macOS: Trackpad swipe navigation

Work in progress. Something breaks down when swiping forward twice...

4 files changed, 255 insertions, 33 deletions

diff --git a/src/app.c b/src/app.c
index accdd991..68b17ade 100644
--- a/src/app.c
+++ b/src/app.c
@@ -1315,28 +1315,6 @@ void processEvents_App(enum iAppEventMode eventMode) {
                 }
                 /* Scroll events may be per-pixel or mouse wheel steps. */
                 if (ev.type == SDL_MOUSEWHEEL) {
-#if defined (iPlatformAppleDesktop)
-                    /* On macOS, we handle both trackpad and mouse events. We expect SDL to identify
-                       which device is sending the event. */
-                    if (ev.wheel.which == 0) {
-                        /* Trackpad with precise scrolling w/inertia (points). */
-                        setPerPixel_MouseWheelEvent(&ev.wheel, iTrue);
-                        ev.wheel.x *= -d->window->base.pixelRatio;
-                        ev.wheel.y *= d->window->base.pixelRatio;
-                        /* Only scroll on one axis at a time. */
-                        if (iAbs(ev.wheel.x) > iAbs(ev.wheel.y)) {
-                            ev.wheel.y = 0;
-                        }
-                        else {
-                            ev.wheel.x = 0;
-                        }
-                    }
-                    else {
-                        /* Disregard wheel acceleration applied by the OS. */
-                        ev.wheel.x = -ev.wheel.x;
-                        ev.wheel.y = iSign(ev.wheel.y);
-                    }
-#endif
 #if defined (iPlatformMsys)
                     ev.wheel.x = -ev.wheel.x;
 #endif
diff --git a/src/macos.m b/src/macos.m
index 5fd76bb9..2d082d28 100644
--- a/src/macos.m
+++ b/src/macos.m
@@ -403,6 +403,94 @@ void registerURLHandler_MacOS(void) {
     [handler release];
 }
 
+#if 0
+static iBool isTracking_;
+
+static void trackSwipe_(NSEvent *event) {
+    if (isTracking_) {
+        return;
+    }
+    isTracking_ = iTrue;
+    [event trackSwipeEventWithOptions:NSEventSwipeTrackingLockDirection
+             dampenAmountThresholdMin:-1.0
+                                  max:1.0
+                         usingHandler:^(CGFloat gestureAmount, NSEventPhase phase,
+                                        BOOL isComplete, BOOL *stop) {
+                        printf("TRACK: amount:%f phase:%lu complete:%d\n",
+                               gestureAmount, (unsigned long) phase, isComplete);
+                        fflush(stdout);
+                        if (isComplete) {
+                            isTracking_ = iFalse;
+                        }
+                      }
+    ];
+}
+#endif
+
+static int swipeDir_ = 0;
+
+static iBool processScrollWheelEvent_(NSEvent *event) {
+    const iBool isPerPixel = (event.hasPreciseScrollingDeltas != 0);
+    const iBool isInertia  = (event.momentumPhase & (NSEventPhaseBegan | NSEventPhaseChanged)) != 0;
+    const iBool isEnded    = event.scrollingDeltaX == 0.0f && event.scrollingDeltaY == 0.0f && !isInertia;
+    const iWindow *win     = &get_MainWindow()->base;
+    /* Post corresponding MOUSEWHEEL events. */
+    SDL_MouseWheelEvent e = { .type = SDL_MOUSEWHEEL };
+    e.timestamp = SDL_GetTicks();
+    e.which = isPerPixel ? 0 : 1; /* Distinction between trackpad and regular mouse. TODO: Still needed? */
+    setPerPixel_MouseWheelEvent(&e, isPerPixel);
+    if (isPerPixel) {
+        setInertia_MouseWheelEvent(&e, isInertia);
+        setScrollFinished_MouseWheelEvent(&e, isEnded);
+        e.x = -event.scrollingDeltaX * win->pixelRatio;
+        e.y = event.scrollingDeltaY * win->pixelRatio;        
+        /* Only scroll on one axis at a time. */
+        if (swipeDir_ == 0) {
+            swipeDir_ = iAbs(e.x) > iAbs(e.y) ? 1 : 2;
+        }
+        if (swipeDir_ == 1) {
+            e.y = 0;
+        }
+        else if (swipeDir_ == 2) {
+            e.x = 0;
+        }
+        if (isEnded) {
+            swipeDir_ = 0;
+        }
+    }
+    else {
+        /* Disregard wheel acceleration applied by the OS. */
+        e.x = -event.scrollingDeltaX;
+        e.y = iSign(event.scrollingDeltaY);
+    }
+//    printf("#### dx:%d dy:%d phase:%ld end:%d\n", e.x, e.y, (long) event.momentumPhase, isEnded); fflush(stdout);
+    SDL_PushEvent((SDL_Event *) &e);
+#if 0
+        /* On macOS, we handle both trackpad and mouse events. We expect SDL to identify
+           which device is sending the event. */
+        if (ev.wheel.which == 0) {
+            /* Trackpad with precise scrolling w/inertia (points). */
+            setPerPixel_MouseWheelEvent(&ev.wheel, iTrue);
+            ev.wheel.x *= -d->window->base.pixelRatio;
+            ev.wheel.y *= d->window->base.pixelRatio;
+            /* Only scroll on one axis at a time. */
+            if (iAbs(ev.wheel.x) > iAbs(ev.wheel.y)) {
+                ev.wheel.y = 0;
+            }
+            else {
+                ev.wheel.x = 0;
+            }
+        }
+        else {
+            /* Disregard wheel acceleration applied by the OS. */
+            ev.wheel.x = -ev.wheel.x;
+            ev.wheel.y = iSign(ev.wheel.y);
+        }
+#endif
+    
+    return iTrue;        
+}
+
 void setupApplication_MacOS(void) {    
     NSApplication *app = [NSApplication sharedApplication];
     [app setActivationPolicy:NSApplicationActivationPolicyRegular];
@@ -424,6 +512,21 @@ void setupApplication_MacOS(void) {
     NSMenuItem *windowCloseItem = [windowMenu itemWithTitle:@"Close"];
     windowCloseItem.target = myDel;
     windowCloseItem.action = @selector(closeTab);
+    [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskScrollWheel
+                                          handler:^NSEvent*(NSEvent *event){
+//                                            printf("event type: %lu\n", (unsigned long) event.type);
+//                                            fflush(stdout);
+//                                            if (event.type == NSEventTypeGesture) {
+//                                                trackSwipe_(event);
+//                                                printf("GESTURE phase:%lu\n", (unsigned long) event.phase);
+//fflush(stdout);
+//                                            }
+                                            if (event.type == NSEventTypeScrollWheel &&
+                                                processScrollWheelEvent_(event)) {
+                                                return nil; /* was eaten */                                                
+                                            }
+                                            return event;
+                                          }];
 }
 
