moonlight-ios/Limelight/Input/StreamView.m

//
//  StreamView.m
//  Moonlight
//
//  Created by Cameron Gutman on 10/19/14.
//  Copyright (c) 2014 Moonlight Stream. All rights reserved.
//

#import "StreamView.h"
#include <Limelight.h>
#import "DataManager.h"
#import "ControllerSupport.h"
#import "KeyboardSupport.h"
#import "RelativeTouchHandler.h"
#import "AbsoluteTouchHandler.h"

static const double X1_MOUSE_SPEED_DIVISOR = 2.5;

@implementation StreamView {
    OnScreenControls* onScreenControls;
    
    UITextField* keyInputField;
    BOOL isInputingText;
    
    float streamAspectRatio;
    
    // iOS 13.4 mouse support
    NSInteger lastMouseButtonMask;
    float lastMouseX;
    float lastMouseY;
    
    // Citrix X1 mouse support
    X1Mouse* x1mouse;
    double accumulatedMouseDeltaX;
    double accumulatedMouseDeltaY;
    
    UIResponder* touchHandler;
    
    id<UserInteractionDelegate> interactionDelegate;
    NSTimer* interactionTimer;
    BOOL hasUserInteracted;
    
    NSDictionary<NSString *, NSNumber *> *dictCodes;
}

- (void) setupStreamView:(ControllerSupport*)controllerSupport
           swipeDelegate:(id<EdgeDetectionDelegate>)swipeDelegate
     interactionDelegate:(id<UserInteractionDelegate>)interactionDelegate
                  config:(StreamConfiguration*)streamConfig {
    self->interactionDelegate = interactionDelegate;
    self->streamAspectRatio = (float)streamConfig.width / (float)streamConfig.height;
    
    TemporarySettings* settings = [[[DataManager alloc] init] getSettings];
    
    keyInputField = [[UITextField alloc] initWithFrame:CGRectZero];
    [self addSubview:keyInputField];
    
#if TARGET_OS_TV
    // tvOS requires RelativeTouchHandler to manage Apple Remote input
    self->touchHandler = [[RelativeTouchHandler alloc] initWithView:self];
#else
    // iOS uses RelativeTouchHandler or AbsoluteTouchHandler depending on user preference
    if (settings.absoluteTouchMode) {
        self->touchHandler = [[AbsoluteTouchHandler alloc] initWithView:self];
    }
    else {
        self->touchHandler = [[RelativeTouchHandler alloc] initWithView:self];
    }
    
    onScreenControls = [[OnScreenControls alloc] initWithView:self controllerSup:controllerSupport swipeDelegate:swipeDelegate];
    OnScreenControlsLevel level = (OnScreenControlsLevel)[settings.onscreenControls integerValue];
    if (settings.absoluteTouchMode) {
        Log(LOG_I, @"On-screen controls disabled in absolute touch mode");
        [onScreenControls setLevel:OnScreenControlsLevelOff];
    }
    else if (level == OnScreenControlsLevelAuto) {
        [controllerSupport initAutoOnScreenControlMode:onScreenControls];
    }
    else {
        Log(LOG_I, @"Setting manual on-screen controls level: %d", (int)level);
        [onScreenControls setLevel:level];
    }
    
    // It would be nice to just use GCMouse on iOS 14+ and the older API on iOS 13
    // but unfortunately that isn't possible today. GCMouse doesn't recognize many
    // mice correctly, but UIKit does. We will register for both and ignore UIKit
    // events if a GCMouse is connected.
    if (@available(iOS 13.4, *)) {
        [self addInteraction:[[UIPointerInteraction alloc] initWithDelegate:self]];
        
        UIPanGestureRecognizer *mouseWheelRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(mouseWheelMoved:)];
        mouseWheelRecognizer.allowedScrollTypesMask = UIScrollTypeMaskAll;
        mouseWheelRecognizer.allowedTouchTypes = @[@(UITouchTypeIndirectPointer)];
        [self addGestureRecognizer:mouseWheelRecognizer];
    }
#endif
    
    x1mouse = [[X1Mouse alloc] init];
    x1mouse.delegate = self;
    
    if (settings.btMouseSupport) {
        [x1mouse start];
    }
}

- (void)startInteractionTimer {
    // Restart user interaction tracking
    hasUserInteracted = NO;
    
