From 8d7602059006677a739c67902a434b70aa7b234c Mon Sep 17 00:00:00 2001
From: Adrien Crivelli <adrien.crivelli@gmail.com>
Date: Sat, 25 Nov 2017 19:26:41 +0900
Subject: [PATCH] Consistent `stringFromColumnIndex()` and
 `columnIndexFromString()`

Column indexes are always based on 1 everywhere in PhpSpreadsheet.
This is consistent with rows starting at 1, as well as Excel
function `COLUMN()`. It should also make it easier to reason about
columns and rows and remove any doubts whether a specific method is
expecting 0 based or 1 based indexes.

Fixes #273
Fixes https://github.com/PHPOffice/PHPExcel/issues/307
Fixes https://github.com/PHPOffice/PHPExcel/issues/476
---
 CHANGELOG.md                                  |   2 +
 docs/topics/accessing-cells.md                |  22 +-
 docs/topics/migration-from-PHPExcel.md        |  63 ++++++
 samples/Basic/40_Duplicate_style.php          |   2 +-
 .../Calculation/Calculation.php               |   4 +-
 src/PhpSpreadsheet/Calculation/LookupRef.php  |   6 +-
 src/PhpSpreadsheet/Cell/Coordinate.php        |  14 +-
 src/PhpSpreadsheet/Collection/Cells.php       |   2 +-
 src/PhpSpreadsheet/Reader/Csv.php             |   2 +-
 src/PhpSpreadsheet/Reader/Gnumeric.php        |  16 +-
 src/PhpSpreadsheet/Reader/Ods.php             |   4 +-
 src/PhpSpreadsheet/Reader/Slk.php             |  16 +-
 src/PhpSpreadsheet/Reader/Xls.php             |  62 +++---
 src/PhpSpreadsheet/Reader/Xls/Escher.php      |   4 +-
 src/PhpSpreadsheet/Reader/Xlsx.php            |  20 +-
 src/PhpSpreadsheet/Reader/Xml.php             |  10 +-
 src/PhpSpreadsheet/ReferenceHelper.php        |  33 ++-
 src/PhpSpreadsheet/Shared/Xls.php             |   6 +-
 src/PhpSpreadsheet/Style/Style.php            |   4 +-
 src/PhpSpreadsheet/Worksheet/AutoFilter.php   |   2 +-
 src/PhpSpreadsheet/Worksheet/CellIterator.php |  11 +-
 .../Worksheet/ColumnCellIterator.php          |  51 +++--
 .../Worksheet/ColumnIterator.php              |  58 ++---
 src/PhpSpreadsheet/Worksheet/PageSetup.php    |   2 +-
 .../Worksheet/RowCellIterator.php             |  74 ++++---
 src/PhpSpreadsheet/Worksheet/Worksheet.php    | 208 +++++++++---------
 src/PhpSpreadsheet/Writer/Html.php            |  13 +-
 src/PhpSpreadsheet/Writer/Xls.php             |   4 +-
 src/PhpSpreadsheet/Writer/Xls/Worksheet.php   |  16 +-
 .../Cell/CoordinateTest.php                   |  20 +-
 .../PhpSpreadsheetTests/Helper/SampleTest.php |   2 +-
 tests/data/ColumnIndex.php                    |  36 +--
 32 files changed, 431 insertions(+), 358 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 04bce8e5..a22b9f34 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -29,6 +29,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### BREAKING CHANGE
 
+- Extracted coordinate method to dedicate class [migration guide](./docs/topics/migration-from-PHPExcel.md).
+- Column indexes are based on 1, see the [migration guide](./docs/topics/migration-from-PHPExcel.md).
 - Standardization of array keys used for style, see the [migration guide](./docs/topics/migration-from-PHPExcel.md).
 - Easier usage of PDF writers, and other custom readers and writers, see the [migration guide](./docs/topics/migration-from-PHPExcel.md).
 - Easier usage of chart renderers, see the [migration guide](./docs/topics/migration-from-PHPExcel.md).
diff --git a/docs/topics/accessing-cells.md b/docs/topics/accessing-cells.md
index 7cc7ed73..241690d5 100644
--- a/docs/topics/accessing-cells.md
+++ b/docs/topics/accessing-cells.md
@@ -261,8 +261,7 @@ the cell's `getFormattedValue()` method.
 
 ``` php
 // Get the value fom cell A6
-$cellValue = $spreadsheet->getActiveSheet()->getCell('A6')
-    ->getFormattedValue();
+$cellValue = $spreadsheet->getActiveSheet()->getCell('A6')->getFormattedValue();
 ```
 
 ## Setting a cell value by column and row
@@ -281,13 +280,12 @@ than from `1`.
 ## Retrieving a cell value by column and row
 
 To retrieve the value of a cell, the cell should first be retrieved from
-the worksheet using the getCellByColumnAndRow method. A cell’s value can
+the worksheet using the `getCellByColumnAndRow()` method. A cell’s value can
 be read again using the following line of code:
 
 ``` php
 // Get the value fom cell B5
-$cellValue = $spreadsheet->getActiveSheet()->getCellByColumnAndRow(1, 5)
-    ->getValue();
+$cellValue = $spreadsheet->getActiveSheet()->getCellByColumnAndRow(2, 5)->getValue();
 ```
 
 If you need the calculated value of a cell, use the following code. This
@@ -295,8 +293,7 @@ is further explained in .
 
 ``` php
 // Get the value fom cell A4
-$cellValue = $spreadsheet->getActiveSheet()->getCellByColumnAndRow(0, 4)
-    ->getCalculatedValue();
+$cellValue = $spreadsheet->getActiveSheet()->getCellByColumnAndRow(1, 4)->getCalculatedValue();
 ```
 
 ## Retrieving a range of cell values to an array
@@ -374,8 +371,7 @@ One can use the possibility to access cell values by column and row
 index like (0,1) instead of 'A1' for reading and writing cell values in
 loops.
 
-Note: In PhpSpreadsheet column index is 0-based while row index is
-1-based. That means 'A1' \~ (0,1)
+Note: In PhpSpreadsheet column index and row index are 1-based. That means `'A1'` ~ `[1, 1]`
 
 Below is an example where we read all the values in a worksheet and
 display them in a table.
@@ -394,11 +390,9 @@ $highestColumnIndex = \PhpOffice\PhpSpreadsheet\Cell\Cell::columnIndexFromString
 echo '<table>' . "\n";
 for ($row = 1; $row <= $highestRow; ++$row) {
     echo '<tr>' . PHP_EOL;
-    for ($col = 0; $col <= $highestColumnIndex; ++$col) {
-        echo '<td>' .
-             $worksheet->getCellByColumnAndRow($col, $row)
-                 ->getValue() .
-             '</td>' . PHP_EOL;
+    for ($col = 1; $col <= $highestColumnIndex; ++$col) {
+        $value = $worksheet->getCellByColumnAndRow($col, $row)->getValue();
+        echo '<td>' . $value . '</td>' . PHP_EOL;
     }
     echo '</tr>' . PHP_EOL;
 }
diff --git a/docs/topics/migration-from-PHPExcel.md b/docs/topics/migration-from-PHPExcel.md
index 5d6b5f6e..cb0025d6 100644
--- a/docs/topics/migration-from-PHPExcel.md
+++ b/docs/topics/migration-from-PHPExcel.md
@@ -363,3 +363,66 @@ $style = [
     ],
 ];
 ```
+
+### Dedicated class to manipulate coordinates
+
+Methods to manipulate coordinates that used to exists in `PHPExcel_Cell` were extracted
+to a dedicated new class `\PhpOffice\PhpSpreadsheet\Cell\Coordinate`. The methods are:
+
+- `absoluteCoordinate()`
+- `absoluteReference()`
+- `buildRange()`
+- `columnIndexFromString()`
+- `coordinateFromString()`
+- `extractAllCellReferencesInRange()`
+- `getRangeBoundaries()`
+- `mergeRangesInCollection()`
+- `rangeBoundaries()`
+- `rangeDimension()`
+- `splitRange()`
+- `stringFromColumnIndex()`
+
+### Column index based on 1
+
+Column indexes are now based on 1. So column `A` is the index `1`. This is consistent
+with rows starting at 1 and Excel function `COLUMN()` that returns `1` for column `A`.
+So the code must be adapted with something like:
+
+```php
+// Before
+$cell = $worksheet->getCellByColumnAndRow($column, $row);
+
+for ($column = 0; $column < $max; $column++) {
+    $worksheet->setCellValueByColumnAndRow($column, $row, 'value ' . $column);
+}
+
+// After
+$cell = $worksheet->getCellByColumnAndRow($column + 1, $row);
+
+for ($column = 1; $column <= $max; $column++) {
+    $worksheet->setCellValueByColumnAndRow($column, $row, 'value ' . $column);
+}
+```
+
+All the following methods are affected:
+
+- `PHPExcel_Worksheet::cellExistsByColumnAndRow()`
+- `PHPExcel_Worksheet::freezePaneByColumnAndRow()`
+- `PHPExcel_Worksheet::getCellByColumnAndRow()`
+- `PHPExcel_Worksheet::getColumnDimensionByColumn()`
+- `PHPExcel_Worksheet::getCommentByColumnAndRow()`
+- `PHPExcel_Worksheet::getStyleByColumnAndRow()`
+- `PHPExcel_Worksheet::insertNewColumnBeforeByIndex()`
+- `PHPExcel_Worksheet::mergeCellsByColumnAndRow()`
+- `PHPExcel_Worksheet::protectCellsByColumnAndRow()`
+- `PHPExcel_Worksheet::removeColumnByIndex()`
+- `PHPExcel_Worksheet::setAutoFilterByColumnAndRow()`
+- `PHPExcel_Worksheet::setBreakByColumnAndRow()`
+- `PHPExcel_Worksheet::setCellValueByColumnAndRow()`
+- `PHPExcel_Worksheet::setCellValueExplicitByColumnAndRow()`
+- `PHPExcel_Worksheet::setSelectedCellByColumnAndRow()`
+- `PHPExcel_Worksheet::stringFromColumnIndex()`
+- `PHPExcel_Worksheet::unmergeCellsByColumnAndRow()`
+- `PHPExcel_Worksheet::unprotectCellsByColumnAndRow()`
+- `PHPExcel_Worksheet_PageSetup::addPrintAreaByColumnAndRow()`
+- `PHPExcel_Worksheet_PageSetup::setPrintAreaByColumnAndRow()`
diff --git a/samples/Basic/40_Duplicate_style.php b/samples/Basic/40_Duplicate_style.php
index 2bddbdaf..a2dc5f5f 100644
--- a/samples/Basic/40_Duplicate_style.php
+++ b/samples/Basic/40_Duplicate_style.php
@@ -20,7 +20,7 @@ for ($i = 0; $i < 10; ++$i) {
 
 $helper->log('Add data (begin)');
 $t = microtime(true);
-for ($col = 0; $col < 50; ++$col) {
+for ($col = 1; $col <= 50; ++$col) {
     for ($row = 0; $row < 100; ++$row) {
         $str = ($row + $col);
         $style = $styles[$row % 10];
diff --git a/src/PhpSpreadsheet/Calculation/Calculation.php b/src/PhpSpreadsheet/Calculation/Calculation.php
index 1d387301..b3665abd 100644
--- a/src/PhpSpreadsheet/Calculation/Calculation.php
+++ b/src/PhpSpreadsheet/Calculation/Calculation.php
@@ -3496,7 +3496,7 @@ class Calculation
                                 $oCol[] = Coordinate::columnIndexFromString($oCR[0]) - 1;
                                 $oRow[] = $oCR[1];
                             }
-                            $cellRef = Coordinate::stringFromColumnIndex(min($oCol)) . min($oRow) . ':' . Coordinate::stringFromColumnIndex(max($oCol)) . max($oRow);
+                            $cellRef = Coordinate::stringFromColumnIndex(min($oCol) + 1) . min($oRow) . ':' . Coordinate::stringFromColumnIndex(max($oCol) + 1) . max($oRow);
                             if ($pCellParent !== null) {
                                 $cellValue = $this->extractCellRange($cellRef, $this->spreadsheet->getSheetByName($sheet1), false);
                             } else {
@@ -3569,7 +3569,7 @@ class Calculation
                                 $cellIntersect[$row] = array_intersect_key($operand1[$row], $operand2[$row]);
                             }
                         }
-                        $cellRef = Coordinate::stringFromColumnIndex(min($oCol)) . min($oRow) . ':' . Coordinate::stringFromColumnIndex(max($oCol)) . max($oRow);
+                        $cellRef = Coordinate::stringFromColumnIndex(min($oCol) + 1) . min($oRow) . ':' . Coordinate::stringFromColumnIndex(max($oCol) + 1) . max($oRow);
                         $this->debugLog->writeDebugLog('Evaluation Result is ', $this->showTypeDetails($cellIntersect));
                         $stack->push('Value', $cellIntersect, $cellRef);
 
diff --git a/src/PhpSpreadsheet/Calculation/LookupRef.php b/src/PhpSpreadsheet/Calculation/LookupRef.php
index e8de720c..bd199663 100644
--- a/src/PhpSpreadsheet/Calculation/LookupRef.php
+++ b/src/PhpSpreadsheet/Calculation/LookupRef.php
@@ -53,7 +53,7 @@ class LookupRef
         }
         if ((!is_bool($referenceStyle)) || $referenceStyle) {
             $rowRelative = $columnRelative = '$';
-            $column = Coordinate::stringFromColumnIndex($column - 1);
+            $column = Coordinate::stringFromColumnIndex($column);
             if (($relativity == 2) || ($relativity == 4)) {
                 $columnRelative = '';
             }
@@ -399,7 +399,7 @@ class LookupRef
         } else {
             $endCellColumn += $columns;
         }
-        $startCellColumn = Coordinate::stringFromColumnIndex($startCellColumn);
+        $startCellColumn = Coordinate::stringFromColumnIndex($startCellColumn + 1);
 
         if (($height != null) && (!is_object($height))) {
             $endCellRow = $startCellRow + $height - 1;
@@ -410,7 +410,7 @@ class LookupRef
         if (($endCellRow <= 0) || ($endCellColumn < 0)) {
             return Functions::REF();
         }
-        $endCellColumn = Coordinate::stringFromColumnIndex($endCellColumn);
+        $endCellColumn = Coordinate::stringFromColumnIndex($endCellColumn + 1);
 
         $cellAddress = $startCellColumn . $startCellRow;
         if (($startCellColumn != $endCellColumn) || ($startCellRow != $endCellRow)) {
diff --git a/src/PhpSpreadsheet/Cell/Coordinate.php b/src/PhpSpreadsheet/Cell/Coordinate.php
index 96ff39a8..82ba5a98 100644
--- a/src/PhpSpreadsheet/Cell/Coordinate.php
+++ b/src/PhpSpreadsheet/Cell/Coordinate.php
@@ -4,6 +4,12 @@ namespace PhpOffice\PhpSpreadsheet\Cell;
 
 use PhpOffice\PhpSpreadsheet\Exception;
 
+/**
+ * Helper class to manipulate cell coordinates.
