[Common] Split RGB into a new Common library

Libraries/Common/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_library(KVGToolsCommon INTERFACE)
+
+target_compile_features(KVGToolsCommon
+    INTERFACE
+    cxx_std_23
+)
+
+target_include_directories(KVGToolsCommon
+    INTERFACE
+    "Include"
+)

Libraries/Common/Include/Common/RGB.hpp

@@ -0,0 +1,111 @@
+#ifndef KVG_TOOLS_COMMON_RGB_HPP
+#define KVG_TOOLS_COMMON_RGB_HPP
+
+#include <cstdint>
+#include <string>
+#include <string_view>
+
+namespace Common
+{
+    namespace Implementation
+    {
+        constexpr std::uint8_t HexToDec(char ch)
+        {
+            if (ch >= '0' && ch <= '9') {
+                return std::uint8_t(ch - '0');
+            }
+
+            if (ch >= 'A' && ch <= 'F') {
+                return std::uint8_t(ch - 'A' + 10);
+            }
+
+            if (ch >= 'a' && ch <= 'f') {
+                return std::uint8_t(ch - 'a' + 10);
+            }
+
+            return 0;
+        }
+
+        constexpr char DecToHex(std::uint8_t val)
+        {
+            if (val < 10) {
+                return char(val + '0');
+            }
+
+            if (val < 16) {
+                return char(val - 10 + 'A');
+            }
+
+            return '0';
+        }
+
+        constexpr std::uint8_t ToDec(char upper, char lower)
+        {
+            return HexToDec(upper) << 4 | HexToDec(lower);
+        }
+
+        constexpr std::uint8_t ToDec(char ch)
+        {
+            return ToDec(ch, ch);
+        }
+
+        constexpr void ChannelToHex(std::uint8_t val, char& ch1, char& ch2)
+        {
+            ch1 = DecToHex(15 & (val >> 4));
+            ch2 = DecToHex(15 & (val));
+        }
+    }
+
+    struct RGB
+    {
+        std::uint8_t Red;
+        std::uint8_t Green;
+        std::uint8_t Blue;
+
+        static constexpr RGB FromHex(std::string_view hex)
+        {
+            if (hex.empty()) {
+                return RGB { .Red = 0, .Green = 0, .Blue = 0 };
+            }
+
+            if (hex[0] == '#') {
+                hex = std::string_view(hex.data() + 1, hex.length() - 1);
+            }
+
+            for (char ch : hex) {
+                if ((ch < '0' || ch > '9') && (ch < 'A' || ch > 'F') && (ch < 'a' && ch > 'f')) {
+                    return RGB { .Red = 0, .Green = 0, .Blue = 0 };
+                }
+            }
+
+            if (hex.length() == 3) {
+                return RGB {
+                    .Red   = Implementation::ToDec(hex[0]),
+                    .Green = Implementation::ToDec(hex[1]),
+                    .Blue  = Implementation::ToDec(hex[2]),
+                };
+            }
+
+            if (hex.length() == 6) {
+                return RGB {
+                    .Red   = Implementation::ToDec(hex[0], hex[1]),
+                    .Green = Implementation::ToDec(hex[2], hex[3]),
+                    .Blue  = Implementation::ToDec(hex[4], hex[5]),
+                };
+            }
+
+            return RGB { .Red = 0, .Green = 0, .Blue = 0 };
+        }
+
+        constexpr std::string ToHex() const
+        {
+            std::string result(7, '#');
+            Implementation::ChannelToHex(Red,   result[1], result[2]);
+            Implementation::ChannelToHex(Green, result[3], result[4]);
+            Implementation::ChannelToHex(Blue,  result[5], result[6]);
+            return result;
+        }
+    };
+}
+
+#endif // KVG_TOOLS_COMMON_RGB_HPP