    BOOL timerAlreadyRunning = interactionTimer != nil;
    
    // Start/restart the timer
    [interactionTimer invalidate];
    interactionTimer = [NSTimer scheduledTimerWithTimeInterval:2.0
                        target:self
                        selector:@selector(interactionTimerExpired:)
                        userInfo:nil
                        repeats:NO];
    
    // Notify the delegate if this was a new user interaction
    if (!timerAlreadyRunning) {
        [interactionDelegate userInteractionBegan];
    }
}

- (void)interactionTimerExpired:(NSTimer *)timer {
    if (!hasUserInteracted) {
        // User has finished touching the screen
        interactionTimer = nil;
        [interactionDelegate userInteractionEnded];
    }
    else {
        // User is still touching the screen. Restart the timer.
        [self startInteractionTimer];
    }
}

- (void) showOnScreenControls {
#if !TARGET_OS_TV
    [onScreenControls show];
    [self becomeFirstResponder];
#endif
}

- (OnScreenControlsLevel) getCurrentOscState {
    if (onScreenControls == nil) {
        return OnScreenControlsLevelOff;
    }
    else {
        return [onScreenControls getLevel];
    }
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    if ([self handleMouseButtonEvent:BUTTON_ACTION_PRESS
                          forTouches:touches
                           withEvent:event]) {
        // If it's a mouse event, we're done
        return;
    }
    
    Log(LOG_D, @"Touch down");
    
    // Notify of user interaction and start expiration timer
    [self startInteractionTimer];
    
    if (![onScreenControls handleTouchDownEvent:touches]) {
        if ([[event allTouches] count] == 3) {
            if (isInputingText) {
                Log(LOG_D, @"Closing the keyboard");
                [keyInputField resignFirstResponder];
                isInputingText = false;
            } else {
                Log(LOG_D, @"Opening the keyboard");
                // Prepare the textbox used to capture keyboard events.
                keyInputField.delegate = self;
                keyInputField.text = @"0";
                [keyInputField becomeFirstResponder];
                [keyInputField addTarget:self action:@selector(onKeyboardPressed:) forControlEvents:UIControlEventEditingChanged];
                
                // Undo causes issues for our state management, so turn it off
                [keyInputField.undoManager disableUndoRegistration];
                
                isInputingText = true;
            }
        }
        else {
            [touchHandler touchesBegan:touches withEvent:event];
        }
    }
}

- (BOOL)handleMouseButtonEvent:(int)buttonAction forTouches:(NSSet *)touches withEvent:(UIEvent *)event {
#if !TARGET_OS_TV
    if (@available(iOS 13.4, *)) {
        UITouch* touch = [touches anyObject];
        if (touch.type == UITouchTypeIndirectPointer) {
            if (@available(iOS 14.0, *)) {
                if ([GCMouse current] != nil) {
                    // We'll handle this with GCMouse. Do nothing here.
                    return YES;
                }
            }
            
            UIEventButtonMask normalizedButtonMask;
            
            // iOS 14 includes the released button in the buttonMask for the release
            // event, while iOS 13 does not. Normalize that behavior here.
            if (@available(iOS 14.0, *)) {
                if (buttonAction == BUTTON_ACTION_RELEASE) {
                    normalizedButtonMask = lastMouseButtonMask & ~event.buttonMask;
                }
                else {
                    normalizedButtonMask = event.buttonMask;
                }
            }
            else {
                normalizedButtonMask = event.buttonMask;
            }
            
