LibWeb: Implement HTMLMarqueeElement.scrollAmount

Userland/Libraries/LibWeb/HTML/AttributeNames.h

@@ -224,6 +224,7 @@ namespace AttributeNames {
     __ENUMERATE_HTML_ATTRIBUTE(rowspan)                    \
     __ENUMERATE_HTML_ATTRIBUTE(rules)                      \
     __ENUMERATE_HTML_ATTRIBUTE(scheme)                     \
+    __ENUMERATE_HTML_ATTRIBUTE(scrollamount)               \
     __ENUMERATE_HTML_ATTRIBUTE(scrolling)                  \
     __ENUMERATE_HTML_ATTRIBUTE(selected)                   \
     __ENUMERATE_HTML_ATTRIBUTE(shadowrootclonable)         \

Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2020, the SerenityOS developers.
+ * Copyright (c) 2024, Jamie Mansfield <jmansfield@cadixdev.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -9,6 +10,7 @@
 #include <LibWeb/CSS/StyleProperties.h>
 #include <LibWeb/CSS/StyleValues/ColorStyleValue.h>
 #include <LibWeb/HTML/HTMLMarqueeElement.h>
+#include <LibWeb/HTML/Numbers.h>
 #include <LibWeb/HTML/Parser/HTMLParser.h>
 
 namespace Web::HTML {
@@ -41,4 +43,21 @@ void HTMLMarqueeElement::apply_presentational_hints(CSS::StyleProperties& style)
     });
 }
 
+// https://html.spec.whatwg.org/multipage/obsolete.html#dom-marquee-scrollamount
+WebIDL::UnsignedLong HTMLMarqueeElement::scroll_amount()
+{
+    // The scrollAmount IDL attribute must reflect the scrollamount content attribute. The default value is 6.
+    if (auto scroll_amount_string = get_attribute(HTML::AttributeNames::scrollamount); scroll_amount_string.has_value()) {
+        if (auto scroll_amount = parse_non_negative_integer(*scroll_amount_string); scroll_amount.has_value())
+            return *scroll_amount;
+    }
+    return 6;
+}
+
+// https://html.spec.whatwg.org/multipage/obsolete.html#dom-marquee-scrollamount
+WebIDL::ExceptionOr<void> HTMLMarqueeElement::set_scroll_amount(WebIDL::UnsignedLong value)
+{
+    return set_attribute(HTML::AttributeNames::scrollamount, MUST(String::number(value)));
+}
+
 }

Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2020, the SerenityOS developers.
+ * Copyright (c) 2024, Jamie Mansfield <jmansfield@cadixdev.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -7,6 +8,7 @@
 #pragma once
 
 #include <LibWeb/HTML/HTMLElement.h>
+#include <LibWeb/WebIDL/Types.h>
 
 namespace Web::HTML {
 
@@ -18,6 +20,9 @@ class HTMLMarqueeElement final : public HTMLElement {
 public:
     virtual ~HTMLMarqueeElement() override;
 
+    WebIDL::UnsignedLong scroll_amount();
+    WebIDL::ExceptionOr<void> set_scroll_amount(WebIDL::UnsignedLong);
+
 private:
     HTMLMarqueeElement(DOM::Document&, DOM::QualifiedName);
 

Userland/Libraries/LibWeb/HTML/HTMLMarqueeElement.idl

@@ -12,7 +12,7 @@ interface HTMLMarqueeElement : HTMLElement {
     [CEReactions, Reflect] attribute DOMString height;
     [CEReactions, Reflect] attribute unsigned long hspace;
     [FIXME, CEReactions] attribute long loop;
-    [FIXME, CEReactions] attribute unsigned long scrollAmount;
+    [CEReactions] attribute unsigned long scrollAmount;
     [FIXME, CEReactions] attribute unsigned long scrollDelay;
     [FIXME, CEReactions] attribute boolean trueSpeed;
     [CEReactions, Reflect] attribute unsigned long vspace;