gdk4/
toplevel.rs

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// Take a look at the license at the top of the repository in the LICENSE file.

use std::{boxed::Box as Box_, mem::transmute};

use glib::{
    signal::{connect_raw, SignalHandlerId},
    translate::*,
};

use crate::{ffi, prelude::*, Toplevel, ToplevelSize};

mod sealed {
    pub trait Sealed {}
    impl<T: super::IsA<super::Toplevel>> Sealed for T {}
}

// rustdoc-stripper-ignore-next
/// Trait containing manually implemented methods of
/// [`Toplevel`](crate::Toplevel).
pub trait ToplevelExtManual: sealed::Sealed + IsA<Toplevel> {
    /// Emitted when the size for the surface needs to be computed, when
    /// it is present.
    ///
    /// This signal will normally be emitted during or after a call to
    /// [`ToplevelExt::present()`][crate::prelude::ToplevelExt::present()], depending on the configuration
    /// received by the windowing system. It may also be emitted at any
    /// other point in time, in response to the windowing system
    /// spontaneously changing the configuration of the toplevel surface.
    ///
    /// It is the responsibility of the toplevel user to handle this signal
    /// and compute the desired size of the toplevel, given the information
    /// passed via the [`ToplevelSize`][crate::ToplevelSize] object. Failing to do so
    /// will result in an arbitrary size being used as a result.
    /// ## `size`
    /// a [`ToplevelSize`][crate::ToplevelSize]
    fn connect_compute_size<F: Fn(&Toplevel, &mut ToplevelSize) + 'static>(
        &self,
        f: F,
    ) -> SignalHandlerId {
        unsafe extern "C" fn compute_size_trampoline<
            F: Fn(&Toplevel, &mut ToplevelSize) + 'static,
        >(
            this: *mut ffi::GdkToplevel,
            size: *mut ffi::GdkToplevelSize,
            f: glib::ffi::gpointer,
        ) {
            let f: &F = &*(f as *const F);
            f(&from_glib_borrow(this), &mut *(size as *mut ToplevelSize))
        }
        unsafe {
            let f: Box_<F> = Box_::new(f);
            connect_raw(
                self.as_ptr() as *mut _,
                b"compute-size\0".as_ptr() as *const _,
                Some(transmute::<*const (), unsafe extern "C" fn()>(
                    compute_size_trampoline::<F> as *const (),
                )),
                Box_::into_raw(f),
            )
        }
    }
}

impl<O: IsA<Toplevel>> ToplevelExtManual for O {}