+ *
+ * Columns indexes and rows are always based on 1, **not** on 0. This match the behavior
+ * that Excel users are used to, and also match the Excel functions `COLUMN()` and `ROW()`.
+ */
 abstract class Coordinate
 {
     /**
@@ -240,7 +246,7 @@ abstract class Coordinate
      *
      * @param string $pString eg 'A'
      *
-     * @return int Column index (base 1 !!!)
+     * @return int Column index (A = 1)
      */
     public static function columnIndexFromString($pString)
     {
@@ -284,9 +290,9 @@ abstract class Coordinate
     }
 
     /**
-     * String from columnindex.
+     * String from column index.
      *
-     * @param int $columnIndex Column index (A = 0)
+     * @param int $columnIndex Column index (A = 1)
      *
      * @return string
      */
@@ -295,7 +301,7 @@ abstract class Coordinate
         static $indexCache = [];
 
         if (!isset($indexCache[$columnIndex])) {
-            $indexValue = $columnIndex + 1;
+            $indexValue = $columnIndex;
             $base26 = null;
             do {
                 $characterValue = ($indexValue % 26) ?: 26;
diff --git a/src/PhpSpreadsheet/Collection/Cells.php b/src/PhpSpreadsheet/Collection/Cells.php
index 8e6fb917..fc81a976 100644
--- a/src/PhpSpreadsheet/Collection/Cells.php
+++ b/src/PhpSpreadsheet/Collection/Cells.php
@@ -248,7 +248,7 @@ class Cells
             $columnList[] = Coordinate::columnIndexFromString($c);
         }
 
-        return Coordinate::stringFromColumnIndex(max($columnList) - 1);
+        return Coordinate::stringFromColumnIndex(max($columnList) + 1);
     }
 
     /**
diff --git a/src/PhpSpreadsheet/Reader/Csv.php b/src/PhpSpreadsheet/Reader/Csv.php
index 388345c1..954b9e8d 100644
--- a/src/PhpSpreadsheet/Reader/Csv.php
+++ b/src/PhpSpreadsheet/Reader/Csv.php
@@ -251,7 +251,7 @@ class Csv extends BaseReader
             $worksheetInfo[0]['lastColumnIndex'] = max($worksheetInfo[0]['lastColumnIndex'], count($rowData) - 1);
         }
 
-        $worksheetInfo[0]['lastColumnLetter'] = Coordinate::stringFromColumnIndex($worksheetInfo[0]['lastColumnIndex']);
+        $worksheetInfo[0]['lastColumnLetter'] = Coordinate::stringFromColumnIndex($worksheetInfo[0]['lastColumnIndex'] + 1);
         $worksheetInfo[0]['totalColumns'] = $worksheetInfo[0]['lastColumnIndex'] + 1;
 
         // Close file
diff --git a/src/PhpSpreadsheet/Reader/Gnumeric.php b/src/PhpSpreadsheet/Reader/Gnumeric.php
index 513246ce..617e23ef 100644
--- a/src/PhpSpreadsheet/Reader/Gnumeric.php
+++ b/src/PhpSpreadsheet/Reader/Gnumeric.php
@@ -138,7 +138,7 @@ class Gnumeric extends BaseReader
                         break;
                     }
                 }
-                $tmpInfo['lastColumnLetter'] = Coordinate::stringFromColumnIndex($tmpInfo['lastColumnIndex']);
+                $tmpInfo['lastColumnLetter'] = Coordinate::stringFromColumnIndex($tmpInfo['lastColumnIndex'] + 1);
                 $worksheetInfo[] = $tmpInfo;
             }
         }
@@ -394,7 +394,7 @@ class Gnumeric extends BaseReader
                     $maxCol = $column;
                 }
 
-                $column = Coordinate::stringFromColumnIndex($column);
+                $column = Coordinate::stringFromColumnIndex($column + 1);
 
                 // Read cell?
                 if ($this->getReadFilter() !== null) {
@@ -472,11 +472,11 @@ class Gnumeric extends BaseReader
                 $styleAttributes = $styleRegion->attributes();
                 if (($styleAttributes['startRow'] <= $maxRow) &&
                     ($styleAttributes['startCol'] <= $maxCol)) {
-                    $startColumn = Coordinate::stringFromColumnIndex((int) $styleAttributes['startCol']);
+                    $startColumn = Coordinate::stringFromColumnIndex((int) $styleAttributes['startCol'] + 1);
                     $startRow = $styleAttributes['startRow'] + 1;
 
                     $endColumn = ($styleAttributes['endCol'] > $maxCol) ? $maxCol : (int) $styleAttributes['endCol'];
-                    $endColumn = Coordinate::stringFromColumnIndex($endColumn);
+                    $endColumn = Coordinate::stringFromColumnIndex($endColumn + 1);
                     $endRow = ($styleAttributes['endRow'] > $maxRow) ? $maxRow : $styleAttributes['endRow'];
                     $endRow += 1;
                     $cellRange = $startColumn . $startRow . ':' . $endColumn . $endRow;
@@ -718,19 +718,19 @@ class Gnumeric extends BaseReader
                     $hidden = ((isset($columnAttributes['Hidden'])) && ($columnAttributes['Hidden'] == '1')) ? true : false;
                     $columnCount = (isset($columnAttributes['Count'])) ? $columnAttributes['Count'] : 1;
                     while ($c < $column) {
-                        $spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c))->setWidth($defaultWidth);
+                        $spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c + 1))->setWidth($defaultWidth);
                         ++$c;
                     }
                     while (($c < ($column + $columnCount)) && ($c <= $maxCol)) {
-                        $spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c))->setWidth($columnWidth);
+                        $spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c + 1))->setWidth($columnWidth);
                         if ($hidden) {
-                            $spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c))->setVisible(false);
+                            $spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c + 1))->setVisible(false);
                         }
                         ++$c;
                     }
                 }
                 while ($c <= $maxCol) {
-                    $spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c))->setWidth($defaultWidth);
+                    $spreadsheet->getActiveSheet()->getColumnDimension(Coordinate::stringFromColumnIndex($c + 1))->setWidth($defaultWidth);
                     ++$c;
                 }
             }
diff --git a/src/PhpSpreadsheet/Reader/Ods.php b/src/PhpSpreadsheet/Reader/Ods.php
index 02050c96..b433c2d9 100644
--- a/src/PhpSpreadsheet/Reader/Ods.php
+++ b/src/PhpSpreadsheet/Reader/Ods.php
@@ -215,7 +215,7 @@ class Ods extends BaseReader
 
                     $tmpInfo['totalColumns'] = max($tmpInfo['totalColumns'], $currCells);
                     $tmpInfo['lastColumnIndex'] = $tmpInfo['totalColumns'] - 1;
-                    $tmpInfo['lastColumnLetter'] = Coordinate::stringFromColumnIndex($tmpInfo['lastColumnIndex']);
+                    $tmpInfo['lastColumnLetter'] = Coordinate::stringFromColumnIndex($tmpInfo['lastColumnIndex'] + 1);
                     $worksheetInfo[] = $tmpInfo;
                 }
             }
@@ -707,7 +707,7 @@ class Ods extends BaseReader
                                             $columnIndex += (int) $cellData->getAttributeNS($tableNs, 'number-columns-spanned');
                                             $columnIndex -= 2;
 
-                                            $columnTo = Coordinate::stringFromColumnIndex($columnIndex);
+                                            $columnTo = Coordinate::stringFromColumnIndex($columnIndex + 1);
                                         }
 
                                         $rowTo = $rowID;
diff --git a/src/PhpSpreadsheet/Reader/Slk.php b/src/PhpSpreadsheet/Reader/Slk.php
index d9d1178b..7892bb0e 100644
--- a/src/PhpSpreadsheet/Reader/Slk.php
+++ b/src/PhpSpreadsheet/Reader/Slk.php
@@ -161,7 +161,7 @@ class Slk extends BaseReader
             }
         }
 
-        $worksheetInfo[0]['lastColumnLetter'] = Coordinate::stringFromColumnIndex($worksheetInfo[0]['lastColumnIndex']);
+        $worksheetInfo[0]['lastColumnLetter'] = Coordinate::stringFromColumnIndex($worksheetInfo[0]['lastColumnIndex'] + 1);
         $worksheetInfo[0]['totalColumns'] = $worksheetInfo[0]['lastColumnIndex'] + 1;
 
         // Close file
@@ -337,7 +337,7 @@ class Slk extends BaseReader
                                         if ($columnReference[0] == '[') {
                                             $columnReference = $column + trim($columnReference, '[]');
                                         }
-                                        $A1CellReference = Coordinate::stringFromColumnIndex($columnReference - 1) . $rowReference;
+                                        $A1CellReference = Coordinate::stringFromColumnIndex($columnReference) . $rowReference;
 
                                         $value = substr_replace($value, $A1CellReference, $cellReference[0][1], strlen($cellReference[0][0]));
                                     }
@@ -351,7 +351,7 @@ class Slk extends BaseReader
                             break;
                     }
                 }
-                $columnLetter = Coordinate::stringFromColumnIndex($column - 1);
+                $columnLetter = Coordinate::stringFromColumnIndex($column);
                 $cellData = Calculation::unwrapResult($cellData);
 
                 // Set cell value
@@ -419,22 +419,22 @@ class Slk extends BaseReader
                     }
                 }
                 if (($formatStyle > '') && ($column > '') && ($row > '')) {
-                    $columnLetter = Coordinate::stringFromColumnIndex($column - 1);
+                    $columnLetter = Coordinate::stringFromColumnIndex($column);
                     if (isset($this->formats[$formatStyle])) {
                         $spreadsheet->getActiveSheet()->getStyle($columnLetter . $row)->applyFromArray($this->formats[$formatStyle]);
                     }
                 }
                 if ((!empty($styleData)) && ($column > '') && ($row > '')) {
-                    $columnLetter = Coordinate::stringFromColumnIndex($column - 1);
+                    $columnLetter = Coordinate::stringFromColumnIndex($column);
                     $spreadsheet->getActiveSheet()->getStyle($columnLetter . $row)->applyFromArray($styleData);
                 }
                 if ($columnWidth > '') {
                     if ($startCol == $endCol) {
-                        $startCol = Coordinate::stringFromColumnIndex($startCol - 1);
+                        $startCol = Coordinate::stringFromColumnIndex($startCol);
                         $spreadsheet->getActiveSheet()->getColumnDimension($startCol)->setWidth($columnWidth);
                     } else {
-                        $startCol = Coordinate::stringFromColumnIndex($startCol - 1);
-                        $endCol = Coordinate::stringFromColumnIndex($endCol - 1);
+                        $startCol = Coordinate::stringFromColumnIndex($startCol);
+                        $endCol = Coordinate::stringFromColumnIndex($endCol);
                         $spreadsheet->getActiveSheet()->getColumnDimension($startCol)->setWidth($columnWidth);
                         do {
                             $spreadsheet->getActiveSheet()->getColumnDimension(++$startCol)->setWidth($columnWidth);
diff --git a/src/PhpSpreadsheet/Reader/Xls.php b/src/PhpSpreadsheet/Reader/Xls.php
index 443fc705..a8cfb8e2 100644
--- a/src/PhpSpreadsheet/Reader/Xls.php
+++ b/src/PhpSpreadsheet/Reader/Xls.php
@@ -602,7 +602,7 @@ class Xls extends BaseReader
                 }
             }
 
-            $tmpInfo['lastColumnLetter'] = Coordinate::stringFromColumnIndex($tmpInfo['lastColumnIndex']);
+            $tmpInfo['lastColumnLetter'] = Coordinate::stringFromColumnIndex($tmpInfo['lastColumnIndex'] + 1);
             $tmpInfo['totalColumns'] = $tmpInfo['lastColumnIndex'] + 1;
 
             $worksheetInfo[] = $tmpInfo;
@@ -3222,7 +3222,7 @@ class Xls extends BaseReader
                 $cl = self::getUInt2d($recordData, 2 + 6 * $i + 4);
 
                 // not sure why two column indexes are necessary?
-                $this->phpSheet->setBreakByColumnAndRow($cf, $r, Worksheet::BREAK_ROW);
+                $this->phpSheet->setBreakByColumnAndRow($cf + 1, $r, Worksheet::BREAK_ROW);
             }
         }
     }
@@ -3249,7 +3249,7 @@ class Xls extends BaseReader
                 $rl = self::getUInt2d($recordData, 2 + 6 * $i + 4);
 
                 // not sure why two row indexes are necessary?
-                $this->phpSheet->setBreakByColumnAndRow($c, $rf, Worksheet::BREAK_COLUMN);
+                $this->phpSheet->setBreakByColumnAndRow($c + 1, $rf, Worksheet::BREAK_COLUMN);
             }
         }
     }
@@ -3593,10 +3593,10 @@ class Xls extends BaseReader
 
         if (!$this->readDataOnly) {
             // offset: 0; size: 2; index to first column in range
-            $fc = self::getUInt2d($recordData, 0); // first column index
+            $firstColumnIndex = self::getUInt2d($recordData, 0);
 
             // offset: 2; size: 2; index to last column in range
-            $lc = self::getUInt2d($recordData, 2); // first column index
+            $lastColumnIndex = self::getUInt2d($recordData, 2);
 
             // offset: 4; size: 2; width of the column in 1/256 of the width of the zero character
             $width = self::getUInt2d($recordData, 4);
@@ -3616,8 +3616,8 @@ class Xls extends BaseReader
 
             // offset: 10; size: 2; not used
 
-            for ($i = $fc; $i <= $lc; ++$i) {
-                if ($lc == 255 || $lc == 256) {
+            for ($i = $firstColumnIndex + 1; $i <= $lastColumnIndex + 1; ++$i) {
+                if ($lastColumnIndex == 255 || $lastColumnIndex == 256) {
                     $this->phpSheet->getDefaultColumnDimension()->setWidth($width / 256);
 
                     break;
@@ -3723,7 +3723,7 @@ class Xls extends BaseReader
 
         // offset: 2; size: 2; index to column
         $column = self::getUInt2d($recordData, 2);
-        $columnString = Coordinate::stringFromColumnIndex($column);
+        $columnString = Coordinate::stringFromColumnIndex($column + 1);
 
         // Read cell?
         if (($this->getReadFilter() !== null) && $this->getReadFilter()->readCell($columnString, $row + 1, $this->phpSheet->getTitle())) {
@@ -3767,7 +3767,7 @@ class Xls extends BaseReader
 
         // offset: 2; size: 2; index to column
         $column = self::getUInt2d($recordData, 2);
-        $columnString = Coordinate::stringFromColumnIndex($column);
+        $columnString = Coordinate::stringFromColumnIndex($column + 1);
 
         $emptyCell = true;
         // Read cell?
