LibPDF: Allow the page rotation to be inherited

Userland/Libraries/LibPDF/Document.cpp

@@ -158,8 +158,9 @@ PDFErrorOr<Page> Document::get_page(u32 index)
         user_unit = raw_page_object->get_value(CommonNames::UserUnit).to_float();
 
     int rotate = 0;
-    if (raw_page_object->contains(CommonNames::Rotate)) {
-        rotate = raw_page_object->get_value(CommonNames::Rotate).get<int>();
+    auto maybe_rotate = TRY(get_inheritable_value(CommonNames::Rotate, raw_page_object));
+    if (maybe_rotate.has_value()) {
+        rotate = maybe_rotate.value().to_int();
         VERIFY(rotate % 90 == 0);
     }
 
@@ -339,6 +340,17 @@ PDFErrorOr<Optional<NonnullRefPtr<Object>>> Document::get_inheritable_object(Dep
     return TRY(object->get_object(this, name));
 }
 
+PDFErrorOr<Optional<Value>> Document::get_inheritable_value(DeprecatedFlyString const& name, NonnullRefPtr<DictObject> object)
+{
+    if (!object->contains(name)) {
+        if (!object->contains(CommonNames::Parent))
+            return { OptionalNone() };
+        auto parent = TRY(object->get_dict(this, CommonNames::Parent));
+        return get_inheritable_value(name, parent);
+    }
+    return object->get(name);
+}
+
 PDFErrorOr<Destination> Document::create_destination_from_dictionary_entry(NonnullRefPtr<Object> const& entry, HashMap<u32, u32> const& page_number_by_index_ref)
 {
     if (entry->is<ArrayObject>()) {

Userland/Libraries/LibPDF/Document.h

@@ -144,6 +144,7 @@ private:
     PDFErrorOr<Destination> create_destination_from_dictionary_entry(NonnullRefPtr<Object> const& entry, HashMap<u32, u32> const& page_number_by_index_ref);
 
     PDFErrorOr<Optional<NonnullRefPtr<Object>>> get_inheritable_object(DeprecatedFlyString const& name, NonnullRefPtr<DictObject>);
+    PDFErrorOr<Optional<Value>> get_inheritable_value(DeprecatedFlyString const& name, NonnullRefPtr<DictObject>);
 
     PDFErrorOr<NonnullRefPtr<Object>> find_in_name_tree(NonnullRefPtr<DictObject> root, DeprecatedFlyString name);
     PDFErrorOr<NonnullRefPtr<Object>> find_in_name_tree_nodes(NonnullRefPtr<ArrayObject> siblings, DeprecatedFlyString name);