layout: Add basic support for getClientRects() queries (#31696)

This adds basic support for `getClientRects()` by sharing code with the
implementation of `getBoundingClientRect()`. In addition to sharing
code, it also shares all of the bugs. Primarily, scrolilng positions are
not taken into account when return boundary rectangles.

components/layout_2020/fragment_tree/fragment_tree.rs

@@ -17,7 +17,7 @@ use super::{ContainingBlockManager, Fragment, Tag};
 use crate::cell::ArcRefCell;
 use crate::display_list::StackingContext;
 use crate::flow::CanvasBackground;
-use crate::geom::PhysicalRect;
+use crate::geom::{physical_rect_to_au_rect, PhysicalRect};
 
 #[derive(Serialize)]
 pub struct FragmentTree {
@@ -97,9 +97,13 @@ impl FragmentTree {
         });
     }
 
-    pub fn get_content_box_for_node(&self, requested_node: OpaqueNode) -> Option<Rect<Au>> {
+    /// Get the vector of rectangles that surrounds the fragments of the node with the given address.
-        let mut bounding_box = PhysicalRect::zero();
+    /// This function answers the `getClientRects()` query and the union of the rectangles answers
-        let mut found_any_nodes = false;
+    /// the `getBoundingClientRect()` query.
+    ///
+    /// TODO: This function is supposed to handle scroll offsets, but that isn't happening at all.
+    pub fn get_content_boxes_for_node(&self, requested_node: OpaqueNode) -> Vec<Rect<Au>> {
+        let mut content_boxes = Vec::new();
         let tag_to_find = Tag::new(requested_node);
         self.find(|fragment, _, containing_block| {
             if fragment.tag() != Some(tag_to_find) {
@@ -121,27 +125,12 @@ impl FragmentTree {
                 Fragment::IFrame(_) => return None,
             };
 
-            found_any_nodes = true;
+            content_boxes.push(physical_rect_to_au_rect(
-            bounding_box = fragment_relative_rect
+                fragment_relative_rect.translate(containing_block.origin.to_vector()),
-                .translate(containing_block.origin.to_vector())
+            ));
-                .union(&bounding_box);
             None::<()>
         });
-
+        content_boxes
-        if found_any_nodes {
-            Some(Rect::new(
-                Point2D::new(
-                    Au::from_f32_px(bounding_box.origin.x.px()),
-                    Au::from_f32_px(bounding_box.origin.y.px()),
-                ),
-                Size2D::new(
-                    Au::from_f32_px(bounding_box.size.width.px()),
-                    Au::from_f32_px(bounding_box.size.height.px()),
-                ),
-            ))
-        } else {
-            None
-        }
     }
 
     pub fn get_border_dimensions_for_node(&self, requested_node: OpaqueNode) -> Rect<i32> {

components/layout_2020/geom.rs

@@ -525,3 +525,17 @@ impl From<LogicalRect<CSSPixelLength>> for LogicalRect<Au> {
         }
     }
 }
+
+/// Convert a `PhysicalRect<Length>` (one that uses CSSPixel as the unit) to an untyped `Rect<Au>`.
+pub fn physical_rect_to_au_rect(rect: PhysicalRect<Length>) -> euclid::default::Rect<Au> {
+    euclid::default::Rect::new(
+        euclid::default::Point2D::new(
+            Au::from_f32_px(rect.origin.x.px()),
+            Au::from_f32_px(rect.origin.y.px()),
+        ),
+        euclid::default::Size2D::new(
+            Au::from_f32_px(rect.size.width.px()),
+            Au::from_f32_px(rect.size.height.px()),
+        ),
+    )
+}

components/layout_2020/query.rs

@@ -179,11 +179,25 @@ pub fn process_content_box_request(
     requested_node: OpaqueNode,
     fragment_tree: Option<Arc<FragmentTree>>,
 ) -> Option<Rect<Au>> {
-    fragment_tree?.get_content_box_for_node(requested_node)
+    let rects = fragment_tree?.get_content_boxes_for_node(requested_node);
+    if rects.is_empty() {
+        return None;
+    }
+
+    Some(
+        rects
+            .iter()
+            .fold(Rect::zero(), |unioned_rect, rect| rect.union(&unioned_rect)),
+    )
 }
 
