gtk: add DrawingArea subclassing support

Author: bilelmoussaoui

gtk4/src/subclass/drawing_area.rs

@@ -0,0 +1,61 @@
+use gtk_sys;
+
+use glib::subclass::prelude::*;
+use glib::translate::*;
+use glib::Cast;
+
+use super::widget::WidgetImpl;
+use DrawingArea;
+use Widget;
+
+pub trait DrawingAreaImpl: DrawingAreaImplExt + WidgetImpl {
+    fn resize(&self, drawing_area: &Self::Type, width: i32, height: i32) {
+        self.parent_resize(drawing_area, width, height)
+    }
+}
+
+pub trait DrawingAreaImplExt: ObjectSubclass {
+    fn parent_resize(&self, drawing_area: &Self::Type, width: i32, height: i32);
+}
+
+impl<T: DrawingAreaImpl> DrawingAreaImplExt for T {
+    fn parent_resize(&self, drawing_area: &Self::Type, width: i32, height: i32) {
+        unsafe {
+            let data = T::type_data();
+            let parent_class =
+                data.as_ref().get_parent_class() as *mut gtk_sys::GtkDrawingAreaClass;
+            let f = (*parent_class)
+                .resize
+                .expect("No parent class impl for \"resize\"");
+            f(
+                drawing_area
+                    .unsafe_cast_ref::<DrawingArea>()
+                    .to_glib_none()
+                    .0,
+                width,
+                height,
+            )
+        }
+    }
+}
+
+unsafe impl<T: DrawingAreaImpl> IsSubclassable<T> for DrawingArea {
+    fn override_vfuncs(class: &mut glib::Class<Self>) {
+        <Widget as IsSubclassable<T>>::override_vfuncs(class);
+
+        let klass = class.as_mut();
+        klass.resize = Some(drawing_area_resize::<T>);
+    }
+}
+
+unsafe extern "C" fn drawing_area_resize<T: DrawingAreaImpl>(
+    ptr: *mut gtk_sys::GtkDrawingArea,
+    width: i32,
+    height: i32,
+) {
+    let instance = &*(ptr as *mut T::Instance);
+    let imp = instance.get_impl();
+    let wrap: Borrowed<DrawingArea> = from_glib_borrow(ptr);
+
+    imp.resize(wrap.unsafe_cast_ref(), width, height)
+}

gtk4/src/subclass/mod.rs

@@ -8,6 +8,7 @@ pub mod application_window;
 pub mod box_;
 pub mod button;
 pub mod dialog;
+pub mod drawing_area;
 pub mod flow_box;
 pub mod flow_box_child;
 pub mod header_bar;
@@ -23,6 +24,7 @@ pub mod prelude {
     pub use super::box_::BoxImpl;
     pub use super::button::ButtonImpl;
     pub use super::dialog::DialogImpl;
+    pub use super::drawing_area::DrawingAreaImpl;
     pub use super::flow_box::FlowBoxImpl;
     pub use super::flow_box_child::FlowBoxChildImpl;
     pub use super::header_bar::HeaderBarImpl;