3 files changed, 19 insertions, 7 deletions
diff --git a/include/cru/ui/ThemeManager.h b/include/cru/ui/ThemeManager.h
index d4e6a096..f3f01313 100644
--- a/include/cru/ui/ThemeManager.h
+++ b/include/cru/ui/ThemeManager.h
@@ -1,6 +1,7 @@
 #pragma once
 #include "Base.h"
 #include "cru/base/Event.h"
+#include "cru/base/Format.h"
 #include "cru/ui/ThemeResourceDictionary.h"
 
 #include <vector>
diff --git a/include/cru/ui/ThemeResourceDictionary.h b/include/cru/ui/ThemeResourceDictionary.h
index 597fe707..c3fcfde2 100644
--- a/include/cru/ui/ThemeResourceDictionary.h
+++ b/include/cru/ui/ThemeResourceDictionary.h
@@ -2,6 +2,7 @@
 #include "Base.h"
 
 #include "cru/base/Base.h"
+#include "cru/base/Format.h"
 #include "cru/xml/XmlNode.h"
 #include "mapper/MapperRegistry.h"
 #include "style/StyleRuleSet.h"
diff --git a/include/cru/ui/render/MeasureRequirement.h b/include/cru/ui/render/MeasureRequirement.h
index 3f4e0a3d..544e0788 100644
--- a/include/cru/ui/render/MeasureRequirement.h
+++ b/include/cru/ui/render/MeasureRequirement.h
@@ -4,7 +4,9 @@
 #include "cru/base/String.h"
 
 #include <algorithm>
+#include <format>
 #include <limits>
+#include <string>
 
 namespace cru::ui::render {
 constexpr Size Min(const Size& left, const Size& right) {
@@ -111,10 +113,13 @@ class MeasureLength final {
     }
   }
 
-  String ToDebugString() const {
-    return IsSpecified() ? ToString(GetLengthOrUndefined()) : u"UNSPECIFIED";
+  std::string ToDebugStringUtf8() const {
+    return IsSpecified() ? std::to_string(GetLengthOrUndefined())
+                         : "UNSPECIFIED";
   }
 
+  String ToDebugString() const { return String::FromUtf8(ToDebugStringUtf8()); }
+
  private:
   // -1 for not specify
   float length_;
@@ -163,10 +168,13 @@ struct MeasureSize {
     };
   }
 
-  String ToDebugString() const {
-    return Format(u"({}, {})", width.ToDebugString(), height.ToDebugString());
+  std::string ToDebugStringUtf8() const {
+    return std::format("({}, {})", width.ToDebugStringUtf8(),
+                       height.ToDebugStringUtf8());
   }
 
+  String ToDebugString() const { return String::FromUtf8(ToDebugStringUtf8()); }
+
   constexpr static MeasureSize NotSpecified() {
     return MeasureSize{MeasureLength::NotSpecified(),
                        MeasureLength::NotSpecified()};
@@ -233,11 +241,13 @@ struct MeasureRequirement {
     return result;
   }
 
-  String ToDebugString() const {
-    return Format(u"{{min: {}, max: {}}}", min.ToDebugString(),
-                  max.ToDebugString());
+  std::string ToDebugStringUtf8() const {
+    return std::format("{{min: {}, max: {}}}", min.ToDebugStringUtf8(),
+                       max.ToDebugStringUtf8());
   }
 
+  String ToDebugString() const { return String::FromUtf8(ToDebugStringUtf8()); }
+
   constexpr static MeasureRequirement Merge(const MeasureRequirement& left,
                                             const MeasureRequirement& right) {
     return MeasureRequirement{MeasureSize::Min(left.max, right.max),