@@ -3859,7 +3859,7 @@ class Xls extends BaseReader
         // offset within record data
         $offset = 4;
 
-        for ($i = 0; $i < $columns; ++$i) {
+        for ($i = 1; $i <= $columns; ++$i) {
             $columnString = Coordinate::stringFromColumnIndex($colFirst + $i);
 
             // Read cell?
@@ -3904,7 +3904,7 @@ class Xls extends BaseReader
 
         // offset: 2; size 2; index to column
         $column = self::getUInt2d($recordData, 2);
-        $columnString = Coordinate::stringFromColumnIndex($column);
+        $columnString = Coordinate::stringFromColumnIndex($column + 1);
 
         // Read cell?
         if (($this->getReadFilter() !== null) && $this->getReadFilter()->readCell($columnString, $row + 1, $this->phpSheet->getTitle())) {
@@ -3945,7 +3945,7 @@ class Xls extends BaseReader
 
         // offset: 2; size: 2; col index
         $column = self::getUInt2d($recordData, 2);
-        $columnString = Coordinate::stringFromColumnIndex($column);
+        $columnString = Coordinate::stringFromColumnIndex($column + 1);
 
         // offset: 20: size: variable; formula structure
         $formulaStructure = substr($recordData, 20);
@@ -3969,7 +3969,7 @@ class Xls extends BaseReader
             // get the base cell, grab tExp token
             $baseRow = self::getUInt2d($formulaStructure, 3);
             $baseCol = self::getUInt2d($formulaStructure, 5);
-            $this->baseCell = Coordinate::stringFromColumnIndex($baseCol) . ($baseRow + 1);
+            $this->baseCell = Coordinate::stringFromColumnIndex($baseCol + 1) . ($baseRow + 1);
         }
 
         // Read cell?
@@ -4129,7 +4129,7 @@ class Xls extends BaseReader
 
         // offset: 2; size: 2; column index
         $column = self::getUInt2d($recordData, 2);
-        $columnString = Coordinate::stringFromColumnIndex($column);
+        $columnString = Coordinate::stringFromColumnIndex($column + 1);
 
         // Read cell?
         if (($this->getReadFilter() !== null) && $this->getReadFilter()->readCell($columnString, $row + 1, $this->phpSheet->getTitle())) {
@@ -4193,7 +4193,7 @@ class Xls extends BaseReader
         // add style information
         if (!$this->readDataOnly && $this->readEmptyCells) {
             for ($i = 0; $i < $length / 2 - 3; ++$i) {
-                $columnString = Coordinate::stringFromColumnIndex($fc + $i);
+                $columnString = Coordinate::stringFromColumnIndex($fc + $i + 1);
 
                 // Read cell?
                 if (($this->getReadFilter() !== null) && $this->getReadFilter()->readCell($columnString, $row + 1, $this->phpSheet->getTitle())) {
@@ -4229,7 +4229,7 @@ class Xls extends BaseReader
 
         // offset: 2; size: 2; index to column
         $column = self::getUInt2d($recordData, 2);
-        $columnString = Coordinate::stringFromColumnIndex($column);
+        $columnString = Coordinate::stringFromColumnIndex($column + 1);
 
         // Read cell?
         if (($this->getReadFilter() !== null) && $this->getReadFilter()->readCell($columnString, $row + 1, $this->phpSheet->getTitle())) {
@@ -4273,7 +4273,7 @@ class Xls extends BaseReader
 
         // offset: 2; size: 2; col index
         $col = self::getUInt2d($recordData, 2);
-        $columnString = Coordinate::stringFromColumnIndex($col);
+        $columnString = Coordinate::stringFromColumnIndex($col + 1);
 
         // Read cell?
         if (($this->getReadFilter() !== null) && $this->getReadFilter()->readCell($columnString, $row + 1, $this->phpSheet->getTitle())) {
@@ -4490,7 +4490,7 @@ class Xls extends BaseReader
 
             if ($this->frozen) {
                 // frozen panes
-                $this->phpSheet->freezePane(Coordinate::stringFromColumnIndex($px) . ($py + 1));
+                $this->phpSheet->freezePane(Coordinate::stringFromColumnIndex($px + 1) . ($py + 1));
             }
             // unfrozen panes; split windows; not supported by PhpSpreadsheet core
         }
@@ -7103,7 +7103,7 @@ class Xls extends BaseReader
 
         // offset: 2; size: 2; index to column or column offset + relative flags
         // bit: 7-0; mask 0x00FF; column index
-        $column = Coordinate::stringFromColumnIndex(0x00FF & self::getUInt2d($cellAddressStructure, 2));
+        $column = Coordinate::stringFromColumnIndex((0x00FF & self::getUInt2d($cellAddressStructure, 2)) + 1);
 
         // bit: 14; mask 0x4000; (1 = relative column index, 0 = absolute column index)
         if (!(0x4000 & self::getUInt2d($cellAddressStructure, 2))) {
@@ -7142,7 +7142,7 @@ class Xls extends BaseReader
             // bit: 7-0; mask 0x00FF; column index
             $colIndex = 0x00FF & self::getUInt2d($cellAddressStructure, 2);
 
-            $column = Coordinate::stringFromColumnIndex($colIndex);
+            $column = Coordinate::stringFromColumnIndex($colIndex + 1);
             $column = '$' . $column;
         } else {
             // offset: 2; size: 2; index to column or column offset + relative flags
@@ -7151,7 +7151,7 @@ class Xls extends BaseReader
             $colIndex = $baseCol + $relativeColIndex;
             $colIndex = ($colIndex < 256) ? $colIndex : $colIndex - 256;
             $colIndex = ($colIndex >= 0) ? $colIndex : $colIndex + 256;
-            $column = Coordinate::stringFromColumnIndex($colIndex);
+            $column = Coordinate::stringFromColumnIndex($colIndex + 1);
         }
 
         // bit: 15; mask 0x8000; (1 = relative row index, 0 = absolute row index)
@@ -7196,8 +7196,8 @@ class Xls extends BaseReader
         }
 
         // column index to letter
-        $fc = Coordinate::stringFromColumnIndex($fc);
-        $lc = Coordinate::stringFromColumnIndex($lc);
+        $fc = Coordinate::stringFromColumnIndex($fc + 1);
+        $lc = Coordinate::stringFromColumnIndex($lc + 1);
 
         if ($fr == $lr and $fc == $lc) {
             return "$fc$fr";
@@ -7237,8 +7237,8 @@ class Xls extends BaseReader
         }
 
         // column index to letter
-        $fc = Coordinate::stringFromColumnIndex($fc);
-        $lc = Coordinate::stringFromColumnIndex($lc);
+        $fc = Coordinate::stringFromColumnIndex($fc + 1);
+        $lc = Coordinate::stringFromColumnIndex($lc + 1);
 
         if ($fr == $lr and $fc == $lc) {
             return "$fc$fr";
@@ -7270,7 +7270,7 @@ class Xls extends BaseReader
         // offset: 4; size: 2; index to first column or column offset + relative flags
 
         // bit: 7-0; mask 0x00FF; column index
-        $fc = Coordinate::stringFromColumnIndex(0x00FF & self::getUInt2d($subData, 4));
+        $fc = Coordinate::stringFromColumnIndex((0x00FF & self::getUInt2d($subData, 4)) + 1);
 
         // bit: 14; mask 0x4000; (1 = relative column index, 0 = absolute column index)
         if (!(0x4000 & self::getUInt2d($subData, 4))) {
@@ -7285,7 +7285,7 @@ class Xls extends BaseReader
         // offset: 6; size: 2; index to last column or column offset + relative flags
 
         // bit: 7-0; mask 0x00FF; column index
-        $lc = Coordinate::stringFromColumnIndex(0x00FF & self::getUInt2d($subData, 6));
+        $lc = Coordinate::stringFromColumnIndex((0x00FF & self::getUInt2d($subData, 6)) + 1);
 
         // bit: 14; mask 0x4000; (1 = relative column index, 0 = absolute column index)
         if (!(0x4000 & self::getUInt2d($subData, 6))) {
@@ -7330,7 +7330,7 @@ class Xls extends BaseReader
             // offset: 4; size: 2; first column with relative/absolute flags
             // bit: 7-0; mask 0x00FF; column index
             $fcIndex = 0x00FF & self::getUInt2d($subData, 4);
-            $fc = Coordinate::stringFromColumnIndex($fcIndex);
+            $fc = Coordinate::stringFromColumnIndex($fcIndex + 1);
             $fc = '$' . $fc;
         } else {
             // column offset
@@ -7340,7 +7340,7 @@ class Xls extends BaseReader
             $fcIndex = $baseCol + $relativeFcIndex;
             $fcIndex = ($fcIndex < 256) ? $fcIndex : $fcIndex - 256;
             $fcIndex = ($fcIndex >= 0) ? $fcIndex : $fcIndex + 256;
-            $fc = Coordinate::stringFromColumnIndex($fcIndex);
+            $fc = Coordinate::stringFromColumnIndex($fcIndex + 1);
         }
 
         // bit: 15; mask 0x8000; (1 = relative row index, 0 = absolute row index)
@@ -7360,7 +7360,7 @@ class Xls extends BaseReader
             // offset: 6; size: 2; last column with relative/absolute flags
             // bit: 7-0; mask 0x00FF; column index
             $lcIndex = 0x00FF & self::getUInt2d($subData, 6);
-            $lc = Coordinate::stringFromColumnIndex($lcIndex);
+            $lc = Coordinate::stringFromColumnIndex($lcIndex + 1);
             $lc = '$' . $lc;
         } else {
             // column offset
@@ -7370,7 +7370,7 @@ class Xls extends BaseReader
             $lcIndex = $baseCol + $relativeLcIndex;
             $lcIndex = ($lcIndex < 256) ? $lcIndex : $lcIndex - 256;
             $lcIndex = ($lcIndex >= 0) ? $lcIndex : $lcIndex + 256;
-            $lc = Coordinate::stringFromColumnIndex($lcIndex);
+            $lc = Coordinate::stringFromColumnIndex($lcIndex + 1);
         }
 
         // bit: 15; mask 0x8000; (1 = relative row index, 0 = absolute row index)
diff --git a/src/PhpSpreadsheet/Reader/Xls/Escher.php b/src/PhpSpreadsheet/Reader/Xls/Escher.php
index 941618e0..0e88936c 100644
--- a/src/PhpSpreadsheet/Reader/Xls/Escher.php
+++ b/src/PhpSpreadsheet/Reader/Xls/Escher.php
@@ -598,7 +598,7 @@ class Escher
         $endOffsetY = Xls::getUInt2d($recordData, 16);
 
         // set the start coordinates
-        $this->object->setStartCoordinates(Coordinate::stringFromColumnIndex($c1) . ($r1 + 1));
+        $this->object->setStartCoordinates(Coordinate::stringFromColumnIndex($c1 + 1) . ($r1 + 1));
 
         // set the start offsetX
         $this->object->setStartOffsetX($startOffsetX);
@@ -607,7 +607,7 @@ class Escher
         $this->object->setStartOffsetY($startOffsetY);
 
         // set the end coordinates
-        $this->object->setEndCoordinates(Coordinate::stringFromColumnIndex($c2) . ($r2 + 1));
+        $this->object->setEndCoordinates(Coordinate::stringFromColumnIndex($c2 + 1) . ($r2 + 1));
 
         // set the end offsetX
         $this->object->setEndOffsetX($endOffsetX);
diff --git a/src/PhpSpreadsheet/Reader/Xlsx.php b/src/PhpSpreadsheet/Reader/Xlsx.php
index 3870498d..1c249cae 100644
--- a/src/PhpSpreadsheet/Reader/Xlsx.php
+++ b/src/PhpSpreadsheet/Reader/Xlsx.php
@@ -230,7 +230,7 @@ class Xlsx extends BaseReader
                         $xml->close();
 
                         $tmpInfo['lastColumnIndex'] = $tmpInfo['totalColumns'] - 1;
-                        $tmpInfo['lastColumnLetter'] = Coordinate::stringFromColumnIndex($tmpInfo['lastColumnIndex']);
+                        $tmpInfo['lastColumnLetter'] = Coordinate::stringFromColumnIndex($tmpInfo['lastColumnIndex'] + 1);
 
                         $worksheetInfo[] = $tmpInfo;
                     }
@@ -734,7 +734,7 @@ class Xlsx extends BaseReader
                                             $ySplit = 1 + (int) ($xmlSheet->sheetViews->sheetView->pane['ySplit']);
                                         }
 
-                                        $docSheet->freezePaneByColumnAndRow($xSplit, $ySplit);
+                                        $docSheet->freezePaneByColumnAndRow($xSplit + 1, $ySplit);
                                     }
                                 }
 
@@ -798,7 +798,7 @@ class Xlsx extends BaseReader
 
                             if (isset($xmlSheet->cols) && !$this->readDataOnly) {
                                 foreach ($xmlSheet->cols->col as $col) {
-                                    for ($i = (int) ($col['min']) - 1; $i < (int) ($col['max']); ++$i) {
+                                    for ($i = (int) ($col['min']); $i <= (int) ($col['max']); ++$i) {
                                         if ($col['style'] && !$this->readDataOnly) {
                                             $docSheet->getColumnDimension(Coordinate::stringFromColumnIndex($i))->setXfIndex((int) ($col['style']));
                                         }
@@ -854,7 +854,7 @@ class Xlsx extends BaseReader
                                         $docSheet->getRowDimension((int) ($row['r']))->setXfIndex((int) ($row['s']));
                                     }
 
-                                    $rowIndex = 0; // Start form zero because Cell::stringFromColumnIndex start from A default, actually is 1
+                                    $rowIndex = 1;
                                     foreach ($row->c as $c) {
                                         $r = (string) $c['r'];
                                         if ($r == '') {
@@ -1214,7 +1214,7 @@ class Xlsx extends BaseReader
                             if ($xmlSheet && $xmlSheet->colBreaks && $xmlSheet->colBreaks->brk && !$this->readDataOnly) {
                                 foreach ($xmlSheet->colBreaks->brk as $brk) {
                                     if ($brk['man']) {
-                                        $docSheet->setBreak(Coordinate::stringFromColumnIndex((string) $brk['id']) . '1', Worksheet::BREAK_COLUMN);
+                                        $docSheet->setBreak(Coordinate::stringFromColumnIndex((string) $brk['id'] + 1) . '1', Worksheet::BREAK_COLUMN);
                                     }
                                 }
                             }
@@ -1568,7 +1568,7 @@ class Xlsx extends BaseReader
                                                         )],
                                                         false
                                                     );
-                                                    $objDrawing->setCoordinates(Coordinate::stringFromColumnIndex((string) $oneCellAnchor->from->col) . ($oneCellAnchor->from->row + 1));
+                                                    $objDrawing->setCoordinates(Coordinate::stringFromColumnIndex(((string) $oneCellAnchor->from->col) + 1) . ($oneCellAnchor->from->row + 1));
                                                     $objDrawing->setOffsetX(Drawing::EMUToPixels($oneCellAnchor->from->colOff));
                                                     $objDrawing->setOffsetY(Drawing::EMUToPixels($oneCellAnchor->from->rowOff));
                                                     $objDrawing->setResizeProportional(false);
@@ -1590,7 +1590,7 @@ class Xlsx extends BaseReader
                                                     $objDrawing->setWorksheet($docSheet);
                                                 } else {
                                                     //    ? Can charts be positioned with a oneCellAnchor ?
