Why your external monitor looks awful on Arm-based Macs, the open source fix – and the guy who wrote it

Q&A with the developer of BetterDummy: from macOS secrets to his motivations

Development history

Can you tell me in a nutshell how you came up with the idea?

BetterDummy is a result of a necessity. My wife is using a 24" display and does not want a bigger display on her desk. The best displays on the market in this size range have QHD (1440p) resolution. She was using this display happily with an Intel Mac mini. Recently I surprised her with a new M1 mini – faster, cooler, nicer. After installation I was astonished to figure out that the usual means to make this mini look right on a QHD display is just missing from macOS and my wife was just unhappy that now she has to look at those small, blurry fonts.

Why the name?

After a lot of internet search I came to a solution: I needed to buy a physical 4K HDMI dummy. A dummy is not a real display, just a plug that pretends to be a display to fool the operating system. Insert it into the HDMI port, and mirror its screen to the actual display, which solves the problem.

I did just that, and the solution indeed worked most of the time, but had various issues with it. The step to create a software display to use as a mirror source was a natural one – especially after I became aware that macOS itself implements an undocumented API to create virtual displays (this is used by Apple's Sidecar and AirPlay as well as some third parties).

I'd like to give credit to a fellow GitHub project – called FluffyDisplay – that utilized this API first for different purposes, and provided an initial implementation upon which I could work towards this purpose.

How long did it take you to get it working from concept to the first working version?

It didn't take much time – a day or two – to come up with an initial usable solution. I did a lot more work on BetterDummy since and I have a lot of plans on how to improve the app.

Would you like for BetterDummy's functionality to become part of macOS?

BetterDummy is just a workaround – I really hope Apple fixes macOS so it will not be needed in the future.

What other display-related software have you written?

I've been working on MonitorControl since summer. I did most of the coding for version 3, with Apple Silicon support and various improvements, and now version 4 with dozens of new features. This involved much much more work than BetterDummy.

I think it is now the best app to control the brightness of third-party displays as if they were Apple displays. Just like BetterDummy, this app is free and open source as well. As with BetterDummy, MonitorControl is a project of love and also of necessity. I considered MonitorControl an essential tool on Mac and was very disappointed when after switching to M1 it did not work. There is a great team behind MonitorControl – I learned a lot from them, and am really thankful for their support and the chance that they selected me as a fellow team member and maintainer of the project.

Do you plan to integrate both?

BetterDummy has some links to MonitorControl. Originally I considered implementing this functionality inside MonitorControl, but eventually decided against it as it would not fit well the scope. It also builds on the work of others in the community – like that of FluffyDisplay or the maintainer of macOS_headers who provides the community with some insight into the undocumented realm of macOS APIs.

What monitor do you use, personally?

I am using an older 2017 LG 4K display and an entry-level M1 MacBook Air with 8GB RAM for development. So I am really amazed in a good way when a new MacBook Pro user equipped with dual Apple Pro XDR displays comes thanking me for a project that makes his $15K setup work well. Originally, I thought the app will appeal to lowly QHD display users only.

Speaking of hardware, with USB-C becoming ubiquitous, and considering DisplayPort is a more robust protocol than the older HDMI, do you have a preference? Do you think HDMI should go away, or are you indifferent?

I don't have a strong opinion about it. HDMI has some advantages in the consumer AV space over DisplayPort right now and I don't think it will go away anytime soon. For computer displays, USB-C can technically carry both DisplayPort and HDMI, although HDMI alt-mode seems to be mostly dead; most USB-C HDMI dongles or cables use DisplayPort alt-mode internally. Ideally the lines between Thunderbolt, USB, and DisplayPort, alt-modes etc will blur eventually and customers won't have to think about what their ports and cables support – it should just work. For now this is not the case, which causes headaches.

Some would read all of the above and think, "wait a minute, this lone guy from Hungary has done a better job than Apple at supporting third-party displays, they should hire him!" Would you agree?

BetterDummy for the most part uses macOS APIs provided by Apple, written using a developer tool made by Apple – Xcode – in a programming language created by Apple – Swift. So I think Apple is more than capable of fixing things without my help. It might be a question of focus or managerial decisions. But of course if Apple wants to recruit me as a developer, I might not resist too much.

Can you tell us a bit about yourself?

I'm István Tóth, 43, and I live in Budapest, Hungary.

How long have you been programming?

I've been programming since I was a kid as a hobby and also as a profession. In the past 10 to 15 years or so I moved to managerial positions and planning so I didn't have the chance to do actual coding. I started rediscovering my love for building actual software, instead of dealing with programmers and customers, in the past few months.

And how long have you been using Macs?

I've been a Mac user for about 15 years. I love Macs but wasn't involved in Mac development at all – I was working on enterprise web applications. My interest was rekindled after buying my first Apple Silicon Mac and was discouraged that my beloved MonitorControl app wasn't compatible. I hopped on as a developer to the project and fixed that.

Are you happy with the tools offered by the macOS ecosystem to developers?

I found Apple's platform and Swift intuitive and fun to use. I was able to get really productive with it in a matter of days. Obviously my background in coding helped a lot.

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Decades ago, we had to struggle with CRT monitors and their internal circuitry not centering the analog SVGA image correctly, which gave birth to software solutions like Display Doctor from SciTech Software, founded by Kendall Bennett. That software was so good that IBM ended up licensing it for its OS/2 operating system. We could say now that BetterDummy is the Display Doctor for M1 Macs – this time solving a different technical problem. As times change, this time the fix is open source.

Could Apple integrate this genius work-around into macOS? Probably. Some might think it's the firm's closed-ecosystem mindset that needs to change for things like that to happen. Maybe they are monitoring the issue from Cupertino and a fix is around the corner? We hope so. In the meantime, you can also show your support for Tóth's project at OpenCollective. ®