Auto merge of #12813 - emilio:hit-test, r=notriddle

dom: getElementsFromPoint does the hit testing on viewport coordinates.

<!-- Please describe your changes on the following line: -->

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors

<!-- Either: -->
- [x] There are tests for these changes OR

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

We got this wrong (I think it wasn't my fault actually), I was just writing a test for #12777 when I found this.

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/12813)
<!-- Reviewable:end -->

1 files changed, 5 insertions, 5 deletions

diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 5f1bf4c45cd..646b307a3e6 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -1583,12 +1583,12 @@ impl Document {
         self.browsing_context.is_none() || !url_has_network_scheme(&self.url)
     }
 
-    pub fn nodes_from_point(&self, page_point: &Point2D<f32>) -> Vec<UntrustedNodeAddress> {
-        let client_point =
-            Point2D::new(page_point.x - self.window.PageXOffset() as f32,
-                         page_point.y - self.window.PageYOffset() as f32);
+    pub fn nodes_from_point(&self, client_point: &Point2D<f32>) -> Vec<UntrustedNodeAddress> {
+        let page_point =
+            Point2D::new(client_point.x + self.window.PageXOffset() as f32,
+                         client_point.y + self.window.PageYOffset() as f32);
 
-        self.window.layout().nodes_from_point(*page_point, client_point)
+        self.window.layout().nodes_from_point(page_point, *client_point)
     }
 }