Route web surface scrolls to Servo hit point

crates/ely_app/src/services/servo_live.rs

@@ -69,7 +69,6 @@ impl ServoLiveClient {
         })
     }
 
-
     pub fn ensure(
         &mut self,
         request: ServoLiveEnsureRequest,
@@ -84,6 +83,8 @@ impl ServoLiveClient {
             device_pixel_ratio: request.device_pixel_ratio,
             scroll_delta_x: request.scroll_delta_x,
             scroll_delta_y: request.scroll_delta_y,
+            scroll_point_x: request.scroll_point_x,
+            scroll_point_y: request.scroll_point_y,
             click_x: request.click_x,
             click_y: request.click_y,
             hover_x: request.hover_x,
@@ -136,9 +137,8 @@ impl ServoLiveClient {
         // upper limit is `width * height * 4` (RGBA8); `0` is the
         // explicit "hardware path active, sample the IOSurface
         // instead" signal — anything else is a protocol violation.
-        let pixel_byte_count = (report.width as u64)
+        let pixel_byte_count =
-            .saturating_mul(report.height as u64)
+            (report.width as u64).saturating_mul(report.height as u64).saturating_mul(4);
-            .saturating_mul(4);
         let advertised = report.rgba_byte_count as u64;
         if advertised != 0 && advertised != pixel_byte_count {
             return Err(ServoLiveError::FrameBudgetExceeded {
@@ -157,9 +157,7 @@ impl ServoLiveClient {
         // fs::read, no temp file.
         let mut rgba_bytes = vec![0u8; report.rgba_byte_count];
         if report.rgba_byte_count > 0 {
-            self.stdout
+            self.stdout.read_exact(&mut rgba_bytes).map_err(ServoLiveError::FrameRead)?;
-                .read_exact(&mut rgba_bytes)
-                .map_err(ServoLiveError::FrameRead)?;
         }
 
         let mut frame = ServoLiveFrame::from_parts(report, rgba_bytes);
@@ -220,6 +218,8 @@ pub(crate) struct ServoLiveEnsureRequest {
     pub(crate) device_pixel_ratio: f32,
     pub(crate) scroll_delta_x: i32,
     pub(crate) scroll_delta_y: i32,
+    pub(crate) scroll_point_x: Option<u32>,
+    pub(crate) scroll_point_y: Option<u32>,
     pub(crate) click_x: Option<u32>,
     pub(crate) click_y: Option<u32>,
     pub(crate) hover_x: Option<u32>,
@@ -410,6 +410,8 @@ enum LiveRequest {
         device_pixel_ratio: f32,
         scroll_delta_x: i32,
         scroll_delta_y: i32,
+        scroll_point_x: Option<u32>,
+        scroll_point_y: Option<u32>,
         click_x: Option<u32>,
         click_y: Option<u32>,
         hover_x: Option<u32>,

crates/ely_app/src/shell/web_surface.rs

@@ -27,11 +27,7 @@ pub(super) struct WebSurfaceStore {
 
 impl WebSurfaceStore {
     pub(super) fn new() -> Self {
-        Self {
+        Self { runtime: WebSurfaceRuntime::new(), surfaces: BTreeMap::new(), keyboard_focus: None }
-            runtime: WebSurfaceRuntime::new(),
-            surfaces: BTreeMap::new(),
-            keyboard_focus: None,
-        }
     }
 
     pub(super) fn state(&self, tab_id: &TabId) -> Option<&WebSurfaceState> {
@@ -102,11 +98,21 @@ impl WebSurfaceStore {
         tab_id: &TabId,
         requested_url: &str,
         delta: Point<Pixels>,
+        position: Point<Pixels>,
         scale_factor: f32,
     ) -> WebSurfaceInputOutcome {
         let Some(delta) = WebSurfaceScrollDelta::from_point(delta, scale_factor) else {
             return WebSurfaceInputOutcome::DroppedZeroDelta;
         };
+        let Some(bounds) = self.surfaces.get(tab_id).and_then(|surface| surface.viewport_bounds)
+        else {
+            return WebSurfaceInputOutcome::DroppedNoViewportBounds;
+        };
+        let Some(point) =
+            WebSurfaceClickPoint::from_window_position(bounds, position, scale_factor)
+        else {
+            return WebSurfaceInputOutcome::DroppedOutOfBounds;
+        };
 
