LibWeb: Add helper to convert CSS LengthPercentage to SVGLength

Userland/Libraries/LibWeb/SVG/SVGLength.cpp

@@ -5,17 +5,65 @@
  */
 
 #include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/CSS/PercentageOr.h>
 #include <LibWeb/SVG/SVGLength.h>
 
 namespace Web::SVG {
 
 JS_DEFINE_ALLOCATOR(SVGLength);
 
+// Same as SVGLength.idl
+constexpr unsigned short SVG_LENGTHTYPE_UNKNOWN = 0;
+constexpr unsigned short SVG_LENGTHTYPE_NUMBER = 1;
+constexpr unsigned short SVG_LENGTHTYPE_PERCENTAGE = 2;
+constexpr unsigned short SVG_LENGTHTYPE_EMS = 3;
+constexpr unsigned short SVG_LENGTHTYPE_EXS = 4;
+constexpr unsigned short SVG_LENGTHTYPE_PX = 5;
+constexpr unsigned short SVG_LENGTHTYPE_CM = 6;
+constexpr unsigned short SVG_LENGTHTYPE_MM = 7;
+constexpr unsigned short SVG_LENGTHTYPE_IN = 8;
+constexpr unsigned short SVG_LENGTHTYPE_PT = 9;
+constexpr unsigned short SVG_LENGTHTYPE_PC = 10;
+
 JS::NonnullGCPtr<SVGLength> SVGLength::create(JS::Realm& realm, u8 unit_type, float value)
 {
     return realm.heap().allocate<SVGLength>(realm, realm, unit_type, value);
 }
 
+JS::NonnullGCPtr<SVGLength> SVGLength::from_length_percentage(JS::Realm& realm, CSS::LengthPercentage const& length_percentage)
+{
+    // FIXME: We can't tell if a CSS::LengthPercentage was a unitless length.
+    (void)SVG_LENGTHTYPE_NUMBER;
+    if (length_percentage.is_percentage())
+        return SVGLength::create(realm, SVG_LENGTHTYPE_PERCENTAGE, length_percentage.percentage().value());
+    if (length_percentage.is_length())
+        return SVGLength::create(
+            realm, [&] {
+                switch (length_percentage.length().type()) {
+                case CSS::Length::Type::Em:
+                    return SVG_LENGTHTYPE_EMS;
+                case CSS::Length::Type::Ex:
+                    return SVG_LENGTHTYPE_EXS;
+                case CSS::Length::Type::Px:
+                    return SVG_LENGTHTYPE_PX;
+                case CSS::Length::Type::Cm:
+                    return SVG_LENGTHTYPE_CM;
+                case CSS::Length::Type::Mm:
+                    return SVG_LENGTHTYPE_MM;
+                case CSS::Length::Type::In:
+                    return SVG_LENGTHTYPE_IN;
+                case CSS::Length::Type::Pt:
+                    return SVG_LENGTHTYPE_PT;
+                case CSS::Length::Type::Pc:
+                    return SVG_LENGTHTYPE_PC;
+                default:
+                    return SVG_LENGTHTYPE_UNKNOWN;
+                }
+            }(),
+            length_percentage.length().raw_value());
+    return SVGLength::create(realm, SVG_LENGTHTYPE_UNKNOWN, 0);
+}
+
 SVGLength::SVGLength(JS::Realm& realm, u8 unit_type, float value)
     : PlatformObject(realm)
     , m_unit_type(unit_type)

Userland/Libraries/LibWeb/SVG/SVGLength.h

@@ -25,6 +25,8 @@ public:
     float value() const { return m_value; }
     WebIDL::ExceptionOr<void> set_value(float value);
 
+    [[nodiscard]] static JS::NonnullGCPtr<SVGLength> from_length_percentage(JS::Realm&, CSS::LengthPercentage const&);
+
 private:
     SVGLength(JS::Realm&, u8 unit_type, float value);