Sample Warning in Php8.5

Sample_11_ReadWord2007 reads a file with color=auto, and RTF Writer doesn't handle it properly. Change to treat it as black.

Author: oleibman

src/PhpWord/Writer/RTF/Part/Header.php

@@ -157,7 +157,11 @@ private function writeColorTable()
         $content .= '{';
         $content .= '\colortbl;';
         foreach ($this->colorTable as $color) {
-            [$red, $green, $blue] = Converter::htmlToRgb($color);
+            $temp = Converter::htmlToRgb($color);
+            $red = $green = $blue = 0;
+            if (is_array($temp)) {
+                [$red, $green, $blue] = $temp;
+            }
             $content .= "\\red{$red}\\green{$green}\\blue{$blue};";
         }
         $content .= '}';

tests/PhpWordTests/Writer/RTF/Sample11Test.php

@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * This file is part of PHPWord - A pure PHP library for reading and writing
+ * word processing documents.
+ *
+ * PHPWord is free software distributed under the terms of the GNU Lesser
+ * General Public License version 3 as published by the Free Software Foundation.
+ *
+ * For the full copyright and license information, please read the LICENSE
+ * file that was distributed with this source code. For the full list of
+ * contributors, visit https://github.com/PHPOffice/PHPWord/contributors.
+ *
+ * @see         https://github.com/PHPOffice/PHPWord
+ *
+ * @license     http://www.gnu.org/licenses/lgpl.txt LGPL version 3
+ */
+
+namespace PhpOffice\PhpWordTests\Writer\RTF;
+
+use PhpOffice\PhpWord\IOFactory;
+use PhpOffice\PhpWord\Writer\RTF;
+
+/**
+ * Test class for PhpOffice\PhpWord\Writer\RTF\Style subnamespace.
+ */
+class Sample11Test extends \PHPUnit\Framework\TestCase
+{
+    public function testSample11(): void
+    {
+        $source = 'samples/resources/Sample_11_ReadWord2007.docx';
+        $phpWord = IOFactory::load($source);
+        $writer = new RTF($phpWord);
+        $content = $writer->getContent();
+        $expected = '{\colortbl;\red255\green0\blue0;\red0\green0\blue0;\red0\green0\blue255;}';
+        self::assertStringContainsString($expected, $content);
+    }
+}