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Great list of the complexity encompassing a proper "GUI" framework. I feel like text / rich text / unicode alone is a huge project (if you include editing, espe

Great list of the complexity encompassing a proper "GUI" framework. I feel like text / rich text / unicode alone is a huge project (if you include editing, especially of large documents). However, one thing not mentioned in this list (which I feel is only becoming more important) is that a modern GUI framework also might want to support iPad / iOS / Android. This complexifies the undertaking by a huge amount as the differences between macOS/win/linux are much smaller than the distance between, say, iOS and macOS. Apple has been going into this direction with SwiftUI where the same code can be run on different systems and behaves differently depending on the platform. However, by doing so, this "common denominator" of all platforms automatically reduces the flexibility of the framework as every "component" needs to be cut wide enough to intelligently behave correctly per platform.

amelius 5y ago
And then there is the question if your GUI framework is even allowed on iOS. For example, Firefox can't use its internal render engine on iOS, but is forced by Apple to use Safari's library.
- terhechte 5y ago
  They can use their internal render engine. What they can't use is their Javascript framework because a modern JIT requires taking compiled javascript code in memory and marking it as executable (e.g. taking any memory page of data and telling the system that this is code now, thus allowing to execute it). This goes against the iOS security mechanism / sandbox because a bug here would allow executing any remote code in the context of the current process. You can even ship a custom Javascript engine on iOS if you disable JIT, it will just be slow. Or, you do it like iSH (https://ish.app https://ish.app) and implement custom execution via a hard-to-debug genius assembly. As an exempla, Ejecta is a custom Javascript library for iOS - just without the JIT to make it fast. https://impactjs.com/ejecta https://impactjs.com/ejecta
  - modeless 5y ago
    > You can even ship a custom Javascript engine on iOS Yes but you can't run code downloaded from the internet or supplied by the user. So you are prohibited from building your own browser, even without JIT. Unless you are Roblox for some reason, then you can run all the downloaded code you want! Sucks to be a Roblox competitor, sorry no running downloaded code for you.
    - terhechte 5y ago
      Fully agree here, these special exceptions for big corp are just terrible. It has such a terrible bribery / corruption feel to it.
    - UnpossibleJim 5y ago
      Apple has long been known to "bend" certain rules for clients of the app store of a certain size. https://www.theverge.com/2020/6/17/21293813/apple-app-store-policies-hey-30-percent-developers-the-trial-by-franz-kafka https://www.theverge.com/2020/6/17/21293813/apple-app-store-...
    - remram 5y ago
      Where do they draw the line for what is "code"? Does HTML/CSS not count? Browsers will take complicated actions based on that downloaded data. Even PDF is up there if you ask me...
    - ProfessorLayton 5y ago
      Pro tip for Roblox competitors: Make a product that children really, really like, and make sure some of those children are those of executive leadership at the company you'd like to influence. You'll get exceptions too, and you don't even have to be a unicorn (Roblox got an exception well before that, after initially getting banned from the App Store).
      - modeless 5y ago
        I am interested to hear more about the history of this exception. Roblox is now a public company worth 40 billion dollars and I believe a large part of that valuation can be attributed to their privileged and protected position in the iOS app store. Did they disclose that in their S-1?
jbluepolarbear 5y ago
Getting rich text right is a huge undertaking. I spent a lot of time on getting text working really well on a few GUI projects I worked on. This is the last big GUI/application framework I coauthored. It’s still getting maintained 10 years later. It’s primarily been used for creative applications, but could just as well build cross platform media rich application. https://github.com/Downstream/ds_cinder https://github.com/Downstream/ds_cinder

amelius 5y ago

And then there is the question if your GUI framework is even allowed on iOS. For example, Firefox can't use its internal render engine on iOS, but is forced by Apple to use Safari's library.

terhechte 5y ago
They can use their internal render engine. What they can't use is their Javascript framework because a modern JIT requires taking compiled javascript code in memory and marking it as executable (e.g. taking any memory page of data and telling the system that this is code now, thus allowing to execute it). This goes against the iOS security mechanism / sandbox because a bug here would allow executing any remote code in the context of the current process. You can even ship a custom Javascript engine on iOS if you disable JIT, it will just be slow. Or, you do it like iSH (https://ish.app https://ish.app) and implement custom execution via a hard-to-debug genius assembly. As an exempla, Ejecta is a custom Javascript library for iOS - just without the JIT to make it fast. https://impactjs.com/ejecta https://impactjs.com/ejecta
- modeless 5y ago
  > You can even ship a custom Javascript engine on iOS Yes but you can't run code downloaded from the internet or supplied by the user. So you are prohibited from building your own browser, even without JIT. Unless you are Roblox for some reason, then you can run all the downloaded code you want! Sucks to be a Roblox competitor, sorry no running downloaded code for you.
  - terhechte 5y ago
    Fully agree here, these special exceptions for big corp are just terrible. It has such a terrible bribery / corruption feel to it.
  - UnpossibleJim 5y ago
    Apple has long been known to "bend" certain rules for clients of the app store of a certain size. https://www.theverge.com/2020/6/17/21293813/apple-app-store-policies-hey-30-percent-developers-the-trial-by-franz-kafka https://www.theverge.com/2020/6/17/21293813/apple-app-store-...
  - remram 5y ago
    Where do they draw the line for what is "code"? Does HTML/CSS not count? Browsers will take complicated actions based on that downloaded data. Even PDF is up there if you ask me...
  - ProfessorLayton 5y ago
    Pro tip for Roblox competitors: Make a product that children really, really like, and make sure some of those children are those of executive leadership at the company you'd like to influence. You'll get exceptions too, and you don't even have to be a unicorn (Roblox got an exception well before that, after initially getting banned from the App Store).
    - modeless 5y ago
      I am interested to hear more about the history of this exception. Roblox is now a public company worth 40 billion dollars and I believe a large part of that valuation can be attributed to their privileged and protected position in the iOS app store. Did they disclose that in their S-1?

jbluepolarbear 5y ago

Getting rich text right is a huge undertaking. I spent a lot of time on getting text working really well on a few GUI projects I worked on. This is the last big GUI/application framework I coauthored. It’s still getting maintained 10 years later. It’s primarily been used for creative applications, but could just as well build cross platform media rich application. https://github.com/Downstream/ds_cinder https://github.com/Downstream/ds_cinder