Re-think about ToString.

ToString for a class should lies in the same namespace of the class.
Argument-dependent name lookup will help make Format work. The problem
is it will hide ToString at parent namespace. But if you call ToString
explicitly, it's you duty to use the ToString in correct namespace.

3 files changed, 17 insertions, 20 deletions

diff --git a/include/cru/platform/Color.h b/include/cru/platform/Color.h
index 0d7bce5b..2b38138a 100644
--- a/include/cru/platform/Color.h
+++ b/include/cru/platform/Color.h
@@ -257,6 +257,11 @@ extern const std::unordered_map<StringView, Color> predefined_name_color_map;
 
 std::optional<Color> GetPredefinedColorByName(StringView name);
 
+inline String ToString(const Color& color) {
+  return cru::Format(u"rgba({}, {}, {}, {})", color.red, color.green,
+                     color.blue, color.alpha);
+}
+
 struct CRU_PLATFORM_API HslColor {
   HslColor() = default;
   HslColor(float h, float s, float l, float a = 1.0f)
@@ -271,10 +276,3 @@ struct CRU_PLATFORM_API HslColor {
   float a;
 };
 }  // namespace cru::platform
-
-namespace cru {
-inline String ToString(const platform::Color& color) {
-  return cru::Format(u"rgba({}, {}, {}, {})", color.red, color.green,
-                     color.blue, color.alpha);
-}
-}  // namespace cru
diff --git a/include/cru/platform/GraphicsBase.h b/include/cru/platform/GraphicsBase.h
index 88dc6ee2..f134e74d 100644
--- a/include/cru/platform/GraphicsBase.h
+++ b/include/cru/platform/GraphicsBase.h
@@ -5,7 +5,11 @@
 #include "cru/common/Range.h"
 #include "cru/common/String.h"
 
+#include <cstdint>
 #include <limits>
+#include <optional>
+#include <string>
+#include <utility>
 
 namespace cru::platform {
 struct Size;
@@ -43,6 +47,10 @@ constexpr bool operator!=(const Point& left, const Point& right) {
   return !(left == right);
 }
 
+inline String ToString(const Point& point) {
+  return Format(u"(x: {}, y: {})", point.x, point.y);
+}
+
 struct CRU_PLATFORM_API Size final {
   static const Size kMax;
   static const Size kZero;
@@ -80,6 +88,10 @@ constexpr bool operator!=(const Size& left, const Size& right) {
   return !(left == right);
 }
 
+inline String ToString(const Size& size) {
+  return Format(u"(width: {}, height: {})", size.width, size.height);
+}
+
 struct Thickness final {
   constexpr Thickness() : Thickness(0) {}
 
@@ -278,14 +290,3 @@ constexpr bool operator!=(const Ellipse& left, const Ellipse& right) {
 
 using TextRange = Range;
 }  // namespace cru::platform
-
-namespace cru {
-
-inline String ToString(const platform::Point& point) {
-  return Format(u"(x: {}, y: {})", point.x, point.y);
-}
-inline String ToString(const platform::Size& size) {
-  return Format(u"(width: {}, height: {})", size.width, size.height);
-}
-
-}  // namespace cru
diff --git a/include/cru/platform/graphics/quartz/Brush.h b/include/cru/platform/graphics/quartz/Brush.h
index f3579771..d5714293 100644
--- a/include/cru/platform/graphics/quartz/Brush.h
+++ b/include/cru/platform/graphics/quartz/Brush.h
@@ -6,8 +6,6 @@
 
 #include <CoreGraphics/CoreGraphics.h>
 
-#include <functional>
-
 namespace cru::platform::graphics::quartz {
 class QuartzBrush : public OsxQuartzResource, public virtual IBrush {
  public: