diff --git a/CHANGELOG.md b/CHANGELOG.md
index 503f1121..5c838750 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -25,6 +25,8 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 
 ### Changed
 
+- Better enforcement of value modification to match specified datatype when using setValueExplicit() 
+- Relax validation of merge cells to allow merge for a single cell reference [Issue #2776](https://github.com/PHPOffice/PhpSpreadsheet/issues/2776)
 - Memory and speed improvements, particularly for the Cell Collection, and the Writers.
 
   See [the Discussion section on github](https://github.com/PHPOffice/PhpSpreadsheet/discussions/2821) for details of performance across versions
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 0a131911..3cc183e2 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -1170,21 +1170,11 @@ parameters:
 			count: 2
 			path: src/PhpSpreadsheet/Chart/DataSeries.php
 
-		-
-			message: "#^Parameter \\#1 \\$angle of method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\GridLines\\:\\:setShadowAngle\\(\\) expects int, int\\|null given\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Chart/GridLines.php
-
 		-
 			message: "#^Parameter \\#1 \\$color of method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\GridLines\\:\\:setGlowColor\\(\\) expects string, string\\|null given\\.$#"
 			count: 1
 			path: src/PhpSpreadsheet/Chart/GridLines.php
 
-		-
-			message: "#^Parameter \\#1 \\$distance of method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\GridLines\\:\\:setShadowDistance\\(\\) expects float, float\\|null given\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Chart/GridLines.php
-
 		-
 			message: "#^Parameter \\#2 \\$alpha of method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\GridLines\\:\\:setGlowColor\\(\\) expects int, int\\|null given\\.$#"
 			count: 1
@@ -1275,36 +1265,6 @@ parameters:
 			count: 1
 			path: src/PhpSpreadsheet/Chart/Properties.php
 
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\Properties\\:\\:getTrueAlpha\\(\\) has no return type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Chart/Properties.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\Properties\\:\\:getTrueAlpha\\(\\) has parameter \\$alpha with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Chart/Properties.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\Properties\\:\\:setColorProperties\\(\\) has no return type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Chart/Properties.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\Properties\\:\\:setColorProperties\\(\\) has parameter \\$alpha with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Chart/Properties.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\Properties\\:\\:setColorProperties\\(\\) has parameter \\$color with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Chart/Properties.php
-
-		-
-			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\Properties\\:\\:setColorProperties\\(\\) has parameter \\$colorType with no type specified\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Chart/Properties.php
-
 		-
 			message: "#^Method PhpOffice\\\\PhpSpreadsheet\\\\Chart\\\\Renderer\\\\JpGraph\\:\\:formatDataSetLabels\\(\\) has no return type specified\\.$#"
 			count: 1
@@ -4467,12 +4427,12 @@ parameters:
 
 		-
 			message: "#^Parameter \\#2 \\$value of method XMLWriter\\:\\:writeAttribute\\(\\) expects string, array\\|int\\|string given\\.$#"
-			count: 8
+			count: 2
 			path: src/PhpSpreadsheet/Writer/Xlsx/Chart.php
 
 		-
 			message: "#^Parameter \\#2 \\$value of method XMLWriter\\:\\:writeAttribute\\(\\) expects string, array\\|int\\|string\\|null given\\.$#"
-			count: 2
+			count: 1
 			path: src/PhpSpreadsheet/Writer/Xlsx/Chart.php
 
 		-
@@ -4515,11 +4475,6 @@ parameters:
 			count: 2
 			path: src/PhpSpreadsheet/Writer/Xlsx/Chart.php
 
-		-
-			message: "#^Part \\$xAxis\\-\\>getShadowProperty\\('effect'\\) \\(array\\|int\\|string\\|null\\) of encapsed string cannot be cast to string\\.$#"
-			count: 1
-			path: src/PhpSpreadsheet/Writer/Xlsx/Chart.php
-
 		-
 			message: "#^Part \\$xAxis\\-\\>getShadowProperty\\(\\['color', 'type'\\]\\) \\(array\\|int\\|string\\|null\\) of encapsed string cannot be cast to string\\.$#"
 			count: 1
diff --git a/src/PhpSpreadsheet/Cell/Cell.php b/src/PhpSpreadsheet/Cell/Cell.php
index 76d5e86d..2005694d 100644
--- a/src/PhpSpreadsheet/Cell/Cell.php
+++ b/src/PhpSpreadsheet/Cell/Cell.php
@@ -202,6 +202,11 @@ class Cell
      *
      * @param mixed $value Value
      * @param string $dataType Explicit data type, see DataType::TYPE_*
+     *        Note that PhpSpreadsheet does not validate that the value and datatype are consistent, in using this
+     *             method, then it is your responsibility as an end-user developer to validate that the value and
+     *             the datatype match.
+     *       If you do mismatch value and datatpe, then the value you enter may be changed to match the datatype
+     *          that you specify.
      *
      * @return Cell
      */
@@ -210,7 +215,7 @@ class Cell
         // set the value according to data type
         switch ($dataType) {
             case DataType::TYPE_NULL:
-                $this->value = $value;
+                $this->value = null;
 
                 break;
             case DataType::TYPE_STRING2:
diff --git a/src/PhpSpreadsheet/Cell/DataType.php b/src/PhpSpreadsheet/Cell/DataType.php
index 0f7efe2a..390dcde5 100644
--- a/src/PhpSpreadsheet/Cell/DataType.php
+++ b/src/PhpSpreadsheet/Cell/DataType.php
@@ -48,7 +48,7 @@ class DataType
      *
      * @param null|RichText|string $textValue Value to sanitize to an Excel string
      *
-     * @return null|RichText|string Sanitized value
+     * @return RichText|string Sanitized value
      */
     public static function checkString($textValue)
     {
@@ -58,7 +58,7 @@ class DataType
         }
 
         // string must never be longer than 32,767 characters, truncate if necessary
-        $textValue = StringHelper::substring($textValue, 0, 32767);
+        $textValue = StringHelper::substring((string) $textValue, 0, 32767);
 
         // we require that newline is represented as "\n" in core, not as "\r\n" or "\r"
         $textValue = str_replace(["\r\n", "\r"], "\n", $textValue);
diff --git a/src/PhpSpreadsheet/Chart/Axis.php b/src/PhpSpreadsheet/Chart/Axis.php
index 3a72e725..69607216 100644
--- a/src/PhpSpreadsheet/Chart/Axis.php
+++ b/src/PhpSpreadsheet/Chart/Axis.php
@@ -89,25 +89,7 @@ class Axis extends Properties
      *
      * @var mixed[]
      */
-    private $shadowProperties = [
-        'presets' => self::SHADOW_PRESETS_NOSHADOW,
-        'effect' => null,
-        'color' => [
-            'type' => self::EXCEL_COLOR_TYPE_STANDARD,
-            'value' => 'black',
-            'alpha' => 40,
-        ],
-        'size' => [
-            'sx' => null,
-            'sy' => null,
-            'kx' => null,
-        ],
-        'blur' => null,
-        'direction' => null,
-        'distance' => null,
-        'algn' => null,
-        'rotWithShape' => null,
-    ];
+    private $shadowProperties = Properties::PRESETS_OPTIONS[0];
 
     /**
      * Glow Properties.
@@ -340,6 +322,20 @@ class Axis extends Properties
         return $this->getLineStyleArrowSize($this->lineStyleProperties['arrow'][$arrow]['size'], 'len');
     }
 
