Fix Servo IOSurface orientation and resize identity

crates/ely_app/src/services/iosurface_metal.rs

@@ -37,7 +37,13 @@ use thiserror::Error;
 /// Constructed lazily by the renderer-side client on the first
 /// hardware-path frame.
 pub(crate) struct IOSurfaceCache {
-    pixel_buffers: HashMap<u64, CVPixelBuffer>,
+    pixel_buffers: HashMap<u64, CachedPixelBuffer>,
+}
+
+struct CachedPixelBuffer {
+    pixel_buffer: CVPixelBuffer,
+    width: u32,
+    height: u32,
 }
 
 #[derive(Debug, Error)]
@@ -54,21 +60,15 @@ impl IOSurfaceCache {
     }
 
     /// Import an IOSurface published by the sidecar's
-    /// `surface_handle` field. Idempotent on `surface_id`: a second
-    /// call with the same id immediately deallocates the duplicate
-    /// mach port without re-importing. The sender's T10.3 dedup means
-    /// the duplicate path should never fire in practice — it's here
-    /// so a misbehaving sidecar can't quietly leak ports.
+    /// `surface_handle` field. Idempotent on `surface_id` plus pixel
+    /// dimensions: duplicate handles for the same sized IOSurface are
+    /// discarded, while a resized IOSurface that reuses the same
+    /// `surface_id` replaces the cached pixel buffer.
     pub fn import(
         &mut self,
         mach_port_name: u32,
         surface_id: u64,
     ) -> Result<(), SurfaceImportError> {
-        if self.pixel_buffers.contains_key(&surface_id) {
-            deallocate_mach_port(mach_port_name);
-            return Ok(());
-        }
-
         let Some(iosurface) = objc2_io_surface::IOSurfaceRef::lookup_from_mach_port(mach_port_name)
         else {
             return Err(SurfaceImportError::LookupFailed { port: mach_port_name });
@@ -91,8 +91,19 @@ impl IOSurfaceCache {
 
         let pixel_buffer = CVPixelBuffer::from_io_surface(&io_surface_view, None)
             .map_err(|status| SurfaceImportError::PixelBufferBuildFailed { status })?;
+        let width = pixel_buffer.get_width() as u32;
+        let height = pixel_buffer.get_height() as u32;
 
-        self.pixel_buffers.insert(surface_id, pixel_buffer);
+        if self
+            .pixel_buffers
+            .get(&surface_id)
+            .is_some_and(|cached| cached.width == width && cached.height == height)
+        {
+            deallocate_mach_port(mach_port_name);
+            return Ok(());
+        }
+
+        self.pixel_buffers.insert(surface_id, CachedPixelBuffer { pixel_buffer, width, height });
         deallocate_mach_port(mach_port_name);
         Ok(())
     }
@@ -104,7 +115,7 @@ impl IOSurfaceCache {
     /// atomic increment) so the caller can hand it to GPUI's
     /// `surface(...)` element without holding a borrow on the cache.
     pub fn pixel_buffer_for(&self, surface_id: u64) -> Option<CVPixelBuffer> {
-        self.pixel_buffers.get(&surface_id).cloned()
+        self.pixel_buffers.get(&surface_id).map(|cached| cached.pixel_buffer.clone())
     }
 
     #[cfg(test)]
@@ -156,9 +167,6 @@ mod tests {
     };
     use std::os::raw::c_void;
 
-    const TEST_WIDTH: u32 = 64;
-    const TEST_HEIGHT: u32 = 48;
-
     /// Build a CPU-backed IOSurface from scratch, the same way
     /// surfman's macOS backend does.
     ///
@@ -167,13 +175,13 @@ mod tests {
     ///
     /// The pointer-casts mirror
     /// `surfman::platform::macos::system::surface::create_io_surface`.
-    fn build_local_iosurface() -> Result<CFRetained<IOSurfaceRef>, String> {
+    fn build_local_iosurface(width: u32, height: u32) -> Result<CFRetained<IOSurfaceRef>, String> {
         let pixel_format: i32 = i32::from_be_bytes(*b"BGRA");
         let bytes_per_element: i32 = 4;
-        let bytes_per_row: i32 = (TEST_WIDTH as i32) * bytes_per_element;
+        let bytes_per_row: i32 = (width as i32) * bytes_per_element;
 