         let surface = self.surface_mut(tab_id);
         let scroll = surface
@@ -121,6 +127,7 @@ impl WebSurfaceStore {
             Some(current) => current.combined_with(delta),
             None => delta,
         });
+        surface.pending_scroll_point = Some(point);
         // Drop any buffered click — its viewport coordinates were
         // captured against the pre-scroll page, so applying it after
         // the scroll would land on the wrong DOM element. Keep
@@ -170,12 +177,14 @@ impl WebSurfaceStore {
         position: Point<Pixels>,
         scale_factor: f32,
     ) -> WebSurfaceInputOutcome {
-        let surface = self.surfaces.get_mut(tab_id).filter(|surface| surface.viewport_bounds.is_some());
+        let surface =
+            self.surfaces.get_mut(tab_id).filter(|surface| surface.viewport_bounds.is_some());
         let Some(surface) = surface else {
             return WebSurfaceInputOutcome::DroppedNoViewportBounds;
         };
         let bounds = surface.viewport_bounds.expect("viewport_bounds checked above");
-        let Some(point) = WebSurfaceClickPoint::from_window_position(bounds, position, scale_factor)
+        let Some(point) =
+            WebSurfaceClickPoint::from_window_position(bounds, position, scale_factor)
         else {
             return WebSurfaceInputOutcome::DroppedOutOfBounds;
         };
@@ -190,12 +199,12 @@ impl WebSurfaceStore {
         position: Point<Pixels>,
         scale_factor: f32,
     ) -> WebSurfaceInputOutcome {
-        let Some(bounds) =
+        let Some(bounds) = self.surfaces.get(tab_id).and_then(|surface| surface.viewport_bounds)
-            self.surfaces.get(tab_id).and_then(|surface| surface.viewport_bounds)
         else {
             return WebSurfaceInputOutcome::DroppedNoViewportBounds;
         };
-        let Some(point) = WebSurfaceClickPoint::from_window_position(bounds, position, scale_factor)
+        let Some(point) =
+            WebSurfaceClickPoint::from_window_position(bounds, position, scale_factor)
         else {
             return WebSurfaceInputOutcome::DroppedOutOfBounds;
         };
@@ -206,11 +215,8 @@ impl WebSurfaceStore {
             .map(|surface| surface.scroll_offset_for(requested_url))
             .unwrap_or_default();
 
-        let state = WebSurfaceClickState {
+        let state =
-            requested_url: requested_url.to_string(),
+            WebSurfaceClickState { requested_url: requested_url.to_string(), scroll_offset, point };
-            scroll_offset,
-            point,
-        };
         self.keyboard_focus = Some(WebSurfaceKeyboardFocusState {
             tab_id: tab_id.clone(),
             requested_url: requested_url.to_string(),
@@ -273,6 +279,7 @@ impl WebSurfaceStore {
         let surface = self.surface_mut(tab_id);
         let scroll_offset = surface.scroll_offset_for(requested_url);
         let scroll_delta = surface.pending_scroll_delta.take();
+        let scroll_point = surface.pending_scroll_point.take();
         let click_point = surface
             .click_point
             .take()
@@ -287,7 +294,14 @@ impl WebSurfaceStore {
             .map(|state| state.text);
         let hover_point = surface.hover_point.take();
 
-        WebSurfacePendingInput { scroll_offset, scroll_delta, click_point, hover_point, typed_text }
+        WebSurfacePendingInput {
+            scroll_offset,
+            scroll_delta,
+            scroll_point,
+            click_point,
+            hover_point,
+            typed_text,
+        }
     }
 
     fn previous_ready_frame(

crates/ely_app/src/shell/web_surface_controller.rs

@@ -67,6 +67,7 @@ impl ElyShell {
         tab_id: TabId,
         requested_url: String,
         delta: Point<Pixels>,
+        position: Point<Pixels>,
         scale_factor: f32,
         cx: &mut Context<Self>,
     ) {
@@ -74,6 +75,7 @@ impl ElyShell {
             &tab_id,
             requested_url.as_str(),
             delta,
+            position,
             scale_factor,
         ) == WebSurfaceInputOutcome::Applied
         {

crates/ely_app/src/shell/web_surface_runtime.rs

@@ -45,6 +45,8 @@ impl WebSurfaceRuntime {
         if active_scope != &scope {
             return Err(active_scope.error_for(&scope));
         }
+        let (scroll_delta_x, scroll_delta_y, scroll_point_x, scroll_point_y) =
+            scroll_wire_fields(input.scroll_delta, input.scroll_point)?;
 
         let session = sessions.entry(tab.id().clone()).or_insert_with(WebSurfaceSession::default);
         let next_scroll_offset = input.scroll_offset;
@@ -58,8 +60,10 @@ impl WebSurfaceRuntime {
                 height: size.height,
                 page_zoom_percent: zoom_percent,
                 device_pixel_ratio: size.device_pixel_ratio_f32(),
-                scroll_delta_x: input.scroll_delta.map_or(0, |delta| delta.x()),
+                scroll_delta_x,
-                scroll_delta_y: input.scroll_delta.map_or(0, |delta| delta.y()),
+                scroll_delta_y,
+                scroll_point_x,
+                scroll_point_y,
                 click_x: input.click_point.map(|point| point.x()),
                 click_y: input.click_point.map(|point| point.y()),
                 hover_x: input.hover_point.map(|point| point.x()),
@@ -227,6 +231,20 @@ fn config_dir_for_scope(
     }
 }
 
