[gnome-shell/wip/exalm/gestures-part-3: 4/6] workspacesView: Use SwipeTracker

[Alexander Mikhaylenko <alexm src gnome org>]

commit 91c45182ff446775d13aa8971326a5609af4daec
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Mon Jul 8 13:47:04 2019 +0500

    workspacesView: Use SwipeTracker
    
    Replace existing panning, touchpad scrolling and four-finger gesture by
    SwipeTracker.
    
    Change programmatic workspace animation to use easeOutCubic interpolator
    to match the gesture.
    
    Also change the dragging distance to always match the current monitor.
    
    Fixes touchpad parts of https://gitlab.gnome.org/GNOME/gnome-shell/issues/1338
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/826

 js/ui/workspacesView.js | 186 ++++++++++++++++++++----------------------------
 1 file changed, 76 insertions(+), 110 deletions(-)
---
diff --git a/js/ui/workspacesView.js b/js/ui/workspacesView.js
index aa4dd65fcf..40587226f1 100644
--- a/js/ui/workspacesView.js
+++ b/js/ui/workspacesView.js
@@ -4,7 +4,7 @@
 const { Clutter, Gio, GLib, GObject, Meta, Shell, St } = imports.gi;
 
 const Main = imports.ui.main;
-const WindowManager = imports.ui.windowManager;
+const SwipeTracker = imports.ui.swipeTracker;
 const Workspace = imports.ui.workspace;
 
 var WORKSPACE_SWITCH_TIME = 250;
@@ -79,7 +79,6 @@ class WorkspacesView extends WorkspacesViewBase {
         super._init(monitorIndex);
 
         this._animating = false; // tweening
-        this._scrolling = false; // swipe-scrolling
         this._gestureActive = false; // touch(pad) gestures
 
         this._scrollAdjustment = scrollAdjustment;
@@ -183,7 +182,7 @@ class WorkspacesView extends WorkspacesViewBase {
             if (showAnimation) {
                 let easeParams = Object.assign(params, {
                     duration: WORKSPACE_SWITCH_TIME,
-                    mode: Clutter.AnimationMode.EASE_OUT_QUAD,
+                    mode: Clutter.AnimationMode.EASE_OUT_CUBIC,
                 });
                 // we have to call _updateVisibility() once before the
                 // animation and once afterwards - it does not really
@@ -211,7 +210,7 @@ class WorkspacesView extends WorkspacesViewBase {
         for (let w = 0; w < this._workspaces.length; w++) {
             let workspace = this._workspaces[w];
 
-            if (this._animating || this._scrolling || this._gestureActive)
+            if (this._animating || this._gestureActive)
                 workspace.show();
             else if (this._inDrag)
                 workspace.visible = Math.abs(w - active) <= 1;
@@ -268,18 +267,6 @@ class WorkspacesView extends WorkspacesViewBase {
         workspaceManager.disconnect(this._reorderWorkspacesId);
     }
 
-    startSwipeScroll() {
-        this._scrolling = true;
-    }
-
-    endSwipeScroll() {
-        this._scrolling = false;
-
-        // Make sure title captions etc are shown as necessary
-        this._updateWorkspaceActors(true);
-        this._updateVisibility();
-    }
-
     startTouchGesture() {
         this._gestureActive = true;
     }
@@ -395,12 +382,6 @@ class ExtraWorkspaceView extends WorkspacesViewBase {
         this._workspace.syncStacking(stackIndices);
     }
 
-    startSwipeScroll() {
-    }
-
-    endSwipeScroll() {
-    }
-
     startTouchGesture() {
     }
 
@@ -438,42 +419,14 @@ class WorkspacesDisplay extends St.Widget {
         });
         Main.overview.addAction(clickAction);
         this.bind_property('mapped', clickAction, 'enabled', GObject.BindingFlags.SYNC_CREATE);
+        this._clickAction = clickAction;
 