 void hideTitleBar_MacOS(iWindow *window) {
diff --git a/src/ui/documentwidget.c b/src/ui/documentwidget.c
index 0a24f7e5..9f6cdc45 100644
--- a/src/ui/documentwidget.c
+++ b/src/ui/documentwidget.c
@@ -234,6 +234,10 @@ enum iDocumentWidgetFlag {
     fromCache_DocumentWidgetFlag             = iBit(16), /* don't write anything to cache */
     animationPlaceholder_DocumentWidgetFlag  = iBit(17), /* avoid slow operations */
     invalidationPending_DocumentWidgetFlag   = iBit(18), /* invalidate as soon as convenient */
+    leftWheelSwipe_DocumentWidgetFlag         = iBit(19), /* swipe state flags are used on desktop */
+    rightWheelSwipe_DocumentWidgetFlag        = iBit(20), 
+    eitherWheelSwipe_DocumentWidgetFlag       = leftWheelSwipe_DocumentWidgetFlag | rightWheelSwipe_DocumentWidgetFlag,
+//    wheelSwipeFinished_DocumentWidgetFlag     = iBit(21),
 };
 
 enum iDocumentLinkOrdinalMode {
@@ -241,6 +245,12 @@ enum iDocumentLinkOrdinalMode {
     homeRow_DocumentLinkOrdinalMode,
 };
 
+enum iWheelSwipeState {
+    none_WheelSwipeState,
+    direct_WheelSwipeState,
+    //inertia_WheelSwipeState,
+};
+
 struct Impl_DocumentWidget {
     iWidget        widget;
     int            flags; /* internal behavior, see enum iDocumentWidgetFlag */
@@ -263,6 +273,9 @@ struct Impl_DocumentWidget {
     int            pinchZoomInitial;
     int            pinchZoomPosted;
     float          swipeSpeed; /* points/sec */
+    uint32_t       lastSwipeTime;
+    int            wheelSwipeDistance;
+    enum iWheelSwipeState wheelSwipeState;
     iString        pendingGotoHeading;
     iString        linePrecedingLink;
     