+fn scroll_wire_fields(
+    delta: Option<super::web_surface_geometry::WebSurfaceScrollDelta>,
+    point: Option<super::web_surface_geometry::WebSurfaceClickPoint>,
+) -> Result<(i32, i32, Option<u32>, Option<u32>), String> {
+    match delta {
+        Some(delta) => {
+            let point = point
+                .ok_or_else(|| "Servo scroll input is missing a viewport point".to_string())?;
+            Ok((delta.x(), delta.y(), Some(point.x()), Some(point.y())))
+        }
+        None => Ok((0, 0, None, None)),
+    }
+}
+
 impl From<&WebSurfaceSitePermission> for ServoLiveSitePermission {
     fn from(permission: &WebSurfaceSitePermission) -> Self {
         Self::new(

crates/ely_app/src/shell/web_surface_state.rs

@@ -45,6 +45,7 @@ pub(super) struct WebSurfaceTextInputState {
 pub(super) struct WebSurfacePendingInput {
     pub(super) scroll_offset: WebSurfaceScrollOffset,
     pub(super) scroll_delta: Option<WebSurfaceScrollDelta>,
+    pub(super) scroll_point: Option<WebSurfaceClickPoint>,
     pub(super) click_point: Option<WebSurfaceClickPoint>,
     pub(super) hover_point: Option<WebSurfaceClickPoint>,
     pub(super) typed_text: Option<String>,
@@ -116,6 +117,7 @@ pub(super) struct PerTabSurface {
     pub(super) hover_point: Option<WebSurfaceClickPoint>,
     pub(super) click_point: Option<WebSurfaceClickState>,
     pub(super) pending_scroll_delta: Option<WebSurfaceScrollDelta>,
+    pub(super) pending_scroll_point: Option<WebSurfaceClickPoint>,
     pub(super) scroll_offset: Option<WebSurfaceScrollState>,
     pub(super) typed_text: Option<WebSurfaceTextInputState>,
     pub(super) state: Option<WebSurfaceState>,
@@ -130,6 +132,7 @@ impl PerTabSurface {
             hover_point: None,
             click_point: None,
             pending_scroll_delta: None,
+            pending_scroll_point: None,
             scroll_offset: None,
             typed_text: None,
             state: None,

crates/ely_app/src/shell/web_surface_tests.rs

@@ -42,12 +42,14 @@ fn scroll_delta_enters_pending_input_after_wheel() -> Result<(), Box<dyn Error>>
         tab.id(),
         tab.url().as_str(),
         point(px(0.0), px(140.0)),
+        point(px(320.0), px(240.0)),
         1.0,
     ));
     assert_applied(store.record_scroll_delta(
         tab.id(),
         tab.url().as_str(),
         point(px(0.0), px(60.0)),
+        point(px(300.0), px(220.0)),
         1.0,
     ));
 
@@ -55,6 +57,7 @@ fn scroll_delta_enters_pending_input_after_wheel() -> Result<(), Box<dyn Error>>
 
     assert_eq!(input.scroll_offset.y(), 200);
     assert_eq!(input.scroll_delta.map(|delta| (delta.x(), delta.y())), Some((0, 200)));
+    assert_eq!(input.scroll_point.map(|point| (point.x(), point.y())), Some((300, 220)));
     Ok(())
 }
 
@@ -91,7 +94,13 @@ fn scroll_after_click_keeps_keyboard_focus_and_typed_text() -> Result<(), Box<dy
     assert_applied(store.record_click_point(tab.id(), url, point(px(160.0), px(120.0)), 1.0));
     assert_applied(store.record_typed_text(tab.id(), url, "h"));
 
-    assert_applied(store.record_scroll_delta(tab.id(), url, point(px(0.0), px(140.0)), 1.0));
+    assert_applied(store.record_scroll_delta(
+        tab.id(),
+        url,
+        point(px(0.0), px(140.0)),
+        point(px(160.0), px(120.0)),
+        1.0,
+    ));
 
     assert_eq!(
         store.record_typed_text(tab.id(), url, "i"),
@@ -134,7 +143,13 @@ fn retina_scale_factor_doubles_every_input_coordinate() -> Result<(), Box<dyn Er
     assert_applied(store.record_viewport_size(tab.id(), web_bounds(), 2.0));
     assert_applied(store.record_click_point(tab.id(), url, point(px(160.0), px(120.0)), 2.0));
     assert_applied(store.record_typed_text(tab.id(), url, "h"));
-    assert_applied(store.record_scroll_delta(tab.id(), url, point(px(0.0), px(140.0)), 2.0));
+    assert_applied(store.record_scroll_delta(
+        tab.id(),
+        url,
+        point(px(0.0), px(140.0)),
+        point(px(160.0), px(120.0)),
+        2.0,
+    ));
 
     let input = store.take_pending_input(tab.id(), url);
 