+    /**
+     * @param mixed $value
+     */
+    public function setShadowProperty(string $propertyName, $value): self
+    {
+        if ($propertyName === 'color' && is_array($value)) {
+            $this->setShadowColor($value['value'], $value['alpha'], $value['type']);
+        } else {
+            $this->shadowProperties[$propertyName] = $value;
+        }
+
+        return $this;
+    }
+
     /**
      * Set Shadow Properties.
      *
@@ -379,6 +375,8 @@ class Axis extends Properties
         return $this;
     }
 
+    private const SHADOW_ARRAY_KEYS = ['size', 'color'];
+
     /**
      * Set Shadow Properties from Mapped Values.
      *
@@ -391,12 +389,10 @@ class Axis extends Properties
         $base_reference = $reference;
         foreach ($propertiesMap as $property_key => $property_val) {
             if (is_array($property_val)) {
-                if ($reference === null) {
+                if (in_array($property_key, self::SHADOW_ARRAY_KEYS, true)) {
                     $reference = &$this->shadowProperties[$property_key];
-                } else {
-                    $reference = &$reference[$property_key];
+                    $this->setShadowPropertiesMapValues($property_val, $reference);
                 }
-                $this->setShadowPropertiesMapValues($property_val, $reference);
             } else {
                 if ($base_reference === null) {
                     $this->shadowProperties[$property_key] = $property_val;
@@ -435,7 +431,7 @@ class Axis extends Properties
     private function setShadowBlur($blur)
     {
         if ($blur !== null) {
-            $this->shadowProperties['blur'] = (string) $this->getExcelPointsWidth($blur);
+            $this->shadowProperties['blur'] = $blur;
         }
 
         return $this;
@@ -444,14 +440,14 @@ class Axis extends Properties
     /**
      * Set Shadow Angle.
      *
-     * @param null|int $angle
+     * @param null|float|int $angle
      *
      * @return $this
      */
     private function setShadowAngle($angle)
     {
-        if ($angle !== null) {
-            $this->shadowProperties['direction'] = (string) $this->getExcelPointsAngle($angle);
+        if (is_numeric($angle)) {
+            $this->shadowProperties['direction'] = $angle;
         }
 
         return $this;
@@ -467,7 +463,7 @@ class Axis extends Properties
     private function setShadowDistance($distance)
     {
         if ($distance !== null) {
-            $this->shadowProperties['distance'] = (string) $this->getExcelPointsWidth($distance);
+            $this->shadowProperties['distance'] = $distance;
         }
 
         return $this;
@@ -525,7 +521,7 @@ class Axis extends Properties
     private function setGlowSize($size)
     {
         if ($size !== null) {
-            $this->glowProperties['size'] = $this->getExcelPointsWidth($size);
+            $this->glowProperties['size'] = $size;
         }
 
         return $this;
@@ -555,7 +551,7 @@ class Axis extends Properties
     public function setSoftEdges($size): void
     {
         if ($size !== null) {
-            $this->softEdges['size'] = (string) $this->getExcelPointsWidth($size);
+            $this->softEdges['size'] = $size;
         }
     }
 
diff --git a/src/PhpSpreadsheet/Chart/GridLines.php b/src/PhpSpreadsheet/Chart/GridLines.php
index 84af3ada..ad254c8c 100644
--- a/src/PhpSpreadsheet/Chart/GridLines.php
+++ b/src/PhpSpreadsheet/Chart/GridLines.php
@@ -45,25 +45,7 @@ class GridLines extends Properties
         ],
     ];
 
-    private $shadowProperties = [
-        'presets' => self::SHADOW_PRESETS_NOSHADOW,
-        'effect' => null,
-        'color' => [
-            'type' => self::EXCEL_COLOR_TYPE_STANDARD,
-            'value' => 'black',
-            'alpha' => 85,
-        ],
-        'size' => [
-            'sx' => null,
-            'sy' => null,
-            'kx' => null,
-        ],
-        'blur' => null,
-        'direction' => null,
-        'distance' => null,
-        'algn' => null,
-        'rotWithShape' => null,
-    ];
+    private $shadowProperties = Properties::PRESETS_OPTIONS[0];
 
     private $glowProperties = [
         'size' => null,
@@ -202,6 +184,18 @@ class GridLines extends Properties
             ->setGlowColor($colorValue, $colorAlpha, $colorType);
     }
 
+    /**
+     * Get Glow Property.
+     *
+     * @param array|string $property
+     *
+     * @return null|string
+     */
+    public function getGlowProperty($property)
+    {
+        return $this->getArrayElementsValue($this->glowProperties, $property);
+    }
+
     /**
      * Get Glow Color Property.
      *
@@ -233,7 +227,7 @@ class GridLines extends Properties
      */
     private function setGlowSize($size)
     {
-        $this->glowProperties['size'] = $this->getExcelPointsWidth((float) $size);
+        $this->glowProperties['size'] = $size;
 
         return $this;
     }
@@ -253,7 +247,7 @@ class GridLines extends Properties
             $this->glowProperties['color']['value'] = (string) $color;
         }
         if ($alpha !== null) {
-            $this->glowProperties['color']['alpha'] = $this->getTrueAlpha((int) $alpha);
+            $this->glowProperties['color']['alpha'] = (int) $alpha;
         }
         if ($colorType !== null) {
             $this->glowProperties['color']['type'] = (string) $colorType;
@@ -275,16 +269,27 @@ class GridLines extends Properties
         return $this->getLineStyleArrowSize($this->lineProperties['style']['arrow'][$arrowSelector]['size'], $propertySelector);
     }
 
+    /**
+     * @param mixed $value
+     */
+    public function setShadowProperty(string $propertyName, $value): self
+    {
+        $this->activateObject();
+        $this->shadowProperties[$propertyName] = $value;
+
+        return $this;
+    }
+
     /**
      * Set Shadow Properties.
      *
      * @param int $presets
      * @param string $colorValue
      * @param string $colorType
-     * @param string $colorAlpha
-     * @param string $blur
-     * @param int $angle
-     * @param float $distance
+     * @param null|float|int|string $colorAlpha
+     * @param null|float $blur
+     * @param null|int $angle
+     * @param null|float $distance
      */
     public function setShadowProperties($presets, $colorValue = null, $colorType = null, $colorAlpha = null, $blur = null, $angle = null, $distance = null): void
     {
@@ -292,10 +297,10 @@ class GridLines extends Properties
             ->setShadowPresetsProperties((int) $presets)
             ->setShadowColor(
                 $colorValue ?? $this->shadowProperties['color']['value'],
-                $colorAlpha === null ? (int) $this->shadowProperties['color']['alpha'] : $this->getTrueAlpha($colorAlpha),
+                $colorAlpha === null ? (int) $this->shadowProperties['color']['alpha'] : (int) $colorAlpha,
                 $colorType ?? $this->shadowProperties['color']['type']
             )
-            ->setShadowBlur((float) $blur)
+            ->setShadowBlur($blur)
             ->setShadowAngle($angle)
             ->setShadowDistance($distance);
     }
@@ -315,6 +320,8 @@ class GridLines extends Properties
         return $this;
     }
 
