surface: process offset request without a buffer change

src/ifs/wl_surface.rs

@@ -910,14 +910,6 @@ impl WlSurface {
                     release,
                 };
                 self.buffer.set(Some(Rc::new(surface_buffer)));
-                self.buf_x.fetch_add(dx);
-                self.buf_y.fetch_add(dy);
-                if (dx, dy) != (0, 0) {
-                    self.need_extents_update.set(true);
-                    for (_, cursor) in &self.cursors {
-                        cursor.dec_hotspot(dx, dy);
-                    }
-                }
             } else {
                 self.buf_x.set(0);
                 self.buf_y.set(0);
@@ -926,6 +918,14 @@ impl WlSurface {
                 }
             }
         }
+        if self.buffer.is_some() && (dx, dy) != (0, 0) {
+            self.buf_x.fetch_add(dx);
+            self.buf_y.fetch_add(dy);
+            self.need_extents_update.set(true);
+            for (_, cursor) in &self.cursors {
+                cursor.dec_hotspot(dx, dy);
+            }
+        }
         let transform_changed = viewport_changed || scale_changed || buffer_transform_changed;
         if buffer_changed || transform_changed {
             let mut buffer_points = self.buffer_points.borrow_mut();

src/it/test_ifs/test_pointer.rs

@@ -2,8 +2,9 @@ use {
     crate::{
         ifs::wl_seat::wl_pointer::WlPointer,
         it::{
-            test_error::TestResult, test_object::TestObject, test_transport::TestTransport,
-            test_utils::test_expected_event::TEEH, testrun::ParseFull,
+            test_error::TestResult, test_ifs::test_surface::TestSurface, test_object::TestObject,
+            test_transport::TestTransport, test_utils::test_expected_event::TEEH,
+            testrun::ParseFull,
         },
         utils::{buffd::MsgParser, clonecell::CloneCell},
         wire::{wl_pointer::*, WlPointerId},
@@ -30,6 +31,23 @@ impl TestPointer {
         Ok(())
     }
 
+    pub fn set_cursor(
+        &self,
+        serial: u32,
+        surface: &TestSurface,
+        hotspot_x: i32,
+        hotspot_y: i32,
+    ) -> TestResult {
+        self.tran.send(SetCursor {
+            self_id: self.id,
+            serial,
+            surface: surface.id,
+            hotspot_x,
+            hotspot_y,
+        })?;
+        Ok(())
+    }
+
     fn handle_enter(&self, parser: MsgParser<'_, '_>) -> TestResult {
         let ev = Enter::parse_full(parser)?;
         self.enter.push(ev);

src/it/test_ifs/test_registry.rs

@@ -124,7 +124,7 @@ impl TestRegistry {
             id: self.tran.id(),
             tran: self.tran.clone(),
         });
-        self.bind(&jc, singletons.wl_compositor, 4)?;
+        self.bind(&jc, singletons.wl_compositor, 6)?;
         self.compositor.set(Some(jc.clone()));
         Ok(jc)
     }

src/it/test_ifs/test_surface.rs

@@ -36,6 +36,15 @@ impl TestSurface {
         Ok(())
     }
 
+    pub fn offset(&self, dx: i32, dy: i32) -> Result<(), TestError> {
+        self.tran.send(Offset {
+            self_id: self.id,
+            x: dx,
+            y: dy,
+        })?;
+        Ok(())
+    }
+
     pub fn commit(&self) -> Result<(), TestError> {
         self.tran.send(Commit { self_id: self.id })?;
         Ok(())

src/it/testrun.rs

@@ -113,7 +113,9 @@ impl TestRun {
             .set_input_device_seat(self.backend.default_kb.common.id, seat.id())?;
         self.cfg
             .set_input_device_seat(self.backend.default_mouse.common.id, seat.id())?;
+        self.backend.default_mouse.click(1);
         self.state.eng.yield_now().await;
+        self.cfg.show_workspace(seat.id(), "")?;
         Ok(DefaultSetup {
             connector: self.backend.default_connector.clone(),
             output,

src/it/tests.rs

@@ -45,6 +45,7 @@ mod t0016_scroll_ws;
 mod t0017_remove_unused_ws;
 mod t0018_click_to_active_ws;
 mod t0019_natural_scrolling;
+mod t0020_surface_offset;
 
 pub trait TestCase: Sync {
     fn name(&self) -> &'static str;
@@ -62,6 +63,7 @@ pub fn tests() -> Vec<&'static dyn TestCase> {
             ]
         }
     }
+
     tests! {
         t0001_shm_formats,
         t0002_window,
@@ -82,5 +84,6 @@ pub fn tests() -> Vec<&'static dyn TestCase> {
         t0017_remove_unused_ws,
         t0018_click_to_active_ws,
         t0019_natural_scrolling,
+        t0020_surface_offset,
     }
 }

src/it/tests/t0020_surface_offset.rs

@@ -0,0 +1,55 @@
+use {
+    crate::{
+        it::{
+            test_error::TestError,
+            test_utils::{
+                test_container_node_ext::TestContainerExt, test_ouput_node_ext::TestOutputNodeExt,
+                test_toplevel_node_ext::TestToplevelNodeExt,
+                test_workspace_node_ext::TestWorkspaceNodeExt,
+            },
+            testrun::TestRun,
+        },
+        theme::Color,
+    },
+    std::rc::Rc,
+};
+
+testcase!();
+
+async fn test(run: Rc<TestRun>) -> Result<(), TestError> {
+    let ds = run.create_default_setup().await?;
+
+    let client = run.create_client().await?;
+    let seat = client.get_default_seat().await?;
+    let enter = seat.pointer.enter.expect()?;
+    let win1 = client.create_window().await?;
+    win1.map2().await?;
+
+    let buffer = client.spbm.create_buffer(Color::from_rgb(255, 0, 0))?;
+    let surface = client.comp.create_surface().await?;
+    let vp = client.viewporter.get_viewport(&surface)?;
+    vp.set_destination(100, 100)?;
+    surface.attach(buffer.id)?;
+    surface.commit()?;
+
+    let (x, y) = ds
+        .output
+        .workspace()?
+        .container()?
+        .first_toplevel()?
+        .center();
+    ds.move_to(x, y);
+
+    client.sync().await;
+    let enter = enter.next()?;
+    seat.pointer.set_cursor(enter.serial, &surface, 0, 0)?;
+
+    client.compare_screenshot("1").await?;
+
+    surface.offset(-100, -100)?;
+    surface.commit()?;
+
+    client.compare_screenshot("2").await?;
+
+    Ok(())
+}