@@ -145,8 +160,7 @@ fn retina_scale_factor_doubles_every_input_coordinate() -> Result<(), Box<dyn Er
     );
     assert_eq!(input.scroll_offset.y(), 280, "scroll offset accumulates in device px");
     assert_eq!(
-        input.click_point,
+        input.click_point, None,
-        None,
         "scroll drops the buffered click — its viewport coords are stale",
     );
     Ok(())
@@ -181,12 +195,7 @@ fn click_before_viewport_measured_reports_no_viewport_bounds() -> Result<(), Box
     let tab = web_tab("https://example.com/form")?;
 
     assert_eq!(
-        store.record_click_point(
+        store.record_click_point(tab.id(), tab.url().as_str(), point(px(160.0), px(120.0)), 1.0,),
-            tab.id(),
-            tab.url().as_str(),
-            point(px(160.0), px(120.0)),
-            1.0,
-        ),
         WebSurfaceInputOutcome::DroppedNoViewportBounds,
     );
     Ok(())
@@ -206,6 +215,7 @@ fn zero_wheel_delta_reports_zero_delta() -> Result<(), Box<dyn Error>> {
             tab.id(),
             tab.url().as_str(),
             point(px(0.0), px(0.0)),
+            point(px(160.0), px(120.0)),
             1.0,
         ),
         WebSurfaceInputOutcome::DroppedZeroDelta,
@@ -276,7 +286,13 @@ fn zero_wheel_delta_must_not_erase_buffered_click() -> Result<(), Box<dyn Error>
     assert_applied(store.record_click_point(tab.id(), url, point(px(160.0), px(120.0)), 1.0));
 
     assert_eq!(
-        store.record_scroll_delta(tab.id(), url, point(px(0.0), px(0.0)), 1.0),
+        store.record_scroll_delta(
+            tab.id(),
+            url,
+            point(px(0.0), px(0.0)),
+            point(px(160.0), px(120.0)),
+            1.0,
+        ),
         WebSurfaceInputOutcome::DroppedZeroDelta,
     );
 

crates/ely_app/src/shell/web_surface_view.rs

@@ -72,12 +72,7 @@ fn error_page(message: &str) -> impl IntoElement {
                 .text_color(rgb(colors::INK))
                 .child("Page unavailable"),
         )
-        .child(
+        .child(div().text_size(px(14.0)).text_color(rgb(colors::INK_3)).child(message.to_string()))
-            div()
-                .text_size(px(14.0))
-                .text_color(rgb(colors::INK_3))
-                .child(message.to_string()),
-        )
 }
 
 fn render_web_surface(
@@ -95,12 +90,7 @@ fn render_web_surface(
         .size_full()
         .min_w_0()
         .overflow_hidden()
-        .child(
+        .child(div().absolute().inset_0().child(content))
-            div()
-                .absolute()
-                .inset_0()
-                .child(content),
-        )
         .child(render_viewport_tracker(tab.id().clone(), tracker_entity))
         .child(render_input_overlay(input_tab_id, input_url, input_entity))
         .into_any_element()
@@ -169,6 +159,7 @@ fn render_input_overlay(
                     scroll_tab_id.clone(),
                     scroll_url.clone(),
                     delta,
+                    event.position,
                     scale_factor,
                     cx,
                 );

crates/ely_servo_host/src/bin/ely_servo_sidecar.rs

@@ -150,6 +150,8 @@ fn apply_scroll_if_requested(
         webview_id: webview_id.clone(),
         delta_x: args.scroll_x,
         delta_y: args.scroll_y,
+        point_x: 0,
+        point_y: 0,
     })?;
     wait_for_changed_or_settled_frame(host, webview_id, previous_frame_hash)
 }

crates/ely_servo_host/src/bin/ely_servo_sidecar/live.rs

@@ -14,10 +14,10 @@ use ely_servo_host::{
 };
 
 use super::args::LiveArgs;
+pub(super) use super::live_protocol::LiveSidecarError;
 use super::live_protocol::{
     LiveFrameReport, LiveOutcome, LiveRequest, LiveSitePermission, PartialFrameTimings,
 };
-pub(super) use super::live_protocol::LiveSidecarError;
 use super::perf::{FramePerfAggregator, FramePerfSummary, FrameStageTimings, elapsed_ns};
 