+    private const SHADOW_ARRAY_KEYS = ['size', 'color'];
+
     /**
      * Set Shadow Properties Values.
      *
@@ -327,12 +334,10 @@ class GridLines extends Properties
         $base_reference = $reference;
         foreach ($propertiesMap as $property_key => $property_val) {
             if (is_array($property_val)) {
-                if ($reference === null) {
+                if (in_array($property_key, self::SHADOW_ARRAY_KEYS, true)) {
                     $reference = &$this->shadowProperties[$property_key];
-                } else {
-                    $reference = &$reference[$property_key];
+                    $this->setShadowPropertiesMapValues($property_val, $reference);
                 }
-                $this->setShadowPropertiesMapValues($property_val, $reference);
             } else {
                 if ($base_reference === null) {
                     $this->shadowProperties[$property_key] = $property_val;
@@ -360,7 +365,7 @@ class GridLines extends Properties
             $this->shadowProperties['color']['value'] = (string) $color;
         }
         if ($alpha !== null) {
-            $this->shadowProperties['color']['alpha'] = $this->getTrueAlpha((int) $alpha);
+            $this->shadowProperties['color']['alpha'] = (int) $alpha;
         }
         if ($colorType !== null) {
             $this->shadowProperties['color']['type'] = (string) $colorType;
@@ -372,14 +377,14 @@ class GridLines extends Properties
     /**
      * Set Shadow Blur.
      *
-     * @param float $blur
+     * @param ?float $blur
      *
      * @return $this
      */
     private function setShadowBlur($blur)
     {
         if ($blur !== null) {
-            $this->shadowProperties['blur'] = (string) $this->getExcelPointsWidth($blur);
+            $this->shadowProperties['blur'] = $blur;
         }
 
         return $this;
@@ -388,14 +393,14 @@ class GridLines extends Properties
     /**
      * Set Shadow Angle.
      *
-     * @param int $angle
+     * @param null|float|int|string $angle
      *
      * @return $this
      */
     private function setShadowAngle($angle)
     {
-        if ($angle !== null) {
-            $this->shadowProperties['direction'] = (string) $this->getExcelPointsAngle($angle);
+        if (is_numeric($angle)) {
+            $this->shadowProperties['direction'] = $angle;
         }
 
         return $this;
@@ -404,14 +409,14 @@ class GridLines extends Properties
     /**
      * Set Shadow Distance.
      *
-     * @param float $distance
+     * @param ?float $distance
      *
      * @return $this
      */
     private function setShadowDistance($distance)
     {
         if ($distance !== null) {
-            $this->shadowProperties['distance'] = (string) $this->getExcelPointsWidth($distance);
+            $this->shadowProperties['distance'] = $distance;
         }
 
         return $this;
@@ -434,11 +439,11 @@ class GridLines extends Properties
      *
      * @param float $size
      */
-    public function setSoftEdgesSize($size): void
+    public function setSoftEdges($size): void
     {
         if ($size !== null) {
             $this->activateObject();
-            $this->softEdges['size'] = (string) $this->getExcelPointsWidth($size);
+            $this->softEdges['size'] = $size;
         }
     }
 
diff --git a/src/PhpSpreadsheet/Chart/Properties.php b/src/PhpSpreadsheet/Chart/Properties.php
index 800f6aaf..01a83915 100644
--- a/src/PhpSpreadsheet/Chart/Properties.php
+++ b/src/PhpSpreadsheet/Chart/Properties.php
@@ -110,7 +110,10 @@ abstract class Properties
     const SHADOW_PRESETS_PERSPECTIVE_UPPER_LEFT = 21;
     const SHADOW_PRESETS_PERSPECTIVE_LOWER_RIGHT = 22;
     const SHADOW_PRESETS_PERSPECTIVE_LOWER_LEFT = 23;
+
     const POINTS_WIDTH_MULTIPLIER = 12700;
+    const ANGLE_MULTIPLIER = 60000; // direction and size-kx size-ky
+    const PERCENTAGE_MULTIPLIER = 100000; // size sx and sy
 
     /**
      * @param float $width
@@ -122,27 +125,58 @@ abstract class Properties
         return $width * self::POINTS_WIDTH_MULTIPLIER;
     }
 
-    /**
-     * @param float $angle
-     *
-     * @return float
-     */
-    protected function getExcelPointsAngle($angle)
+    public static function pointsToXml(float $width): string
     {
-        return $angle * 60000;
+        return (string) (int) ($width * self::POINTS_WIDTH_MULTIPLIER);
     }
 
-    protected function getTrueAlpha($alpha)
+    public static function xmlToPoints(string $width): float
+    {
+        return ((float) $width) / self::POINTS_WIDTH_MULTIPLIER;
+    }
+
+    public static function angleToXml(float $angle): string
+    {
+        return (string) (int) ($angle * self::ANGLE_MULTIPLIER);
+    }
+
+    public static function xmlToAngle(string $angle): float
+    {
+        return ((float) $angle) / self::ANGLE_MULTIPLIER;
+    }
+
+    public static function tenthOfPercentToXml(float $value): string
+    {
+        return (string) (int) ($value * self::PERCENTAGE_MULTIPLIER);
+    }
+
+    public static function xmlToTenthOfPercent(string $value): float
+    {
+        return ((float) $value) / self::PERCENTAGE_MULTIPLIER;
+    }
+
+    public static function alphaToXml(int $alpha): string
     {
         return (string) (100 - $alpha) . '000';
     }
 
-    protected function setColorProperties($color, $alpha, $colorType)
+    /**
+     * @param float|int|string $alpha
+     */
+    public static function alphaFromXml($alpha): int
+    {
+        return 100 - ((int) $alpha / 1000);
+    }
+
+    /**
+     * @param null|float|int|string $alpha
+     */
+    protected function setColorProperties(?string $color, $alpha, ?string $colorType): array
     {
         return [
-            'type' => (string) $colorType,
-            'value' => (string) $color,
-            'alpha' => (string) $this->getTrueAlpha($alpha),
+            'type' => $colorType,
+            'value' => $color,
+            'alpha' => (int) $alpha,
         ];
     }
 
@@ -163,196 +197,217 @@ abstract class Properties
         return $sizes[$arraySelector][$arrayKaySelector];
     }
 
