Make text_input_byte_offset_for_position and text_input_cursor_rect_for_byte_offset
low-level in the API, where the implementation becomes easier. Two
helper functions in TextInput in turn collect the necessary parameters
and thus also reduce the amount of duplicated code.
This also decouples the renderer further from the window.
Don't require passing a dyn WindowAdapter. This was only used for
calling request_redraw(), which a proper window adapter should do anyway
if has_active_animations() is true.
Remove the generic window handle owner part of the API. Instead assume
that the caller provides safety for the given window handles, like we do
for FemtoVG and like softbuffer does it in its public API.
So that we don't need to query the geometry multiple time, and this pave
the way to not have the geometry in the items
Part of #1932
As a drive by, fix the clipping of the Path element which incorrectly
offseted the clip by (x,y).
Similar fixes happen in the Clip element in some renderer, but that
didn't have effect because x and y are always 0 for the Clip element
Return the path events for rendering as an Option, so that if the path is empty,
we simply return.
This avoids a double property dependency in the (likely) event the path is not empty.
The crate is an internal crate until the API has been polished and
documented, after which we can call slint-renderer-skia for example.
This also duplicates a little bit of the glutin setup code, because
that would otherwise have to go into another shared crate.