 /// Per-`Ensure` budget for Servo to paint after input dispatch.
@@ -65,13 +65,7 @@ pub(super) fn run_live(args: LiveArgs) -> Result<(), LiveSidecarError> {
             ),
             Err(error) => Err(LiveSidecarError::Json(error)),
         };
-        write_outcome(
+        write_outcome(&mut stdout, &mut perf, &mut pending_summary, outcome, frame_started_at)?;
-            &mut stdout,
-            &mut perf,
-            &mut pending_summary,
-            outcome,
-            frame_started_at,
-        )?;
     }
 
     Ok(())
@@ -102,6 +96,8 @@ fn handle_request(
             device_pixel_ratio,
             scroll_delta_x,
             scroll_delta_y,
+            scroll_point_x,
+            scroll_point_y,
             click_x,
             click_y,
             hover_x,
@@ -115,14 +111,7 @@ fn handle_request(
             let session =
                 ensure_session(host, sessions, tab_id.clone(), &tab, &profile, width, height)?;
 
-            if apply_layout(
+            if apply_layout(host, session, width, height, page_zoom_percent, device_pixel_ratio)? {
-                host,
-                session,
-                width,
-                height,
-                page_zoom_percent,
-                device_pixel_ratio,
-            )? {
                 session.awaiting_visible_frame = true;
             }
             apply_permissions(host, session, &profile, site_permissions)?;
@@ -141,17 +130,18 @@ fn handle_request(
                 // the gate skip blank loading frames again.
                 session.ever_visible_frame = false;
             }
-            if apply_input(
+            let input = LiveInput {
-                host,
-                session,
                 scroll_delta_x,
                 scroll_delta_y,
+                scroll_point_x,
+                scroll_point_y,
                 click_x,
                 click_y,
                 hover_x,
                 hover_y,
                 typed_text,
-            )? {
+            };
+            if apply_input(host, session, input)? {
                 // Tell poll_frame to actually wait for Servo to paint
                 // a response to this input. The visible-content gate
                 // is bypassed on the hardware path inside poll_frame,
@@ -162,7 +152,13 @@ fn handle_request(
             }
             let webview_id = session.webview_id.clone();
             let mut outcome = poll_frame(host, session, rendering_context_kind)?;
-            populate_surface_fields(host, &webview_id, &tab_id, published_surface_ids, &mut outcome);
+            populate_surface_fields(
+                host,
+                &webview_id,
+                &tab_id,
+                published_surface_ids,
+                &mut outcome,
+            );
             Ok(outcome)
         }
         LiveRequest::Poll { tab_id } => {
@@ -171,7 +167,13 @@ fn handle_request(
             };
             let webview_id = session.webview_id.clone();
             let mut outcome = poll_frame(host, session, rendering_context_kind)?;
-            populate_surface_fields(host, &webview_id, &tab_id, published_surface_ids, &mut outcome);
+            populate_surface_fields(
+                host,
+                &webview_id,
+                &tab_id,
+                published_surface_ids,
+                &mut outcome,
+            );
             Ok(outcome)
         }
     }
@@ -255,19 +257,19 @@ fn write_outcome(
     // header so the client knows nothing follows). At 1080p × 60 fps
     // that's 8 MB × 60 = ~480 MB/s of pipe traffic eliminated.
     let drop_rgba_payload = outcome.response.current_surface_id.is_some();
-    if drop_rgba_payload {
+    if drop_rgba_payload
-        if let Some(report) = outcome.response.frame.as_mut() {
+        && let Some(report) = outcome.response.frame.as_mut()
+    {
         report.rgba_byte_count = 0;
     }
-    }
     let write_started_at = Instant::now();
     serde_json::to_writer(&mut *stdout, &outcome.response)?;
     stdout.write_all(b"\n")?;
-    if !drop_rgba_payload {
+    if !drop_rgba_payload
-        if let Some(frame) = outcome.frame.as_ref() {
+        && let Some(frame) = outcome.frame.as_ref()
+    {
         stdout.write_all(frame.rgba_bytes())?;
     }
-    }
     stdout.flush()?;
     if frame_present {
         let write_ns = elapsed_ns(write_started_at);
@@ -390,37 +392,34 @@ fn apply_permissions(
 fn apply_input(
     host: &mut SoftwareServoHost,
     session: &mut LiveSession,
-    scroll_delta_x: i32,
+    input: LiveInput,
-    scroll_delta_y: i32,
-    click_x: Option<u32>,
-    click_y: Option<u32>,
-    hover_x: Option<u32>,
-    hover_y: Option<u32>,
-    typed_text: Option<String>,
 ) -> Result<bool, LiveSidecarError> {
     let mut changed = false;
-    if scroll_delta_x != 0 || scroll_delta_y != 0 {
+    if input.scroll_delta_x != 0 || input.scroll_delta_y != 0 {
+        let (point_x, point_y) = input.scroll_point()?;
         host.scroll(ScrollRequest {
             webview_id: session.webview_id.clone(),
-            delta_x: scroll_delta_x,
+            delta_x: input.scroll_delta_x,
-            delta_y: scroll_delta_y,
+            delta_y: input.scroll_delta_y,
+            point_x,
+            point_y,
         })?;
-        session.scroll_x = positive_scroll_component(session.scroll_x, scroll_delta_x);
+        session.scroll_x = positive_scroll_component(session.scroll_x, input.scroll_delta_x);
-        session.scroll_y = positive_scroll_component(session.scroll_y, scroll_delta_y);
+        session.scroll_y = positive_scroll_component(session.scroll_y, input.scroll_delta_y);
         changed = true;
     }
 
