Disable 77% scaling for Mac Catalyst apps. (Swift)

OverrideCatalystScaleFactor.swift

let overrideCatalystScaleFactor: Void = {
    guard let sceneViewClass = NSClassFromString("UINSSceneView") as? NSObject.Type else {
        return
    }
    if sceneViewClass.instancesRespond(to: NSSelectorFromString("scaleFactor")) {
        // old
        swizzleInstanceMethod(
            class: sceneViewClass,
            originalSelector: NSSelectorFromString("scaleFactor"),
            swizzledSelector: #selector(swizzle_scaleFactor)
        )
    } else {
        // macOS 11.3 Beta 3+
        swizzleInstanceMethod(
            class: sceneViewClass,
            originalSelector: NSSelectorFromString("sceneToSceneViewScaleFactor"),
            swizzledSelector: #selector(swizzle_scaleFactor)
        )
        swizzleInstanceMethod(
            class: sceneViewClass,
            originalSelector: NSSelectorFromString("fixedSceneToSceneViewScaleFactor"),
            swizzledSelector: #selector(swizzle_scaleFactor2)
        )
        swizzleInstanceMethod(
            class: NSClassFromString("UINSSceneContainerView"),
            originalSelector: NSSelectorFromString("sceneToSceneViewScaleForLayout"),
            swizzledSelector: #selector(swizzle_scaleFactor3)
        )
    }
}()

@objc private extension NSObject {
    func swizzle_scaleFactor() -> CGFloat { 1 }
    func swizzle_scaleFactor2() -> CGFloat { 1 }
    func swizzle_scaleFactor3() -> CGFloat { 1 }
}

For implementation of swizzleInstanceMethod, check Swizzle.swift

Thanks works well overall but I have an issue:

When picking a photo using UIImagePickerController or PHPickerViewController the touches/clicks are not registered correctly. It's probably best to have the picker stick to the default 77% scaling. Any tips on how to do this?

@Janneman84 you could:
A. open those remote view controllers on a separated window scene, where scaling is set to 77% (requires modification on the swizzled methods);
or B. replace PHPickerViewController with a macOS equivalent such as UIDocumentPickerViewController or NSOpenPanel.

Thanks for the tip!

I figured out image pickers are pretty useless in MacOS anyway. A document picker works much better!

tks, Can you please tell me where to place these code? I have tried in MacOS 14.5, but is doesn't work
`
#import "KGMacCatalystScaleDisabler.h"
#import <KGSafeKit/NSObject+KGSwizzle.h>

@implementation KGMacCatalystScaleDisabler
#if TARGET_OS_MACCATALYST

• (void)load {
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
  Class sceneViewClass = NSClassFromString(@"UINSSceneView");
  if (sceneViewClass) {
  SEL originalSelector = NSSelectorFromString(@"scaleFactor");
  SEL swizzledSelector = @selector(swizzle_scaleFactor);

        if ([sceneViewClass instancesRespondToSelector:originalSelector]) {
            // Swizzle scaleFactor for older versions
            [sceneViewClass kg_swizzleInstanceMethod:originalSelector withMethod:swizzledSelector];
        } else {
            // Swizzle methods for macOS 11.3 Beta 3+
            originalSelector = NSSelectorFromString(@"sceneToSceneViewScaleFactor");
            [sceneViewClass kg_swizzleInstanceMethod:originalSelector withMethod:swizzledSelector];
  
            originalSelector = NSSelectorFromString(@"fixedSceneToSceneViewScaleFactor");
            SEL swizzledSelector2 = @selector(swizzle_scaleFactor2);
            [sceneViewClass kg_swizzleInstanceMethod:originalSelector withMethod:swizzledSelector2];
  
            Class sceneContainerViewClass = NSClassFromString(@"UINSSceneContainerView");
            if (sceneContainerViewClass) {
                originalSelector = NSSelectorFromString(@"sceneToSceneViewScaleForLayout");
                SEL swizzledSelector3 = @selector(swizzle_scaleFactor3);
                [sceneContainerViewClass kg_swizzleInstanceMethod:originalSelector withMethod:swizzledSelector3];
            }
        }
    }
  

  });
  }

• (CGFloat)swizzle_scaleFactor {
  return 1.0;
  }

• (CGFloat)swizzle_scaleFactor2 {
  return 1.0;
  }

• (CGFloat)swizzle_scaleFactor3 {
  return 1.0;
  }
  #endif
  @EnD

`

I run the code in my AppDelegate.init()

I run the code in my AppDelegate.init()

Thanks, I used your code instead of the OC code I wrote according to your logic, and it works now. I have another question, how did you find these methods to hook? I am considering whether to use this solution, because the API may change when the system is updated, and I don't know if there is any risk of audit for hooking this?

Is any of this considered using a private API and risk rejectoin from the App Store?

Is any of this considered using a private API and risk rejection from the App Store?

Running fine for years. Apple don't cares.