It would likely mean losing lots of integration and special features though. If it's outside of the app how would you have a modal UI which would change what's in the right click menu of the canvas ? You would also have to wait for your OS to implement 10-bit support for it - I'm pretty sure that e.g. Krita had 10-bit canvas before MS Paint :)
Also enjoy teaching students or even learning to do anything. With big software like Photoshop (or musical equivalents), you can take the book that comes with it and become fairly proficient at pretty much everything that the app allows. How would that work if there is no individual software ? What screenshot do you show on the docs ? How do you make YouTube videos when most people may have a different setup than yours ?
> If it's outside of the app how would you have a modal UI which would change what's in the right click menu of the canvas ?
Simple. The object that owns the "modal UI" part would own, or at least aggregate, a right-click menu. The canvas shouldn't be busy handling right-click menus anyway, it should provide an interface to access and manipulate the underlying bitmap. The "modal UI" would own the right-click handler, and would populate the context menu with a filtered choice of options, including functionality provided by different objects.
It's more complex than naive approach with everything being owned by a single one, but fundamentally not that different from a design you'd arrive to if you were intended to allow for plugins in your application - except now the "plugin manager" isn't in your app, but in your OS.
> You would also have to wait for your OS to implement 10-bit support for it - I'm pretty sure that e.g. Krita had 10-bit canvas before MS Paint :)
Krita people could provide a 10-bit canvas implementation that offers an 8-bit canvas-compatible interface. Alternatively, your UI could require canvas objects implementing a 10-bit canvas interface, but you - or a third party - would also provide an adapter (polyfill, as the kids say today) that wraps the MS Paint 8-bit canvas behind a 10-bit canvas interface.
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The teaching point you bring up is a strong one, and I don't have a good answer. I think Microsoft's COM, the Emacs ecosystem and every game with a large modding scene (e.g. Kerbal Space Program) all provide evidence that a fully interoperable system turns users into sysadmins. You don't need to code to use such a system, but you'd better be prepared to be aware of all the components, and do a bit of configuring, if you want anything other than the defaults.
(But, as every game with a large modding scene demonstrates, it's not necessarily that hard for regular non-tech-savvy users either.)
Also enjoy teaching students or even learning to do anything. With big software like Photoshop (or musical equivalents), you can take the book that comes with it and become fairly proficient at pretty much everything that the app allows. How would that work if there is no individual software ? What screenshot do you show on the docs ? How do you make YouTube videos when most people may have a different setup than yours ?