+    protected const PRESETS_OPTIONS = [
+        //NONE
+        0 => [
+            'presets' => self::SHADOW_PRESETS_NOSHADOW,
+            'effect' => null,
+            'color' => [
+                'type' => self::EXCEL_COLOR_TYPE_STANDARD,
+                'value' => 'black',
+                'alpha' => 40,
+            ],
+            'size' => [
+                'sx' => null,
+                'sy' => null,
+                'kx' => null,
+                'ky' => null,
+            ],
+            'blur' => null,
+            'direction' => null,
+            'distance' => null,
+            'algn' => null,
+            'rotWithShape' => null,
+        ],
+        //OUTER
+        1 => [
+            'effect' => 'outerShdw',
+            'blur' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 38100 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 2700000 / self::ANGLE_MULTIPLIER,
+            'algn' => 'tl',
+            'rotWithShape' => '0',
+        ],
+        2 => [
+            'effect' => 'outerShdw',
+            'blur' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 38100 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 5400000 / self::ANGLE_MULTIPLIER,
+            'algn' => 't',
+            'rotWithShape' => '0',
+        ],
+        3 => [
+            'effect' => 'outerShdw',
+            'blur' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 38100 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 8100000 / self::ANGLE_MULTIPLIER,
+            'algn' => 'tr',
+            'rotWithShape' => '0',
+        ],
+        4 => [
+            'effect' => 'outerShdw',
+            'blur' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 38100 / self::POINTS_WIDTH_MULTIPLIER,
+            'algn' => 'l',
+            'rotWithShape' => '0',
+        ],
+        5 => [
+            'effect' => 'outerShdw',
+            'size' => [
+                'sx' => 102000 / self::PERCENTAGE_MULTIPLIER,
+                'sy' => 102000 / self::PERCENTAGE_MULTIPLIER,
+            ],
+            'blur' => 63500 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 38100 / self::POINTS_WIDTH_MULTIPLIER,
+            'algn' => 'ctr',
+            'rotWithShape' => '0',
+        ],
+        6 => [
+            'effect' => 'outerShdw',
+            'blur' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 38100 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 10800000 / self::ANGLE_MULTIPLIER,
+            'algn' => 'r',
+            'rotWithShape' => '0',
+        ],
+        7 => [
+            'effect' => 'outerShdw',
+            'blur' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 38100 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 18900000 / self::ANGLE_MULTIPLIER,
+            'algn' => 'bl',
+            'rotWithShape' => '0',
+        ],
+        8 => [
+            'effect' => 'outerShdw',
+            'blur' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 38100 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 16200000 / self::ANGLE_MULTIPLIER,
+            'rotWithShape' => '0',
+        ],
+        9 => [
+            'effect' => 'outerShdw',
+            'blur' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 38100 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 13500000 / self::ANGLE_MULTIPLIER,
+            'algn' => 'br',
+            'rotWithShape' => '0',
+        ],
+        //INNER
+        10 => [
+            'effect' => 'innerShdw',
+            'blur' => 63500 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 2700000 / self::ANGLE_MULTIPLIER,
+        ],
+        11 => [
+            'effect' => 'innerShdw',
+            'blur' => 63500 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 5400000 / self::ANGLE_MULTIPLIER,
+        ],
+        12 => [
+            'effect' => 'innerShdw',
+            'blur' => 63500 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 8100000 / self::ANGLE_MULTIPLIER,
+        ],
+        13 => [
+            'effect' => 'innerShdw',
+            'blur' => 63500 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+        ],
+        14 => [
+            'effect' => 'innerShdw',
+            'blur' => 114300 / self::POINTS_WIDTH_MULTIPLIER,
+        ],
+        15 => [
+            'effect' => 'innerShdw',
+            'blur' => 63500 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 10800000 / self::ANGLE_MULTIPLIER,
+        ],
+        16 => [
+            'effect' => 'innerShdw',
+            'blur' => 63500 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 18900000 / self::ANGLE_MULTIPLIER,
+        ],
+        17 => [
+            'effect' => 'innerShdw',
+            'blur' => 63500 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 16200000 / self::ANGLE_MULTIPLIER,
+        ],
+        18 => [
+            'effect' => 'innerShdw',
+            'blur' => 63500 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 50800 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 13500000 / self::ANGLE_MULTIPLIER,
+        ],
+        //perspective
+        19 => [
+            'effect' => 'outerShdw',
+            'blur' => 152400 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 317500 / self::POINTS_WIDTH_MULTIPLIER,
+            'size' => [
+                'sx' => 90000 / self::PERCENTAGE_MULTIPLIER,
+                'sy' => -19000 / self::PERCENTAGE_MULTIPLIER,
+            ],
+            'direction' => 5400000 / self::ANGLE_MULTIPLIER,
+            'rotWithShape' => '0',
+        ],
+        20 => [
+            'effect' => 'outerShdw',
+            'blur' => 76200 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 18900000 / self::ANGLE_MULTIPLIER,
+            'size' => [
+                'sy' => 23000 / self::PERCENTAGE_MULTIPLIER,
+                'kx' => -1200000 / self::ANGLE_MULTIPLIER,
+            ],
+            'algn' => 'bl',
+            'rotWithShape' => '0',
+        ],
+        21 => [
+            'effect' => 'outerShdw',
+            'blur' => 76200 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 13500000 / self::ANGLE_MULTIPLIER,
+            'size' => [
+                'sy' => 23000 / self::PERCENTAGE_MULTIPLIER,
+                'kx' => 1200000 / self::ANGLE_MULTIPLIER,
+            ],
+            'algn' => 'br',
+            'rotWithShape' => '0',
+        ],
+        22 => [
+            'effect' => 'outerShdw',
+            'blur' => 76200 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 12700 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 2700000 / self::ANGLE_MULTIPLIER,
+            'size' => [
+                'sy' => -23000 / self::PERCENTAGE_MULTIPLIER,
+                'kx' => -800400 / self::ANGLE_MULTIPLIER,
+            ],
+            'algn' => 'bl',
+            'rotWithShape' => '0',
+        ],
+        23 => [
+            'effect' => 'outerShdw',
+            'blur' => 76200 / self::POINTS_WIDTH_MULTIPLIER,
+            'distance' => 12700 / self::POINTS_WIDTH_MULTIPLIER,
+            'direction' => 8100000 / self::ANGLE_MULTIPLIER,
+            'size' => [
+                'sy' => -23000 / self::PERCENTAGE_MULTIPLIER,
+                'kx' => 800400 / self::ANGLE_MULTIPLIER,
+            ],
+            'algn' => 'br',
+            'rotWithShape' => '0',
+        ],
+    ];
+
     protected function getShadowPresetsMap($presetsOption)
     {
-        $presets_options = [
-            //OUTER
-            1 => [
-                'effect' => 'outerShdw',
-                'blur' => '50800',
-                'distance' => '38100',
-                'direction' => '2700000',
-                'algn' => 'tl',
-                'rotWithShape' => '0',
-            ],
-            2 => [
-                'effect' => 'outerShdw',
-                'blur' => '50800',
-                'distance' => '38100',
-                'direction' => '5400000',
-                'algn' => 't',
-                'rotWithShape' => '0',
-            ],
-            3 => [
-                'effect' => 'outerShdw',
-                'blur' => '50800',
-                'distance' => '38100',
-                'direction' => '8100000',
-                'algn' => 'tr',
-                'rotWithShape' => '0',
-            ],
-            4 => [
-                'effect' => 'outerShdw',
-                'blur' => '50800',
-                'distance' => '38100',
-                'algn' => 'l',
-                'rotWithShape' => '0',
-            ],
-            5 => [
-                'effect' => 'outerShdw',
-                'size' => [
-                    'sx' => '102000',
-                    'sy' => '102000',
-                ],
-                'blur' => '63500',
-                'distance' => '38100',
-                'algn' => 'ctr',
-                'rotWithShape' => '0',
-            ],
-            6 => [
-                'effect' => 'outerShdw',
-                'blur' => '50800',
-                'distance' => '38100',
-                'direction' => '10800000',
-                'algn' => 'r',
-                'rotWithShape' => '0',
-            ],
-            7 => [
-                'effect' => 'outerShdw',
-                'blur' => '50800',
-                'distance' => '38100',
-                'direction' => '18900000',
-                'algn' => 'bl',
-                'rotWithShape' => '0',
-            ],
-            8 => [
-                'effect' => 'outerShdw',
-                'blur' => '50800',
-                'distance' => '38100',
-                'direction' => '16200000',
-                'rotWithShape' => '0',
-            ],
-            9 => [
-                'effect' => 'outerShdw',
-                'blur' => '50800',
-                'distance' => '38100',
-                'direction' => '13500000',
-                'algn' => 'br',
-                'rotWithShape' => '0',
-            ],
-            //INNER
-            10 => [
-                'effect' => 'innerShdw',
-                'blur' => '63500',
-                'distance' => '50800',
-                'direction' => '2700000',
-            ],
-            11 => [
-                'effect' => 'innerShdw',
-                'blur' => '63500',
-                'distance' => '50800',
-                'direction' => '5400000',
-            ],
-            12 => [
-                'effect' => 'innerShdw',
-                'blur' => '63500',
-                'distance' => '50800',
-                'direction' => '8100000',
-            ],
-            13 => [
-                'effect' => 'innerShdw',
-                'blur' => '63500',
-                'distance' => '50800',
-            ],
-            14 => [
-                'effect' => 'innerShdw',
-                'blur' => '114300',
-            ],
-            15 => [
-                'effect' => 'innerShdw',
-                'blur' => '63500',
-                'distance' => '50800',
-                'direction' => '10800000',
-            ],
-            16 => [
-                'effect' => 'innerShdw',
-                'blur' => '63500',
-                'distance' => '50800',
-                'direction' => '18900000',
-            ],
-            17 => [
-                'effect' => 'innerShdw',
-                'blur' => '63500',
-                'distance' => '50800',
-                'direction' => '16200000',
-            ],
-            18 => [
-                'effect' => 'innerShdw',
-                'blur' => '63500',
-                'distance' => '50800',
-                'direction' => '13500000',
-            ],
-            //perspective
-            19 => [
-                'effect' => 'outerShdw',
-                'blur' => '152400',
-                'distance' => '317500',
-                'size' => [
-                    'sx' => '90000',
-                    'sy' => '-19000',
-                ],
-                'direction' => '5400000',
-                'rotWithShape' => '0',
-            ],
-            20 => [
-                'effect' => 'outerShdw',
-                'blur' => '76200',
-                'direction' => '18900000',
-                'size' => [
-                    'sy' => '23000',
-                    'kx' => '-1200000',
-                ],
-                'algn' => 'bl',
-                'rotWithShape' => '0',
-            ],
-            21 => [
-                'effect' => 'outerShdw',
-                'blur' => '76200',
-                'direction' => '13500000',
-                'size' => [
-                    'sy' => '23000',
-                    'kx' => '1200000',
-                ],
-                'algn' => 'br',
-                'rotWithShape' => '0',
-            ],
-            22 => [
-                'effect' => 'outerShdw',
-                'blur' => '76200',
-                'distance' => '12700',
-                'direction' => '2700000',
-                'size' => [
-                    'sy' => '-23000',
-                    'kx' => '-800400',
-                ],
-                'algn' => 'bl',
-                'rotWithShape' => '0',
-            ],
-            23 => [
-                'effect' => 'outerShdw',
-                'blur' => '76200',
-                'distance' => '12700',
-                'direction' => '8100000',
-                'size' => [
-                    'sy' => '-23000',
-                    'kx' => '800400',
-                ],
-                'algn' => 'br',
-                'rotWithShape' => '0',
-            ],
-        ];
-
-        return $presets_options[$presetsOption];
+        return self::PRESETS_OPTIONS[$presetsOption] ?? self::PRESETS_OPTIONS[0];
     }
 
