fix: make scrolled_window always scrolled to the end

src/chat/gui/mod.rs

@@ -46,6 +46,7 @@ use super::{
 
 mod preferences;
 mod page;
+mod widgets;
 
 use page::*;
 use preferences::*;

src/chat/gui/page.rs

@@ -35,6 +35,7 @@ use crate::chat::{
     on_send_message, parse_message, SERVER_LIST,
 };
 
+use super::widgets::CustomLayout;
 use super::{add_chat_messages, get_avatar_id, get_message_sign, load_pixbuf, send_notification, try_save_config, update_window_title, UiModel};
 
 pub fn get_message_box(
@@ -359,6 +360,21 @@ pub fn build_page_box(ctx: Arc<Context>, app: &Application) -> (GtkBox, GtkBox,
         .propagate_natural_height(true)
         .build();
 
+    let layout = CustomLayout::default();
+
+    layout.connect_local("size-changed", false, {
+        let chat_scrolled = chat_scrolled.downgrade();
+        move |_| {
+            if let Some(chat_scrolled) = chat_scrolled.upgrade() {
+                let value = chat_scrolled.vadjustment().upper() - chat_scrolled.vadjustment().page_size();
+                chat_scrolled.vadjustment().set_value(value);
+            }
+            return None;
+        }
+    });
+
+    page_box.set_layout_manager(Some(layout));
+
     timeout_add_local_once(Duration::ZERO, clone!(
         #[weak] chat_scrolled,
         move || {

src/chat/gui/widgets/imp.rs

@@ -0,0 +1,53 @@
+use libadwaita::{glib, gtk};
+
+use glib::object::ObjectExt;
+use gtk::{subclass::prelude::*, prelude::LayoutManagerExt, BoxLayout};
+
+#[derive(Debug)]
+pub struct CustomLayout {
+    box_layout: BoxLayout
+}
+
+impl Default for CustomLayout {
+    fn default() -> Self {
+        CustomLayout {
+            box_layout: BoxLayout::builder()
+                .orientation(gtk::Orientation::Vertical)
+                .spacing(5)
+                .build()
+        }
+    }
+}
+
+#[glib::object_subclass]
+impl ObjectSubclass for CustomLayout {
+    const NAME: &'static str = "CustomLayout";
+    type Type = super::CustomLayout;
+    type ParentType = gtk::LayoutManager;
+}
+
+impl ObjectImpl for CustomLayout {
+    fn signals() -> &'static [glib::subclass::Signal] {
+        use std::sync::OnceLock;
+        
+        static SIGNALS: OnceLock<Vec<glib::subclass::Signal>> = OnceLock::new();
+
+        SIGNALS.get_or_init(|| {
+            vec![glib::subclass::Signal::builder("size-changed").build()]
+        })
+    }
+}
+impl LayoutManagerImpl for CustomLayout {
+    fn allocate(&self, widget: &gtk::Widget, width: i32, height: i32, baseline: i32) {
+        self.obj().emit_by_name::<()>("size-changed", &[]);
+        self.box_layout.allocate(widget, width, height, baseline)
+    }
+    fn measure(
+            &self,
+            widget: &gtk::Widget,
+            orientation: gtk::Orientation,
+            for_size: i32,
+        ) -> (i32, i32, i32, i32) {
+        self.box_layout.measure(widget, orientation, for_size)
+    }
+}

src/chat/gui/widgets/mod.rs

@@ -0,0 +1,15 @@
+mod imp;
+
+use libadwaita::gtk::glib;
+use libadwaita::gtk;
+
+glib::wrapper! {
+    pub struct CustomLayout(ObjectSubclass<imp::CustomLayout>)
+        @extends gtk::LayoutManager;
+}
+
+impl Default for CustomLayout {
+    fn default() -> Self {
+        glib::Object::new()
+    }
+}