Added color_utils

src/color_utils.cpp

@@ -0,0 +1,30 @@
+#include "color_utils.h"
+
+// 3rdparty lib includes
+#include <fmt/core.h>
+
+namespace cpputils {
+std::string toString(ColorHelper color)
+{
+    return fmt::format("#{:02X}{:02X}{:02X}", color.r, color.g, color.b);
+}
+
+tl::expected<ColorHelper, std::string> parseColor(std::string_view str)
+{
+    // input may be "#FFF" or "#FFFFFF" or "#FFFFFFFF"
+
+    if (ColorHelper helper; std::sscanf(str.data(), "#%2hhx%2hhx%2hhx", &helper.r, &helper.g, &helper.b) == 3)
+        return helper;
+
+    if (ColorHelper helper; std::sscanf(str.data(), "#%1hhx%1hhx%1hhx", &helper.r, &helper.g, &helper.b) == 3)
+    {
+        helper.r <<= 4;
+        helper.g <<= 4;
+        helper.b <<= 4;
+        return helper;
+    }
+
+    return tl::make_unexpected(fmt::format("invalid color {}", str));
+}
+
+} // namespace cpputils