-                                                    $coordinates = Coordinate::stringFromColumnIndex((string) $oneCellAnchor->from->col) . ($oneCellAnchor->from->row + 1);
+                                                    $coordinates = Coordinate::stringFromColumnIndex(((string) $oneCellAnchor->from->col) + 1) . ($oneCellAnchor->from->row + 1);
                                                     $offsetX = Drawing::EMUToPixels($oneCellAnchor->from->colOff);
                                                     $offsetY = Drawing::EMUToPixels($oneCellAnchor->from->rowOff);
                                                     $width = Drawing::EMUToPixels(self::getArrayItem($oneCellAnchor->ext->attributes(), 'cx'));
@@ -1615,7 +1615,7 @@ class Xlsx extends BaseReader
                                                         )],
                                                         false
                                                     );
-                                                    $objDrawing->setCoordinates(Coordinate::stringFromColumnIndex((string) $twoCellAnchor->from->col) . ($twoCellAnchor->from->row + 1));
+                                                    $objDrawing->setCoordinates(Coordinate::stringFromColumnIndex(((string) $twoCellAnchor->from->col) + 1) . ($twoCellAnchor->from->row + 1));
                                                     $objDrawing->setOffsetX(Drawing::EMUToPixels($twoCellAnchor->from->colOff));
                                                     $objDrawing->setOffsetY(Drawing::EMUToPixels($twoCellAnchor->from->rowOff));
                                                     $objDrawing->setResizeProportional(false);
@@ -1637,10 +1637,10 @@ class Xlsx extends BaseReader
                                                     }
                                                     $objDrawing->setWorksheet($docSheet);
                                                 } elseif (($this->includeCharts) && ($twoCellAnchor->graphicFrame)) {
-                                                    $fromCoordinate = Coordinate::stringFromColumnIndex((string) $twoCellAnchor->from->col) . ($twoCellAnchor->from->row + 1);
+                                                    $fromCoordinate = Coordinate::stringFromColumnIndex(((string) $twoCellAnchor->from->col) + 1) . ($twoCellAnchor->from->row + 1);
                                                     $fromOffsetX = Drawing::EMUToPixels($twoCellAnchor->from->colOff);
                                                     $fromOffsetY = Drawing::EMUToPixels($twoCellAnchor->from->rowOff);
-                                                    $toCoordinate = Coordinate::stringFromColumnIndex((string) $twoCellAnchor->to->col) . ($twoCellAnchor->to->row + 1);
+                                                    $toCoordinate = Coordinate::stringFromColumnIndex(((string) $twoCellAnchor->to->col) + 1) . ($twoCellAnchor->to->row + 1);
                                                     $toOffsetX = Drawing::EMUToPixels($twoCellAnchor->to->colOff);
                                                     $toOffsetY = Drawing::EMUToPixels($twoCellAnchor->to->rowOff);
                                                     $graphic = $twoCellAnchor->graphicFrame->children('http://schemas.openxmlformats.org/drawingml/2006/main')->graphic;
diff --git a/src/PhpSpreadsheet/Reader/Xml.php b/src/PhpSpreadsheet/Reader/Xml.php
index c08a84a7..b0173836 100644
--- a/src/PhpSpreadsheet/Reader/Xml.php
+++ b/src/PhpSpreadsheet/Reader/Xml.php
@@ -207,7 +207,7 @@ class Xml extends BaseReader
                 }
             }
 
-            $tmpInfo['lastColumnLetter'] = Coordinate::stringFromColumnIndex($tmpInfo['lastColumnIndex']);
+            $tmpInfo['lastColumnLetter'] = Coordinate::stringFromColumnIndex($tmpInfo['lastColumnIndex'] + 1);
             $tmpInfo['totalColumns'] = $tmpInfo['lastColumnIndex'] + 1;
 
             $worksheetInfo[] = $tmpInfo;
@@ -587,7 +587,7 @@ class Xml extends BaseReader
                 foreach ($worksheet->Table->Column as $columnData) {
                     $columnData_ss = $columnData->attributes($namespaces['ss']);
                     if (isset($columnData_ss['Index'])) {
-                        $columnID = Coordinate::stringFromColumnIndex($columnData_ss['Index'] - 1);
+                        $columnID = Coordinate::stringFromColumnIndex((int) $columnData_ss['Index']);
                     }
                     if (isset($columnData_ss['Width'])) {
                         $columnWidth = $columnData_ss['Width'];
@@ -611,7 +611,7 @@ class Xml extends BaseReader
                     foreach ($rowData->Cell as $cell) {
                         $cell_ss = $cell->attributes($namespaces['ss']);
                         if (isset($cell_ss['Index'])) {
-                            $columnID = Coordinate::stringFromColumnIndex($cell_ss['Index'] - 1);
+                            $columnID = Coordinate::stringFromColumnIndex((int) $cell_ss['Index']);
                         }
                         $cellRange = $columnID . $rowID;
 
@@ -631,7 +631,7 @@ class Xml extends BaseReader
                             $columnTo = $columnID;
                             if (isset($cell_ss['MergeAcross'])) {
                                 $additionalMergedCells += (int) $cell_ss['MergeAcross'];
-                                $columnTo = Coordinate::stringFromColumnIndex(Coordinate::columnIndexFromString($columnID) + $cell_ss['MergeAcross'] - 1);
+                                $columnTo = Coordinate::stringFromColumnIndex(Coordinate::columnIndexFromString($columnID) + $cell_ss['MergeAcross']);
                             }
                             $rowTo = $rowID;
                             if (isset($cell_ss['MergeDown'])) {
@@ -739,7 +739,7 @@ class Xml extends BaseReader
                                                 if ($columnReference[0] == '[') {
                                                     $columnReference = $columnNumber + trim($columnReference, '[]');
                                                 }
-                                                $A1CellReference = Coordinate::stringFromColumnIndex($columnReference - 1) . $rowReference;
+                                                $A1CellReference = Coordinate::stringFromColumnIndex($columnReference) . $rowReference;
                                                 $value = substr_replace($value, $A1CellReference, $cellReference[0][1], strlen($cellReference[0][0]));
                                             }
                                         }
diff --git a/src/PhpSpreadsheet/ReferenceHelper.php b/src/PhpSpreadsheet/ReferenceHelper.php
index 1faafed5..bfa14108 100644
--- a/src/PhpSpreadsheet/ReferenceHelper.php
+++ b/src/PhpSpreadsheet/ReferenceHelper.php
@@ -372,8 +372,6 @@ class ReferenceHelper
         $allCoordinates = $pSheet->getCoordinates();
 
         // Get coordinate of $pBefore
-        $beforeColumn = 'A';
-        $beforeRow = 1;
         list($beforeColumn, $beforeRow) = Coordinate::coordinateFromString($pBefore);
         $beforeColumnIndex = Coordinate::columnIndexFromString($beforeColumn);
 
@@ -385,7 +383,7 @@ class ReferenceHelper
         if ($pNumCols < 0 && $beforeColumnIndex - 2 + $pNumCols > 0) {
             for ($i = 1; $i <= $highestRow - 1; ++$i) {
                 for ($j = $beforeColumnIndex - 1 + $pNumCols; $j <= $beforeColumnIndex - 2; ++$j) {
-                    $coordinate = Coordinate::stringFromColumnIndex($j) . $i;
+                    $coordinate = Coordinate::stringFromColumnIndex($j + 1) . $i;
                     $pSheet->removeConditionalStyles($coordinate);
                     if ($pSheet->cellExists($coordinate)) {
                         $pSheet->getCell($coordinate)->setValueExplicit('', DataType::TYPE_NULL);
@@ -399,7 +397,7 @@ class ReferenceHelper
         if ($pNumRows < 0 && $beforeRow - 1 + $pNumRows > 0) {
             for ($i = $beforeColumnIndex - 1; $i <= Coordinate::columnIndexFromString($highestColumn) - 1; ++$i) {
                 for ($j = $beforeRow + $pNumRows; $j <= $beforeRow - 1; ++$j) {
-                    $coordinate = Coordinate::stringFromColumnIndex($i) . $j;
+                    $coordinate = Coordinate::stringFromColumnIndex($i + 1) . $j;
                     $pSheet->removeConditionalStyles($coordinate);
                     if ($pSheet->cellExists($coordinate)) {
                         $pSheet->getCell($coordinate)->setValueExplicit('', DataType::TYPE_NULL);
@@ -423,7 +421,7 @@ class ReferenceHelper
             }
 
             // New coordinate
-            $newCoordinate = Coordinate::stringFromColumnIndex($cellIndex - 1 + $pNumCols) . ($cell->getRow() + $pNumRows);
+            $newCoordinate = Coordinate::stringFromColumnIndex($cellIndex + $pNumCols) . ($cell->getRow() + $pNumRows);
 
             // Should the cell be updated? Move value and cellXf index from one cell to another.
             if (($cellIndex >= $beforeColumnIndex) && ($cell->getRow() >= $beforeRow)) {
@@ -459,12 +457,12 @@ class ReferenceHelper
         if ($pNumCols > 0 && $beforeColumnIndex - 2 > 0) {
             for ($i = $beforeRow; $i <= $highestRow - 1; ++$i) {
                 // Style
-                $coordinate = Coordinate::stringFromColumnIndex($beforeColumnIndex - 2) . $i;
+                $coordinate = Coordinate::stringFromColumnIndex($beforeColumnIndex - 1) . $i;
                 if ($pSheet->cellExists($coordinate)) {
                     $xfIndex = $pSheet->getCell($coordinate)->getXfIndex();
                     $conditionalStyles = $pSheet->conditionalStylesExists($coordinate) ?
                         $pSheet->getConditionalStyles($coordinate) : false;
-                    for ($j = $beforeColumnIndex - 1; $j <= $beforeColumnIndex - 2 + $pNumCols; ++$j) {
+                    for ($j = $beforeColumnIndex; $j <= $beforeColumnIndex - 1 + $pNumCols; ++$j) {
                         $pSheet->getCellByColumnAndRow($j, $i)->setXfIndex($xfIndex);
                         if ($conditionalStyles) {
                             $cloned = [];
@@ -479,7 +477,7 @@ class ReferenceHelper
         }
 
         if ($pNumRows > 0 && $beforeRow - 1 > 0) {
-            for ($i = $beforeColumnIndex - 1; $i <= Coordinate::columnIndexFromString($highestColumn) - 1; ++$i) {
+            for ($i = $beforeColumnIndex; $i <= Coordinate::columnIndexFromString($highestColumn); ++$i) {
                 // Style
                 $coordinate = Coordinate::stringFromColumnIndex($i) . ($beforeRow - 1);
                 if ($pSheet->cellExists($coordinate)) {
@@ -541,8 +539,8 @@ class ReferenceHelper
                             $deleteColumn = $columnIndex + $pNumCols - 1;
                             $deleteCount = abs($pNumCols);
                             for ($i = 1; $i <= $deleteCount; ++$i) {
-                                if (isset($autoFilterColumns[Coordinate::stringFromColumnIndex($deleteColumn)])) {
-                                    $autoFilter->clearColumn(Coordinate::stringFromColumnIndex($deleteColumn));
+                                if (isset($autoFilterColumns[Coordinate::stringFromColumnIndex($deleteColumn + 1)])) {
+                                    $autoFilter->clearColumn(Coordinate::stringFromColumnIndex($deleteColumn + 1));
                                 }
                                 ++$deleteColumn;
                             }
@@ -551,25 +549,20 @@ class ReferenceHelper
 
                         //    Shuffle columns in autofilter range
                         if ($pNumCols > 0) {
-                            //    For insert, we shuffle from end to beginning to avoid overwriting
-                            $startColID = Coordinate::stringFromColumnIndex($startCol - 1);
-                            $toColID = Coordinate::stringFromColumnIndex($startCol + $pNumCols - 1);
-                            $endColID = Coordinate::stringFromColumnIndex($rangeEnd[0]);
-
                             $startColRef = $startCol;
                             $endColRef = $rangeEnd[0];
                             $toColRef = $rangeEnd[0] + $pNumCols;
 
                             do {
-                                $autoFilter->shiftColumn(Coordinate::stringFromColumnIndex($endColRef - 1), Coordinate::stringFromColumnIndex($toColRef - 1));
+                                $autoFilter->shiftColumn(Coordinate::stringFromColumnIndex($endColRef), Coordinate::stringFromColumnIndex($toColRef));
                                 --$endColRef;
                                 --$toColRef;
                             } while ($startColRef <= $endColRef);
                         } else {
                             //    For delete, we shuffle from beginning to end to avoid overwriting
-                            $startColID = Coordinate::stringFromColumnIndex($startCol - 1);
-                            $toColID = Coordinate::stringFromColumnIndex($startCol + $pNumCols - 1);
-                            $endColID = Coordinate::stringFromColumnIndex($rangeEnd[0]);
+                            $startColID = Coordinate::stringFromColumnIndex($startCol);
+                            $toColID = Coordinate::stringFromColumnIndex($startCol + $pNumCols);
+                            $endColID = Coordinate::stringFromColumnIndex($rangeEnd[0] + 1);
                             do {
                                 $autoFilter->shiftColumn($startColID, $toColID);
                                 ++$startColID;
@@ -881,7 +874,7 @@ class ReferenceHelper
 
             // Create new column reference
             if ($updateColumn) {
-                $newColumn = Coordinate::stringFromColumnIndex(Coordinate::columnIndexFromString($newColumn) - 1 + $pNumCols);
+                $newColumn = Coordinate::stringFromColumnIndex(Coordinate::columnIndexFromString($newColumn) + $pNumCols);
             }
 
             // Create new row reference
diff --git a/src/PhpSpreadsheet/Shared/Xls.php b/src/PhpSpreadsheet/Shared/Xls.php
index e25394bc..177779f8 100644
--- a/src/PhpSpreadsheet/Shared/Xls.php
+++ b/src/PhpSpreadsheet/Shared/Xls.php
@@ -111,8 +111,8 @@ class Xls
         $distanceX = 0;
 
         // add the widths of the spanning columns
-        $startColumnIndex = Coordinate::columnIndexFromString($startColumn) - 1; // 1-based
-        $endColumnIndex = Coordinate::columnIndexFromString($endColumn) - 1; // 1-based
+        $startColumnIndex = Coordinate::columnIndexFromString($startColumn);
+        $endColumnIndex = Coordinate::columnIndexFromString($endColumn);
         for ($i = $startColumnIndex; $i <= $endColumnIndex; ++$i) {
             $distanceX += self::sizeCol($sheet, Coordinate::stringFromColumnIndex($i));
         }
@@ -212,7 +212,7 @@ class Xls
     public static function oneAnchor2twoAnchor($sheet, $coordinates, $offsetX, $offsetY, $width, $height)
     {
         list($column, $row) = Coordinate::coordinateFromString($coordinates);
-        $col_start = Coordinate::columnIndexFromString($column) - 1;
+        $col_start = Coordinate::columnIndexFromString($column);
         $row_start = $row - 1;
 
         $x1 = $offsetX;
diff --git a/src/PhpSpreadsheet/Style/Style.php b/src/PhpSpreadsheet/Style/Style.php
index fa49a2e1..549303e3 100644
--- a/src/PhpSpreadsheet/Style/Style.php
+++ b/src/PhpSpreadsheet/Style/Style.php
@@ -210,8 +210,8 @@ class Style extends Supervisor
             $rangeEnd = Coordinate::coordinateFromString($rangeB);
 
             // Translate column into index
-            $rangeStart[0] = Coordinate::columnIndexFromString($rangeStart[0]) - 1;
-            $rangeEnd[0] = Coordinate::columnIndexFromString($rangeEnd[0]) - 1;
+            $rangeStart[0] = Coordinate::columnIndexFromString($rangeStart[0]);
+            $rangeEnd[0] = Coordinate::columnIndexFromString($rangeEnd[0]);
 
             // Make sure we can loop upwards on rows and columns
             if ($rangeStart[0] > $rangeEnd[0] && $rangeStart[1] > $rangeEnd[1]) {
diff --git a/src/PhpSpreadsheet/Worksheet/AutoFilter.php b/src/PhpSpreadsheet/Worksheet/AutoFilter.php
index 515e3781..cb0e2e29 100644
--- a/src/PhpSpreadsheet/Worksheet/AutoFilter.php
+++ b/src/PhpSpreadsheet/Worksheet/AutoFilter.php
@@ -202,7 +202,7 @@ class AutoFilter
     public function getColumnByOffset($pColumnOffset)
     {
         list($rangeStart, $rangeEnd) = Coordinate::rangeBoundaries($this->range);
-        $pColumn = Coordinate::stringFromColumnIndex($rangeStart[0] + $pColumnOffset - 1);
+        $pColumn = Coordinate::stringFromColumnIndex($rangeStart[0] + $pColumnOffset);
 
         return $this->getColumn($pColumn);
     }
diff --git a/src/PhpSpreadsheet/Worksheet/CellIterator.php b/src/PhpSpreadsheet/Worksheet/CellIterator.php
index ef2ca89d..d97e33f7 100644
--- a/src/PhpSpreadsheet/Worksheet/CellIterator.php
+++ b/src/PhpSpreadsheet/Worksheet/CellIterator.php
@@ -11,14 +11,7 @@ abstract class CellIterator implements \Iterator
      *
      * @var Worksheet
      */
-    protected $subject;
-
-    /**
-     * Current iterator position.
