
+  constructor(threshold: number, maxAngle: number) {
+    super(threshold);
+    this.maxAngle = maxAngle * degresToRadians;
+  }
+
+  start(coord: Coordinates) {
+    super.start(coord);
+    this._isPanX = false;
+  }
+
+  isPanX(): boolean {
+    return this._isPanX;
+  }
+
+  detect(coord: Coordinates): boolean {
+    if (super.detect(coord)) {
+      let angle = Math.abs(this.angle());
+      this._isPanX = (angle < this.maxAngle || Math.abs(angle - Math.PI) < this.maxAngle);
+      return true;
+    }
     return false;
   }
-  return !!closest(button, 'ion-item-options', true);
 }

src/components/item/item-sliding.ts

@@ -5,7 +5,7 @@ import { Item } from './item';
 import { isPresent } from '../../util/util';
 import { List } from '../list/list';
 
-const SWIPE_MARGIN = 20;
+const SWIPE_MARGIN = 30;
 const ELASTIC_FACTOR = 0.55;
 
 export const enum ItemSideFlags {

src/components/picker/picker-component.ts

@@ -74,11 +74,12 @@ export class PickerColumnCmp {
     this.setSelected(this.col.selectedIndex, 0);
 
     // Listening for pointer events
-    this.events.pointerEventsRef(this.elementRef,
-      (ev: any) => this.pointerStart(ev),
-      (ev: any) => this.pointerMove(ev),
-      (ev: any) => this.pointerEnd(ev)
-    );
+    this.events.pointerEvents({
+      elementRef: this.elementRef,
+      pointerDown: this.pointerStart.bind(this),
+      pointerMove: this.pointerMove.bind(this),
+      pointerUp: this.pointerEnd.bind(this)
+    });
   }
 
   ngOnDestroy() {

src/components/range/range.ts

@@ -364,11 +364,12 @@ export class Range implements AfterViewInit, ControlValueAccessor, OnDestroy {
     this._renderer.setElementStyle(this._bar.nativeElement, 'right', barR);
 
     // add touchstart/mousedown listeners
-    this._events.pointerEventsRef(this._slider,
-      this.pointerDown.bind(this),
-      this.pointerMove.bind(this),
-      this.pointerUp.bind(this));
-
+    this._events.pointerEvents({
+      elementRef: this._slider,
+      pointerDown: this.pointerDown.bind(this),
+      pointerMove: this.pointerMove.bind(this),
+      pointerUp: this.pointerUp.bind(this)
+    });
     this.createTicks();
   }
 

src/components/refresher/refresher.ts

@@ -462,10 +462,12 @@ export class Refresher {
     this._events.unlistenAll();
     this._pointerEvents = null;
     if (shouldListen) {
-      this._pointerEvents = this._events.pointerEvents(this._content.getScrollElement(),
-        this._onStart.bind(this),
-        this._onMove.bind(this),
-        this._onEnd.bind(this));
+      this._pointerEvents = this._events.pointerEvents({
+        element: this._content.getScrollElement(),
+        pointerDown: this._onStart.bind(this),
+        pointerMove: this._onMove.bind(this),
+        pointerUp: this._onEnd.bind(this)
+      });
     }
   }
 

src/components/toggle/toggle.ts

@@ -242,11 +242,12 @@ export class Toggle implements AfterContentInit, ControlValueAccessor, OnDestroy
    */
   ngAfterContentInit() {
     this._init = true;
-    this._events.pointerEventsRef(this._elementRef,
-      (ev: any) => this.pointerDown(ev),
-      (ev: any) => this.pointerMove(ev),
-      (ev: any) => this.pointerUp(ev)
-    );
+    this._events.pointerEvents({
+      elementRef: this._elementRef,
+      pointerDown: this.pointerDown.bind(this),
+      pointerMove: this.pointerMove.bind(this),
+      pointerUp: this.pointerUp.bind(this)
+    });
   }
 
   /**

src/util/dom.ts

@@ -190,8 +190,10 @@ export function pointerCoord(ev: any): Coordinates {
 }
 
 export function hasPointerMoved(threshold: number, startCoord: Coordinates, endCoord: Coordinates) {
-  return startCoord && endCoord &&
-         (Math.abs(startCoord.x - endCoord.x) > threshold || Math.abs(startCoord.y - endCoord.y) > threshold);
+  let deltaX = (startCoord.x - endCoord.x);
+  let deltaY = (startCoord.y - endCoord.y);
+  let distance = deltaX * deltaX + deltaY * deltaY;
+  return distance > (threshold * threshold);
 }
 
 export function isActive(ele: HTMLElement) {