[OH] Provide correct geometry offset and fix available screen dimensions (#36915)

This commit corrects the geometry details provided under the OH platform
by getting the offset from the OS. OH port provides correct offset and
available space.

Fixes: #36466

---------

Signed-off-by: Astraea Quinn Skoutelli <astraea.quinn.skoutelli@huawei.com>
Signed-off-by: Jonathan Schwender <55576758+jschwe@users.noreply.github.com>
Co-authored-by: Jonathan Schwender <55576758+jschwe@users.noreply.github.com>

ports/servoshell/egl/app_state.rs

@@ -38,6 +38,14 @@ impl Coordinates {
             viewport: Rect::new(Point2D::new(x, y), Size2D::new(width, height)),
         }
     }
+
+    pub fn origin(&self) -> Point2D<i32, DevicePixel> {
+        self.viewport.origin
+    }
+
+    pub fn size(&self) -> Size2D<i32, DevicePixel> {
+        self.viewport.size
+    }
 }
 
 pub(super) struct ServoWindowCallbacks {
@@ -115,11 +123,13 @@ impl ServoDelegate for ServoShellServoDelegate {
 impl WebViewDelegate for RunningAppState {
     fn screen_geometry(&self, _webview: WebView) -> Option<ScreenGeometry> {
         let coord = self.callbacks.coordinates.borrow();
-        let screen_size = DeviceIntSize::new(coord.viewport.size.width, coord.viewport.size.height);
+        let offset = coord.origin();
+        let available_size = coord.size();
+        let screen_size = coord.size();
         Some(ScreenGeometry {
             size: screen_size,
-            available_size: screen_size,
-            offset: Point2D::zero(),
+            available_size,
+            offset,
         })
     }
 

ports/servoshell/egl/ohos.rs

@@ -28,8 +28,9 @@ use servo::{
 use xcomponent_sys::{
     OH_NativeXComponent, OH_NativeXComponent_Callback, OH_NativeXComponent_GetKeyEvent,
     OH_NativeXComponent_GetKeyEventAction, OH_NativeXComponent_GetKeyEventCode,
-    OH_NativeXComponent_GetTouchEvent, OH_NativeXComponent_GetXComponentSize,
-    OH_NativeXComponent_KeyAction, OH_NativeXComponent_KeyCode, OH_NativeXComponent_KeyEvent,
+    OH_NativeXComponent_GetTouchEvent, OH_NativeXComponent_GetXComponentOffset,
+    OH_NativeXComponent_GetXComponentSize, OH_NativeXComponent_KeyAction,
+    OH_NativeXComponent_KeyCode, OH_NativeXComponent_KeyEvent,
     OH_NativeXComponent_RegisterCallback, OH_NativeXComponent_RegisterKeyEventCallback,
     OH_NativeXComponent_TouchEvent, OH_NativeXComponent_TouchEventType,
 };
@@ -267,6 +268,33 @@ extern "C" fn on_surface_created_cb(xcomponent: *mut OH_NativeXComponent, window
     info!("Returning from on_surface_created_cb");
 }
 
+/// Returns the offset of the surface relative to its parent's top left corner
+///
+/// # Safety
+///
+/// `xcomponent` and `native_window` must be valid, non-null and aligned pointers to a
+/// live xcomponent and associated native window surface.
+unsafe fn get_xcomponent_offset(
+    xcomponent: *mut OH_NativeXComponent,
+    native_window: *mut c_void,
+) -> Result<(i32, i32), i32> {
+    let mut x: f64 = 0.0;
+    let mut y: f64 = 0.0;
+
+    let result = unsafe {
+        OH_NativeXComponent_GetXComponentOffset(xcomponent, native_window, &raw mut x, &raw mut y)
+    };
+    if result != 0 {
+        error!("OH_NativeXComponent_GetXComponentOffset failed with {result}");
+        return Err(result);
+    }
+
+    Ok((
+        (x.round() as i64).try_into().expect("X offset too large"),
+        (y.round() as i64).try_into().expect("Y offset too large"),
+    ))
+}
+
 /// Returns the size of the surface
 ///
 /// # Safety

ports/servoshell/egl/ohos/simpleservo.rs

@@ -97,7 +97,10 @@ pub fn init(
     let Ok(window_size) = (unsafe { super::get_xcomponent_size(xcomponent, native_window) }) else {
         return Err("Failed to get xcomponent size");
     };
-    let coordinates = Coordinates::new(0, 0, window_size.width, window_size.height);
+    let Ok((x, y)) = (unsafe { super::get_xcomponent_offset(xcomponent, native_window) }) else {
+        return Err("Failed to get xcomponent offset");
+    };
+    let coordinates = Coordinates::new(x, y, window_size.width, window_size.height);
 
     let display_handle = RawDisplayHandle::Ohos(OhosDisplayHandle::new());
     let display_handle = unsafe { DisplayHandle::borrow_raw(display_handle) };