-     *
-     * @var mixed
-     */
-    protected $position;
+    protected $worksheet;
 
     /**
      * Iterate only existing cells.
@@ -32,7 +25,7 @@ abstract class CellIterator implements \Iterator
      */
     public function __destruct()
     {
-        unset($this->subject);
+        unset($this->worksheet);
     }
 
     /**
diff --git a/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php b/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php
index b1d505fd..76ca596d 100644
--- a/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php
+++ b/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php
@@ -7,26 +7,33 @@ use PhpOffice\PhpSpreadsheet\Exception as PhpSpreadsheetException;
 
 class ColumnCellIterator extends CellIterator
 {
+    /**
+     * Current iterator position.
+     *
+     * @var int
+     */
+    private $currentRow;
+
     /**
      * Column index.
      *
      * @var string
      */
-    protected $columnIndex;
+    private $columnIndex;
 
     /**
      * Start position.
      *
      * @var int
      */
-    protected $startRow = 1;
+    private $startRow = 1;
 
     /**
      * End position.
      *
      * @var int
      */
-    protected $endRow = 1;
+    private $endRow = 1;
 
     /**
      * Create a new row iterator.
@@ -39,8 +46,8 @@ class ColumnCellIterator extends CellIterator
     public function __construct(Worksheet $subject = null, $columnIndex = 'A', $startRow = 1, $endRow = null)
     {
         // Set subject
-        $this->subject = $subject;
-        $this->columnIndex = Coordinate::columnIndexFromString($columnIndex) - 1;
+        $this->worksheet = $subject;
+        $this->columnIndex = Coordinate::columnIndexFromString($columnIndex);
         $this->resetEnd($endRow);
         $this->resetStart($startRow);
     }
@@ -50,7 +57,7 @@ class ColumnCellIterator extends CellIterator
      */
     public function __destruct()
     {
-        unset($this->subject);
+        unset($this->worksheet);
     }
 
     /**
@@ -82,7 +89,7 @@ class ColumnCellIterator extends CellIterator
      */
     public function resetEnd($endRow = null)
     {
-        $this->endRow = ($endRow) ? $endRow : $this->subject->getHighestRow();
+        $this->endRow = ($endRow) ? $endRow : $this->worksheet->getHighestRow();
         $this->adjustForExistingOnlyRange();
 
         return $this;
@@ -101,10 +108,10 @@ class ColumnCellIterator extends CellIterator
     {
         if (($row < $this->startRow) || ($row > $this->endRow)) {
             throw new PhpSpreadsheetException("Row $row is out of range ({$this->startRow} - {$this->endRow})");
-        } elseif ($this->onlyExistingCells && !($this->subject->cellExistsByColumnAndRow($this->columnIndex, $row))) {
+        } elseif ($this->onlyExistingCells && !($this->worksheet->cellExistsByColumnAndRow($this->columnIndex, $row))) {
             throw new PhpSpreadsheetException('In "IterateOnlyExistingCells" mode and Cell does not exist');
         }
-        $this->position = $row;
+        $this->currentRow = $row;
 
         return $this;
     }
@@ -114,7 +121,7 @@ class ColumnCellIterator extends CellIterator
      */
     public function rewind()
     {
-        $this->position = $this->startRow;
+        $this->currentRow = $this->startRow;
     }
 
     /**
@@ -124,7 +131,7 @@ class ColumnCellIterator extends CellIterator
      */
     public function current()
     {
-        return $this->subject->getCellByColumnAndRow($this->columnIndex, $this->position);
+        return $this->worksheet->getCellByColumnAndRow($this->columnIndex, $this->currentRow);
     }
 
     /**
@@ -134,7 +141,7 @@ class ColumnCellIterator extends CellIterator
      */
     public function key()
     {
-        return $this->position;
+        return $this->currentRow;
     }
 
     /**
@@ -143,10 +150,10 @@ class ColumnCellIterator extends CellIterator
     public function next()
     {
         do {
-            ++$this->position;
+            ++$this->currentRow;
         } while (($this->onlyExistingCells) &&
-            (!$this->subject->cellExistsByColumnAndRow($this->columnIndex, $this->position)) &&
-            ($this->position <= $this->endRow));
+            (!$this->worksheet->cellExistsByColumnAndRow($this->columnIndex, $this->currentRow)) &&
+            ($this->currentRow <= $this->endRow));
     }
 
     /**
@@ -154,15 +161,15 @@ class ColumnCellIterator extends CellIterator
      */
     public function prev()
     {
-        if ($this->position <= $this->startRow) {
+        if ($this->currentRow <= $this->startRow) {
             throw new PhpSpreadsheetException("Row is already at the beginning of range ({$this->startRow} - {$this->endRow})");
         }
 
         do {
-            --$this->position;
+            --$this->currentRow;
         } while (($this->onlyExistingCells) &&
-            (!$this->subject->cellExistsByColumnAndRow($this->columnIndex, $this->position)) &&
-            ($this->position >= $this->startRow));
+            (!$this->worksheet->cellExistsByColumnAndRow($this->columnIndex, $this->currentRow)) &&
+            ($this->currentRow >= $this->startRow));
     }
 
     /**
@@ -172,7 +179,7 @@ class ColumnCellIterator extends CellIterator
      */
     public function valid()
     {
-        return $this->position <= $this->endRow;
+        return $this->currentRow <= $this->endRow;
     }
 
     /**
@@ -183,14 +190,14 @@ class ColumnCellIterator extends CellIterator
     protected function adjustForExistingOnlyRange()
     {
         if ($this->onlyExistingCells) {
-            while ((!$this->subject->cellExistsByColumnAndRow($this->columnIndex, $this->startRow)) &&
+            while ((!$this->worksheet->cellExistsByColumnAndRow($this->columnIndex, $this->startRow)) &&
                 ($this->startRow <= $this->endRow)) {
                 ++$this->startRow;
             }
             if ($this->startRow > $this->endRow) {
                 throw new PhpSpreadsheetException('No cells exist within the specified range');
             }
-            while ((!$this->subject->cellExistsByColumnAndRow($this->columnIndex, $this->endRow)) &&
+            while ((!$this->worksheet->cellExistsByColumnAndRow($this->columnIndex, $this->endRow)) &&
                 ($this->endRow >= $this->startRow)) {
                 --$this->endRow;
             }
diff --git a/src/PhpSpreadsheet/Worksheet/ColumnIterator.php b/src/PhpSpreadsheet/Worksheet/ColumnIterator.php
index caee73f7..6fdfe3ba 100644
--- a/src/PhpSpreadsheet/Worksheet/ColumnIterator.php
+++ b/src/PhpSpreadsheet/Worksheet/ColumnIterator.php
@@ -13,40 +13,40 @@ class ColumnIterator implements \Iterator
      *
      * @var Worksheet
      */
-    private $subject;
+    private $worksheet;
 
     /**
      * Current iterator position.
      *
      * @var int
      */
-    private $position = 0;
+    private $currentColumnIndex = 1;
 
     /**
      * Start position.
      *
      * @var int
      */
-    private $startColumn = 0;
+    private $startColumnIndex = 1;
 
     /**
      * End position.
      *
      * @var int
      */
-    private $endColumn = 0;
+    private $endColumnIndex = 1;
 
     /**
      * Create a new column iterator.
      *
-     * @param Worksheet $subject The worksheet to iterate over
+     * @param Worksheet $worksheet The worksheet to iterate over
      * @param string $startColumn The column address at which to start iterating
      * @param string $endColumn Optionally, the column address at which to stop iterating
      */
-    public function __construct(Worksheet $subject, $startColumn = 'A', $endColumn = null)
+    public function __construct(Worksheet $worksheet, $startColumn = 'A', $endColumn = null)
     {
         // Set subject
-        $this->subject = $subject;
+        $this->worksheet = $worksheet;
         $this->resetEnd($endColumn);
         $this->resetStart($startColumn);
     }
@@ -56,13 +56,13 @@ class ColumnIterator implements \Iterator
      */
     public function __destruct()
     {
-        unset($this->subject);
+        unset($this->worksheet);
     }
 
     /**
      * (Re)Set the start column and the current column pointer.
      *
-     * @param int $startColumn The column address at which to start iterating
+     * @param string $startColumn The column address at which to start iterating
      *
      * @throws Exception
      *
@@ -70,14 +70,14 @@ class ColumnIterator implements \Iterator
      */
     public function resetStart($startColumn = 'A')
     {
-        $startColumnIndex = Coordinate::columnIndexFromString($startColumn) - 1;
-        if ($startColumnIndex > Coordinate::columnIndexFromString($this->subject->getHighestColumn()) - 1) {
-            throw new Exception("Start column ({$startColumn}) is beyond highest column ({$this->subject->getHighestColumn()})");
+        $startColumnIndex = Coordinate::columnIndexFromString($startColumn);
+        if ($startColumnIndex > Coordinate::columnIndexFromString($this->worksheet->getHighestColumn())) {
+            throw new Exception("Start column ({$startColumn}) is beyond highest column ({$this->worksheet->getHighestColumn()})");
         }
 
-        $this->startColumn = $startColumnIndex;
-        if ($this->endColumn < $this->startColumn) {
-            $this->endColumn = $this->startColumn;
+        $this->startColumnIndex = $startColumnIndex;
+        if ($this->endColumnIndex < $this->startColumnIndex) {
+            $this->endColumnIndex = $this->startColumnIndex;
         }
         $this->seek($startColumn);
 
@@ -93,8 +93,8 @@ class ColumnIterator implements \Iterator
      */
     public function resetEnd($endColumn = null)
     {
-        $endColumn = ($endColumn) ? $endColumn : $this->subject->getHighestColumn();
-        $this->endColumn = Coordinate::columnIndexFromString($endColumn) - 1;
+        $endColumn = $endColumn ? $endColumn : $this->worksheet->getHighestColumn();
+        $this->endColumnIndex = Coordinate::columnIndexFromString($endColumn);
 
         return $this;
     }
@@ -110,11 +110,11 @@ class ColumnIterator implements \Iterator
      */
     public function seek($column = 'A')
     {
-        $column = Coordinate::columnIndexFromString($column) - 1;
-        if (($column < $this->startColumn) || ($column > $this->endColumn)) {
-            throw new PhpSpreadsheetException("Column $column is out of range ({$this->startColumn} - {$this->endColumn})");
+        $column = Coordinate::columnIndexFromString($column);
+        if (($column < $this->startColumnIndex) || ($column > $this->endColumnIndex)) {
+            throw new PhpSpreadsheetException("Column $column is out of range ({$this->startColumnIndex} - {$this->endColumnIndex})");
         }
-        $this->position = $column;
+        $this->currentColumnIndex = $column;
 
         return $this;
     }
@@ -124,7 +124,7 @@ class ColumnIterator implements \Iterator
      */
     public function rewind()
     {
-        $this->position = $this->startColumn;
+        $this->currentColumnIndex = $this->startColumnIndex;
     }
 
     /**
@@ -134,7 +134,7 @@ class ColumnIterator implements \Iterator
      */
     public function current()
     {
-        return new Column($this->subject, Coordinate::stringFromColumnIndex($this->position));
+        return new Column($this->worksheet, Coordinate::stringFromColumnIndex($this->currentColumnIndex));
     }
 
     /**
@@ -144,7 +144,7 @@ class ColumnIterator implements \Iterator
      */
     public function key()
     {
-        return Coordinate::stringFromColumnIndex($this->position);
+        return Coordinate::stringFromColumnIndex($this->currentColumnIndex);
     }
 
     /**
@@ -152,7 +152,7 @@ class ColumnIterator implements \Iterator
      */
     public function next()
     {
-        ++$this->position;
+        ++$this->currentColumnIndex;
     }
 
     /**
@@ -162,10 +162,10 @@ class ColumnIterator implements \Iterator
      */
     public function prev()
     {
-        if ($this->position <= $this->startColumn) {
-            throw new PhpSpreadsheetException('Column is already at the beginning of range (' . Coordinate::stringFromColumnIndex($this->endColumn) . ' - ' . Coordinate::stringFromColumnIndex($this->endColumn) . ')');
+        if ($this->currentColumnIndex <= $this->startColumnIndex) {
+            throw new PhpSpreadsheetException('Column is already at the beginning of range (' . Coordinate::stringFromColumnIndex($this->endColumnIndex) . ' - ' . Coordinate::stringFromColumnIndex($this->endColumnIndex) . ')');
         }
-        --$this->position;
+        --$this->currentColumnIndex;
     }
 
     /**
@@ -175,6 +175,6 @@ class ColumnIterator implements \Iterator
      */
     public function valid()
     {
-        return $this->position <= $this->endColumn;
+        return $this->currentColumnIndex <= $this->endColumnIndex;
     }
 }
diff --git a/src/PhpSpreadsheet/Worksheet/PageSetup.php b/src/PhpSpreadsheet/Worksheet/PageSetup.php
index 175a8c11..ab007f61 100644
--- a/src/PhpSpreadsheet/Worksheet/PageSetup.php
+++ b/src/PhpSpreadsheet/Worksheet/PageSetup.php
@@ -749,7 +749,7 @@ class PageSetup
      * @param int $index Identifier for a specific print area range allowing several ranges to be set
      *                                When the method is "O"verwrite, then a positive integer index will overwrite that indexed
      *                                    entry in the print areas list; a negative index value will identify which entry to
-     *                                    overwrite working bacward through the print area to the list, with the last entry as -1.