            UIEventButtonMask changedButtons = lastMouseButtonMask ^ normalizedButtonMask;
                        
            for (int i = BUTTON_LEFT; i <= BUTTON_X2; i++) {
                UIEventButtonMask buttonFlag;
                
                switch (i) {
                    // Right and Middle are reversed from what iOS uses
                    case BUTTON_RIGHT:
                        buttonFlag = UIEventButtonMaskForButtonNumber(2);
                        break;
                    case BUTTON_MIDDLE:
                        buttonFlag = UIEventButtonMaskForButtonNumber(3);
                        break;
                        
                    default:
                        buttonFlag = UIEventButtonMaskForButtonNumber(i);
                        break;
                }
                
                if (changedButtons & buttonFlag) {
                    LiSendMouseButtonEvent(buttonAction, i);
                }
            }
            
            lastMouseButtonMask = normalizedButtonMask;
            return YES;
        }
    }
#endif
    
    return NO;
}

- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
#if !TARGET_OS_TV
    if (@available(iOS 13.4, *)) {
        UITouch *touch = [touches anyObject];
        if (touch.type == UITouchTypeIndirectPointer) {
            if (@available(iOS 14.0, *)) {
                if ([GCMouse current] != nil) {
                    // We'll handle this with GCMouse. Do nothing here.
                    return;
                }
            }
            
            // We must handle this event to properly support
            // drags while the middle, X1, or X2 mouse buttons are
            // held down. For some reason, left and right buttons
            // don't require this, but we do it anyway for them too.
            // Cursor movement without a button held down is handled
            // in pointerInteraction:regionForRequest:defaultRegion.
            [self updateCursorLocation:[touch locationInView:self] isMouse:YES];
            return;
        }
    }
#endif
    
    hasUserInteracted = YES;
    
    if (![onScreenControls handleTouchMovedEvent:touches]) {
        [touchHandler touchesMoved:touches withEvent:event];
    }
}

- (void)pressesBegan:(NSSet<UIPress *> *)presses withEvent:(UIPressesEvent *)event {
    BOOL handled = NO;
    
    if (@available(iOS 13.4, tvOS 13.4, *)) {
        for (UIPress* press in presses) {
            // For now, we'll treated it as handled if we handle at least one of the
            // UIPress events inside the set.
            if (press.key != nil && [KeyboardSupport sendKeyEvent:press.key down:YES]) {
                // This will prevent the legacy UITextField from receiving the event
                handled = YES;
            }
        }
    }
    
    if (!handled) {
        [super pressesBegan:presses withEvent:event];
    }
}

- (void)pressesEnded:(NSSet<UIPress *> *)presses withEvent:(UIPressesEvent *)event {
    BOOL handled = NO;
    
    if (@available(iOS 13.4, tvOS 13.4, *)) {
        for (UIPress* press in presses) {
            // For now, we'll treated it as handled if we handle at least one of the
            // UIPress events inside the set.
            if (press.key != nil && [KeyboardSupport sendKeyEvent:press.key down:NO]) {
                // This will prevent the legacy UITextField from receiving the event
                handled = YES;
            }
        }
    }
    
    if (!handled) {
        [super pressesEnded:presses withEvent:event];
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    if ([self handleMouseButtonEvent:BUTTON_ACTION_RELEASE
                          forTouches:touches
                           withEvent:event]) {
        // If it's a mouse event, we're done
        return;
    }
    
    Log(LOG_D, @"Touch up");
    
    hasUserInteracted = YES;
    
    if (![onScreenControls handleTouchUpEvent:touches]) {
        [touchHandler touchesEnded:touches withEvent:event];
    }
}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
    [touchHandler touchesCancelled:touches withEvent:event];
    [self handleMouseButtonEvent:BUTTON_ACTION_RELEASE
                      forTouches:touches
                       withEvent:event];
}

#if !TARGET_OS_TV
- (void) updateCursorLocation:(CGPoint)location isMouse:(BOOL)isMouse {
    // These are now relative to the StreamView, however we need to scale them
    // further to make them relative to the actual video portion.
    float x = location.x - self.bounds.origin.x;
    float y = location.y - self.bounds.origin.y;
    
    // For some reason, we don't seem to always get to the bounds of the window
    // so we'll subtract 1 pixel if we're to the left/below of the origin and
    // and add 1 pixel if we're to the right/above. It should be imperceptible
    // to the user but it will allow activation of gestures that require contact
    // with the edge of the screen (like Aero Snap).
    if (x < self.bounds.size.width / 2) {
        x--;
    }
    else {
        x++;
    }
    if (y < self.bounds.size.height / 2) {
        y--;
    }
    else {
        y++;
    }
    
