gtk4/subclass/
scale_button.rs

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

// rustdoc-stripper-ignore-next
//! Traits intended for subclassing [`ScaleButton`].

use glib::translate::*;

use crate::{ffi, prelude::*, subclass::prelude::*, Orientable, ScaleButton};

pub trait ScaleButtonImpl:
    WidgetImpl + ObjectSubclass<Type: IsA<ScaleButton> + IsA<Orientable>>
{
    fn value_changed(&self, new_value: f64) {
        self.parent_value_changed(new_value)
    }
}

pub trait ScaleButtonImplExt: ScaleButtonImpl {
    fn parent_value_changed(&self, new_value: f64) {
        unsafe {
            let data = Self::type_data();
            let parent_class = data.as_ref().parent_class() as *mut ffi::GtkScaleButtonClass;
            if let Some(f) = (*parent_class).value_changed {
                f(
                    self.obj().unsafe_cast_ref::<ScaleButton>().to_glib_none().0,
                    new_value,
                )
            }
        }
    }
}

impl<T: ScaleButtonImpl> ScaleButtonImplExt for T {}

unsafe impl<T: ScaleButtonImpl> IsSubclassable<T> for ScaleButton {
    fn class_init(class: &mut glib::Class<Self>) {
        Self::parent_class_init::<T>(class);

        let klass = class.as_mut();
        klass.value_changed = Some(scale_button_value_changed::<T>);
    }
}

unsafe extern "C" fn scale_button_value_changed<T: ScaleButtonImpl>(
    ptr: *mut ffi::GtkScaleButton,
    new_value: f64,
) {
    let instance = &*(ptr as *mut T::Instance);
    let imp = instance.imp();

    imp.value_changed(new_value)
}