nburatovich

This is an excerpt from our internal documentation describing an issue with drawing in NSViews on macOS Big Sur.

1️⃣ Introduction

In macOS Big Sur (probably starting with β9), Apple changed the default contents format for backing layers of NSViews. Instead of an explicit CALayerContentsFormat.RGBA8Uint value, an „Automatic“ value is now used. Even though it also resolves into „RGBA8“ in our testing, it has some serious implications as it breaks assumptions our code relies on.

I first stumbled upon this issue in this tweet by Frank. It links to a thread on Apple Forums by Mark that contains valuable information as well as ideas for workarounds. The changed behavior was also confirmed by Marcin in this tweet.

2️⃣ Impact on Diagrams

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.
Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

Is AppKit causing you frustration? Instead of just complaining about it, lets try to make it better by compiling a list of specific problems with AppKit. Leave a comment below, and I'll include it in the list.

##NSView##

NSView does not have the ability to set an affine transform (rdar://15608609)
Controls that have cells (such as NSTextField) do not respond properly when layer-backed. Take NSButton as an example. When not layer-backed, it will animate properly using the animator proxy. When layer-backed, using the animator proxy breaks focus rings (they jump to destination immediately). Currently, directly manipulating the layer of a cell-based control is not supported (and will lead to a broken interface), but is much needed. (rdar://15608822)

##NSViewController##

NSViewController could be more useful. It has -loadView but no other lifecycle methods. (rdar://15608948)

	//
	// NSApplication+NSResponderDebug.swift
	//
	// Created by Stephan Casas on 3/18/24.
	//

	import Cocoa;

	extension NSApplication {

	// This code is based on https://en.wikipedia.org/wiki/HSL_and_HSV
	// Free to use for any purpose. No attribution needed.

	function rgbToHsl(r, g, b) {
	r /= 255; g /= 255; b /= 255;
	let max = Math.max(r, g, b);
	let min = Math.min(r, g, b);
	let d = max - min;
	let h;
	if (d === 0) h = 0;

	//
	// UIResponder+FTAdditions.h
	// Streets
	//
	// Created by Ortwin Gentz on 09.05.16.
	// Copyright © 2016 FutureTap. All rights reserved.
	//

	#import <UIKit/UIKit.h>

	###
	###
	### UPDATE: For Win 11, I recommend using this tool in place of this script:
	### https://christitus.com/windows-tool/
	### https://github.com/ChrisTitusTech/winutil
	### https://www.youtube.com/watch?v=6UQZ5oQg8XA
	### iwr -useb https://christitus.com/win \| iex
	###
	### OR take a look at
	### https://github.com/HotCakeX/Harden-Windows-Security

	/// Observes a run loop to detect any stalling or blocking that occurs.
	///
	/// This class is thread-safe.
	@interface GHRunLoopWatchdog : NSObject

	/// Initializes the receiver to watch the specified run loop, using a default
	/// stalling threshold.
	- (id)initWithRunLoop:(CFRunLoopRef)runLoop;

	/// Initializes the receiver to detect when the specified run loop blocks for

	// gcc Cocoa.m -o OSXWindow -framework Cocoa -framework Quartz -framework OpenGL

	#import <Cocoa/Cocoa.h>
	#import <QuartzCore/CVDisplayLink.h>
	#import <OpenGL/OpenGL.h>
	#include <OpenGL/gl.h>

	@class View;
	static CVReturn GlobalDisplayLinkCallback(CVDisplayLinkRef, const CVTimeStamp, const CVTimeStamp, CVOptionFlags, CVOptionFlags, void);

	CIFilter *resizeFilter = [CIFilter filterWithName:@"CILanczosScaleTransform"];
	[resizeFilter setValue:ciImage forKey:@"inputImage"];
	[resizeFilter setValue:[NSNumber numberWithFloat:1.0f] forKey:@"inputAspectRatio"];
	[resizeFilter setValue:[NSNumber numberWithFloat:xRatio] forKey:@"inputScale"];

	CIFilter *cropFilter = [CIFilter filterWithName:@"CICrop"];
	CIVector *cropRect = [CIVector vectorWithX:rect.origin.x Y:rect.origin.y Z:rect.size.width W:rect.size.height];
	[cropFilter setValue:resizeFilter.outputImage forKey:@"inputImage"];
	[cropFilter setValue:cropRect forKey:@"inputRectangle"];
	CIImage *croppedImage = cropFilter.outputImage;