    // This logic mimics what iOS does with AVLayerVideoGravityResizeAspect
    CGSize videoSize;
    CGPoint videoOrigin;
    if (self.bounds.size.width > self.bounds.size.height * streamAspectRatio) {
        videoSize = CGSizeMake(self.bounds.size.height * streamAspectRatio, self.bounds.size.height);
    } else {
        videoSize = CGSizeMake(self.bounds.size.width, self.bounds.size.width / streamAspectRatio);
    }
    videoOrigin = CGPointMake(self.bounds.size.width / 2 - videoSize.width / 2,
                              self.bounds.size.height / 2 - videoSize.height / 2);
    
    // Confine the cursor to the video region. We don't just discard events outside
    // the region because we won't always get one exactly when the mouse leaves the region.
    x = MIN(MAX(x, videoOrigin.x), videoOrigin.x + videoSize.width);
    y = MIN(MAX(y, videoOrigin.y), videoOrigin.y + videoSize.height);
    
    // Send the mouse position relative to the video region if it has changed
    // if we're receiving coordinates from a real mouse.
    //
    // NB: It is important for functionality (not just optimization) to only
    // send it if the value has changed. We will receive one of these events
    // any time the user presses a modifier key, which can result in errant
    // mouse motion when using a Citrix X1 mouse.
    if (x != lastMouseX || y != lastMouseY || !isMouse) {
        if (lastMouseX != 0 || lastMouseY != 0 || !isMouse) {
            LiSendMousePositionEvent(x - videoOrigin.x, y - videoOrigin.y,
                                     videoSize.width, videoSize.height);
        }
        
        if (isMouse) {
            lastMouseX = x;
            lastMouseY = y;
        }
    }
}

- (UIPointerRegion *)pointerInteraction:(UIPointerInteraction *)interaction
                       regionForRequest:(UIPointerRegionRequest *)request
                          defaultRegion:(UIPointerRegion *)defaultRegion API_AVAILABLE(ios(13.4)) {
    if (@available(iOS 14.0, *)) {
        if ([GCMouse current] != nil) {
            // We'll handle this with GCMouse. Do nothing here.
            return nil;
        }
    }
    
    // This logic mimics what iOS does with AVLayerVideoGravityResizeAspect
    CGSize videoSize;
    CGPoint videoOrigin;
    if (self.bounds.size.width > self.bounds.size.height * streamAspectRatio) {
        videoSize = CGSizeMake(self.bounds.size.height * streamAspectRatio, self.bounds.size.height);
    } else {
        videoSize = CGSizeMake(self.bounds.size.width, self.bounds.size.width / streamAspectRatio);
    }
    videoOrigin = CGPointMake(self.bounds.size.width / 2 - videoSize.width / 2,
                              self.bounds.size.height / 2 - videoSize.height / 2);
    
    // Move the cursor on the host if no buttons are pressed.
    // Motion with buttons pressed in handled in touchesMoved:
    if (lastMouseButtonMask == 0) {
        [self updateCursorLocation:request.location isMouse:YES];
    }
    
    // The pointer interaction should cover the video region only
    return [UIPointerRegion regionWithRect:CGRectMake(videoOrigin.x, videoOrigin.y, videoSize.width, videoSize.height) identifier:nil];
}

- (UIPointerStyle *)pointerInteraction:(UIPointerInteraction *)interaction styleForRegion:(UIPointerRegion *)region  API_AVAILABLE(ios(13.4)) {
    // Always hide the mouse cursor over our stream view
    return [UIPointerStyle hiddenPointerStyle];
}

- (void)mouseWheelMoved:(UIPanGestureRecognizer *)gesture {
    if (@available(iOS 14.0, *)) {
        if ([GCMouse current] != nil) {
            // We'll handle this with GCMouse. Do nothing here.
            return;
        }
    }
    
    switch (gesture.state) {
        case UIGestureRecognizerStateBegan:
        case UIGestureRecognizerStateChanged:
        case UIGestureRecognizerStateEnded:
            break;
            
        default:
            // Ignore recognition failure and other states
            return;
    }

    CGPoint velocity = [gesture velocityInView:self];
    if ((short)velocity.y != 0) {
        LiSendHighResScrollEvent((short)velocity.y);
    }
}