     protected function getArrayElementsValue($properties, $elements)
diff --git a/src/PhpSpreadsheet/Reader/Xlsx/Chart.php b/src/PhpSpreadsheet/Reader/Xlsx/Chart.php
index 67af04b2..55a150b7 100644
--- a/src/PhpSpreadsheet/Reader/Xlsx/Chart.php
+++ b/src/PhpSpreadsheet/Reader/Xlsx/Chart.php
@@ -6,6 +6,7 @@ use PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;
 use PhpOffice\PhpSpreadsheet\Chart\Axis;
 use PhpOffice\PhpSpreadsheet\Chart\DataSeries;
 use PhpOffice\PhpSpreadsheet\Chart\DataSeriesValues;
+use PhpOffice\PhpSpreadsheet\Chart\GridLines;
 use PhpOffice\PhpSpreadsheet\Chart\Layout;
 use PhpOffice\PhpSpreadsheet\Chart\Legend;
 use PhpOffice\PhpSpreadsheet\Chart\PlotArea;
@@ -71,6 +72,7 @@ class Chart
         $rotX = $rotY = $rAngAx = $perspective = null;
         $xAxis = new Axis();
         $yAxis = new Axis();
+        $majorGridlines = $minorGridlines = null;
         foreach ($chartElementsC as $chartElementKey => $chartElement) {
             switch ($chartElementKey) {
                 case 'chart':
@@ -108,26 +110,52 @@ class Chart
                                             break;
                                         case 'valAx':
                                             $whichAxis = null;
-                                            if (isset($chartDetail->title, $chartDetail->axPos)) {
-                                                $axisLabel = $this->chartTitle($chartDetail->title->children($this->cNamespace));
+                                            $axPos = null;
+                                            if (isset($chartDetail->axPos)) {
                                                 $axPos = self::getAttribute($chartDetail->axPos, 'val', 'string');
 
                                                 switch ($axPos) {
                                                     case 't':
                                                     case 'b':
-                                                        $XaxisLabel = $axisLabel;
                                                         $whichAxis = $xAxis;
 
                                                         break;
                                                     case 'r':
                                                     case 'l':
-                                                        $YaxisLabel = $axisLabel;
                                                         $whichAxis = $yAxis;
 
                                                         break;
                                                 }
                                             }
+                                            if (isset($chartDetail->title)) {
+                                                $axisLabel = $this->chartTitle($chartDetail->title->children($this->cNamespace));
+
+                                                switch ($axPos) {
+                                                    case 't':
+                                                    case 'b':
+                                                        $XaxisLabel = $axisLabel;
+
+                                                        break;
+                                                    case 'r':
+                                                    case 'l':
+                                                        $YaxisLabel = $axisLabel;
+
+                                                        break;
+                                                }
+                                            }
                                             $this->readEffects($chartDetail, $whichAxis);
+                                            if (isset($chartDetail->majorGridlines)) {
+                                                $majorGridlines = new GridLines();
+                                                if (isset($chartDetail->majorGridlines->spPr)) {
+                                                    $this->readEffects($chartDetail->majorGridlines, $majorGridlines);
+                                                }
+                                            }
+                                            if (isset($chartDetail->minorGridlines)) {
+                                                $minorGridlines = new GridLines();
+                                                if (isset($chartDetail->minorGridlines->spPr)) {
+                                                    $this->readEffects($chartDetail->minorGridlines, $minorGridlines);
+                                                }
+                                            }
 
                                             break;
                                         case 'barChart':
@@ -249,7 +277,7 @@ class Chart
                     }
             }
         }
-        $chart = new \PhpOffice\PhpSpreadsheet\Chart\Chart($chartName, $title, $legend, $plotArea, $plotVisOnly, (string) $dispBlanksAs, $XaxisLabel, $YaxisLabel, $xAxis, $yAxis);
+        $chart = new \PhpOffice\PhpSpreadsheet\Chart\Chart($chartName, $title, $legend, $plotArea, $plotVisOnly, (string) $dispBlanksAs, $XaxisLabel, $YaxisLabel, $xAxis, $yAxis, $majorGridlines, $minorGridlines);
         if (is_int($rotX)) {
             $chart->setRotX($rotX);
         }
@@ -893,7 +921,7 @@ class Chart
     }
 
