Add types for Gdk.Display and Gdk.Monitor

[mswiger]

I added the typing information using these docs:

https://lazka.github.io/pgi-docs/#Gdk-3.0/classes/Display.html#Gdk.Display
https://lazka.github.io/pgi-docs/#Gdk-3.0/classes/Monitor.html#Gdk.Monitor

I wasn't sure exactly how to type the return values for Gdk.Display.get_maximal_cursor_size or Gdk.Display.get_pointer, so I did not update the typings. Maybe they should be NamedTuples?

[cal0pteryx]

Both methods return a Tuple. For example: def get_maximal_cursor_size(self) -> tuple[int, int]

[mswiger]

The fields of the returned tuple have names though:

(Pdb) p display.get_maximal_cursor_size()
(width=256, height=256)

Fields are width and height.

(Pdb) p display.get_pointer()
(screen=<__gi__.GdkWaylandScreen object at 0x7fc1645abf80 (GdkWaylandScreen at 0x563452d42010)>, x=0, y=0, mask=<flags 0 of type Gdk.ModifierType>)

Fields are screen, x, y, and mask.

Using a regular tuple would work, but it might be nice to keep these field names. It's just not clear to me what the best way to do this would be. We could explicitly create new types to support these return types, but I'm not sure if that's the right approach. For example:

class Size(NamedTuple):
    width: int
    height: int

def get_maximal_cursor_size(self) -> Size: ...

[lovetox]

Its a ResultTuple object, but i think it only exists in C code.

A namedtuple would be a bit too misleading as it has many methods that this object does not have

something like this would be more fitting

class Size(Tuple[int, int]):
    width: int
    height: int

[mswiger]

Makes sense! I've updated this branch with Size and Pointer return types for the Gdk.Display.get_maximal_cursor_size and Gdk.Display.get_pointer. Does this look like what you were thinking?

As a side note, is there a recommended way of testing these changes? The instructions in CONTRIBUTING.md seem incomplete/did not work for me.

[lovetox]

what did not work?

There is no way to test your changes, we just do a test that you dont introduce syntax errors, thats why we run mypy on the examples folder.

[mswiger]

I see, thanks for the explanation!