#endif

- (BOOL)textFieldShouldReturn:(UITextField *)textField {
    // This method is called when the "Return" key is pressed.
    LiSendKeyboardEvent(0x0d, KEY_ACTION_DOWN, 0);
    usleep(50 * 1000);
    LiSendKeyboardEvent(0x0d, KEY_ACTION_UP, 0);
    return NO;
}

- (void)onKeyboardPressed:(UITextField *)textField {
    NSString* inputText = textField.text;
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
        // If the text became empty, we know the user pressed the backspace key.
        if ([inputText isEqual:@""]) {
            LiSendKeyboardEvent(0x08, KEY_ACTION_DOWN, 0);
            usleep(50 * 1000);
            LiSendKeyboardEvent(0x08, KEY_ACTION_UP, 0);
        } else {
            // Character 0 will be our known sentinel value
            for (int i = 1; i < [inputText length]; i++) {
                struct KeyEvent event = [KeyboardSupport translateKeyEvent:[inputText characterAtIndex:i] withModifierFlags:0];
                if (event.keycode == 0) {
                    // If we don't know the code, don't send anything.
                    Log(LOG_W, @"Unknown key code: [%c]", [inputText characterAtIndex:i]);
                    continue;
                }
                [self sendLowLevelEvent:event];
            }
        }
    });
    
    // Reset text field back to known state
    textField.text = @"0";
    
    // Move the insertion point back to the end of the text box
    UITextRange *textRange = [textField textRangeFromPosition:textField.endOfDocument toPosition:textField.endOfDocument];
    [textField setSelectedTextRange:textRange];
}

- (void)specialCharPressed:(UIKeyCommand *)cmd {
    struct KeyEvent event = [KeyboardSupport translateKeyEvent:0x20 withModifierFlags:[cmd modifierFlags]];
    event.keycode = [[dictCodes valueForKey:[cmd input]] intValue];
    [self sendLowLevelEvent:event];
}

- (void)keyPressed:(UIKeyCommand *)cmd {
    struct KeyEvent event = [KeyboardSupport translateKeyEvent:[[cmd input] characterAtIndex:0] withModifierFlags:[cmd modifierFlags]];
    [self sendLowLevelEvent:event];
}

- (void)sendLowLevelEvent:(struct KeyEvent)event {
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
        // When we want to send a modified key (like uppercase letters) we need to send the
        // modifier ("shift") seperately from the key itself.
        if (event.modifier != 0) {
            LiSendKeyboardEvent(event.modifierKeycode, KEY_ACTION_DOWN, event.modifier);
        }
        LiSendKeyboardEvent(event.keycode, KEY_ACTION_DOWN, event.modifier);
        usleep(50 * 1000);
        LiSendKeyboardEvent(event.keycode, KEY_ACTION_UP, event.modifier);
        if (event.modifier != 0) {
            LiSendKeyboardEvent(event.modifierKeycode, KEY_ACTION_UP, event.modifier);
        }
    });
}

- (BOOL)canBecomeFirstResponder {
    return YES;
}

- (NSArray<UIKeyCommand *> *)keyCommands
{
    NSString *charset = @"qwertyuiopasdfghjklzxcvbnm1234567890\t§[]\\'\"/.,`<>-´ç+`¡'º;ñ= ";
    
    NSMutableArray<UIKeyCommand *> * commands = [NSMutableArray<UIKeyCommand *> array];
    dictCodes = [[NSDictionary alloc] initWithObjectsAndKeys: [NSNumber numberWithInt: 0x0d], @"\r", [NSNumber numberWithInt: 0x08], @"\b", [NSNumber numberWithInt: 0x1b], UIKeyInputEscape, [NSNumber numberWithInt: 0x28], UIKeyInputDownArrow, [NSNumber numberWithInt: 0x26], UIKeyInputUpArrow, [NSNumber numberWithInt: 0x25], UIKeyInputLeftArrow, [NSNumber numberWithInt: 0x27], UIKeyInputRightArrow, nil];
    