     /**
-     * @param null|Axis $chartObject may be extended to include other types
+     * @param null|Axis|GridLines $chartObject may be extended to include other types
      */
     private function readEffects(SimpleXMLElement $chartDetail, $chartObject): void
     {
@@ -905,18 +933,75 @@ class Chart
         if (isset($sppr->effectLst->glow)) {
             $axisGlowSize = (float) self::getAttribute($sppr->effectLst->glow, 'rad', 'integer') / Properties::POINTS_WIDTH_MULTIPLIER;
             if ($axisGlowSize != 0.0) {
-                $srgbClr = $schemeClr = '';
-                $colorArray = $this->readColor($sppr->effectLst->glow, $srgbClr, $schemeClr);
+                $colorArray = $this->readColor($sppr->effectLst->glow);
                 $chartObject->setGlowProperties($axisGlowSize, $colorArray['value'], $colorArray['alpha'], $colorArray['type']);
             }
         }
 
         if (isset($sppr->effectLst->softEdge)) {
-            $chartObject->setSoftEdges((float) self::getAttribute($sppr->effectLst->softEdge, 'rad', 'string') / Properties::POINTS_WIDTH_MULTIPLIER);
+            /** @var string */
+            $softEdgeSize = self::getAttribute($sppr->effectLst->softEdge, 'rad', 'string');
+            if (is_numeric($softEdgeSize)) {
+                $chartObject->setSoftEdges((float) Properties::xmlToPoints($softEdgeSize));
+            }
+        }
+
+        $type = '';
+        foreach (self::SHADOW_TYPES as $shadowType) {
+            if (isset($sppr->effectLst->$shadowType)) {
+                $type = $shadowType;
+
+                break;
+            }
+        }
+        if ($type !== '') {
+            /** @var string */
+            $blur = self::getAttribute($sppr->effectLst->$type, 'blurRad', 'string');
+            $blur = is_numeric($blur) ? Properties::xmlToPoints($blur) : null;
+            /** @var string */
+            $dist = self::getAttribute($sppr->effectLst->$type, 'dist', 'string');
+            $dist = is_numeric($dist) ? Properties::xmlToPoints($dist) : null;
+            /** @var string */
+            $direction = self::getAttribute($sppr->effectLst->$type, 'dir', 'string');
+            $direction = is_numeric($direction) ? Properties::xmlToAngle($direction) : null;
+            $algn = self::getAttribute($sppr->effectLst->$type, 'algn', 'string');
+            $rot = self::getAttribute($sppr->effectLst->$type, 'rotWithShape', 'string');
+            $size = [];
+            foreach (['sx', 'sy'] as $sizeType) {
+                $sizeValue = self::getAttribute($sppr->effectLst->$type, $sizeType, 'string');
+                if (is_numeric($sizeValue)) {
+                    $size[$sizeType] = Properties::xmlToTenthOfPercent((string) $sizeValue);
+                } else {
+                    $size[$sizeType] = null;
+                }
+            }
+            foreach (['kx', 'ky'] as $sizeType) {
+                $sizeValue = self::getAttribute($sppr->effectLst->$type, $sizeType, 'string');
+                if (is_numeric($sizeValue)) {
+                    $size[$sizeType] = Properties::xmlToAngle((string) $sizeValue);
+                } else {
+                    $size[$sizeType] = null;
+                }
+            }
+            $colorArray = $this->readColor($sppr->effectLst->$type);
+            $chartObject
+                ->setShadowProperty('effect', $type)
+                ->setShadowProperty('blur', $blur)
+                ->setShadowProperty('direction', $direction)
+                ->setShadowProperty('distance', $dist)
+                ->setShadowProperty('algn', $algn)
+                ->setShadowProperty('rotWithShape', $rot)
+                ->setShadowProperty('size', $size)
+                ->setShadowProperty('color', $colorArray);
         }
     }
 
-    private function readColor(SimpleXMLElement $colorXml, ?string &$srgbClr, ?string &$schemeClr): array
+    private const SHADOW_TYPES = [
+        'outerShdw',
+        'innerShdw',
+    ];
+
+    private function readColor(SimpleXMLElement $colorXml, ?string &$srgbClr = null, ?string &$schemeClr = null): array
     {
         $result = [
             'type' => null,
@@ -927,16 +1012,27 @@ class Chart
             $result['type'] = Properties::EXCEL_COLOR_TYPE_ARGB;
             $result['value'] = $srgbClr = self::getAttribute($colorXml->srgbClr, 'val', 'string');
             if (isset($colorXml->srgbClr->alpha)) {
-                $alpha = (int) self::getAttribute($colorXml->srgbClr->alpha, 'val', 'string');
-                $alpha = 100 - (int) ($alpha / 1000);
+                /** @var string */
+                $alpha = self::getAttribute($colorXml->srgbClr->alpha, 'val', 'string');
+                $alpha = Properties::alphaFromXml($alpha);
                 $result['alpha'] = $alpha;
             }
         } elseif (isset($colorXml->schemeClr)) {
             $result['type'] = Properties::EXCEL_COLOR_TYPE_SCHEME;
             $result['value'] = $schemeClr = self::getAttribute($colorXml->schemeClr, 'val', 'string');
             if (isset($colorXml->schemeClr->alpha)) {
-                $alpha = (int) self::getAttribute($colorXml->schemeClr->alpha, 'val', 'string');
-                $alpha = 100 - (int) ($alpha / 1000);
+                /** @var string */
+                $alpha = self::getAttribute($colorXml->schemeClr->alpha, 'val', 'string');
+                $alpha = Properties::alphaFromXml($alpha);
+                $result['alpha'] = $alpha;
+            }
+        } elseif (isset($colorXml->prstClr)) {
+            $result['type'] = Properties::EXCEL_COLOR_TYPE_STANDARD;
+            $result['value'] = self::getAttribute($colorXml->prstClr, 'val', 'string');
+            if (isset($colorXml->prstClr->alpha)) {
+                /** @var string */
+                $alpha = self::getAttribute($colorXml->prstClr->alpha, 'val', 'string');
+                $alpha = Properties::alphaFromXml($alpha);
                 $result['alpha'] = $alpha;
             }
         }
diff --git a/src/PhpSpreadsheet/Worksheet/Worksheet.php b/src/PhpSpreadsheet/Worksheet/Worksheet.php
index 54785bfa..b23fc6a7 100644
--- a/src/PhpSpreadsheet/Worksheet/Worksheet.php
+++ b/src/PhpSpreadsheet/Worksheet/Worksheet.php
@@ -1177,6 +1177,11 @@ class Worksheet implements IComparable
      *               or as an array of [$columnIndex, $row] (e.g. [3, 5]), or a CellAddress object.
      * @param mixed $value Value of the cell
      * @param string $dataType Explicit data type, see DataType::TYPE_*
+     *        Note that PhpSpreadsheet does not validate that the value and datatype are consistent, in using this
+     *             method, then it is your responsibility as an end-user developer to validate that the value and
+     *             the datatype match.
+     *       If you do mismatch value and datatpe, then the value you enter may be changed to match the datatype
+     *          that you specify.
      *
      * @return $this
      */
@@ -1199,6 +1204,11 @@ class Worksheet implements IComparable
      * @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_*
+     *        Note that PhpSpreadsheet does not validate that the value and datatype are consistent, in using this
+     *             method, then it is your responsibility as an end-user developer to validate that the value and
+     *             the datatype match.
+     *       If you do mismatch value and datatpe, then the value you enter may be changed to match the datatype
+     *          that you specify.
      *
      * @return $this
      */
@@ -1752,31 +1762,39 @@ class Worksheet implements IComparable
     {
         $range = Functions::trimSheetFromCellReference(Validations::validateCellRange($range));
 
