nsPrintfCString hex(8, "%02x%02x%02x", uint8_t(r*255.0), uint8_t(g*255.0), uint8_t(b*255.0));
nsPrintfCString hex(8, "%02x%02x%02x", PRUint8(r*255.0), PRUint8(g*255.0), PRUint8(b*255.0));
    void Hex(nsACString& result) const {        nsPrintfCString hex(8, "%02x%02x%02x", uint8_t(r*255.0), uint8_t(g*255.0), uint8_t(b*255.0));        result.Assign(hex);    }