-pub fn process_content_boxes_request(_requested_node: OpaqueNode) -> Vec<Rect<Au>> {
+pub fn process_content_boxes_request(
-    vec![]
+    requested_node: OpaqueNode,
+    fragment_tree: Option<Arc<FragmentTree>>,
+) -> Vec<Rect<Au>> {
+    fragment_tree
+        .map(|tree| tree.get_content_boxes_for_node(requested_node))
+        .unwrap_or_default()
 }
 
 pub fn process_node_geometry_request(

components/layout_thread_2020/lib.rs

@@ -857,7 +857,8 @@ impl LayoutThread {
                         process_content_box_request(node, self.fragment_tree.borrow().clone());
                 },
                 &QueryMsg::ContentBoxesQuery(node) => {
-                    rw_data.content_boxes_response = process_content_boxes_request(node);
+                    rw_data.content_boxes_response =
+                        process_content_boxes_request(node, self.fragment_tree.borrow().clone());
                 },
                 &QueryMsg::TextIndexQuery(node, point_in_node) => {
                     let point_in_node = Point2D::new(

tests/wpt/meta/css/cssom-view/cssom-getClientRects-002.html.ini

@@ -1,3 +0,0 @@
-[cssom-getClientRects-002.html]
-  [CSSOM View - GetClientRects().length is the same regardless source new lines]
-    expected: FAIL

tests/wpt/meta/css/cssom-view/getClientRects-br-htb-ltr.html.ini

@@ -1,3 +0,0 @@
-[getClientRects-br-htb-ltr.html]
-  [Position of the BR element]
-    expected: FAIL

tests/wpt/meta/css/cssom-view/getClientRects-br-vlr-ltr.html.ini

@@ -1,4 +0,0 @@
-[getClientRects-br-vlr-ltr.html]
-  [Position of the BR element]
-    expected: FAIL
-

tests/wpt/meta/css/cssom-view/getClientRects-inline-atomic-child.html.ini

@@ -1,10 +0,0 @@
-[getClientRects-inline-atomic-child.html]
-  [getClientRects-inline-atomic-child]
-    expected: FAIL
-
-  [getClientRects-inline-atomic-child 2]
-    expected: FAIL
-
-  [getClientRects-inline-atomic-child 1]
-    expected: FAIL
-

tests/wpt/meta/css/cssom-view/getClientRects-inline.html.ini

@@ -1,2 +0,0 @@
-[getClientRects-inline.html]
-  expected: FAIL

tests/wpt/meta/css/cssom-view/getClientRects-zoom.html.ini

@@ -1,7 +1,4 @@
 [getClientRects-zoom.html]
-  [getBoundingClientRect for elements with css zoom 1]
-    expected: FAIL
-
   [getBoundingClientRect for elements with css zoom 2]
     expected: FAIL
 

tests/wpt/meta/css/cssom-view/scroll-behavior-smooth-navigation.html.ini

@@ -4,3 +4,6 @@
 
   [Make sure the page is ready for animation.]
     expected: FAIL
+
+  [Smooth scrolling while doing history navigation.]
+    expected: FAIL

tests/wpt/meta/css/cssom-view/ttwf-js-cssomview-getclientrects-length.html.ini

@@ -1,9 +0,0 @@
-[ttwf-js-cssomview-getclientrects-length.html]
-  [assert_length_of_getClientRects_from_Link]
-    expected: FAIL
-
-  [assert_length_of_getClientRects_from_Parent]
-    expected: FAIL
-
-  [assert_length_of_getClientRects_from_Button]
-    expected: FAIL

tests/wpt/meta/css/geometry/DOMRectList.html.ini

@@ -7,9 +7,3 @@
 
   [DOMRectList item()]
     expected: FAIL
-
-  [DOMRectList length]
-    expected: FAIL
-
-  [DOMRectList indexed getter]
-    expected: FAIL

tests/wpt/meta/css/geometry/structured-serialization.html.ini

@@ -88,6 +88,3 @@
 
   [DOMMatrix clone: non-initial values (3d)]
     expected: FAIL
-
-  [DOMRectList clone]
-    expected: FAIL

tests/wpt/meta/html/semantics/embedded-content/the-canvas-element/canvas-descendants-focusability-003.tentative.html.ini

@@ -1,5 +1,4 @@
 [canvas-descendants-focusability-003.tentative.html]
-  expected: ERROR
   [<div tabindex="-1" data-focusable="false">]
     expected: FAIL