@@ -329,7 +342,12 @@ void init_DocumentWidget(iDocumentWidget *d) {
     init_Widget(w);
     setId_Widget(w, format_CStr("document%03d", ++docEnum_));
     setFlags_Widget(w, hover_WidgetFlag | noBackground_WidgetFlag, iTrue);
-    if (deviceType_App() != desktop_AppDeviceType) {
+#if defined (iPlatformAppleDesktop)    
+    iBool enableSwipeNavigation = iTrue; /* swipes on the trackpad */
+#else
+    iBool enableSwipeNavigation = (deviceType_App() != desktop_AppDeviceType);
+#endif
+    if (enableSwipeNavigation) {
         setFlags_Widget(w, leftEdgeDraggable_WidgetFlag | rightEdgeDraggable_WidgetFlag |
                         horizontalOffset_WidgetFlag, iTrue);
     }
@@ -358,6 +376,7 @@ void init_DocumentWidget(iDocumentWidget *d) {
     }
     d->animWideRunId = 0;
     init_Anim(&d->animWideRunOffset, 0);
+    d->wheelSwipeState  = none_WheelSwipeState;
     d->selectMark       = iNullRange;
     d->foundMark        = iNullRange;
     d->pageMargin       = 5;
@@ -1942,8 +1961,7 @@ static void updateFromCachedResponse_DocumentWidget_(iDocumentWidget *d, float n
 
 static iBool updateFromHistory_DocumentWidget_(iDocumentWidget *d) {
     const iRecentUrl *recent = constMostRecentUrl_History(d->mod.history);
-    iAssert(equalCase_String(&recent->url, d->mod.url));
-    if (recent && recent->cachedResponse) {
+    if (recent && recent->cachedResponse && equalCase_String(&recent->url, d->mod.url)) {
         iChangeFlags(d->flags,
                      openedFromSidebar_DocumentWidgetFlag,
                      recent->flags.openedFromSidebar);
@@ -2043,10 +2061,10 @@ static void scrollToHeading_DocumentWidget_(iDocumentWidget *d, const char *head
     }
 }
 
-static void scrollWideBlock_DocumentWidget_(iDocumentWidget *d, iInt2 mousePos, int delta,
+static iBool scrollWideBlock_DocumentWidget_(iDocumentWidget *d, iInt2 mousePos, int delta,
                                             int duration) {
-    if (delta == 0) {
-        return;
+    if (delta == 0 || d->flags & eitherWheelSwipe_DocumentWidgetFlag) {
+        return iFalse;
     }
     const iInt2 docPos = documentPos_DocumentWidget_(d, mousePos);
     iConstForEach(PtrArray, i, &d->visibleWideRuns) {
@@ -2087,9 +2105,10 @@ static void scrollWideBlock_DocumentWidget_(iDocumentWidget *d, iInt2 mousePos,
                 d->animWideRunId = 0;
                 init_Anim(&d->animWideRunOffset, 0);
             }
-            break;
+            return iTrue;
         }
     }
+    return iFalse;
 }
 
 static void togglePreFold_DocumentWidget_(iDocumentWidget *d, uint16_t preId) {
@@ -2691,7 +2710,7 @@ static void setupSwipeOverlay_DocumentWidget_(iDocumentWidget *d, iWidget *overl
     const int toPos   = width_Widget(overlay);
     setVisualOffset_Widget(overlay, fromPos, 0, 0);
     /* Bigger screen, faster swipes. */
-    const float devFactor = (deviceType_App() == tablet_AppDeviceType ? 2.0f : 1.0f);
+    const float devFactor = (deviceType_App() == phone_AppDeviceType ? 1.0f : 2.0f);
     float swipe = iClamp(d->swipeSpeed, devFactor * 400, devFactor * 1000) * gap_UI;
     uint32_t span = ((toPos - fromPos) / swipe) * 1000;
 //    printf("from:%d to:%d swipe:%f span:%u\n", fromPos, toPos, d->swipeSpeed, span);
@@ -2841,6 +2860,7 @@ static iBool handleSwipe_DocumentWidget_(iDocumentWidget *d, const char *cmd) {
                 target->flags |= animationPlaceholder_DocumentWidgetFlag;
                 addChildPos_Widget(swipeParent, iClob(target), back_WidgetAddPos);
                 setId_Widget(as_Widget(target), "swipeout");
+                setFlags_Widget(as_Widget(target), disabled_WidgetFlag, iTrue);
                 swap_DocumentWidget_(target, d->doc, d);
                 setUrlAndSource_DocumentWidget(d,
                                                swipeIn->mod.url,
@@ -3870,6 +3890,105 @@ static void interactingWithLink_DocumentWidget_(iDocumentWidget *d, iGmLinkId id
     setRange_String(&d->linePrecedingLink, loc);
 }
 