-        let panAction = new Clutter.PanAction({ threshold_trigger_edge: Clutter.GestureTriggerEdge.AFTER });
-        panAction.connect('pan', this._onPan.bind(this));
-        panAction.connect('gesture-begin', () => {
-            if (this._workspacesOnlyOnPrimary) {
-                let event = Clutter.get_current_event();
-                if (this._getMonitorIndexForEvent(event) != this._primaryIndex)
-                    return false;
-            }
-
-            this._startSwipeScroll();
-            return true;
-        });
-        panAction.connect('gesture-cancel', () => {
-            clickAction.release();
-            this._endSwipeScroll();
-        });
-        panAction.connect('gesture-end', () => {
-            clickAction.release();
-            this._endSwipeScroll();
-        });
-        Main.overview.addAction(panAction);
-        this.bind_property('mapped', panAction, 'enabled', GObject.BindingFlags.SYNC_CREATE);
-
-        let allowedModes = Shell.ActionMode.OVERVIEW;
-        let switchGesture = new WindowManager.WorkspaceSwitchAction(allowedModes);
-        switchGesture.connect('motion', this._onSwitchWorkspaceMotion.bind(this));
-        switchGesture.connect('activated', this._onSwitchWorkspaceActivated.bind(this));
-        switchGesture.connect('cancel', this._endTouchGesture.bind(this));
-        Main.overview.addAction(switchGesture);
-        this.bind_property('mapped', switchGesture, 'enabled', GObject.BindingFlags.SYNC_CREATE);
-
-        switchGesture = new WindowManager.TouchpadWorkspaceSwitchAction(global.stage, allowedModes);
-        switchGesture.connect('motion', this._onSwitchWorkspaceMotion.bind(this));
-        switchGesture.connect('activated', this._onSwitchWorkspaceActivated.bind(this));
-        switchGesture.connect('cancel', this._endTouchGesture.bind(this));
+        this._swipeTracker = new SwipeTracker.SwipeTracker(
+            Main.layoutManager.overviewGroup, Shell.ActionMode.OVERVIEW);
+        this._swipeTracker.connect('begin', this._switchWorkspaceBegin.bind(this));
+        this._swipeTracker.connect('update', this._switchWorkspaceUpdate.bind(this));
+        this._swipeTracker.connect('end', this._switchWorkspaceEnd.bind(this));
+        this.bind_property('mapped', this._swipeTracker, 'enabled', GObject.BindingFlags.SYNC_CREATE);
 
         this._primaryIndex = Main.layoutManager.primaryIndex;
         this._workspacesViews = [];
@@ -491,7 +444,6 @@ class WorkspacesDisplay extends St.Widget {
 
         this._fullGeometry = null;
 
-        this._scrolling = false; // swipe-scrolling
         this._gestureActive = false; // touch(pad) gestures
         this._canScroll = true; // limiting scrolling speed
 
@@ -528,7 +480,7 @@ class WorkspacesDisplay extends St.Widget {
     }
 
     _activeWorkspaceChanged(_wm, _from, _to, _direction) {
-        if (this._scrolling)
+        if (this._gestureActive)
             return;
 
         this._scrollToActive();
@@ -542,77 +494,90 @@ class WorkspacesDisplay extends St.Widget {
     }
 
     _updateScrollAdjustment(index) {
-        if (this._scrolling || this._gestureActive)
+        if (this._gestureActive)
             return;
 
         this._scrollAdjustment.ease(index, {
-            mode: Clutter.AnimationMode.EASE_OUT_QUAD,
+            mode: Clutter.AnimationMode.EASE_OUT_CUBIC,
             duration: WORKSPACE_SWITCH_TIME,
         });
     }
 
-    _onPan(action) {
-        let [dist_, dx, dy] = action.get_motion_delta(0);
-        let adjustment = this._scrollAdjustment;
-        if (global.workspace_manager.layout_rows == -1)
-            adjustment.value -= (dy / this.height) * adjustment.page_size;
-        else if (this.text_direction == Clutter.TextDirection.RTL)
-            adjustment.value += (dx / this.width) * adjustment.page_size;
-        else
-            adjustment.value -= (dx / this.width) * adjustment.page_size;
-        return false;
+    _directionForProgress(progress) {
+        if (global.workspace_manager.layout_rows === -1) {
+            return progress > 0
+                ? Meta.MotionDirection.DOWN
+                : Meta.MotionDirection.UP;
+        } else if (this.text_direction === Clutter.TextDirection.RTL) {
+            return progress > 0
+                ? Meta.MotionDirection.LEFT
+                : Meta.MotionDirection.RIGHT;
+        } else {
+            return progress > 0
+                ? Meta.MotionDirection.RIGHT
+                : Meta.MotionDirection.LEFT;
+        }
     }
 
-    _startSwipeScroll() {
-        for (let i = 0; i < this._workspacesViews.length; i++)
-            this._workspacesViews[i].startSwipeScroll();
-        this._scrolling = true;
-    }
+    _switchWorkspaceBegin(tracker, monitor) {
+        if (this._workspacesOnlyOnPrimary && monitor !== this._primaryIndex)
+            return;
 
