Provide a way to get the Min / Max / Close- Button positions

Is your feature request related to a problem? Please describe. I like the idea to render extend into the title bar and keep the system chrome alive with the Min/ Max/ Close buttons. Then I would like to place content like Tabs into the TitleBar. the issue I have is, that I cannot now how much space I have to reserve for the system window Buttons or on which side they are (I think on Mac they are on a different side then for Windows)

Describe the solution you’d like A property on the Window which tells me where some reserved space is, for example:

ReservedSpace[] ReservedSpaces = new ReservedSpace[] 
{ 
     new ReservedSpace (width: 75, height: 20, Position: Position.TopRight)
};

Describe alternatives you’ve considered

• Hardcode these properties
• Use custom buttons, but I learned that this is not a good idea, especially on Linux

Additional context See also: https://docs.avaloniaui.net/tutorials/music-store-app/creating-a-modern-looking-window

/cc @danwalmsley @ahopper this is a follow-up issue from our discussion on telegram.

Happy coding Tim

[Symbai]

On several WPF third party themes the customizable window header area is only from left to the first start of (min or max or close) button so you cannot draw anything on top of these controls. This seems to be much better than adding a new property which only returns the size and the developer has to calculate the distance himself .

[maxkatz6]

Couple of thoughts:

1. There should be an event, so application can adjust elements dynamically (on macos these buttons are hidden in fullscreen, and visible again in normal mode…). See https://stackoverflow.com/a/52803798
2. Same API potentially can be used for reserved parts on mobile screens, including iphone notch
3. It should use native APIs instead of some hardcoded “well known” values.
4. I guess this API won’t be possible on Linux with some desktop implementations