-        let width_num = CFNumber::new_i32(TEST_WIDTH as i32);
-        let height_num = CFNumber::new_i32(TEST_HEIGHT as i32);
+        let width_num = CFNumber::new_i32(width as i32);
+        let height_num = CFNumber::new_i32(height as i32);
         let bpe_num = CFNumber::new_i32(bytes_per_element);
         let bpr_num = CFNumber::new_i32(bytes_per_row);
         let pf_num = CFNumber::new_i32(pixel_format);
@@ -207,7 +215,7 @@ mod tests {
     #[test]
     fn imports_local_iosurface_into_pixel_buffer() -> Result<(), String> {
         let mut cache = IOSurfaceCache::new();
-        let iosurface = build_local_iosurface()?;
+        let iosurface = build_local_iosurface(64, 48)?;
         let mach_port = iosurface.create_mach_port();
         assert!(mach_port != 0, "IOSurfaceCreateMachPort must yield a real port");
         let surface_id: u64 = 0xDEAD_BEEFu64;
@@ -219,12 +227,12 @@ mod tests {
             .ok_or_else(|| "imported pixel buffer was missing".to_string())?;
         assert_eq!(
             pixel_buffer.get_width() as u32,
-            TEST_WIDTH,
+            64,
             "CVPixelBuffer width must match the source IOSurface",
         );
         assert_eq!(
             pixel_buffer.get_height() as u32,
-            TEST_HEIGHT,
+            48,
             "CVPixelBuffer height must match the source IOSurface",
         );
         assert_eq!(cache.cached_surface_count(), 1);
@@ -234,7 +242,7 @@ mod tests {
     #[test]
     fn second_import_with_same_surface_id_is_idempotent() -> Result<(), String> {
         let mut cache = IOSurfaceCache::new();
-        let iosurface = build_local_iosurface()?;
+        let iosurface = build_local_iosurface(64, 48)?;
         let port_a = iosurface.create_mach_port();
         let port_b = iosurface.create_mach_port();
         assert!(port_a != 0 && port_b != 0 && port_a != port_b);
@@ -246,4 +254,23 @@ mod tests {
         assert_eq!(cache.cached_surface_count(), 1);
         Ok(())
     }
+
+    #[test]
+    fn same_surface_id_with_changed_dimensions_replaces_pixel_buffer() -> Result<(), String> {
+        let mut cache = IOSurfaceCache::new();
+        let initial = build_local_iosurface(64, 48)?;
+        let resized = build_local_iosurface(96, 72)?;
+        let surface_id = 0xBBBB_BBBB;
+
+        cache.import(initial.create_mach_port(), surface_id).map_err(|error| error.to_string())?;
+        cache.import(resized.create_mach_port(), surface_id).map_err(|error| error.to_string())?;
+
+        let pixel_buffer = cache
+            .pixel_buffer_for(surface_id)
+            .ok_or_else(|| "resized pixel buffer was missing".to_string())?;
+        assert_eq!(pixel_buffer.get_width() as u32, 96);
+        assert_eq!(pixel_buffer.get_height() as u32, 72);
+        assert_eq!(cache.cached_surface_count(), 1);
+        Ok(())
+    }
 }

crates/ely_app/src/shell/web_surface_live_site_tests.rs

@@ -28,6 +28,8 @@ use super::WebSurfaceStore;
 
 const LIVE_SURFACE_WIDTH: u32 = 934;
 const LIVE_SURFACE_HEIGHT: u32 = 657;
+const RESIZED_LIVE_SURFACE_WIDTH: u32 = LIVE_SURFACE_WIDTH + 12;
+const RESIZED_LIVE_SURFACE_HEIGHT: u32 = LIVE_SURFACE_HEIGHT + 20;
 const MINIMUM_CONTENT_PIXELS: u64 = 1_000;
 const LIVE_SITE_RENDER_ATTEMPTS: usize = 3;
 const LIVE_SITE_WAIT_TIMEOUT: Duration = Duration::from_secs(20);
@@ -64,6 +66,13 @@ fn web_surface_scrolls_prd_site_down_and_up() -> Result<(), Box<dyn Error>> {
     })
 }
 
+#[test]
+fn web_surface_resizes_prd_site_without_failed_state() -> Result<(), Box<dyn Error>> {
+    run_isolated_live_site_test("web_surface_resizes_prd_site_without_failed_state", || {
+        assert_web_surface_resizes_prd_site()
+    })
+}
+
 fn run_isolated_live_site_test(
     test_name: &str,
     test: impl FnOnce() -> Result<(), Box<dyn Error>>,
@@ -166,6 +175,54 @@ fn assert_web_surface_scrolls_prd_site() -> Result<(), Box<dyn Error>> {
     Ok(())
 }
 