-        if (preg_match('/^([A-Z]+)(\\d+):([A-Z]+)(\\d+)$/', $range, $matches) === 1) {
-            $this->mergeCells[$range] = $range;
-            $firstRow = (int) $matches[2];
-            $lastRow = (int) $matches[4];
-            $firstColumn = $matches[1];
-            $lastColumn = $matches[3];
-            $firstColumnIndex = Coordinate::columnIndexFromString($firstColumn);
-            $lastColumnIndex = Coordinate::columnIndexFromString($lastColumn);
-            $numberRows = $lastRow - $firstRow;
-            $numberColumns = $lastColumnIndex - $firstColumnIndex;
+        if (strpos($range, ':') === false) {
+            $range .= ":{$range}";
+        }
 
-            // create upper left cell if it does not already exist
-            $upperLeft = "{$firstColumn}{$firstRow}";
-            if (!$this->cellExists($upperLeft)) {
-                $this->getCell($upperLeft)->setValueExplicit(null, DataType::TYPE_NULL);
-            }
+        if (preg_match('/^([A-Z]+)(\\d+):([A-Z]+)(\\d+)$/', $range, $matches) !== 1) {
+            throw new Exception('Merge must be on a valid range of cells.');
+        }
 
-            // Blank out the rest of the cells in the range (if they exist)
-            if ($numberRows > $numberColumns) {
-                $this->clearMergeCellsByColumn($firstColumn, $lastColumn, $firstRow, $lastRow, $upperLeft);
-            } else {
-                $this->clearMergeCellsByRow($firstColumn, $lastColumnIndex, $firstRow, $lastRow, $upperLeft);
-            }
+        $this->mergeCells[$range] = $range;
+        $firstRow = (int) $matches[2];
+        $lastRow = (int) $matches[4];
+        $firstColumn = $matches[1];
+        $lastColumn = $matches[3];
+        $firstColumnIndex = Coordinate::columnIndexFromString($firstColumn);
+        $lastColumnIndex = Coordinate::columnIndexFromString($lastColumn);
+        $numberRows = $lastRow - $firstRow;
+        $numberColumns = $lastColumnIndex - $firstColumnIndex;
+
+        if ($numberRows === 1 && $numberColumns === 1) {
+            return $this;
+        }
+
+        // create upper left cell if it does not already exist
+        $upperLeft = "{$firstColumn}{$firstRow}";
+        if (!$this->cellExists($upperLeft)) {
+            $this->getCell($upperLeft)->setValueExplicit(null, DataType::TYPE_NULL);
+        }
+
+        // Blank out the rest of the cells in the range (if they exist)
+        if ($numberRows > $numberColumns) {
+            $this->clearMergeCellsByColumn($firstColumn, $lastColumn, $firstRow, $lastRow, $upperLeft);
         } else {
-            throw new Exception('Merge must be set on a range of cells.');
+            $this->clearMergeCellsByRow($firstColumn, $lastColumnIndex, $firstRow, $lastRow, $upperLeft);
         }
 
         return $this;
diff --git a/src/PhpSpreadsheet/Writer/Xlsx/Chart.php b/src/PhpSpreadsheet/Writer/Xlsx/Chart.php
index 0aae3646..e24afbac 100644
--- a/src/PhpSpreadsheet/Writer/Xlsx/Chart.php
+++ b/src/PhpSpreadsheet/Writer/Xlsx/Chart.php
@@ -9,6 +9,7 @@ use PhpOffice\PhpSpreadsheet\Chart\GridLines;
 use PhpOffice\PhpSpreadsheet\Chart\Layout;
 use PhpOffice\PhpSpreadsheet\Chart\Legend;
 use PhpOffice\PhpSpreadsheet\Chart\PlotArea;
+use PhpOffice\PhpSpreadsheet\Chart\Properties;
 use PhpOffice\PhpSpreadsheet\Chart\Title;
 use PhpOffice\PhpSpreadsheet\Shared\XMLWriter;
 use PhpOffice\PhpSpreadsheet\Writer\Exception as WriterException;
@@ -499,22 +500,9 @@ class Chart extends WriterPart
 
         $objWriter->startElement('c:spPr');
         $objWriter->startElement('a:effectLst');
-        if ($yAxis->getGlowProperty('size') !== null) {
-            $objWriter->startElement('a:glow');
-            $objWriter->writeAttribute('rad', $yAxis->getGlowProperty('size'));
-            $objWriter->startElement("a:{$yAxis->getGlowProperty(['color', 'type'])}");
-            $objWriter->writeAttribute('val', (string) $yAxis->getGlowProperty(['color', 'value']));
-            $objWriter->startElement('a:alpha');
-            $objWriter->writeAttribute('val', (string) $yAxis->getGlowProperty(['color', 'alpha']));
-            $objWriter->endElement();
-            $objWriter->endElement();
-            $objWriter->endElement();
-        }
-        if ($yAxis->getSoftEdgesSize() !== null) {
-            $objWriter->startElement('a:softEdge');
-            $objWriter->writeAttribute('rad', $yAxis->getSoftEdgesSize());
-            $objWriter->endElement(); //end softEdge
-        }
+        $this->writeGlow($objWriter, $yAxis);
+        $this->writeShadow($objWriter, $yAxis);
+        $this->writeSoftEdge($objWriter, $yAxis);
         $objWriter->endElement(); // effectLst
         $objWriter->endElement(); // spPr
 
@@ -640,61 +628,9 @@ class Chart extends WriterPart
             $objWriter->endElement(); //end ln
         }
         $objWriter->startElement('a:effectLst');
-
-        if ($majorGridlines->getGlowSize() !== null) {
-            $objWriter->startElement('a:glow');
-            $objWriter->writeAttribute('rad', $majorGridlines->getGlowSize());
-            $objWriter->startElement("a:{$majorGridlines->getGlowColor('type')}");
-            $objWriter->writeAttribute('val', $majorGridlines->getGlowColor('value'));
-            $objWriter->startElement('a:alpha');
-            $objWriter->writeAttribute('val', $majorGridlines->getGlowColor('alpha'));
-            $objWriter->endElement(); //end alpha
-            $objWriter->endElement(); //end schemeClr
-            $objWriter->endElement(); //end glow
-        }
-
-        if ($majorGridlines->getShadowProperty('presets') !== null) {
-            $objWriter->startElement("a:{$majorGridlines->getShadowProperty('effect')}");
-            if ($majorGridlines->getShadowProperty('blur') !== null) {
-                $objWriter->writeAttribute('blurRad', $majorGridlines->getShadowProperty('blur'));
-            }
-            if ($majorGridlines->getShadowProperty('distance') !== null) {
-                $objWriter->writeAttribute('dist', $majorGridlines->getShadowProperty('distance'));
-            }
-            if ($majorGridlines->getShadowProperty('direction') !== null) {
-                $objWriter->writeAttribute('dir', $majorGridlines->getShadowProperty('direction'));
-            }
-            if ($majorGridlines->getShadowProperty('algn') !== null) {
-                $objWriter->writeAttribute('algn', $majorGridlines->getShadowProperty('algn'));
-            }
-            if ($majorGridlines->getShadowProperty(['size', 'sx']) !== null) {
-                $objWriter->writeAttribute('sx', $majorGridlines->getShadowProperty(['size', 'sx']));
-            }
-            if ($majorGridlines->getShadowProperty(['size', 'sy']) !== null) {
-                $objWriter->writeAttribute('sy', $majorGridlines->getShadowProperty(['size', 'sy']));
-            }
-            if ($majorGridlines->getShadowProperty(['size', 'kx']) !== null) {
-                $objWriter->writeAttribute('kx', $majorGridlines->getShadowProperty(['size', 'kx']));
-            }
-            if ($majorGridlines->getShadowProperty('rotWithShape') !== null) {
-                $objWriter->writeAttribute('rotWithShape', $majorGridlines->getShadowProperty('rotWithShape'));
-            }
-            $objWriter->startElement("a:{$majorGridlines->getShadowProperty(['color', 'type'])}");
-            $objWriter->writeAttribute('val', $majorGridlines->getShadowProperty(['color', 'value']));
-
-            $objWriter->startElement('a:alpha');
-            $objWriter->writeAttribute('val', $majorGridlines->getShadowProperty(['color', 'alpha']));
-            $objWriter->endElement(); //end alpha
-
-            $objWriter->endElement(); //end color:type
-            $objWriter->endElement(); //end shadow
-        }
-
-        if ($majorGridlines->getSoftEdgesSize() !== null) {
-            $objWriter->startElement('a:softEdge');
-            $objWriter->writeAttribute('rad', $majorGridlines->getSoftEdgesSize());
-            $objWriter->endElement(); //end softEdge
-        }
+        $this->writeGlow($objWriter, $majorGridlines);
+        $this->writeShadow($objWriter, $majorGridlines);
+        $this->writeSoftEdge($objWriter, $majorGridlines);
 