-    if let (Some(x), Some(y)) = (hover_x, hover_y) {
+    if let (Some(x), Some(y)) = (input.hover_x, input.hover_y) {
         host.hover(MouseHoverRequest { webview_id: session.webview_id.clone(), x, y })?;
         changed = true;
     }
 
-    if let (Some(x), Some(y)) = (click_x, click_y) {
+    if let (Some(x), Some(y)) = (input.click_x, input.click_y) {
         host.click(MouseClickRequest { webview_id: session.webview_id.clone(), x, y })?;
         changed = true;
     }
 
-    if let Some(text) = typed_text {
+    if let Some(text) = input.typed_text {
         host.type_text(KeyboardTextRequest { webview_id: session.webview_id.clone(), text })?;
         changed = true;
     }
@@ -428,6 +427,28 @@ fn apply_input(
     Ok(changed)
 }
 
+struct LiveInput {
+    scroll_delta_x: i32,
+    scroll_delta_y: i32,
+    scroll_point_x: Option<u32>,
+    scroll_point_y: Option<u32>,
+    click_x: Option<u32>,
+    click_y: Option<u32>,
+    hover_x: Option<u32>,
+    hover_y: Option<u32>,
+    typed_text: Option<String>,
+}
+
+impl LiveInput {
+    fn scroll_point(&self) -> Result<(u32, u32), LiveSidecarError> {
+        let point = match (self.scroll_point_x, self.scroll_point_y) {
+            (Some(x), Some(y)) => (x, y),
+            _ => return Err(LiveSidecarError::IncompleteScrollPoint),
+        };
+        Ok(point)
+    }
+}
+
 fn poll_frame(
     host: &mut SoftwareServoHost,
     session: &mut LiveSession,
@@ -469,8 +490,7 @@ fn poll_frame(
             let has_visible_content = match rendering_context_kind {
                 RenderingContextKind::Software => {
                     session.ever_visible_frame
-                        || (frame.non_white_pixel_count() > 0
+                        || (frame.non_white_pixel_count() > 0 && frame.content_pixel_count() > 0)
-                            && frame.content_pixel_count() > 0)
                 }
                 #[cfg(feature = "hardware-render")]
                 RenderingContextKind::Hardware => true,

crates/ely_servo_host/src/bin/ely_servo_sidecar/live_protocol.rs

@@ -3,7 +3,9 @@
 
 use std::io;
 
-use ely_servo_host::{IOSurfaceHandle, RenderedFrame, ServoHostError, WebViewSnapshot, WebViewState};
+use ely_servo_host::{
+    IOSurfaceHandle, RenderedFrame, ServoHostError, WebViewSnapshot, WebViewState,
+};
 use serde::{Deserialize, Serialize};
 use thiserror::Error;
 
@@ -29,6 +31,8 @@ pub(super) enum LiveRequest {
         device_pixel_ratio: f32,
         scroll_delta_x: i32,
         scroll_delta_y: i32,
+        scroll_point_x: Option<u32>,
+        scroll_point_y: Option<u32>,
         click_x: Option<u32>,
         click_y: Option<u32>,
         #[serde(default)]
@@ -195,6 +199,9 @@ pub(super) enum LiveSidecarError {
     #[error("live session is unavailable after creation")]
     SessionUnavailable,
 
+    #[error("scroll input requires both scroll_point_x and scroll_point_y")]
+    IncompleteScrollPoint,
+
     #[error(transparent)]
     Domain(#[from] ely_domain::DomainError),
 

crates/ely_servo_host/src/bin/ely_servo_sidecar/perf.rs

@@ -262,17 +262,19 @@ mod tests {
     }
 
     #[test]
-    fn aggregator_emits_summary_after_window_size_records() {
+    fn aggregator_emits_summary_after_window_size_records() -> Result<(), &'static str> {
         let mut aggregator =
             FramePerfAggregator::new("software", FramePerfAggregator::DEFAULT_WINDOW_SIZE);
         for index in 0..(FramePerfAggregator::DEFAULT_WINDOW_SIZE - 1) {
             let result = aggregator.record(constant_timing());
             assert!(result.is_none(), "should not flush at frame {index}");
         }
-        let summary = aggregator.record(constant_timing());
+        let summary = aggregator
-        let summary = summary.expect("aggregator must flush at window boundary");
+            .record(constant_timing())
+            .ok_or("aggregator must flush at window boundary")?;
         assert_eq!(summary.window, FramePerfAggregator::DEFAULT_WINDOW_SIZE);
         assert_eq!(summary.context, "software");
+        Ok(())
     }
 