+fn assert_web_surface_resizes_prd_site() -> Result<(), Box<dyn Error>> {
+    let mut store = WebSurfaceStore::new();
+    let profile_id = ProfileId::new();
+    let case = PRD_TOP_SITE_CASES
+        .iter()
+        .find(|case| case.url == "https://servo.org/")
+        .ok_or("missing servo.org live-site case")?;
+    let tab = web_tab(profile_id, case.url)?;
+
+    assert_eq!(
+        store.record_viewport_size(tab.id(), live_surface_bounds(), 1.0),
+        WebSurfaceInputOutcome::Applied,
+        "{}",
+        case.url,
+    );
+    store.ensure_surface(&tab, ProfileDataMode::Transient, &[]);
+    let _ = wait_for_ready_frame_at_size(
+        &mut store,
+        tab.id(),
+        case,
+        LIVE_SURFACE_WIDTH,
+        LIVE_SURFACE_HEIGHT,
+    )?;
+
+    assert_eq!(
+        store.record_viewport_size(tab.id(), resized_live_surface_bounds(), 1.0),
+        WebSurfaceInputOutcome::Buffered,
+        "{}",
+        case.url,
+    );
+    assert_eq!(
+        store.record_viewport_size(tab.id(), resized_live_surface_bounds(), 1.0),
+        WebSurfaceInputOutcome::Applied,
+        "{}",
+        case.url,
+    );
+    store.ensure_surface(&tab, ProfileDataMode::Transient, &[]);
+    wait_for_ready_frame_at_size(
+        &mut store,
+        tab.id(),
+        case,
+        RESIZED_LIVE_SURFACE_WIDTH,
+        RESIZED_LIVE_SURFACE_HEIGHT,
+    )?;
+    store.close_surface(tab.id());
+    Ok(())
+}
+
 fn render_web_surface_frame(
     store: &mut WebSurfaceStore,
     profile_id: &ProfileId,
@@ -283,6 +340,49 @@ fn wait_for_ready_frame_at_scroll(
     }
 }
 
+fn wait_for_ready_frame_at_size(
+    store: &mut WebSurfaceStore,
+    tab_id: &TabId,
+    case: &LiveSiteCase,
+    expected_width: u32,
+    expected_height: u32,
+) -> Result<WebSurfaceFrame, String> {
+    let started_at = Instant::now();
+    let mut last_error = None;
+
+    loop {
+        if started_at.elapsed() >= LIVE_SITE_WAIT_TIMEOUT {
+            return Err(last_error.unwrap_or_else(|| {
+                format!("timed out rendering {} at {expected_width}x{expected_height}", case.url)
+            }));
+        }
+
+        store.tick(std::slice::from_ref(tab_id));
+        match store.state(tab_id) {
+            Some(WebSurfaceState::Ready(frame))
+                if frame.size().width == expected_width
+                    && frame.size().height == expected_height =>
+            {
+                if let Err(error) =
+                    validate_prd_frame_at_size(frame, case, expected_width, expected_height)
+                {
+                    last_error = Some(error);
+                    thread::sleep(LIVE_SITE_WAIT_INTERVAL);
+                    continue;
+                }
+                return Ok(frame.clone());
+            }
+            Some(WebSurfaceState::Ready(_)) => {}
+            Some(WebSurfaceState::Failed { message, .. }) => {
+                return Err(format!("{} failed: {message}", case.url));
+            }
+            Some(WebSurfaceState::Loading { .. }) | None => {}
+        }
+
+        thread::sleep(LIVE_SITE_WAIT_INTERVAL);
+    }
+}
+
 fn validate_prd_frame(
     frame: &WebSurfaceFrame,
     case: &LiveSiteCase,
@@ -330,6 +430,41 @@ fn validate_prd_frame(
     require(frame.sample_hash() > 0, case.url.to_string())
 }
 
