LibWebView+WebConent: Add an IPC to get an element's absolute rect

Author: https://github.com/trflynn89
Commit: https://github.com/SerenityOS/serenity/commit/995f3db384
Pull-request: https://github.com/SerenityOS/serenity/pull/15909
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibWebView/OutOfProcessWebView.cpp

@@ -560,6 +560,11 @@ String OutOfProcessWebView::get_element_tag_name(i32 element_id)
     return client().get_element_tag_name(element_id);
 }
 
+Gfx::IntRect OutOfProcessWebView::get_element_rect(i32 element_id)
+{
+    return client().get_element_rect(element_id);
+}
+
 void OutOfProcessWebView::set_content_filters(Vector<String> filters)
 {
     client().async_set_content_filters(filters);

Userland/Libraries/LibWebView/OutOfProcessWebView.h

@@ -71,6 +71,7 @@ public:
     String get_computed_value_for_element(i32 element_id, String const& property_name);
     String get_element_text(i32 element_id);
     String get_element_tag_name(i32 element_id);
+    Gfx::IntRect get_element_rect(i32 element_id);
 
     void set_content_filters(Vector<String>);
     void set_proxy_mappings(Vector<String> proxies, HashMap<String, size_t> mappings);

Userland/Services/WebContent/ConnectionFromClient.cpp

@@ -24,6 +24,7 @@
 #include <LibWeb/DOM/Document.h>
 #include <LibWeb/DOM/NodeList.h>
 #include <LibWeb/Dump.h>
+#include <LibWeb/Geometry/DOMRect.h>
 #include <LibWeb/HTML/BrowsingContext.h>
 #include <LibWeb/HTML/Scripting/ClassicScript.h>
 #include <LibWeb/HTML/Storage.h>
@@ -585,6 +586,36 @@ Messages::WebContentServer::GetElementTagNameResponse ConnectionFromClient::get_
     return { element->tag_name() };
 }
 
+// https://w3c.github.io/webdriver/#dfn-calculate-the-absolute-position
+static Gfx::IntPoint calculate_absolute_position_of_element(Web::Page const& page, JS::NonnullGCPtr<Web::Geometry::DOMRect> rect)
+{
+    // 1. Let rect be the value returned by calling getBoundingClientRect().
+
+    // 2. Let window be the associated window of current top-level browsing context.
+    auto const* window = page.top_level_browsing_context().active_window();
+
+    // 3. Let x be (scrollX of window + rect’s x coordinate).
+    auto x = (window ? static_cast<int>(window->scroll_x()) : 0) + static_cast<int>(rect->x());
+
+    // 4. Let y be (scrollY of window + rect’s y coordinate).
+    auto y = (window ? static_cast<int>(window->scroll_y()) : 0) + static_cast<int>(rect->y());
+
+    // 5. Return a pair of (x, y).
+    return { x, y };
+}
+
+Messages::WebContentServer::GetElementRectResponse ConnectionFromClient::get_element_rect(i32 element_id)
+{
+    auto element = find_element_by_id(element_id);
+    if (!element.has_value())
+        return { {} };
+
+    auto bounding_rect = element->get_bounding_client_rect();
+    auto coordinates = calculate_absolute_position_of_element(page(), bounding_rect);
+
+    return { { coordinates.x(), coordinates.y(), static_cast<int>(bounding_rect->width()), static_cast<int>(bounding_rect->height()) } };
+}
+
 Messages::WebContentServer::GetSelectedTextResponse ConnectionFromClient::get_selected_text()
 {
     return page().focused_context().selected_text();

Userland/Services/WebContent/ConnectionFromClient.h

@@ -90,6 +90,7 @@ private:
     virtual Messages::WebContentServer::GetComputedValueForElementResponse get_computed_value_for_element(i32 element_id, String const& property_name) override;
     virtual Messages::WebContentServer::GetElementTextResponse get_element_text(i32 element_id) override;
     virtual Messages::WebContentServer::GetElementTagNameResponse get_element_tag_name(i32 element_id) override;
+    virtual Messages::WebContentServer::GetElementRectResponse get_element_rect(i32 element_id) override;
 
     virtual Messages::WebContentServer::GetLocalStorageEntriesResponse get_local_storage_entries() override;
     virtual Messages::WebContentServer::GetSessionStorageEntriesResponse get_session_storage_entries() override;

Userland/Services/WebContent/WebContentServer.ipc

@@ -1,6 +1,7 @@
 #include <AK/URL.h>
 #include <LibIPC/File.h>
 #include <LibCore/AnonymousBuffer.h>
+#include <LibGfx/Rect.h>
 #include <LibGfx/ShareableBitmap.h>
 #include <LibWeb/CSS/PreferredColorScheme.h>
 #include <LibWeb/CSS/Selector.h>
@@ -47,6 +48,7 @@ endpoint WebContentServer
     get_computed_value_for_element(i32 element_id, String property_name) => (String computed_value)
     get_element_text(i32 element_id) => (String text)
     get_element_tag_name(i32 element_id) => (String tag_name)
+    get_element_rect(i32 element_id) => (Gfx::IntRect rect)
 
     webdriver_execute_script(String body, Vector<String> json_arguments, Optional<u64> timeout, bool async) => (Web::WebDriver::ExecuteScriptResultType result_type, String json_result)