-    _endSwipeScroll() {
-        for (let i = 0; i < this._workspacesViews.length; i++)
-            this._workspacesViews[i].endSwipeScroll();
-        this._scrolling = false;
-        this._scrollToActive();
-    }
+        let adjustment = this._scrollAdjustment;
+        if (this._gestureActive)
+            adjustment.remove_transition('value');
+
+        let horiz = global.workspace_manager.layout_rows !== -1;
+        tracker.orientation = horiz ? Clutter.Orientation.HORIZONTAL
+            : Clutter.Orientation.VERTICAL;
 
-    _startTouchGesture() {
         for (let i = 0; i < this._workspacesViews.length; i++)
             this._workspacesViews[i].startTouchGesture();
-        this._gestureActive = true;
-    }
 
-    _endTouchGesture() {
-        for (let i = 0; i < this._workspacesViews.length; i++)
-            this._workspacesViews[i].endTouchGesture();
-        this._gestureActive = false;
-        this._scrollToActive();
-    }
+        let workspaceManager = global.workspace_manager;
 
-    _onSwitchWorkspaceMotion(action, xRel, yRel) {
-        // We don't have a way to hook into start of touchpad actions,
-        // luckily this is safe to call repeatedly.
-        this._startTouchGesture();
+        let monitors = Main.layoutManager.monitors;
+        let geometry = monitor === this._primaryIndex
+            ? this._fullGeometry : monitors[monitor];
+        let distance = global.workspace_manager.layout_rows === -1
+            ? geometry.height : geometry.width;
 
-        let workspaceManager = global.workspace_manager;
-        let active = workspaceManager.get_active_workspace_index();
+        let progress = adjustment.value / adjustment.page_size;
+        let points = Array.from(
+            { length: workspaceManager.n_workspaces }, (v, i) => i);
+
+        tracker.confirmSwipe(distance, points, progress, Math.round(progress));
+
+        this._gestureActive = true;
+    }
+
+    _switchWorkspaceUpdate(tracker, progress) {
         let adjustment = this._scrollAdjustment;
-        if (workspaceManager.layout_rows == -1)
-            adjustment.value = (active - yRel / this.height) * adjustment.page_size;
-        else if (this.text_direction == Clutter.TextDirection.RTL)
-            adjustment.value = (active + xRel / this.width) * adjustment.page_size;
-        else
-            adjustment.value = (active - xRel / this.width) * adjustment.page_size;
+        adjustment.value = progress * adjustment.page_size;
     }
 
-    _onSwitchWorkspaceActivated(action, direction) {
+    _switchWorkspaceEnd(tracker, duration, endProgress) {
+        this._clickAction.release();
+
         let workspaceManager = global.workspace_manager;
         let activeWorkspace = workspaceManager.get_active_workspace();
-        let newWs = activeWorkspace.get_neighbor(direction);
-        if (newWs != activeWorkspace)
-            newWs.activate(global.get_current_time());
+        let newWs = workspaceManager.get_workspace_by_index(endProgress);
+
+        this._scrollAdjustment.ease(endProgress, {
+            mode: Clutter.AnimationMode.EASE_OUT_CUBIC,
+            duration,
+            onComplete: () => {
+                if (newWs !== activeWorkspace)
+                    newWs.activate(global.get_current_time());
+                this._endTouchGesture();
+            },
+        });
+    }
 
-        this._endTouchGesture();
+    _endTouchGesture() {
+        for (let i = 0; i < this._workspacesViews.length; i++)
+            this._workspacesViews[i].endTouchGesture();
+        this._gestureActive = false;
     }
 
     vfunc_navigate_focus(from, direction) {
@@ -692,8 +657,6 @@ class WorkspacesDisplay extends St.Widget {
             else
                 view = new WorkspacesView(i, this._scrollAdjustment);
 
-            view.connect('scroll-event', this._onScrollEvent.bind(this));
-
             // HACK: Avoid spurious allocation changes while updating views
             view.hide();
 
@@ -793,6 +756,9 @@ class WorkspacesDisplay extends St.Widget {
     }
 
     _onScrollEvent(actor, event) {
+        if (this._swipeTracker.canHandleScrollEvent(event))
+            return Clutter.EVENT_PROPAGATE;
+
         if (!this.mapped)
             return Clutter.EVENT_PROPAGATE;