+fn validate_prd_frame_at_size(
+    frame: &WebSurfaceFrame,
+    case: &LiveSiteCase,
+    expected_width: u32,
+    expected_height: u32,
+) -> Result<(), String> {
+    require(
+        frame.size()
+            == WebSurfaceSize {
+                width: expected_width,
+                height: expected_height,
+                device_pixel_ratio_percent: 100,
+            },
+        format!("{} size: {:?}", case.url, frame.size()),
+    )?;
+    require_render_state_is_open(frame.render_state(), case.url)?;
+    require(
+        frame.url_label().contains(normalized_url(case.url)),
+        format!("url: {}", frame.url_label()),
+    )?;
+    require(
+        frame.title_label().contains(case.title_fragment),
+        format!("title: {}", frame.title_label()),
+    )?;
+    if frame.has_hardware_surface() {
+        return Ok(());
+    }
+    require(frame.non_white_pixel_count() > 0, case.url.to_string())?;
+    require(
+        frame.content_pixel_count() >= MINIMUM_CONTENT_PIXELS,
+        format!("{} content pixels: {}", case.url, frame.content_pixel_count()),
+    )?;
+    require(frame.sample_hash() > 0, case.url.to_string())
+}
+
 fn log_prd_frame(label: &str, frame: &WebSurfaceFrame, case: &LiveSiteCase) {
     eprintln!(
         "prd-live-site {label} url={} loaded={} title={} state={} size={}x{} content_pixels={} non_white_pixels={} sample_hash={}",
@@ -360,6 +495,13 @@ fn live_surface_bounds() -> Bounds<gpui::Pixels> {
     )
 }
 
+fn resized_live_surface_bounds() -> Bounds<gpui::Pixels> {
+    Bounds::new(
+        point(px(0.0), px(0.0)),
+        size(px(RESIZED_LIVE_SURFACE_WIDTH as f32), px(RESIZED_LIVE_SURFACE_HEIGHT as f32)),
+    )
+}
+
 fn live_scroll_point() -> gpui::Point<gpui::Pixels> {
     point(px(LIVE_SITE_SCROLL_POINT_X), px(LIVE_SITE_SCROLL_POINT_Y))
 }

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

@@ -8,9 +8,10 @@ use std::{
 
 use ely_domain::{DEFAULT_ZOOM_PERCENT, ProfileId, TabId, UrlText};
 use ely_servo_host::{
-    KeyboardTextRequest, MouseClickRequest, MouseHoverRequest, NavigationRequest, PageZoomRequest,
-    PermissionDecision, PermissionRequest, RenderingContextKind, ResizeRequest, ScrollRequest,
-    ServoHost, ServoSurfaceSize, SoftwareServoHost,
+    IOSurfaceIdentity, KeyboardTextRequest, MouseClickRequest, MouseHoverRequest,
+    NavigationRequest, PageZoomRequest, PermissionDecision, PermissionRequest,
+    RenderingContextKind, ResizeRequest, ScrollRequest, ServoHost, ServoSurfaceSize,
+    SoftwareServoHost,
 };
 
 use super::args::LiveArgs;
@@ -47,7 +48,7 @@ pub(super) fn run_live(args: LiveArgs) -> Result<(), LiveSidecarError> {
     let mut perf =
         FramePerfAggregator::new(context_label, FramePerfAggregator::DEFAULT_WINDOW_SIZE);
     let mut pending_summary: Option<FramePerfSummary> = None;
-    let mut published_surface_ids: HashMap<String, HashSet<u64>> = HashMap::new();
+    let mut published_surface_ids: HashMap<String, HashSet<IOSurfaceIdentity>> = HashMap::new();
     let stdin = io::stdin();
     let mut stdout = io::stdout().lock();
 
@@ -91,7 +92,7 @@ const fn rendering_context_label(kind: RenderingContextKind) -> &'static str {
 fn handle_request(
     host: &mut SoftwareServoHost,
     sessions: &mut HashMap<String, LiveSession>,
-    published_surface_ids: &mut HashMap<String, HashSet<u64>>,
+    published_surface_ids: &mut HashMap<String, HashSet<IOSurfaceIdentity>>,
     rendering_context_kind: RenderingContextKind,
     request: LiveRequest,
 ) -> Result<LiveOutcome, LiveSidecarError> {

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

@@ -29,7 +29,7 @@ pub(super) fn populate_surface_fields(
     host: &SoftwareServoHost,
     webview_id: &ely_domain::WebViewId,
     tab_id: &str,
-    published_surface_ids: &mut HashMap<String, HashSet<u64>>,
+    published_surface_ids: &mut HashMap<String, HashSet<IOSurfaceIdentity>>,
     outcome: &mut LiveOutcome,
 ) {
     if outcome.response.frame.is_none() {
@@ -40,6 +40,7 @@ pub(super) fn populate_surface_fields(
         let Ok(Some(identity)) = host.peek_iosurface_identity(webview_id) else {
             return;
         };
+        align_report_to_surface_identity(outcome, identity);
         let handle = if surface_has_been_published(published_surface_ids, tab_id, identity) {
             None
         } else {
@@ -57,13 +58,11 @@ pub(super) fn populate_surface_fields(
 
