Add alternative width calculation option with empty space

src/Spout/Writer/Common/Entity/Worksheet.php

@@ -34,6 +34,7 @@ class Worksheet
 
     public const W_FULL = 1;
     public const W_FIXED = 2;
+    public const W_FULL_ALT = 3;
     public const W_NONE = 0;
     public const DEFAULT_COL_WIDTH = 30;
     public const DEFAULT_FIXED_WIDTH = 320;

src/Spout/Writer/Common/Helper/AppendHelper.php

@@ -28,4 +28,21 @@ class AppendHelper {
         fwrite($fp, $trailer);
         return $fp;
     }
+
+    /**
+     * This function overwrite data in pointer from specified position
+     *  
+     * @param $fp Pointer to file only
+     * @param $pos Position to insert
+     * @param $content Content to insert
+     */
+    public static function overwriteToFile($fp, $pos, $content)
+    {
+        $cur = ftell($fp);
+        fseek($fp, $pos);
+        fwrite($fp, $content);
+        fseek($fp, $cur);
+        return $fp;
+    }
+
 }

src/Spout/Writer/XLSX/Manager/WorksheetManager.php

@@ -125,6 +125,15 @@ EOD;
         if ($worksheet->getWidthCalculation() != Worksheet::W_NONE) {
             $this->headWritePosition = ftell($sheetFilePointer);
         }
+        //width calculation style 3 with empty spaces.. not suitable if column sizes more than 40
+        if ($worksheet->getWidthCalculation() == Worksheet::W_FULL_ALT) {
+            //insert dummy nodes for up to 40 columns
+            for ($i = 0; $i < 40; $i++) {
+                $dummy = "                                                                             ";
+                \fwrite($sheetFilePointer, $dummy);
+            }
+        }
+
         \fwrite($sheetFilePointer, '<sheetData>');
     }
 
@@ -330,7 +339,11 @@ EOD;
                 $colNode .= '<col hidden="false" collapsed="false" min="'.$colAffect.'" max="'.$colAffect.'" width="'.$width.'" customWidth="true"/>';
             }
             $colNode .= '</cols>';
-            $worksheetFilePointer = AppendHelper::insertToFile($worksheetFilePointer, $this->headWritePosition, $colNode);
+            if ($worksheet->getWidthCalculation() == Worksheet::W_FULL_ALT) {
+                $worksheetFilePointer = AppendHelper::overwriteToFile($worksheetFilePointer, $this->headWritePosition, $colNode);
+            } else {
+                $worksheetFilePointer = AppendHelper::insertToFile($worksheetFilePointer, $this->headWritePosition, $colNode);
+            }
         }
 
         \fwrite($worksheetFilePointer, '</worksheet>');