    [charset enumerateSubstringsInRange:NSMakeRange(0, charset.length)
                                options:NSStringEnumerationByComposedCharacterSequences
                             usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
                                 [commands addObject:[UIKeyCommand keyCommandWithInput:substring modifierFlags:0 action:@selector(keyPressed:)]];
                                 [commands addObject:[UIKeyCommand keyCommandWithInput:substring modifierFlags:UIKeyModifierShift action:@selector(keyPressed:)]];
                                 [commands addObject:[UIKeyCommand keyCommandWithInput:substring modifierFlags:UIKeyModifierControl action:@selector(keyPressed:)]];
                                 [commands addObject:[UIKeyCommand keyCommandWithInput:substring modifierFlags:UIKeyModifierAlternate action:@selector(keyPressed:)]];
                             }];
    
    for (NSString *c in [dictCodes keyEnumerator]) {
        [commands addObject:[UIKeyCommand keyCommandWithInput:c
                                                modifierFlags:0
                                                       action:@selector(specialCharPressed:)]];
        [commands addObject:[UIKeyCommand keyCommandWithInput:c
                                                modifierFlags:UIKeyModifierShift
                                                       action:@selector(specialCharPressed:)]];
        [commands addObject:[UIKeyCommand keyCommandWithInput:c
                                                modifierFlags:UIKeyModifierShift | UIKeyModifierAlternate
                                                       action:@selector(specialCharPressed:)]];
        [commands addObject:[UIKeyCommand keyCommandWithInput:c
                                                modifierFlags:UIKeyModifierShift | UIKeyModifierControl
                                                       action:@selector(specialCharPressed:)]];
        [commands addObject:[UIKeyCommand keyCommandWithInput:c
                                                modifierFlags:UIKeyModifierControl
                                                       action:@selector(specialCharPressed:)]];
        [commands addObject:[UIKeyCommand keyCommandWithInput:c
                                                modifierFlags:UIKeyModifierControl | UIKeyModifierAlternate
                                                       action:@selector(specialCharPressed:)]];
        [commands addObject:[UIKeyCommand keyCommandWithInput:c
                                                modifierFlags:UIKeyModifierAlternate
                                                       action:@selector(specialCharPressed:)]];
    }
    
    return commands;
}

- (void)connectedStateDidChangeWithIdentifier:(NSUUID * _Nonnull)identifier isConnected:(BOOL)isConnected {
    NSLog(@"Citrix X1 mouse state change: %@ -> %s",
          identifier, isConnected ? "connected" : "disconnected");
}

- (void)mouseDidMoveWithIdentifier:(NSUUID * _Nonnull)identifier deltaX:(int16_t)deltaX deltaY:(int16_t)deltaY {
    accumulatedMouseDeltaX += deltaX / X1_MOUSE_SPEED_DIVISOR;
    accumulatedMouseDeltaY += deltaY / X1_MOUSE_SPEED_DIVISOR;
    
    short shortX = (short)accumulatedMouseDeltaX;
    short shortY = (short)accumulatedMouseDeltaY;
    
    if (shortX == 0 && shortY == 0) {
        return;
    }
    
    LiSendMouseMoveEvent(shortX, shortY);
    
    accumulatedMouseDeltaX -= shortX;
    accumulatedMouseDeltaY -= shortY;
}

- (int) buttonFromX1ButtonCode:(enum X1MouseButton)button {
    switch (button) {
        case X1MouseButtonLeft:
            return BUTTON_LEFT;
        case X1MouseButtonRight:
            return BUTTON_RIGHT;
        case X1MouseButtonMiddle:
            return BUTTON_MIDDLE;
        default:
            return -1;
    }
}

- (void)mouseDownWithIdentifier:(NSUUID * _Nonnull)identifier button:(enum X1MouseButton)button {
    LiSendMouseButtonEvent(BUTTON_ACTION_PRESS, [self buttonFromX1ButtonCode:button]);
}

- (void)mouseUpWithIdentifier:(NSUUID * _Nonnull)identifier button:(enum X1MouseButton)button {
    LiSendMouseButtonEvent(BUTTON_ACTION_RELEASE, [self buttonFromX1ButtonCode:button]);
}

- (void)wheelDidScrollWithIdentifier:(NSUUID * _Nonnull)identifier deltaZ:(int8_t)deltaZ {
    LiSendScrollEvent(deltaZ);
}

@end