 #[cfg(any(test, all(feature = "hardware-render", target_os = "macos")))]
 fn surface_has_been_published(
-    published_surface_ids: &HashMap<String, HashSet<u64>>,
+    published_surface_ids: &HashMap<String, HashSet<IOSurfaceIdentity>>,
     tab_id: &str,
     identity: IOSurfaceIdentity,
 ) -> bool {
-    published_surface_ids
-        .get(tab_id)
-        .is_some_and(|published| published.contains(&identity.surface_id))
+    published_surface_ids.get(tab_id).is_some_and(|published| published.contains(&identity))
 }
 
 #[cfg(any(test, all(feature = "hardware-render", target_os = "macos")))]
@@ -75,7 +74,7 @@ struct SurfacePublication {
 
 #[cfg(any(test, all(feature = "hardware-render", target_os = "macos")))]
 fn surface_publication_for(
-    published_surface_ids: &mut HashMap<String, HashSet<u64>>,
+    published_surface_ids: &mut HashMap<String, HashSet<IOSurfaceIdentity>>,
     tab_id: &str,
     identity: IOSurfaceIdentity,
     handle: Option<IOSurfaceHandle>,
@@ -91,7 +90,10 @@ fn surface_publication_for(
         return SurfacePublication { current_surface_id: None, surface_handle: None };
     };
 
-    published_surface_ids.entry(tab_id.to_string()).or_default().insert(handle.surface_id);
+    published_surface_ids
+        .entry(tab_id.to_string())
+        .or_default()
+        .insert(IOSurfaceIdentity::from_handle(handle));
     SurfacePublication { current_surface_id: Some(handle.surface_id), surface_handle: Some(handle) }
 }
 
@@ -102,6 +104,14 @@ fn handle_matches_identity(handle: IOSurfaceHandle, identity: IOSurfaceIdentity)
         && handle.height == identity.height
 }
 
+#[cfg(any(test, all(feature = "hardware-render", target_os = "macos")))]
+fn align_report_to_surface_identity(outcome: &mut LiveOutcome, identity: IOSurfaceIdentity) {
+    if let Some(frame) = outcome.response.frame.as_mut() {
+        frame.width = identity.width;
+        frame.height = identity.height;
+    }
+}
+
 /// Serialise the response then stream the optional raw RGBA frame on
 /// the same stdout pipe. The client reads the JSON line, takes
 /// `rgba_byte_count` from the report, then reads that many bytes
@@ -163,11 +173,7 @@ pub(super) fn write_outcome(
 
 #[cfg(test)]
 mod tests {
-    use std::{
-        collections::{HashMap, HashSet},
-        error::Error,
-        time::Instant,
-    };
+    use std::{collections::HashMap, error::Error, time::Instant};
 
     use ely_servo_host::{IOSurfaceHandle, IOSurfaceIdentity};
 
@@ -175,7 +181,7 @@ mod tests {
         live_protocol::{LiveFrameReport, LiveOutcome, PartialFrameTimings},
         perf::FramePerfAggregator,
     };
-    use super::{surface_publication_for, write_outcome};
+    use super::{align_report_to_surface_identity, surface_publication_for, write_outcome};
 
     #[test]
     fn unpublished_surface_without_handle_leaves_selector_empty() {
@@ -197,12 +203,15 @@ mod tests {
 
         assert_eq!(publication.current_surface_id, Some(7));
         assert_eq!(publication.surface_handle, Some(handle));
-        assert!(published.get("tab-1").is_some_and(|ids| ids.contains(&7)));
+        assert!(published.get("tab-1").is_some_and(|ids| ids.contains(&identity(7, 800, 600))));
     }
 
     #[test]
     fn published_surface_reuses_selector_without_republishing_handle() {
-        let mut published = HashMap::from([("tab-1".to_string(), HashSet::from([7]))]);
+        let mut published = HashMap::new();
+        let handle = handle(7, 800, 600);
+        let _ =
+            surface_publication_for(&mut published, "tab-1", identity(7, 800, 600), Some(handle));
         let publication =
             surface_publication_for(&mut published, "tab-1", identity(7, 800, 600), None);
 
@@ -210,6 +219,36 @@ mod tests {
         assert!(publication.surface_handle.is_none());
     }
 
