Help to implement Zoom In, Zoom out VZVirtualMachineView

[Code-Hex]

It is not among the features provided by Apple but, I attempted to provide pinch-in zoom-in, and zoom-out functionality like iPhone for the window that serves as the GUI display in this package.

However, This was too difficult than expected and was once out of the scope.

VZVirtualMachineView inherits from NSView. So I was thinking that if I made the document view of the NSScrollView and applied the scroll view to the window, it would be complete.

The problem is...

• VZVirtualMachineView receives the VZVirtualMachine object via property. After receiving it, this view no longer accepts multi-touch gestures. Instead, these events are proxied to the guest OS.
• Therefore necessary to temporarily prevent the events related to mouse movements from being transmitted to this view.
• This has been successful. However, it was not possible to perform operations such as zooming in on the key views.
• As I will be described later, this view has an internal NSTrackingArea, which probably needs to do anything.

[Code-Hex]

This is a result of dumped VZVirtualMachineView (/System/Library/Frameworks/Virtualization.framework/Versions/A/Virtualization)

@interface VZVirtualMachineView : NSView {
    id  _becomeKeyWindowObserver;
    bool  _capturesSystemKeys;
    NSCursor * _currentGuestCursor;
    <_VZVirtualMachineViewDelegate> * _delegate;
    id  _eventMonitor;
    _VZFramebufferView * _framebufferView;
    bool  _guestIsUsingHostCursor;
    id  _keyEventMonitor;
    struct vector<unsigned short, std::allocator<unsigned short>> { 
        unsigned short *__begin_; 
        unsigned short *__end_; 
        struct __compressed_pair<unsigned short *, std::allocator<unsigned short>> { 
            unsigned short *__value_; 
        } __end_cap_; 
    }  _keys_down;
    bool  _mouseIsInTrackingArea;
    id  _resignKeyWindowObserver;
    long long  _scaleMode;
    bool  _showsHostCursor;
    NSTrackingArea * _trackingArea;
    VZVirtualMachine * _virtualMachine;
    bool  _virtualMachineIsRunning;
    VZObserverProxy * _virtualMachineObserver;
}

@property (readonly) bool _canGrabMouseInput;
@property (readonly) bool _canReleaseMouseInput;
@property (setter=_setDelegate:) <_VZVirtualMachineViewDelegate> *_delegate;
@property (setter=_setScaleMode:) long long _scaleMode;
@property bool capturesSystemKeys;
@property (retain) VZVirtualMachine *virtualMachine;

- (id).cxx_construct;
- (void).cxx_destruct;
- (bool)acceptsFirstResponder;
- (bool)becomeFirstResponder;
- (bool)capturesSystemKeys;
- (void)dealloc;
- (void)flagsChanged:(id)arg1;
- (id)initWithCoder:(id)arg1;
- (id)initWithFrame:(struct CGRect { struct CGPoint { double x_1_1_1; double x_1_1_2; } x1; struct CGSize { double x_2_1_1; double x_2_1_2; } x2; })arg1;
- (void)keyDown:(id)arg1;
- (void)keyUp:(id)arg1;
- (void)layout;
- (void)magnifyWithEvent:(id)arg1;
- (void)mouseDown:(id)arg1;
- (void)mouseDragged:(id)arg1;
- (void)mouseEntered:(id)arg1;
- (void)mouseExited:(id)arg1;
- (void)mouseMoved:(id)arg1;
- (void)mouseUp:(id)arg1;
- (void)observeValueForKeyPath:(id)arg1 ofObject:(id)arg2 change:(id)arg3 context:(void*)arg4;
- (void)otherMouseDown:(id)arg1;
- (void)otherMouseDragged:(id)arg1;
- (void)otherMouseUp:(id)arg1;
- (void)quickLookWithEvent:(id)arg1;
- (bool)resignFirstResponder;
- (void)rightMouseDown:(id)arg1;
- (void)rightMouseDragged:(id)arg1;
- (void)rightMouseUp:(id)arg1;
- (void)rotateWithEvent:(id)arg1;
- (void)scrollWheel:(id)arg1;
- (void)setCapturesSystemKeys:(bool)arg1;
- (void)setVirtualMachine:(id)arg1;
- (void)smartMagnifyWithEvent:(id)arg1;
- (void)updateTrackingAreas;
- (void)viewDidMoveToWindow;
- (void)viewWillMoveToWindow:(id)arg1;
- (id)virtualMachine;

// VZVirtualMachineView (VZPrivate)

- (bool)_canGrabMouseInput;
- (bool)_canReleaseMouseInput;
- (id)_delegate;
- (bool)_grabMouseInput;
- (bool)_releaseMouseInput;
- (long long)_scaleMode;
- (void)_setDelegate:(id)arg1;
- (void)_setScaleMode:(long long)arg1;

@end

[Code-Hex]

A test repository is available here. https://github.com/Code-Hex/vm-scroll-test

You can try it out by creating a VM.bundle directory on your home directory with the file AuxiliaryStorage Disk.img HardwareModel MachineIdentifier RestoreImage.ipsw. These can be created by preparing a Restore Image according to the examples for macOS in this package. (also followed as Apple Running macOS in a Virtual Machine on Apple Silicon Macs instruction)