LibWeb: Run IntersectionObserver steps only when needed

Instead of updating IOs in every iteration of the HTML event loop, we now only do it after a relayout, or after the viewport changes.
Author: https://github.com/awesomekling Commit: 11b4216e65 Pull-request: https://github.com/SerenityOS/serenity/pull/23328 Reviewed-by: https://github.com/tcl3
2025-08-01 21:59:07 +00:00 · 2024-02-24 08:09:42 +01:00 · 2024-02-24 08:09:42 +01:00 · 11b4216e65 · 2024-07-17 07:35:03 +09:00
commit 11b4216e65
parent d3f8d24abb
3 changed files with 8 additions and 3 deletions
--- a/Userland/Libraries/LibWeb/DOM/Document.cpp
+++ b/Userland/Libraries/LibWeb/DOM/Document.cpp
@ -1106,6 +1106,9 @@ void Document::update_layout()

    m_needs_layout = false;
    m_layout_update_timer->stop();
+
+    // OPTIMIZATION: We do this here instead of in HTML::EventLoop::process() to avoid redundant work.
+    run_the_update_intersection_observations_steps(HighResolutionTime::unsafe_shared_current_time());
 }

 [[nodiscard]] static Element::RequiredInvalidationAfterStyleChange update_style_recursively(Node& node)