tree: use trunc instead of round when scrolling containers

src/it/tests/t0015_scroll_partial.rs

@@ -0,0 +1,48 @@
+use {
+    crate::{
+        it::{test_error::TestResult, testrun::TestRun},
+        tree::ToplevelNode,
+    },
+    std::rc::Rc,
+};
+
+testcase!();
+
+async fn test(run: Rc<TestRun>) -> TestResult {
+    let ds = run.create_default_setup().await?;
+    ds.mouse.rel(1.0, 1.0);
+
+    let client = run.create_client().await?;
+    let dss = client.get_default_seat().await?;
+
+    let w_mono1 = client.create_window().await?;
+    w_mono1.map2().await?;
+    let w_mono2 = client.create_window().await?;
+    w_mono2.map2().await?;
+
+    run.cfg.set_mono(ds.seat.id(), true)?;
+
+    client.sync().await;
+
+    let container = w_mono2.tl.container_parent()?;
+    let pos = container.tl_data().pos.get();
+    let w_mono1_title = container.render_data.borrow_mut().title_rects[0].move_(pos.x1(), pos.y1());
+    ds.mouse.abs(
+        &ds.connector,
+        w_mono1_title.x1() as f64,
+        w_mono1_title.y1() as f64,
+    );
+    client.sync().await;
+
+    let enters = dss.kb.enter.expect()?;
+
+    ds.mouse.scroll_px(-14);
+    client.sync().await;
+    tassert!(enters.next().is_err());
+
+    ds.mouse.scroll_px(-1);
+    client.sync().await;
+    tassert!(enters.next().is_ok());
+
+    Ok(())
+}