Merge pull request #26 from crupest/3-scrollview

Develop scrollview.

1 files changed, 69 insertions, 0 deletions

diff --git a/src/math_util.hpp b/src/math_util.hpp
new file mode 100644
index 00000000..b9830d6b
--- /dev/null
+++ b/src/math_util.hpp
@@ -0,0 +1,69 @@
+#pragma once
+
+// ReSharper disable once CppUnusedIncludeDirective
+#include "pre.hpp"
+
+// ReSharper disable once CppUnusedIncludeDirective
+#include <type_traits>
+#include <optional>
+
+namespace cru
+{
+        template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T>>>
+    float Coerce(const T n, const std::optional<T> min, const std::optional<T> max)
+    {
+        if (min.has_value() && n < min.value())
+            return min.value();
+        if (max.has_value() && n > max.value())
+            return max.value();
+        return n;
+    }
+    
+    template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T>>>
+    float Coerce(const T n, const T min, const T max)
+    {
+        if (n < min)
+            return min;
+        if (n > max)
+            return max;
+        return n;
+    }
+
+    template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T>>>
+    float Coerce(const T n, const std::nullopt_t, const std::optional<T> max)
+    {
+        if (max.has_value() && n > max.value())
+            return max.value();
+        return n;
+    }
+
+    template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T>>>
+    float Coerce(const T n, const std::optional<T> min, const std::nullopt_t)
+    {
+        if (min.has_value() && n < min.value())
+            return min.value();
+        return n;
+    }
+    
+    template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T>>>
+    float Coerce(const T n, const std::nullopt_t, const T max)
+    {
+        if (n > max)
+            return max;
+        return n;
+    }
+
+    template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T>>>
+    float Coerce(const T n, const T min, const std::nullopt_t)
+    {
+        if (n < min)
+            return min;
+        return n;
+    }
+
+    template <typename T, typename = std::enable_if_t<std::is_arithmetic_v<T>>>
+    T AtLeast0(const T value)
+    {
+        return value < static_cast<T>(0) ? static_cast<T>(0) : value;
+    }
+}