+    #[test]
+    fn same_surface_id_with_changed_dimensions_republishes_handle() {
+        let mut published = HashMap::new();
+        let initial = handle(7, 800, 600);
+        let resized = handle(7, 1024, 768);
+
+        let _ =
+            surface_publication_for(&mut published, "tab-1", identity(7, 800, 600), Some(initial));
+        let publication =
+            surface_publication_for(&mut published, "tab-1", identity(7, 1024, 768), Some(resized));
+
+        assert_eq!(publication.current_surface_id, Some(7));
+        assert_eq!(publication.surface_handle, Some(resized));
+    }
+
+    #[test]
+    fn hardware_report_uses_surface_identity_dimensions() -> Result<(), Box<dyn Error>> {
+        let mut outcome = LiveOutcome::from_report(
+            report_with_size(2180, 1586),
+            PartialFrameTimings { paint_ns: 1_000, encode_ns: 2_000 },
+        );
+
+        align_report_to_surface_identity(&mut outcome, identity(7, 2168, 1566));
+
+        let report = outcome.response.frame.ok_or("report must remain present")?;
+        assert_eq!(report.width, 2168);
+        assert_eq!(report.height, 1566);
+        Ok(())
+    }
+
     #[test]
     fn mismatched_handle_leaves_surface_unpublished() {
         let mut published = HashMap::new();
@@ -263,13 +302,19 @@ mod tests {
     }
 
     fn report_with_byte_count(rgba_byte_count: usize) -> LiveFrameReport {
+        let mut report = report_with_size(2, 2);
+        report.rgba_byte_count = rgba_byte_count;
+        report
+    }
+
+    fn report_with_size(width: u32, height: u32) -> LiveFrameReport {
         LiveFrameReport {
             loaded_url: Some("https://example.com/".to_string()),
             title: Some("Example".to_string()),
             state: "complete",
-            width: 2,
-            height: 2,
-            rgba_byte_count,
+            width,
+            height,
+            rgba_byte_count: 0,
             non_white_pixel_count: 0,
             content_pixel_count: 0,
             sample_hash: 0,

crates/ely_servo_host/src/iosurface_handle.rs

@@ -16,10 +16,11 @@
 /// a Metal texture without copying pixels.
 ///
 /// `surface_id` is the stable surfman `SurfaceID` (a pointer-shaped
-/// `usize` widened to `u64` for the wire). It lets the receiver dedup:
-/// when two consecutive frames carry the same `surface_id` the
-/// imported `MTLTexture` is reused without re-importing. `width` and
-/// `height` are reported in surface pixels (post-DPR).
+/// `usize` widened to `u64` for the wire). Together with `width` and
+/// `height` it lets the receiver dedup imported IOSurfaces. The pixel
+/// dimensions are part of the identity because a resize can reuse the
+/// same surfman id for a newly-sized IOSurface. `width` and `height`
+/// are reported in surface pixels (post-DPR).
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 #[cfg_attr(feature = "servo-engine", derive(serde::Serialize, serde::Deserialize))]
 pub struct IOSurfaceHandle {
@@ -33,9 +34,15 @@ pub struct IOSurfaceHandle {
 /// "same surface as last frame" from "resize/swap rotated to a new
 /// surface" without minting a fresh mach port (mach ports are a scarce
 /// kernel resource and `IOSurfaceCreateMachPort` is not cheap).
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 pub struct IOSurfaceIdentity {
     pub surface_id: u64,
     pub width: u32,
     pub height: u32,
 }
+
+impl IOSurfaceIdentity {
+    pub fn from_handle(handle: IOSurfaceHandle) -> Self {
+        Self { surface_id: handle.surface_id, width: handle.width, height: handle.height }
+    }
+}

third_party/gpui/src/platform/mac/shaders.metal

@@ -890,10 +890,10 @@ fragment float4 surface_bgra_fragment(SurfaceFragmentInput input [[stage_in]],
                                       texture2d<float> bgra_texture
                                       [[texture(SurfaceInputIndex_YTexture)]]) {
   constexpr sampler texture_sampler(mag_filter::linear, min_filter::linear);
-  // Servo's CGL-backed IOSurfaces use the opposite framebuffer origin from
-  // GPUI's surface quad, so flip both texture axes for browser frames.
+  // Servo's CGL-backed IOSurfaces use the opposite vertical framebuffer origin
+  // from GPUI's surface quad, matching the software readback path.
   float2 texture_position =
-      float2(1.0 - input.texture_position.x, 1.0 - input.texture_position.y);
+      float2(input.texture_position.x, 1.0 - input.texture_position.y);
   return bgra_texture.sample(texture_sampler, texture_position);
 }