v1.1.0 (#3)

* Swapped regex pattern for more widely supported version

* Added blank space handling

Author: TomWilford

src/CharacterConverter.php

@@ -30,11 +30,11 @@ public function findAndReplace(string $string): string
 
     public function locateCharactersInString(string $string): array
     {
-        preg_match_all("/[^\x00-\x7F]/u", $string, $matches);
+        preg_match_all("/[^ -~]/u", $string, $matches);
 
         $characters = [];
         foreach ($matches[0] as $match) {
-            if (!in_array($match, $characters)) {
+            if (trim($match) && !in_array($match, $characters)) {
                 $characters[] = $match;
             }
         }
@@ -46,7 +46,7 @@ public function convertArrayToRtf(array $strings): array
     {
         $convertedStrings = [];
         foreach ($strings as $string) {
-            if (!array_key_exists($string, $convertedStrings)) {
+            if (trim($string) && !array_key_exists($string, $convertedStrings)) {
                 $convertedStrings[$string] = $this->convertStringToRtf($string);
             }
         }