+iLocalDef int wheelSwipeSide_DocumentWidget_(const iDocumentWidget *d) {
+    return (d->flags & rightWheelSwipe_DocumentWidgetFlag  ? 2
+            : d->flags & leftWheelSwipe_DocumentWidgetFlag ? 1
+                                                          : 0);
+}
+
+static void finishWheelSwipe_DocumentWidget_(iDocumentWidget *d) {
+    if (d->flags & eitherWheelSwipe_DocumentWidgetFlag &&
+        d->wheelSwipeState == direct_WheelSwipeState) {
+//        ~d->flags & wheelSwipeFinished_DocumentWidgetFlag) {
+//        d->wheelSwipeState = inertia_WheelSwipeState;
+        const int side = wheelSwipeSide_DocumentWidget_(d);
+//        d->flags |= wheelSwipeFinished_DocumentWidgetFlag;
+        int abort = (side == 1 && d->swipeSpeed < 0 || side == 2 && d->swipeSpeed > 0);
+        printf("speed:%f\n", d->swipeSpeed / gap_UI);
+        if (iAbs(d->wheelSwipeDistance) < width_Widget(d) / 4 && iAbs(d->swipeSpeed) < 4 * gap_UI) {
+            abort = 1;
+        }
+        postCommand_Widget(d, "edgeswipe.ended side:%d abort:%d", side, abort);
+        d->flags &= ~eitherWheelSwipe_DocumentWidgetFlag;
+    }
+}
+
+static iBool handleWheelSwipe_DocumentWidget_(iDocumentWidget *d, const SDL_MouseWheelEvent *ev) {
+    iWidget *w = as_Widget(d);
+    if (~flags_Widget(w) & horizontalOffset_WidgetFlag) {
+        return iFalse;
+    }
+    iAssert(~d->flags & animationPlaceholder_DocumentWidgetFlag);
+//    printf("STATE:%d wheel x:%d inert:%d end:%d\n", d->wheelSwipeState,
+//           ev->x, isInertia_MouseWheelEvent(ev),
+//           isScrollFinished_MouseWheelEvent(ev));
+//    fflush(stdout);
+    switch (d->wheelSwipeState) {
+        case none_WheelSwipeState:
+            /* A new swipe starts. */
+            if (!isInertia_MouseWheelEvent(ev) && !isScrollFinished_MouseWheelEvent(ev)) {
+                int side = ev->x < 0 ? 1 : 2;
+                d->wheelSwipeDistance = -ev->x;
+                d->flags &= ~eitherWheelSwipe_DocumentWidgetFlag;
+                d->flags |= (side == 1 ? leftWheelSwipe_DocumentWidgetFlag
+                                       : rightWheelSwipe_DocumentWidgetFlag);
+                //        printf("swipe starts at %d, side %d\n", d->wheelSwipeDistance, side);
+                d->wheelSwipeState = direct_WheelSwipeState;
+                d->swipeSpeed = 0;
+                postCommand_Widget(d, "edgeswipe.moved arg:%d side:%d", d->wheelSwipeDistance, side);
+                return iTrue;
+            }
+            break;
+        case direct_WheelSwipeState:
+            if (isInertia_MouseWheelEvent(ev) || isScrollFinished_MouseWheelEvent(ev)) {
+                finishWheelSwipe_DocumentWidget_(d);
+                d->wheelSwipeState = none_WheelSwipeState;
+            }
+//            else if (isInertia_MouseWheelEvent(ev)) {
+//                finishWheelSwipe_DocumentWidget_(d);
+//                d->wheelSwipeState = inertia_WheelSwipeState;
+//            }
+            else {
+                int step = -ev->x * 2;
+                d->wheelSwipeDistance += step;
+                /* Remember the maximum speed. */
+                if (d->swipeSpeed < 0 && step < 0) {
+                    d->swipeSpeed = iMin(d->swipeSpeed, step);
+                }
+                else if (d->swipeSpeed > 0 && step > 0) {
+                    d->swipeSpeed = iMax(d->swipeSpeed, step);
+                }
+                else {
+                    d->swipeSpeed = step;
+                }
+                switch (wheelSwipeSide_DocumentWidget_(d)) {
+                    case 1:
+                        d->wheelSwipeDistance = iMax(0, d->wheelSwipeDistance);
+                        d->wheelSwipeDistance = iMin(width_Widget(d), d->wheelSwipeDistance);
+                        break;
+                    case 2:
+                        d->wheelSwipeDistance = iMin(0, d->wheelSwipeDistance);
+                        d->wheelSwipeDistance = iMax(-width_Widget(d), d->wheelSwipeDistance);
+                        break;
+                }
+                /* TODO: calculate speed, rememeber direction */
+                //printf("swipe moved to %d, side %d\n", d->wheelSwipeDistance, side);
+                postCommand_Widget(d, "edgeswipe.moved arg:%d side:%d", d->wheelSwipeDistance,
+                                   wheelSwipeSide_DocumentWidget_(d));
+            }
+            return iTrue;
+//        case inertia_WheelSwipeState:
+//            if (isScrollFinished_MouseWheelEvent(ev)) {
+//                d->wheelSwipeState = none_WheelSwipeState;
+//            }
+//            else if (!isInertia_MouseWheelEvent(ev)) {
+//                d->wheelSwipeState = none_WheelSwipeState;
+//            }
+//            return iTrue;
+    }
+    return iFalse;
+}
+
 static iBool processEvent_DocumentWidget_(iDocumentWidget *d, const SDL_Event *ev) {
     iWidget *w = as_Widget(d);
     if (isMetricsChange_UserEvent(ev)) {
@@ -3967,13 +4086,20 @@ static iBool processEvent_DocumentWidget_(iDocumentWidget *d, const SDL_Event *e
 #endif
         }
     }
+    else if (ev->type == SDL_MOUSEWHEEL && ev->wheel.y == 0 &&
+             handleWheelSwipe_DocumentWidget_(d, &ev->wheel)) {
+        return iTrue;
+    }
     else if (ev->type == SDL_MOUSEWHEEL && isHover_Widget(w)) {
         const iInt2 mouseCoord = coord_MouseWheelEvent(&ev->wheel);
         if (isPerPixel_MouseWheelEvent(&ev->wheel)) {
             const iInt2 wheel = init_I2(ev->wheel.x, ev->wheel.y);
             stop_Anim(&d->scrollY.pos);
             immediateScroll_DocumentWidget_(d, -wheel.y);
-            scrollWideBlock_DocumentWidget_(d, mouseCoord, -wheel.x, 0);
+            if (!scrollWideBlock_DocumentWidget_(d, mouseCoord, -wheel.x, 0) &&
+                wheel.x) {
+                handleWheelSwipe_DocumentWidget_(d, &ev->wheel);
+            }
         }
         else {
             /* Traditional mouse wheel. */
diff --git a/src/ui/util.h b/src/ui/util.h
index b9109aee..4fedd083 100644
--- a/src/ui/util.h
+++ b/src/ui/util.h
@@ -47,16 +47,31 @@ iLocalDef iBool isMetricsChange_UserEvent(const SDL_Event *d) {
 }
 