     #[test]
@@ -286,7 +288,7 @@ mod tests {
     }
 
     #[test]
-    fn aggregator_percentiles_track_increasing_paint_durations() {
+    fn aggregator_percentiles_track_increasing_paint_durations() -> Result<(), &'static str> {
         let mut aggregator = FramePerfAggregator::new("software", 4);
         let paint_durations_us = [10u64, 100, 1_000, 10_000];
         let mut summary = None;
@@ -298,11 +300,12 @@ mod tests {
                 Duration::from_micros(paint_us + 2),
             ));
         }
-        let summary = summary.expect("4-frame window must flush");
+        let summary = summary.ok_or("4-frame window must flush")?;
         assert!(
             summary.paint_p50_us < summary.paint_p99_us,
             "p99 must dominate p50 for increasing samples: {summary:?}"
         );
+        Ok(())
     }
 
     fn constant_timing() -> FrameStageTimings {

crates/ely_servo_host/src/host.rs

@@ -220,6 +220,8 @@ pub struct ScrollRequest {
     pub webview_id: WebViewId,
     pub delta_x: i32,
     pub delta_y: i32,
+    pub point_x: u32,
+    pub point_y: u32,
 }
 
 #[derive(Clone, Debug, Eq, PartialEq)]

crates/ely_servo_host/src/runtime.rs

@@ -16,17 +16,15 @@ use dpi::PhysicalSize;
 use ely_domain::{ProfileId, TabId, WebViewId};
 use euclid::Scale;
 use servo::{
-    DeviceIndependentPixel, DeviceIntPoint, DeviceIntRect, DeviceIntSize, DevicePixel,
+    DeviceIndependentPixel, DeviceIntPoint, DeviceIntRect, DeviceIntSize, DevicePixel, DevicePoint,
-    DevicePoint, DeviceVector2D, Opts, RenderingContext, Scroll, Servo, ServoBuilder,
+    DeviceVector2D, Opts, RenderingContext, Scroll, Servo, ServoBuilder, WebViewBuilder,
-    WebViewBuilder, WebViewPoint, WebViewVector,
+    WebViewPoint, WebViewVector,
 };
 
 /// Wrap an `f32` scale factor in Servo's typed `Scale<f32, DeviceIndependentPixel,
 /// DevicePixel>`. The clamp guards against `NaN`/`inf` reaching Servo's
 /// layout (which assumes a positive finite scale).
-fn hidpi_scale_from_factor(
+fn hidpi_scale_from_factor(scale_factor: f32) -> Scale<f32, DeviceIndependentPixel, DevicePixel> {
-    scale_factor: f32,
-) -> Scale<f32, DeviceIndependentPixel, DevicePixel> {
     let safe = if scale_factor.is_finite() && scale_factor > 0.0 {
         scale_factor.clamp(0.5, 5.0)
     } else {
@@ -37,10 +35,10 @@ fn hidpi_scale_from_factor(
 use url::Url;
 
 use crate::{
-    HidpiScaleRequest, KeyboardTextRequest, MouseClickRequest, MouseDragRequest,
+    HidpiScaleRequest, KeyboardTextRequest, MouseClickRequest, MouseDragRequest, MouseHoverRequest,
-    MouseHoverRequest, NavigationRequest, PageZoomRequest, PermissionDecision, PermissionRequest,
+    NavigationRequest, PageZoomRequest, PermissionDecision, PermissionRequest, RenderedFrame,
-    RenderedFrame, ResizeRequest, ScreenshotRequest, ScrollRequest, ServoHost, ServoHostError,
+    ResizeRequest, ScreenshotRequest, ScrollRequest, ServoHost, ServoHostError, TouchTapRequest,
-    TouchTapRequest, WebViewSnapshot, WebViewState,
+    WebViewSnapshot, WebViewState,
     runtime_input::{
         send_keyboard_text, send_mouse_click, send_mouse_drag, send_mouse_hover, send_touch_tap,
     },
@@ -265,7 +263,7 @@ impl ServoHost for SoftwareServoHost {
                 request.delta_x as f32,
                 request.delta_y as f32,
             ))),
-            WebViewPoint::Device(DevicePoint::zero()),
+            WebViewPoint::Device(DevicePoint::new(request.point_x as f32, request.point_y as f32)),
         );
         Ok(())
     }
@@ -544,9 +542,7 @@ impl SoftwareServoHost {
                     crate::HardwareOffscreenContext::new(size.physical())
                         .map_err(|_| ServoHostError::RenderingContextUnavailable)?,
                 );
-                hardware
+                hardware.make_current().map_err(|_| ServoHostError::RenderingContextNotCurrent)?;
-                    .make_current()
-                    .map_err(|_| ServoHostError::RenderingContextNotCurrent)?;
                 Ok(RenderingContextHandles {
                     rendering_context: hardware.clone(),
                     hardware_context: Some(hardware),
@@ -576,10 +572,7 @@ impl SoftwareServoHost {
     /// Re-asserting per dispatch keeps the invariant on the dispatch
     /// path instead of spread across creation, navigation, and
     /// tab-switching.
-    fn webview_for_input(
+    fn webview_for_input(&self, webview_id: &WebViewId) -> Result<&HostWebView, ServoHostError> {
-        &self,
-        webview_id: &WebViewId,
-    ) -> Result<&HostWebView, ServoHostError> {
         let webview = self.webview(webview_id)?;
         webview.webview.show();
         webview.webview.focus();

