Fix #297 (#299)

src/Spout/Writer/XLSX/Helper/StyleHelper.php

@@ -69,23 +69,30 @@ class StyleHelper extends AbstractStyleHelper
         // so $backgroundColor is a scalar value (RGB Color)
         $backgroundColor = $style->getBackgroundColor();
 
+        if ($backgroundColor) {
+            $isBackgroundColorRegistered = isset($this->registeredFills[$backgroundColor]);
+            
             // We need to track the already registered background definitions
-        if (isset($backgroundColor) && !isset($this->registeredFills[$backgroundColor])) {
+            if ($isBackgroundColorRegistered) {
+                $registeredStyleId = $this->registeredFills[$backgroundColor];
+                $registeredFillId = $this->styleIdToFillMappingTable[$registeredStyleId];
+                $this->styleIdToFillMappingTable[$styleId] = $registeredFillId;
+            } else {
                 $this->registeredFills[$backgroundColor] = $styleId;
+                $this->styleIdToFillMappingTable[$styleId] = $this->fillIndex++;
             }
 
-        if (!isset($this->styleIdToFillMappingTable[$styleId])) {
+        } else {
             // The fillId maps a style to a fill declaration
             // When there is no background color definition - we default to 0
-            $fillId = $backgroundColor !== null ? $this->fillIndex++ : 0;
+            $this->styleIdToFillMappingTable[$styleId] = 0;
-            $this->styleIdToFillMappingTable[$styleId] = $fillId;
         }
     }
 
     /**
      * Register a border definition
      *
-     * @param $style
+     * @param \Box\Spout\Writer\Style\Style $style
      */
     protected function registerBorder($style)
     {

tests/Spout/Writer/XLSX/WriterWithStyleTest.php

@@ -261,6 +261,45 @@ class WriterWithStyleTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals(2, (int)$customFillId, 'The custom fill id should have the index 2');
     }
 
+    /**
+     * @return void
+     */
+    public function testReuseBackgroundColorSharedDefinition()
+    {
+        $fileName = 'test_add_background_color_shared_definition.xlsx';
+        $dataRows = [
+            ["row-bold-background-red"],
+            ["row-background-red"],
+        ];
+
+        $styles = [
+            (new StyleBuilder())->setBackgroundColor(Color::RED)->setFontBold()->build(),
+            (new StyleBuilder())->setBackgroundColor(Color::RED)->build()
+        ];
+
+        $this->writeToXLSXFileWithMultipleStyles($dataRows, $fileName, $styles);
+
+        $fillsDomElement = $this->getXmlSectionFromStylesXmlFile($fileName, 'fills');
+        $this->assertEquals(
+            3,
+            $fillsDomElement->getAttribute('count'),
+            'There should be 3 fills, including the 2 default ones'
+        );
+
+        $styleXfsElements = $this->getXmlSectionFromStylesXmlFile($fileName, 'cellXfs');
+        $this->assertEquals(
+            3,
+            $styleXfsElements->getAttribute('count'),
+            '3 cell xfs present - a default one and two custom ones'
+        );
+
+        $firstCustomId = $styleXfsElements->childNodes->item(1)->getAttribute('fillId');
+        $this->assertEquals(2, (int)$firstCustomId, 'The first custom fill id should have the index 2');
+
+        $secondCustomId = $styleXfsElements->childNodes->item(2)->getAttribute('fillId');
+        $this->assertEquals(2, (int)$secondCustomId, 'The second custom fill id should have the index 2');
+    }
+
     /**
      * @return void
      */