 enum iMouseWheelFlag {
-    perPixel_MouseWheelFlag = iBit(9), /* e.g., trackpad or finger scroll; applied to `direction` */
+    /* Note: A future version of SDL may support per-pixel scrolling, but 2.0.x doesn't. */
+    perPixel_MouseWheelFlag       = iBit(9), /* e.g., trackpad or finger scroll; applied to `direction` */
+    inertia_MouseWheelFlag        = iBit(10),
+    scrollFinished_MouseWheelFlag = iBit(11),
 };
 
-/* Note: A future version of SDL may support per-pixel scrolling, but 2.0.x doesn't. */
 iLocalDef void setPerPixel_MouseWheelEvent(SDL_MouseWheelEvent *ev, iBool set) {
     iChangeFlags(ev->direction, perPixel_MouseWheelFlag, set);
 }
+iLocalDef void setInertia_MouseWheelEvent(SDL_MouseWheelEvent *ev, iBool set) {
+    iChangeFlags(ev->direction, inertia_MouseWheelFlag, set);
+}
+iLocalDef void setScrollFinished_MouseWheelEvent(SDL_MouseWheelEvent *ev, iBool set) {
+    iChangeFlags(ev->direction, scrollFinished_MouseWheelFlag, set);
+}
+
 iLocalDef iBool isPerPixel_MouseWheelEvent(const SDL_MouseWheelEvent *ev) {
     return (ev->direction & perPixel_MouseWheelFlag) != 0;
 }
+iLocalDef iBool isInertia_MouseWheelEvent(const SDL_MouseWheelEvent *ev) {
+    return (ev->direction & inertia_MouseWheelFlag) != 0;
+}
+iLocalDef iBool isScrollFinished_MouseWheelEvent(const SDL_MouseWheelEvent *ev) {
+    return (ev->direction & scrollFinished_MouseWheelFlag) != 0;
+}
 
 iInt2   coord_MouseWheelEvent   (const SDL_MouseWheelEvent *);