+     *                                    overwrite working backward through the print area to the list, with the last entry as -1.
      *                                    Specifying an index value of 0, will overwrite <b>all</b> existing print ranges.
      *                                When the method is "I"nsert, then a positive index will insert after that indexed entry in
      *                                    the print areas list, while a negative index will insert before the indexed entry.
diff --git a/src/PhpSpreadsheet/Worksheet/RowCellIterator.php b/src/PhpSpreadsheet/Worksheet/RowCellIterator.php
index 99fabc6a..b839a3c4 100644
--- a/src/PhpSpreadsheet/Worksheet/RowCellIterator.php
+++ b/src/PhpSpreadsheet/Worksheet/RowCellIterator.php
@@ -7,39 +7,46 @@ use PhpOffice\PhpSpreadsheet\Exception as PhpSpreadsheetException;
 
 class RowCellIterator extends CellIterator
 {
+    /**
+     * Current iterator position.
+     *
+     * @var int
+     */
+    private $currentColumnIndex;
+
     /**
      * Row index.
      *
      * @var int
      */
-    protected $rowIndex;
+    private $rowIndex = 1;
 
     /**
      * Start position.
      *
      * @var int
      */
-    protected $startColumn = 0;
+    private $startColumnIndex = 1;
 
     /**
      * End position.
      *
      * @var int
      */
-    protected $endColumn = 0;
+    private $endColumnIndex = 1;
 
     /**
      * Create a new column iterator.
      *
-     * @param Worksheet $subject The worksheet to iterate over
+     * @param Worksheet $worksheet The worksheet to iterate over
      * @param int $rowIndex The row that we want to iterate
      * @param string $startColumn The column address at which to start iterating
      * @param string $endColumn Optionally, the column address at which to stop iterating
      */
-    public function __construct(Worksheet $subject = null, $rowIndex = 1, $startColumn = 'A', $endColumn = null)
+    public function __construct(Worksheet $worksheet = null, $rowIndex = 1, $startColumn = 'A', $endColumn = null)
     {
         // Set subject and row index
-        $this->subject = $subject;
+        $this->worksheet = $worksheet;
         $this->rowIndex = $rowIndex;
         $this->resetEnd($endColumn);
         $this->resetStart($startColumn);
@@ -50,13 +57,13 @@ class RowCellIterator extends CellIterator
      */
     public function __destruct()
     {
-        unset($this->subject);
+        unset($this->worksheet);
     }
 
     /**
      * (Re)Set the start column and the current column pointer.
      *
-     * @param int $startColumn The column address at which to start iterating
+     * @param string $startColumn The column address at which to start iterating
      *
      * @throws PhpSpreadsheetException
      *
@@ -64,10 +71,9 @@ class RowCellIterator extends CellIterator
      */
     public function resetStart($startColumn = 'A')
     {
-        $startColumnIndex = Coordinate::columnIndexFromString($startColumn) - 1;
-        $this->startColumn = $startColumnIndex;
+        $this->startColumnIndex = Coordinate::columnIndexFromString($startColumn);
         $this->adjustForExistingOnlyRange();
-        $this->seek(Coordinate::stringFromColumnIndex($this->startColumn));
+        $this->seek(Coordinate::stringFromColumnIndex($this->startColumnIndex));
 
         return $this;
     }
@@ -83,8 +89,8 @@ class RowCellIterator extends CellIterator
      */
     public function resetEnd($endColumn = null)
     {
-        $endColumn = ($endColumn) ? $endColumn : $this->subject->getHighestColumn();
-        $this->endColumn = Coordinate::columnIndexFromString($endColumn) - 1;
+        $endColumn = $endColumn ? $endColumn : $this->worksheet->getHighestColumn();
+        $this->endColumnIndex = Coordinate::columnIndexFromString($endColumn);
         $this->adjustForExistingOnlyRange();
 
         return $this;
@@ -101,13 +107,13 @@ class RowCellIterator extends CellIterator
      */
     public function seek($column = 'A')
     {
-        $column = Coordinate::columnIndexFromString($column) - 1;
-        if (($column < $this->startColumn) || ($column > $this->endColumn)) {
-            throw new PhpSpreadsheetException("Column $column is out of range ({$this->startColumn} - {$this->endColumn})");
-        } elseif ($this->onlyExistingCells && !($this->subject->cellExistsByColumnAndRow($column, $this->rowIndex))) {
+        $column = Coordinate::columnIndexFromString($column);
+        if (($column < $this->startColumnIndex) || ($column > $this->endColumnIndex)) {
+            throw new PhpSpreadsheetException("Column $column is out of range ({$this->startColumnIndex} - {$this->endColumnIndex})");
+        } elseif ($this->onlyExistingCells && !($this->worksheet->cellExistsByColumnAndRow($column, $this->rowIndex))) {
             throw new PhpSpreadsheetException('In "IterateOnlyExistingCells" mode and Cell does not exist');
         }
-        $this->position = $column;
+        $this->currentColumnIndex = $column;
 
         return $this;
     }
@@ -117,7 +123,7 @@ class RowCellIterator extends CellIterator
      */
     public function rewind()
     {
-        $this->position = $this->startColumn;
+        $this->currentColumnIndex = $this->startColumnIndex;
     }
 
     /**
@@ -127,7 +133,7 @@ class RowCellIterator extends CellIterator
      */
     public function current()
     {
-        return $this->subject->getCellByColumnAndRow($this->position, $this->rowIndex);
+        return $this->worksheet->getCellByColumnAndRow($this->currentColumnIndex, $this->rowIndex);
     }
 
     /**
@@ -137,7 +143,7 @@ class RowCellIterator extends CellIterator
      */
     public function key()
     {
-        return Coordinate::stringFromColumnIndex($this->position);
+        return Coordinate::stringFromColumnIndex($this->currentColumnIndex);
     }
 
     /**
@@ -146,8 +152,8 @@ class RowCellIterator extends CellIterator
     public function next()
     {
         do {
-            ++$this->position;
-        } while (($this->onlyExistingCells) && (!$this->subject->cellExistsByColumnAndRow($this->position, $this->rowIndex)) && ($this->position <= $this->endColumn));
+            ++$this->currentColumnIndex;
+        } while (($this->onlyExistingCells) && (!$this->worksheet->cellExistsByColumnAndRow($this->currentColumnIndex, $this->rowIndex)) && ($this->currentColumnIndex <= $this->endColumnIndex));
     }
 
     /**
@@ -157,12 +163,12 @@ class RowCellIterator extends CellIterator
      */
     public function prev()
     {
-        if ($this->position <= $this->startColumn) {
-            throw new PhpSpreadsheetException('Column is already at the beginning of range (' . Coordinate::stringFromColumnIndex($this->endColumn) . ' - ' . Coordinate::stringFromColumnIndex($this->endColumn) . ')');
+        if ($this->currentColumnIndex <= $this->startColumnIndex) {
+            throw new PhpSpreadsheetException('Column is already at the beginning of range (' . Coordinate::stringFromColumnIndex($this->endColumnIndex) . ' - ' . Coordinate::stringFromColumnIndex($this->endColumnIndex) . ')');
         }
         do {
-            --$this->position;
-        } while (($this->onlyExistingCells) && (!$this->subject->cellExistsByColumnAndRow($this->position, $this->rowIndex)) && ($this->position >= $this->startColumn));
+            --$this->currentColumnIndex;
+        } while (($this->onlyExistingCells) && (!$this->worksheet->cellExistsByColumnAndRow($this->currentColumnIndex, $this->rowIndex)) && ($this->currentColumnIndex >= $this->startColumnIndex));
     }
 
     /**
@@ -172,7 +178,7 @@ class RowCellIterator extends CellIterator
      */
     public function valid()
     {
-        return $this->position <= $this->endColumn;
+        return $this->currentColumnIndex <= $this->endColumnIndex;
     }
 
     /**
@@ -183,16 +189,16 @@ class RowCellIterator extends CellIterator
     protected function adjustForExistingOnlyRange()
     {
         if ($this->onlyExistingCells) {
-            while ((!$this->subject->cellExistsByColumnAndRow($this->startColumn, $this->rowIndex)) && ($this->startColumn <= $this->endColumn)) {
-                ++$this->startColumn;
+            while ((!$this->worksheet->cellExistsByColumnAndRow($this->startColumnIndex, $this->rowIndex)) && ($this->startColumnIndex <= $this->endColumnIndex)) {
+                ++$this->startColumnIndex;
             }
-            if ($this->startColumn > $this->endColumn) {
+            if ($this->startColumnIndex > $this->endColumnIndex) {
                 throw new PhpSpreadsheetException('No cells exist within the specified range');
             }
-            while ((!$this->subject->cellExistsByColumnAndRow($this->endColumn, $this->rowIndex)) && ($this->endColumn >= $this->startColumn)) {
-                --$this->endColumn;
+            while ((!$this->worksheet->cellExistsByColumnAndRow($this->endColumnIndex, $this->rowIndex)) && ($this->endColumnIndex >= $this->startColumnIndex)) {
+                --$this->endColumnIndex;
             }
-            if ($this->endColumn < $this->startColumn) {
+            if ($this->endColumnIndex < $this->startColumnIndex) {
                 throw new PhpSpreadsheetException('No cells exist within the specified range');
             }
         }
diff --git a/src/PhpSpreadsheet/Worksheet/Worksheet.php b/src/PhpSpreadsheet/Worksheet/Worksheet.php
index 0e5fd0d6..04277a7f 100644
--- a/src/PhpSpreadsheet/Worksheet/Worksheet.php
+++ b/src/PhpSpreadsheet/Worksheet/Worksheet.php
@@ -1123,15 +1123,15 @@ class Worksheet implements IComparable
     /**
      * Set a cell value by using numeric cell coordinates.
      *
-     * @param int $pColumn Numeric column coordinate of the cell (A = 0)
-     * @param int $pRow Numeric row coordinate of the cell
-     * @param mixed $pValue Value of the cell
+     * @param int $columnIndex Numeric column coordinate of the cell
+     * @param int $row Numeric row coordinate of the cell
+     * @param mixed $value Value of the cell
      *
      * @return Worksheet
      */
-    public function setCellValueByColumnAndRow($pColumn, $pRow, $pValue)
+    public function setCellValueByColumnAndRow($columnIndex, $row, $value)
     {
-        $this->getCellByColumnAndRow($pColumn, $pRow)->setValue($pValue);
+        $this->getCellByColumnAndRow($columnIndex, $row)->setValue($value);
 
         return $this;
     }
@@ -1156,16 +1156,16 @@ class Worksheet implements IComparable
     /**
      * Set a cell value by using numeric cell coordinates.
      *
-     * @param int $pColumn Numeric column coordinate of the cell (A = 0)
-     * @param int $pRow Numeric row coordinate of the cell
-     * @param mixed $pValue Value of the cell
-     * @param string $pDataType Explicit data type, see DataType::TYPE_*
+     * @param int $columnIndex Numeric column coordinate of the cell
+     * @param int $row Numeric row coordinate of the cell
+     * @param mixed $value Value of the cell
+     * @param string $dataType Explicit data type, see DataType::TYPE_*
      *
      * @return Worksheet
      */
-    public function setCellValueExplicitByColumnAndRow($pColumn, $pRow, $pValue, $pDataType)
+    public function setCellValueExplicitByColumnAndRow($columnIndex, $row, $value, $dataType)
     {
-        $this->getCellByColumnAndRow($pColumn, $pRow)->setValueExplicit($pValue, $pDataType);
+        $this->getCellByColumnAndRow($columnIndex, $row)->setValueExplicit($value, $dataType);
 
         return $this;
     }
@@ -1222,17 +1222,17 @@ class Worksheet implements IComparable
     /**
      * Get cell at a specific coordinate by using numeric cell coordinates.
      *
-     * @param string $pColumn Numeric column coordinate of the cell
-     * @param string $pRow Numeric row coordinate of the cell
+     * @param int $columnIndex Numeric column coordinate of the cell
+     * @param int $row Numeric row coordinate of the cell
      * @param bool $createIfNotExists Flag indicating whether a new cell should be created if it doesn't
      *                                       already exist, or a null should be returned instead
      *
      * @return null|Cell Cell that was found/created or null
      */
-    public function getCellByColumnAndRow($pColumn, $pRow, $createIfNotExists = true)
+    public function getCellByColumnAndRow($columnIndex, $row, $createIfNotExists = true)
     {
-        $columnLetter = Coordinate::stringFromColumnIndex($pColumn);
-        $coordinate = $columnLetter . $pRow;
+        $columnLetter = Coordinate::stringFromColumnIndex($columnIndex);
+        $coordinate = $columnLetter . $row;
 
         if ($this->cellCollection->has($coordinate)) {
             return $this->cellCollection->get($coordinate);
@@ -1330,14 +1330,14 @@ class Worksheet implements IComparable
     /**
      * Cell at a specific coordinate by using numeric cell coordinates exists?
      *
-     * @param string $pColumn Numeric column coordinate of the cell (A = 0)
-     * @param string $pRow Numeric row coordinate of the cell
+     * @param int $columnIndex Numeric column coordinate of the cell
+     * @param int $row Numeric row coordinate of the cell
      *
      * @return bool
      */
-    public function cellExistsByColumnAndRow($pColumn, $pRow)
+    public function cellExistsByColumnAndRow($columnIndex, $row)
     {
-        return $this->cellExists(Coordinate::stringFromColumnIndex($pColumn) . $pRow);
+        return $this->cellExists(Coordinate::stringFromColumnIndex($columnIndex) . $row);
     }
 
     /**
@@ -1397,13 +1397,13 @@ class Worksheet implements IComparable
     /**
      * Get column dimension at a specific column by using numeric cell coordinates.