crates/ely_servo_host/tests/live_perf_bench.rs

@@ -332,6 +332,11 @@ fn build_ensure(
 ) -> String {
     let hover_x = if include_hover { Some(256u32) } else { None };
     let hover_y = if include_hover { Some(256u32) } else { None };
+    let scroll_point = if scroll_dx != 0 || scroll_dy != 0 {
+        Some((256u32, 256u32))
+    } else {
+        None
+    };
     let hover_x_json = match hover_x {
         Some(value) => format!("{value}"),
         None => "null".to_string(),
@@ -340,8 +345,16 @@ fn build_ensure(
         Some(value) => format!("{value}"),
         None => "null".to_string(),
     };
+    let scroll_point_x_json = match scroll_point {
+        Some((x, _)) => format!("{x}"),
+        None => "null".to_string(),
+    };
+    let scroll_point_y_json = match scroll_point {
+        Some((_, y)) => format!("{y}"),
+        None => "null".to_string(),
+    };
     format!(
-        r#"{{"type":"ensure","tab_id":"{tab}","profile_id":"{profile}","url":{url},"width":{w},"height":{h},"page_zoom_percent":100,"scroll_delta_x":{dx},"scroll_delta_y":{dy},"click_x":null,"click_y":null,"hover_x":{hx},"hover_y":{hy},"typed_text":null,"site_permissions":[]}}"#,
+        r#"{{"type":"ensure","tab_id":"{tab}","profile_id":"{profile}","url":{url},"width":{w},"height":{h},"page_zoom_percent":100,"scroll_delta_x":{dx},"scroll_delta_y":{dy},"scroll_point_x":{sx},"scroll_point_y":{sy},"click_x":null,"click_y":null,"hover_x":{hx},"hover_y":{hy},"typed_text":null,"site_permissions":[]}}"#,
         tab = tab.as_str(),
         profile = profile_id.as_str(),
         url = serde_json::to_string(url).unwrap_or_else(|_| "\"\"".to_string()),
@@ -349,6 +362,8 @@ fn build_ensure(
         h = VIEWPORT_HEIGHT,
         dx = scroll_dx,
         dy = scroll_dy,
+        sx = scroll_point_x_json,
+        sy = scroll_point_y_json,
         hx = hover_x_json,
         hy = hover_y_json,
     )
@@ -391,12 +406,12 @@ fn read_response_with_bytes(
     }
     let response: LiveResponse = serde_json::from_str(json_line.trim_end())?;
     let mut rgba = Vec::new();
-    if let Some(frame) = response.frame.as_ref() {
+    if let Some(frame) = response.frame.as_ref()
-        if frame.rgba_byte_count > 0 {
+        && frame.rgba_byte_count > 0
+    {
         rgba.resize(frame.rgba_byte_count, 0);
         reader.read_exact(&mut rgba)?;
     }
-    }
     Ok((response, rgba))
 }
 

crates/ely_servo_host/tests/software_host.rs

@@ -226,7 +226,13 @@ fn exercise_real_servo_webview_lifecycle() -> Result<(), Box<dyn Error>> {
     }
 
     let previous_frame_hash = host.last_rendered_frame()?.sample_hash();
-    host.scroll(ScrollRequest { webview_id: webview_id.clone(), delta_x: 0, delta_y: 480 })?;
+    host.scroll(ScrollRequest {
+        webview_id: webview_id.clone(),
+        delta_x: 0,
+        delta_y: 480,
+        point_x: 0,
+        point_y: 0,
+    })?;
     let snapshot = wait_for_rendered_webview(&mut host, &webview_id, Some(previous_frame_hash))?;
     assert_eq!(snapshot.state(), &WebViewState::Complete, "snapshot: {snapshot:?}");
     assert_rendered_frame_has_content(&host, "https://servo.org scrolled", MINIMUM_CONTENT_PIXELS)?;