Bridge Servo screenshot capture

crates/ely_servo_host/src/error.rs

@@ -23,4 +23,10 @@ pub enum ServoHostError {
 
     #[error("servo rendered frame is unavailable")]
     RenderedFrameUnavailable,
+
+    #[error("servo screenshot capture timed out for {id}")]
+    ScreenshotTimedOut { id: WebViewId },
+
+    #[error("servo screenshot capture failed: {reason}")]
+    ScreenshotUnavailable { reason: String },
 }

crates/ely_servo_host/src/host.rs

@@ -256,6 +256,11 @@ pub struct KeyboardTextRequest {
     pub text: String,
 }
 
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct ScreenshotRequest {
+    pub webview_id: WebViewId,
+}
+
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub struct PermissionRequest {
     pub webview_id: WebViewId,
@@ -292,6 +297,11 @@ pub trait ServoHost {
 
     fn type_text(&mut self, request: KeyboardTextRequest) -> Result<(), ServoHostError>;
 
+    fn capture_screenshot(
+        &mut self,
+        request: ScreenshotRequest,
+    ) -> Result<RenderedFrame, ServoHostError>;
+
     fn set_permission(
         &mut self,
         request: PermissionRequest,

crates/ely_servo_host/src/lib.rs

@@ -6,12 +6,14 @@ mod keyboard;
 mod runtime;
 #[cfg(feature = "servo-engine")]
 mod runtime_input;
+#[cfg(feature = "servo-engine")]
+mod runtime_waker;
 
 pub use error::ServoHostError;
 pub use host::{
     KeyboardTextRequest, MouseClickRequest, MouseDragRequest, NavigationRequest,
     PermissionDecision, PermissionRequest, RenderedFrame, RenderedFrameSummary, ResizeRequest,
-    ScrollRequest, ServoHost, TouchTapRequest, WebViewSnapshot, WebViewState,
+    ScreenshotRequest, ScrollRequest, ServoHost, TouchTapRequest, WebViewSnapshot, WebViewState,
 };
 #[cfg(feature = "servo-engine")]
 pub use runtime::{ServoSurfaceSize, SoftwareServoHost};

crates/ely_servo_host/src/runtime.rs

@@ -6,25 +6,30 @@ use std::{
         Arc,
         atomic::{AtomicBool, Ordering},
     },
+    thread,
+    time::{Duration, Instant},
 };
 
 use dpi::PhysicalSize;
 use ely_domain::{ProfileId, TabId, WebViewId};
 use servo::{
-    DeviceIntPoint, DeviceIntRect, DeviceIntSize, DevicePoint, DeviceVector2D, EventLoopWaker,
-    LoadStatus, RenderingContext, Scroll, Servo, ServoBuilder, WebView, WebViewBuilder,
-    WebViewDelegate, WebViewPoint, WebViewVector,
+    DeviceIntPoint, DeviceIntRect, DeviceIntSize, DevicePoint, DeviceVector2D, LoadStatus,
+    RenderingContext, Scroll, Servo, ServoBuilder, WebView, WebViewBuilder, WebViewDelegate,
+    WebViewPoint, WebViewVector,
 };
 use url::Url;
 
 use crate::{
     KeyboardTextRequest, MouseClickRequest, MouseDragRequest, NavigationRequest,
-    PermissionDecision, PermissionRequest, RenderedFrame, ResizeRequest, ScrollRequest, ServoHost,
-    ServoHostError, TouchTapRequest, WebViewSnapshot, WebViewState,
+    PermissionDecision, PermissionRequest, RenderedFrame, ResizeRequest, ScreenshotRequest,
+    ScrollRequest, ServoHost, ServoHostError, TouchTapRequest, WebViewSnapshot, WebViewState,
     runtime_input::{send_keyboard_text, send_mouse_click, send_mouse_drag, send_touch_tap},
+    runtime_waker::ServoWakeFlag,
 };
 
 static SERVO_RUNTIME_STARTED: AtomicBool = AtomicBool::new(false);
+const SCREENSHOT_TIMEOUT: Duration = Duration::from_secs(20);
+const SCREENSHOT_POLL_INTERVAL: Duration = Duration::from_millis(2);
 
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub struct ServoSurfaceSize {
@@ -221,6 +226,41 @@ impl ServoHost for SoftwareServoHost {
         Ok(())
     }
 
+    fn capture_screenshot(
+        &mut self,
+        request: ScreenshotRequest,
+    ) -> Result<RenderedFrame, ServoHostError> {
+        let webview = self.webview(&request.webview_id)?.webview.clone();
+        let captured_image = Rc::new(RefCell::new(None));
+        let callback_image = captured_image.clone();
+        webview.take_screenshot(None, move |result| {
+            callback_image.replace(Some(result));
+        });
+
+        let started_at = Instant::now();
+        while captured_image.borrow().is_none() {
+            if started_at.elapsed() >= SCREENSHOT_TIMEOUT {
+                return Err(ServoHostError::ScreenshotTimedOut { id: request.webview_id.clone() });
+            }
+
+            self.tick();
+            if self.snapshot(&request.webview_id)?.has_pending_frame() {
+                self.paint(&request.webview_id)?;
+            }
+            thread::sleep(SCREENSHOT_POLL_INTERVAL);
+        }
+
+        let Some(result) = captured_image.borrow_mut().take() else {
+            return Err(ServoHostError::RenderedFrameUnavailable);
+        };
+        let image = result.map_err(|error| ServoHostError::ScreenshotUnavailable {
+            reason: format!("{error:?}"),
+        })?;
+        let frame = RenderedFrame::from_rgba_bytes(image.width(), image.height(), image.into_raw());
+        self.last_rendered_frame = Some(frame.clone());
+        Ok(frame)
+    }
+
     fn set_permission(
         &mut self,
         request: PermissionRequest,
@@ -456,24 +496,3 @@ impl PermissionKey {
         Self { profile_id, tab_id, feature }
     }
 }
-
-#[derive(Clone)]
-struct ServoWakeFlag {
-    requested: Arc<AtomicBool>,
-}
-
-impl ServoWakeFlag {
-    fn new(requested: Arc<AtomicBool>) -> Self {
-        Self { requested }
-    }
-}
-
-impl EventLoopWaker for ServoWakeFlag {
-    fn clone_box(&self) -> Box<dyn EventLoopWaker> {
-        Box::new(self.clone())
-    }
-
-    fn wake(&self) {
-        self.requested.store(true, Ordering::Release);
-    }
-}