      *
-     * @param int $pColumn Numeric column coordinate of the cell (A = 0)
+     * @param int $columnIndex Numeric column coordinate of the cell
      *
      * @return ColumnDimension
      */
-    public function getColumnDimensionByColumn($pColumn)
+    public function getColumnDimensionByColumn($columnIndex)
     {
-        return $this->getColumnDimension(Coordinate::stringFromColumnIndex($pColumn));
+        return $this->getColumnDimension(Coordinate::stringFromColumnIndex($columnIndex));
     }
 
     /**
@@ -1511,24 +1511,24 @@ class Worksheet implements IComparable
     /**
      * Get style for cell by using numeric cell coordinates.
      *
-     * @param int $pColumn Numeric column coordinate of the cell (A = 0)
-     * @param int $pRow Numeric row coordinate of the cell
-     * @param int pColumn2 Numeric column coordinate of the range cell (A = 0)
-     * @param int pRow2 Numeric row coordinate of the range cell
-     * @param null|mixed $pColumn2
-     * @param null|mixed $pRow2
+     * @param int $columnIndex1 Numeric column coordinate of the cell
+     * @param int $row1 Numeric row coordinate of the cell
+     * @param int $columnIndex2 Numeric column coordinate of the range cell
+     * @param int $row2 Numeric row coordinate of the range cell
+     * @param null|int $columnIndex2
+     * @param null|int $row2
      *
      * @return Style
      */
-    public function getStyleByColumnAndRow($pColumn, $pRow, $pColumn2 = null, $pRow2 = null)
+    public function getStyleByColumnAndRow($columnIndex1, $row1, $columnIndex2 = null, $row2 = null)
     {
-        if ($pColumn2 !== null && $pRow2 !== null) {
-            $cellRange = Coordinate::stringFromColumnIndex($pColumn) . $pRow . ':' . Coordinate::stringFromColumnIndex($pColumn2) . $pRow2;
+        if ($columnIndex2 !== null && $row2 !== null) {
+            $cellRange = Coordinate::stringFromColumnIndex($columnIndex1) . $row1 . ':' . Coordinate::stringFromColumnIndex($columnIndex2) . $row2;
 
             return $this->getStyle($cellRange);
         }
 
-        return $this->getStyle(Coordinate::stringFromColumnIndex($pColumn) . $pRow);
+        return $this->getStyle(Coordinate::stringFromColumnIndex($columnIndex1) . $row1);
     }
 
     /**
@@ -1569,7 +1569,7 @@ class Worksheet implements IComparable
         // Loop through cells and apply styles
         for ($col = $rangeStart[0]; $col <= $rangeEnd[0]; ++$col) {
             for ($row = $rangeStart[1]; $row <= $rangeEnd[1]; ++$row) {
-                $this->getCell(Coordinate::stringFromColumnIndex($col - 1) . $row)->setXfIndex($xfIndex);
+                $this->getCell(Coordinate::stringFromColumnIndex($col) . $row)->setXfIndex($xfIndex);
             }
         }
 
@@ -1609,7 +1609,7 @@ class Worksheet implements IComparable
         // Loop through cells and apply styles
         for ($col = $rangeStart[0]; $col <= $rangeEnd[0]; ++$col) {
             for ($row = $rangeStart[1]; $row <= $rangeEnd[1]; ++$row) {
-                $this->setConditionalStyles(Coordinate::stringFromColumnIndex($col - 1) . $row, $pCellStyle);
+                $this->setConditionalStyles(Coordinate::stringFromColumnIndex($col) . $row, $pCellStyle);
             }
         }
 
@@ -1649,15 +1649,15 @@ class Worksheet implements IComparable
     /**
      * Set break on a cell by using numeric cell coordinates.
      *
-     * @param int $pColumn Numeric column coordinate of the cell (A = 0)
-     * @param int $pRow Numeric row coordinate of the cell
-     * @param int $pBreak Break type (type of Worksheet::BREAK_*)
+     * @param int $columnIndex Numeric column coordinate of the cell
+     * @param int $row Numeric row coordinate of the cell
+     * @param int $break Break type (type of Worksheet::BREAK_*)
      *
      * @return Worksheet
      */
-    public function setBreakByColumnAndRow($pColumn, $pRow, $pBreak)
+    public function setBreakByColumnAndRow($columnIndex, $row, $break)
     {
-        return $this->setBreak(Coordinate::stringFromColumnIndex($pColumn) . $pRow, $pBreak);
+        return $this->setBreak(Coordinate::stringFromColumnIndex($columnIndex) . $row, $break);
     }
 
     /**
@@ -1715,18 +1715,18 @@ class Worksheet implements IComparable
     /**
      * Set merge on a cell range by using numeric cell coordinates.
      *
-     * @param int $pColumn1 Numeric column coordinate of the first cell (A = 0)
-     * @param int $pRow1 Numeric row coordinate of the first cell
-     * @param int $pColumn2 Numeric column coordinate of the last cell (A = 0)
-     * @param int $pRow2 Numeric row coordinate of the last cell
+     * @param int $columnIndex1 Numeric column coordinate of the first cell
+     * @param int $row1 Numeric row coordinate of the first cell
+     * @param int $columnIndex2 Numeric column coordinate of the last cell
+     * @param int $row2 Numeric row coordinate of the last cell
      *
      * @throws Exception
      *
      * @return Worksheet
      */
-    public function mergeCellsByColumnAndRow($pColumn1, $pRow1, $pColumn2, $pRow2)
+    public function mergeCellsByColumnAndRow($columnIndex1, $row1, $columnIndex2, $row2)
     {
-        $cellRange = Coordinate::stringFromColumnIndex($pColumn1) . $pRow1 . ':' . Coordinate::stringFromColumnIndex($pColumn2) . $pRow2;
+        $cellRange = Coordinate::stringFromColumnIndex($columnIndex1) . $row1 . ':' . Coordinate::stringFromColumnIndex($columnIndex2) . $row2;
 
         return $this->mergeCells($cellRange);
     }
@@ -1761,18 +1761,18 @@ class Worksheet implements IComparable
     /**
      * Remove merge on a cell range by using numeric cell coordinates.
      *
-     * @param int $pColumn1 Numeric column coordinate of the first cell (A = 0)
-     * @param int $pRow1 Numeric row coordinate of the first cell
-     * @param int $pColumn2 Numeric column coordinate of the last cell (A = 0)
-     * @param int $pRow2 Numeric row coordinate of the last cell
+     * @param int $columnIndex1 Numeric column coordinate of the first cell
+     * @param int $row1 Numeric row coordinate of the first cell
+     * @param int $columnIndex2 Numeric column coordinate of the last cell
+     * @param int $row2 Numeric row coordinate of the last cell
      *
      * @throws Exception
      *
      * @return Worksheet
      */
-    public function unmergeCellsByColumnAndRow($pColumn1, $pRow1, $pColumn2, $pRow2)
+    public function unmergeCellsByColumnAndRow($columnIndex1, $row1, $columnIndex2, $row2)
     {
-        $cellRange = Coordinate::stringFromColumnIndex($pColumn1) . $pRow1 . ':' . Coordinate::stringFromColumnIndex($pColumn2) . $pRow2;
+        $cellRange = Coordinate::stringFromColumnIndex($columnIndex1) . $row1 . ':' . Coordinate::stringFromColumnIndex($columnIndex2) . $row2;
 
         return $this->unmergeCells($cellRange);
     }
@@ -1828,22 +1828,22 @@ class Worksheet implements IComparable
     /**
      * Set protection on a cell range by using numeric cell coordinates.
      *
-     * @param int $pColumn1 Numeric column coordinate of the first cell (A = 0)
-     * @param int $pRow1 Numeric row coordinate of the first cell
-     * @param int $pColumn2 Numeric column coordinate of the last cell (A = 0)
-     * @param int $pRow2 Numeric row coordinate of the last cell
-     * @param string $pPassword Password to unlock the protection
-     * @param bool $pAlreadyHashed If the password has already been hashed, set this to true
+     * @param int $columnIndex1 Numeric column coordinate of the first cell
+     * @param int $row1 Numeric row coordinate of the first cell
+     * @param int $columnIndex2 Numeric column coordinate of the last cell
+     * @param int $row2 Numeric row coordinate of the last cell
+     * @param string $password Password to unlock the protection
+     * @param bool $alreadyHashed If the password has already been hashed, set this to true
      *
      * @throws Exception
      *
      * @return Worksheet
      */
-    public function protectCellsByColumnAndRow($pColumn1, $pRow1, $pColumn2, $pRow2, $pPassword, $pAlreadyHashed = false)
+    public function protectCellsByColumnAndRow($columnIndex1, $row1, $columnIndex2, $row2, $password, $alreadyHashed = false)
     {
-        $cellRange = Coordinate::stringFromColumnIndex($pColumn1) . $pRow1 . ':' . Coordinate::stringFromColumnIndex($pColumn2) . $pRow2;
+        $cellRange = Coordinate::stringFromColumnIndex($columnIndex1) . $row1 . ':' . Coordinate::stringFromColumnIndex($columnIndex2) . $row2;
 
-        return $this->protectCells($cellRange, $pPassword, $pAlreadyHashed);
+        return $this->protectCells($cellRange, $password, $alreadyHashed);
     }
 
     /**
@@ -1872,18 +1872,18 @@ class Worksheet implements IComparable
     /**
      * Remove protection on a cell range by using numeric cell coordinates.
      *
-     * @param int $pColumn1 Numeric column coordinate of the first cell (A = 0)
-     * @param int $pRow1 Numeric row coordinate of the first cell
-     * @param int $pColumn2 Numeric column coordinate of the last cell (A = 0)
-     * @param int $pRow2 Numeric row coordinate of the last cell
+     * @param int $columnIndex1 Numeric column coordinate of the first cell
+     * @param int $row1 Numeric row coordinate of the first cell
+     * @param int $columnIndex2 Numeric column coordinate of the last cell
+     * @param int $row2 Numeric row coordinate of the last cell
      *
      * @throws Exception
      *
      * @return Worksheet
      */
-    public function unprotectCellsByColumnAndRow($pColumn1, $pRow1, $pColumn2, $pRow2)
+    public function unprotectCellsByColumnAndRow($columnIndex1, $row1, $columnIndex2, $row2)
     {
-        $cellRange = Coordinate::stringFromColumnIndex($pColumn1) . $pRow1 . ':' . Coordinate::stringFromColumnIndex($pColumn2) . $pRow2;
+        $cellRange = Coordinate::stringFromColumnIndex($columnIndex1) . $row1 . ':' . Coordinate::stringFromColumnIndex($columnIndex2) . $row2;
 
         return $this->unprotectCells($cellRange);
     }
@@ -1932,21 +1932,21 @@ class Worksheet implements IComparable
     /**
      * Set Autofilter Range by using numeric cell coordinates.
      *
-     * @param int $pColumn1 Numeric column coordinate of the first cell (A = 0)
-     * @param int $pRow1 Numeric row coordinate of the first cell
-     * @param int $pColumn2 Numeric column coordinate of the second cell (A = 0)
-     * @param int $pRow2 Numeric row coordinate of the second cell
+     * @param int $columnIndex1 Numeric column coordinate of the first cell
+     * @param int $row1 Numeric row coordinate of the first cell
+     * @param int $columnIndex2 Numeric column coordinate of the second cell
+     * @param int $row2 Numeric row coordinate of the second cell
      *
      * @throws Exception
      *
      * @return Worksheet
      */
-    public function setAutoFilterByColumnAndRow($pColumn1, $pRow1, $pColumn2, $pRow2)
+    public function setAutoFilterByColumnAndRow($columnIndex1, $row1, $columnIndex2, $row2)
     {
         return $this->setAutoFilter(
-            Coordinate::stringFromColumnIndex($pColumn1) . $pRow1
+            Coordinate::stringFromColumnIndex($columnIndex1) . $row1
             . ':' .
-            Coordinate::stringFromColumnIndex($pColumn2) . $pRow2
+            Coordinate::stringFromColumnIndex($columnIndex2) . $row2
         );
     }
 
@@ -2002,16 +2002,16 @@ class Worksheet implements IComparable
     /**
      * Freeze Pane by using numeric cell coordinates.
      *
-     * @param int $pColumn Numeric column coordinate of the cell (A = 0)
-     * @param int $pRow Numeric row coordinate of the cell
+     * @param int $columnIndex Numeric column coordinate of the cell
+     * @param int $row Numeric row coordinate of the cell
      *
      * @throws Exception
      *
      * @return Worksheet
      */
-    public function freezePaneByColumnAndRow($pColumn, $pRow)
+    public function freezePaneByColumnAndRow($columnIndex, $row)
     {
-        return $this->freezePane(Coordinate::stringFromColumnIndex($pColumn) . $pRow);
+        return $this->freezePane(Coordinate::stringFromColumnIndex($columnIndex) . $row);
     }
 
     /**
@@ -2071,20 +2071,20 @@ class Worksheet implements IComparable
     /**
      * Insert a new column, updating all possible related data.
      *
-     * @param int $pBefore Insert before this one (numeric column coordinate of the cell, A = 0)
+     * @param int $beforeColumnIndex Insert before this one (numeric column coordinate of the cell)
      * @param int $pNumCols Number of columns to insert
      *
      * @throws Exception
      *
      * @return Worksheet
      */
-    public function insertNewColumnBeforeByIndex($pBefore, $pNumCols = 1)
+    public function insertNewColumnBeforeByIndex($beforeColumnIndex, $pNumCols = 1)
     {
-        if ($pBefore >= 0) {
-            return $this->insertNewColumnBefore(Coordinate::stringFromColumnIndex($pBefore), $pNumCols);
+        if ($beforeColumnIndex >= 1) {
+            return $this->insertNewColumnBefore(Coordinate::stringFromColumnIndex($beforeColumnIndex), $pNumCols);
         }
 
-        throw new Exception('Columns can only be inserted before at least column A (0).');
+        throw new Exception('Columns can only be inserted before at least column A (1).');
     }
 
     /**
@@ -2128,12 +2128,12 @@ class Worksheet implements IComparable
     {
         if (!is_numeric($pColumn)) {
             $highestColumn = $this->getHighestDataColumn();
-            $pColumn = Coordinate::stringFromColumnIndex(Coordinate::columnIndexFromString($pColumn) - 1 + $pNumCols);
+            $pColumn = Coordinate::stringFromColumnIndex(Coordinate::columnIndexFromString($pColumn) + $pNumCols);
             $objReferenceHelper = ReferenceHelper::getInstance();
             $objReferenceHelper->insertNewBefore($pColumn . '1', -$pNumCols, 0, $this);
             for ($c = 0; $c < $pNumCols; ++$c) {
                 $this->getCellCollection()->removeColumn($highestColumn);
-                $highestColumn = Coordinate::stringFromColumnIndex(Coordinate::columnIndexFromString($highestColumn) - 2);
+                $highestColumn = Coordinate::stringFromColumnIndex(Coordinate::columnIndexFromString($highestColumn) - 1);
             }
         } else {
             throw new Exception('Column references should not be numeric.');
@@ -2145,20 +2145,20 @@ class Worksheet implements IComparable
     /**
      * Remove a column, updating all possible related data.
