Add support for reading Worksheet Visibility for Gnumeric

src/PhpSpreadsheet/Reader/Gnumeric.php

@@ -272,6 +272,11 @@ class Gnumeric extends BaseReader
             //        name in line with the formula, not the reverse
             $this->spreadsheet->getActiveSheet()->setTitle($worksheetName, false, false);
 
+            $visibility = $sheetOrNull->attributes()['Visibility'] ?? 'GNM_SHEET_VISIBILITY_VISIBLE';
+            if ((string) $visibility !== 'GNM_SHEET_VISIBILITY_VISIBLE') {
+                $this->spreadsheet->getActiveSheet()->setSheetState(Worksheet::SHEETSTATE_HIDDEN);
+            }
+
             if (!$this->readDataOnly) {
                 (new PageSetup($this->spreadsheet))
                     ->printInformation($sheet)

tests/PhpSpreadsheetTests/Reader/Gnumeric/HiddenWorksheetTest.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Reader\Gnumeric;
+
+use PhpOffice\PhpSpreadsheet\Reader\Gnumeric;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
+use PHPUnit\Framework\TestCase;
+
+class HiddenWorksheetTest extends TestCase
+{
+    /**
+     * @var Spreadsheet
+     */
+    private $spreadsheet;
+
+    protected function setup(): void
+    {
+        $filename = 'tests/data/Reader/Gnumeric/HiddenSheet.gnumeric';
+        $reader = new Gnumeric();
+        $this->spreadsheet = $reader->load($filename);
+    }
+
+    public function testPageSetup(): void
+    {
+        $assertions = $this->worksheetAssertions();
+
+        foreach ($this->spreadsheet->getAllSheets() as $worksheet) {
+            if (!array_key_exists($worksheet->getTitle(), $assertions)) {
+                continue;
+            }
+
+            $sheetAssertions = $assertions[$worksheet->getTitle()];
+            foreach ($sheetAssertions as $test => $expectedResult) {
+                $actualResult = $worksheet->getSheetState();
+                self::assertSame(
+                    $expectedResult,
+                    $actualResult,
+                    "Failed asserting sheet state {$expectedResult} for Worksheet '{$worksheet->getTitle()}' {$test}"
+                );
+            }
+        }
+    }
+
+    private function worksheetAssertions(): array
+    {
+        return [
+            'Sheet1' => [
+                'sheetState' => Worksheet::SHEETSTATE_VISIBLE,
+            ],
+            'Sheet2' => [
+                'sheetState' => Worksheet::SHEETSTATE_HIDDEN,
+            ],
+        ];
+    }
+}