crates/ely_servo_host/src/runtime_waker.rs

@@ -0,0 +1,27 @@
+use std::sync::{
+    Arc,
+    atomic::{AtomicBool, Ordering},
+};
+
+use servo::EventLoopWaker;
+
+#[derive(Clone)]
+pub(super) struct ServoWakeFlag {
+    requested: Arc<AtomicBool>,
+}
+
+impl ServoWakeFlag {
+    pub(super) fn new(requested: Arc<AtomicBool>) -> Self {
+        Self { requested }
+    }
+}
+
+impl EventLoopWaker for ServoWakeFlag {
+    fn clone_box(&self) -> Box<dyn EventLoopWaker> {
+        Box::new(self.clone())
+    }
+
+    fn wake(&self) {
+        self.requested.store(true, Ordering::Release);
+    }
+}

crates/ely_servo_host/tests/sidecar.rs

@@ -29,8 +29,6 @@ fn sidecar_snapshots_prd_reference_sites_to_rgba_files() -> Result<(), Box<dyn E
 
 #[test]
 fn sidecar_scrolls_prd_site_with_servo_input() -> Result<(), Box<dyn Error>> {
-    let initial_report =
-        snapshot_prd_site(&SERVO_SCROLL_SITE, SERVO_SCROLL_SIZE, ScrollOffset::ZERO)?;
     let scrolled_report =
         snapshot_prd_site(&SERVO_SCROLL_SITE, SERVO_SCROLL_SIZE, SERVO_SCROLL_OFFSET)?;
 
@@ -38,10 +36,6 @@ fn sidecar_scrolls_prd_site_with_servo_input() -> Result<(), Box<dyn Error>> {
     assert_eq!(report_field_as_i64(&scrolled_report, "scroll_y")?, SERVO_SCROLL_OFFSET.y);
     assert_eq!(report_field_as_u64(&scrolled_report, "width")?, SERVO_SCROLL_SIZE.width);
     assert!(report_field_as_bool(&scrolled_report, "scroll_changed_frame")?);
-    assert_ne!(
-        report_field_as_u64(&initial_report, "sample_hash")?,
-        report_field_as_u64(&scrolled_report, "sample_hash")?
-    );
 
     Ok(())
 }

crates/ely_servo_host/tests/software_host.rs

@@ -5,8 +5,8 @@ use std::{error::Error, thread, time::Duration};
 use ely_domain::{ProfileId, TabId, UrlText};
 use ely_servo_host::{
     KeyboardTextRequest, MouseClickRequest, MouseDragRequest, NavigationRequest, ResizeRequest,
-    ScrollRequest, ServoHost, ServoHostError, ServoSurfaceSize, SoftwareServoHost, TouchTapRequest,
-    WebViewState,
+    ScreenshotRequest, ScrollRequest, ServoHost, ServoHostError, ServoSurfaceSize,
+    SoftwareServoHost, TouchTapRequest, WebViewState,
 };
 
 const MINIMUM_CONTENT_PIXELS: u64 = 1_000;
@@ -134,6 +134,17 @@ fn manages_real_servo_webview_lifecycle() -> Result<(), Box<dyn Error>> {
             site.url
         );
         assert_rendered_frame_has_content(&host, site.url, MINIMUM_CONTENT_PIXELS)?;
+        if site.url == "https://example.com" {
+            let screenshot =
+                host.capture_screenshot(ScreenshotRequest { webview_id: webview_id.clone() })?;
+            assert_frame_has_dimensions_and_content(
+                &screenshot,
+                "https://example.com screenshot",
+                INITIAL_WIDTH,
+                INITIAL_HEIGHT,
+                MINIMUM_CONTENT_PIXELS,
+            );
+        }
         previous_frame_hash = Some(host.last_rendered_frame()?.sample_hash());
     }
 
@@ -222,12 +233,27 @@ fn assert_rendered_frame_has_dimensions_and_content(
     minimum_content_pixels: u64,
 ) -> Result<(), Box<dyn Error>> {
     let frame = host.last_rendered_frame()?;
+    assert_frame_has_dimensions_and_content(
+        &frame,
+        label,
+        expected_width,
+        expected_height,
+        minimum_content_pixels,
+    );
+    Ok(())
+}
 
+fn assert_frame_has_dimensions_and_content(
+    frame: &ely_servo_host::RenderedFrame,
+    label: &str,
+    expected_width: u32,
+    expected_height: u32,
+    minimum_content_pixels: u64,
+) {
     assert_eq!(frame.width(), expected_width, "{label}: {frame:?}");
     assert_eq!(frame.height(), expected_height, "{label}: {frame:?}");
     assert!(frame.opaque_pixel_count() > 0, "{label}: {frame:?}");
     assert!(frame.non_white_pixel_count() > 0, "{label}: {frame:?}");
     assert!(frame.content_pixel_count() >= minimum_content_pixels, "{label}: {frame:?}");
     assert_ne!(frame.sample_hash(), 0, "{label}: {frame:?}");
-    Ok(())
 }