      *
-     * @param int $pColumn Remove starting with this one (numeric column coordinate of the cell A = 0)
-     * @param int $pNumCols Number of columns to remove
+     * @param int $columnIndex Remove starting with this one (numeric column coordinate of the cell)
+     * @param int $numColumns Number of columns to remove
      *
      * @throws Exception
      *
      * @return Worksheet
      */
-    public function removeColumnByIndex($pColumn, $pNumCols = 1)
+    public function removeColumnByIndex($columnIndex, $numColumns = 1)
     {
-        if ($pColumn >= 0) {
-            return $this->removeColumn(Coordinate::stringFromColumnIndex($pColumn), $pNumCols);
+        if ($columnIndex >= 1) {
+            return $this->removeColumn(Coordinate::stringFromColumnIndex($columnIndex), $numColumns);
         }
 
-        throw new Exception('Columns to be deleted should at least start from column 0');
+        throw new Exception('Columns to be deleted should at least start from column A (1)');
     }
 
     /**
@@ -2343,14 +2343,14 @@ class Worksheet implements IComparable
     /**
      * Get comment for cell by using numeric cell coordinates.
      *
-     * @param int $pColumn Numeric column coordinate of the cell (A = 0)
-     * @param int $pRow Numeric row coordinate of the cell
+     * @param int $columnIndex Numeric column coordinate of the cell
+     * @param int $row Numeric row coordinate of the cell
      *
      * @return Comment
      */
-    public function getCommentByColumnAndRow($pColumn, $pRow)
+    public function getCommentByColumnAndRow($columnIndex, $row)
     {
-        return $this->getComment(Coordinate::stringFromColumnIndex($pColumn) . $pRow);
+        return $this->getComment(Coordinate::stringFromColumnIndex($columnIndex) . $row);
     }
 
     /**
@@ -2425,16 +2425,16 @@ class Worksheet implements IComparable
     /**
      * Selected cell by using numeric cell coordinates.
      *
-     * @param int $pColumn Numeric column coordinate of the cell (A = 0)
-     * @param int $pRow Numeric row coordinate of the cell
+     * @param int $columnIndex Numeric column coordinate of the cell
+     * @param int $row Numeric row coordinate of the cell
      *
      * @throws Exception
      *
      * @return Worksheet
      */
-    public function setSelectedCellByColumnAndRow($pColumn, $pRow)
+    public function setSelectedCellByColumnAndRow($columnIndex, $row)
     {
-        return $this->setSelectedCells(Coordinate::stringFromColumnIndex($pColumn) . $pRow);
+        return $this->setSelectedCells(Coordinate::stringFromColumnIndex($columnIndex) . $row);
     }
 
     /**
@@ -2524,9 +2524,9 @@ class Worksheet implements IComparable
         $returnValue = [];
         //    Identify the range that we need to extract from the worksheet
         list($rangeStart, $rangeEnd) = Coordinate::rangeBoundaries($pRange);
-        $minCol = Coordinate::stringFromColumnIndex($rangeStart[0] - 1);
+        $minCol = Coordinate::stringFromColumnIndex($rangeStart[0]);
         $minRow = $rangeStart[1];
-        $maxCol = Coordinate::stringFromColumnIndex($rangeEnd[0] - 1);
+        $maxCol = Coordinate::stringFromColumnIndex($rangeEnd[0]);
         $maxRow = $rangeEnd[1];
 
         ++$maxCol;
@@ -2653,7 +2653,7 @@ class Worksheet implements IComparable
     }
 
     /**
-     * Run PhpSpreadsheet garabage collector.
+     * Run PhpSpreadsheet garbage collector.
      *
      * @return Worksheet
      */
@@ -2678,10 +2678,10 @@ class Worksheet implements IComparable
         }
 
         // Cache values
-        if ($highestColumn < 0) {
+        if ($highestColumn < 1) {
             $this->cachedHighestColumn = 'A';
         } else {
-            $this->cachedHighestColumn = Coordinate::stringFromColumnIndex(--$highestColumn);
+            $this->cachedHighestColumn = Coordinate::stringFromColumnIndex($highestColumn);
         }
         $this->cachedHighestRow = $highestRow;
 
diff --git a/src/PhpSpreadsheet/Writer/Html.php b/src/PhpSpreadsheet/Writer/Html.php
index eecd9fa8..7e1a0048 100644
--- a/src/PhpSpreadsheet/Writer/Html.php
+++ b/src/PhpSpreadsheet/Writer/Html.php
@@ -434,9 +434,9 @@ class Html extends BaseWriter
             // Get worksheet dimension
             $dimension = explode(':', $sheet->calculateWorksheetDimension());
             $dimension[0] = Coordinate::coordinateFromString($dimension[0]);
-            $dimension[0][0] = Coordinate::columnIndexFromString($dimension[0][0]) - 1;
+            $dimension[0][0] = Coordinate::columnIndexFromString($dimension[0][0]);
             $dimension[1] = Coordinate::coordinateFromString($dimension[1]);
-            $dimension[1][0] = Coordinate::columnIndexFromString($dimension[1][0]) - 1;
+            $dimension[1][0] = Coordinate::columnIndexFromString($dimension[1][0]);
 
             // row min,max
             $rowMin = $dimension[0][1];
@@ -476,14 +476,15 @@ class Html extends BaseWriter
                     // Start a new rowData
                     $rowData = [];
                     // Loop through columns
-                    $column = $dimension[0][0] - 1;
-                    while ($column++ < $dimension[1][0]) {
+                    $column = $dimension[0][0];
+                    while ($column <= $dimension[1][0]) {
                         // Cell exists?
                         if ($sheet->cellExistsByColumnAndRow($column, $row)) {
                             $rowData[$column] = Coordinate::stringFromColumnIndex($column) . $row;
                         } else {
                             $rowData[$column] = '';
                         }
+                        ++$column;
                     }
                     $html .= $this->generateRow($sheet, $rowData, $row - 1, $cellType);
                 }
@@ -1210,7 +1211,7 @@ class Html extends BaseWriter
         $colNum = 0;
         foreach ($pValues as $cellAddress) {
             $cell = ($cellAddress > '') ? $pSheet->getCell($cellAddress) : '';
-            $coordinate = Coordinate::stringFromColumnIndex($colNum) . ($pRow + 1);
+            $coordinate = Coordinate::stringFromColumnIndex($colNum + 1) . ($pRow + 1);
             if (!$this->useInlineCss) {
                 $cssClass = 'column' . $colNum;
             } else {
@@ -1340,7 +1341,7 @@ class Html extends BaseWriter
 
                 //    Also apply style from last cell in merge to fix borders -
                 //        relies on !important for non-none border declarations in createCSSStyleBorder
-                $endCellCoord = Coordinate::stringFromColumnIndex($colNum + $colSpan - 1) . ($pRow + $rowSpan);
+                $endCellCoord = Coordinate::stringFromColumnIndex($colNum + $colSpan) . ($pRow + $rowSpan);
                 if (!$this->useInlineCss) {
                     $cssClass .= ' style' . $pSheet->getCell($endCellCoord)->getXfIndex();
                 }
diff --git a/src/PhpSpreadsheet/Writer/Xls.php b/src/PhpSpreadsheet/Writer/Xls.php
index effa3782..6dff1342 100644
--- a/src/PhpSpreadsheet/Writer/Xls.php
+++ b/src/PhpSpreadsheet/Writer/Xls.php
@@ -334,7 +334,7 @@ class Xls extends BaseWriter
                     // create an Drawing Object for the dropdown
                     $oDrawing = new BaseDrawing();
                     // get the coordinates of drawing
-                    $cDrawing = Coordinate::stringFromColumnIndex($iInc - 1) . $rangeBounds[0][1];
+                    $cDrawing = Coordinate::stringFromColumnIndex($iInc) . $rangeBounds[0][1];
                     $oDrawing->setCoordinates($cDrawing);
                     $oDrawing->setWorksheet($sheet);
 
@@ -363,7 +363,7 @@ class Xls extends BaseWriter
                     $spContainer->setOPT(0x03BF, 0x000A0000); // Group Shape -> fPrint
 
                     // set coordinates and offsets, client anchor
-                    $endCoordinates = Coordinate::stringFromColumnIndex($iInc - 1);
+                    $endCoordinates = Coordinate::stringFromColumnIndex($iInc);
                     $endCoordinates .= $rangeBounds[0][1] + 1;
 
                     $spContainer->setStartCoordinates($cDrawing);
diff --git a/src/PhpSpreadsheet/Writer/Xls/Worksheet.php b/src/PhpSpreadsheet/Writer/Xls/Worksheet.php
index 96600169..5f374781 100644
--- a/src/PhpSpreadsheet/Writer/Xls/Worksheet.php
+++ b/src/PhpSpreadsheet/Writer/Xls/Worksheet.php
@@ -310,7 +310,7 @@ class Worksheet extends BIFFwriter
 
             $width = $defaultWidth;
 
-            $columnLetter = Coordinate::stringFromColumnIndex($i);
+            $columnLetter = Coordinate::stringFromColumnIndex($i + 1);
             if (isset($columnDimensions[$columnLetter])) {
                 $columnDimension = $columnDimensions[$columnLetter];
                 if ($columnDimension->getWidth() >= 0) {
@@ -2288,7 +2288,7 @@ class Worksheet extends BIFFwriter
         $row_end = $row_start; // Row containing bottom right corner of object
 
         // Zero the specified offset if greater than the cell dimensions
-        if ($x1 >= Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_start))) {
+        if ($x1 >= Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_start + 1))) {
             $x1 = 0;
         }
         if ($y1 >= Xls::sizeRow($this->phpSheet, $row_start + 1)) {
@@ -2299,8 +2299,8 @@ class Worksheet extends BIFFwriter
         $height = $height + $y1 - 1;
 
         // Subtract the underlying cell widths to find the end cell of the image
-        while ($width >= Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_end))) {
-            $width -= Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_end));
+        while ($width >= Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_end + 1))) {
+            $width -= Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_end + 1));
             ++$col_end;
         }
 
@@ -2313,10 +2313,10 @@ class Worksheet extends BIFFwriter
         // Bitmap isn't allowed to start or finish in a hidden cell, i.e. a cell
         // with zero eight or width.
         //
-        if (Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_start)) == 0) {
+        if (Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_start + 1)) == 0) {
             return;
         }
-        if (Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_end)) == 0) {
+        if (Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_end + 1)) == 0) {
             return;
         }
         if (Xls::sizeRow($this->phpSheet, $row_start + 1) == 0) {
@@ -2327,9 +2327,9 @@ class Worksheet extends BIFFwriter
         }
 
         // Convert the pixel values to the percentage value expected by Excel
-        $x1 = $x1 / Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_start)) * 1024;
+        $x1 = $x1 / Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_start + 1)) * 1024;
         $y1 = $y1 / Xls::sizeRow($this->phpSheet, $row_start + 1) * 256;
-        $x2 = $width / Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_end)) * 1024; // Distance to right side of object
+        $x2 = $width / Xls::sizeCol($this->phpSheet, Coordinate::stringFromColumnIndex($col_end + 1)) * 1024; // Distance to right side of object
         $y2 = $height / Xls::sizeRow($this->phpSheet, $row_end + 1) * 256; // Distance to bottom of object
 
         $this->writeObjPicture($col_start, $x1, $row_start, $y1, $col_end, $x2, $row_end, $y2);
diff --git a/tests/PhpSpreadsheetTests/Cell/CoordinateTest.php b/tests/PhpSpreadsheetTests/Cell/CoordinateTest.php
index 41235f6d..e6efa88e 100644
--- a/tests/PhpSpreadsheetTests/Cell/CoordinateTest.php
+++ b/tests/PhpSpreadsheetTests/Cell/CoordinateTest.php
@@ -12,11 +12,15 @@ class CoordinateTest extends TestCase
      * @dataProvider providerColumnString
      *
      * @param mixed $expectedResult
+     * @param mixed $string
      */
-    public function testColumnIndexFromString($expectedResult, ...$args)
+    public function testColumnIndexFromString($expectedResult, $string)
     {
-        $result = Coordinate::columnIndexFromString(...$args);
-        self::assertEquals($expectedResult, $result);
+        $columnIndex = Coordinate::columnIndexFromString($string);
+        self::assertEquals($expectedResult, $columnIndex);
+
+        $stringBack = Coordinate::stringFromColumnIndex($columnIndex);
+        self::assertEquals($stringBack, $string, 'should be able to get the original input with opposite method');
     }
 
     public function providerColumnString()
@@ -58,11 +62,15 @@ class CoordinateTest extends TestCase
      * @dataProvider providerColumnIndex
      *
      * @param mixed $expectedResult
+     * @param int $columnIndex
      */
-    public function testStringFromColumnIndex($expectedResult, ...$args)
+    public function testStringFromColumnIndex($expectedResult, $columnIndex)
     {
-        $result = Coordinate::stringFromColumnIndex(...$args);
-        self::assertEquals($expectedResult, $result);
+        $string = Coordinate::stringFromColumnIndex($columnIndex);
+        self::assertEquals($expectedResult, $string);
+
+        $columnIndexBack = Coordinate::columnIndexFromString($string);
+        self::assertEquals($columnIndexBack, $columnIndex, 'should be able to get the original input with opposite method');
     }
 
     public function providerColumnIndex()
diff --git a/tests/PhpSpreadsheetTests/Helper/SampleTest.php b/tests/PhpSpreadsheetTests/Helper/SampleTest.php
index 09d6e5c2..2f87d058 100644
--- a/tests/PhpSpreadsheetTests/Helper/SampleTest.php
+++ b/tests/PhpSpreadsheetTests/Helper/SampleTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheetTests\Sample;
+namespace PhpOffice\PhpSpreadsheetTests\Helper;
 
 use PhpOffice\PhpSpreadsheet\Helper\Sample;
 use PHPUnit\Framework\TestCase;
diff --git a/tests/data/ColumnIndex.php b/tests/data/ColumnIndex.php
index 597451fd..750ef823 100644
--- a/tests/data/ColumnIndex.php
+++ b/tests/data/ColumnIndex.php
@@ -3,50 +3,50 @@
 return [
     [
         'A',
-        0,
+        1,
     ],
     [
         'Z',
-        25,
-    ],
-    [
-        'AA',
         26,
     ],
     [
-        'AB',
+        'AA',
         27,
     ],
     [
-        'AZ',
-        51,
+        'AB',
+        28,
     ],
     [
-        'BA',
+        'AZ',
         52,
     ],
     [
-        'BZ',
-        77,
+        'BA',
+        53,
     ],
     [
-        'CA',
+        'BZ',
         78,
     ],
+    [
+        'CA',
+        79,
+    ],
     [
         'IV',
-        255,
+        256,
     ],
     [
         'ZZ',
-        701,
-    ],
-    [
-        'AAA',
         702,
     ],
+    [
+        'AAA',
+        703,
+    ],
     [
         'BAA',
-        1378,
+        1379,
     ],
 ];