         $objWriter->endElement(); //end effectLst
         $objWriter->endElement(); //end spPr
@@ -748,61 +684,11 @@ class Chart extends WriterPart
             }
 
             $objWriter->startElement('a:effectLst');
-
-            if ($minorGridlines->getGlowSize() !== null) {
-                $objWriter->startElement('a:glow');
-                $objWriter->writeAttribute('rad', $minorGridlines->getGlowSize());
-                $objWriter->startElement("a:{$minorGridlines->getGlowColor('type')}");
-                $objWriter->writeAttribute('val', $minorGridlines->getGlowColor('value'));
-                $objWriter->startElement('a:alpha');
-                $objWriter->writeAttribute('val', $minorGridlines->getGlowColor('alpha'));
-                $objWriter->endElement(); //end alpha
-                $objWriter->endElement(); //end schemeClr
-                $objWriter->endElement(); //end glow
-            }
-
-            if ($minorGridlines->getShadowProperty('presets') !== null) {
-                $objWriter->startElement("a:{$minorGridlines->getShadowProperty('effect')}");
-                if ($minorGridlines->getShadowProperty('blur') !== null) {
-                    $objWriter->writeAttribute('blurRad', $minorGridlines->getShadowProperty('blur'));
-                }
-                if ($minorGridlines->getShadowProperty('distance') !== null) {
-                    $objWriter->writeAttribute('dist', $minorGridlines->getShadowProperty('distance'));
-                }
-                if ($minorGridlines->getShadowProperty('direction') !== null) {
-                    $objWriter->writeAttribute('dir', $minorGridlines->getShadowProperty('direction'));
-                }
-                if ($minorGridlines->getShadowProperty('algn') !== null) {
-                    $objWriter->writeAttribute('algn', $minorGridlines->getShadowProperty('algn'));
-                }
-                if ($minorGridlines->getShadowProperty(['size', 'sx']) !== null) {
-                    $objWriter->writeAttribute('sx', $minorGridlines->getShadowProperty(['size', 'sx']));
-                }
-                if ($minorGridlines->getShadowProperty(['size', 'sy']) !== null) {
-                    $objWriter->writeAttribute('sy', $minorGridlines->getShadowProperty(['size', 'sy']));
-                }
-                if ($minorGridlines->getShadowProperty(['size', 'kx']) !== null) {
-                    $objWriter->writeAttribute('kx', $minorGridlines->getShadowProperty(['size', 'kx']));
-                }
-                if ($minorGridlines->getShadowProperty('rotWithShape') !== null) {
-                    $objWriter->writeAttribute('rotWithShape', $minorGridlines->getShadowProperty('rotWithShape'));
-                }
-                $objWriter->startElement("a:{$minorGridlines->getShadowProperty(['color', 'type'])}");
-                $objWriter->writeAttribute('val', $minorGridlines->getShadowProperty(['color', 'value']));
-                $objWriter->startElement('a:alpha');
-                $objWriter->writeAttribute('val', $minorGridlines->getShadowProperty(['color', 'alpha']));
-                $objWriter->endElement(); //end alpha
-                $objWriter->endElement(); //end color:type
-                $objWriter->endElement(); //end shadow
-            }
-
-            if ($minorGridlines->getSoftEdgesSize() !== null) {
-                $objWriter->startElement('a:softEdge');
-                $objWriter->writeAttribute('rad', $minorGridlines->getSoftEdgesSize());
-                $objWriter->endElement(); //end softEdge
-            }
-
+            $this->writeGlow($objWriter, $minorGridlines);
+            $this->writeShadow($objWriter, $minorGridlines);
+            $this->writeSoftEdge($objWriter, $minorGridlines);
             $objWriter->endElement(); //end effectLst
+
             $objWriter->endElement(); //end spPr
             $objWriter->endElement(); //end minorGridLines
         }
@@ -925,64 +811,11 @@ class Chart extends WriterPart
         $objWriter->endElement();
 
         $objWriter->startElement('a:effectLst');
-
-        if ($xAxis->getGlowProperty('size') !== null) {
-            $objWriter->startElement('a:glow');
-            $objWriter->writeAttribute('rad', $xAxis->getGlowProperty('size'));
-            $objWriter->startElement("a:{$xAxis->getGlowProperty(['color', 'type'])}");
-            $objWriter->writeAttribute('val', (string) $xAxis->getGlowProperty(['color', 'value']));
-            $objWriter->startElement('a:alpha');
-            $objWriter->writeAttribute('val', (string) $xAxis->getGlowProperty(['color', 'alpha']));
-            $objWriter->endElement();
-            $objWriter->endElement();
-            $objWriter->endElement();
-        }
-
-        if ($xAxis->getShadowProperty('presets') !== null) {
-            $objWriter->startElement("a:{$xAxis->getShadowProperty('effect')}");
-
-            if ($xAxis->getShadowProperty('blur') !== null) {
-                $objWriter->writeAttribute('blurRad', $xAxis->getShadowProperty('blur'));
-            }
-            if ($xAxis->getShadowProperty('distance') !== null) {
-                $objWriter->writeAttribute('dist', $xAxis->getShadowProperty('distance'));
-            }
-            if ($xAxis->getShadowProperty('direction') !== null) {
-                $objWriter->writeAttribute('dir', $xAxis->getShadowProperty('direction'));
-            }
-            if ($xAxis->getShadowProperty('algn') !== null) {
-                $objWriter->writeAttribute('algn', $xAxis->getShadowProperty('algn'));
-            }
-            if ($xAxis->getShadowProperty(['size', 'sx']) !== null) {
-                $objWriter->writeAttribute('sx', $xAxis->getShadowProperty(['size', 'sx']));
-            }
-            if ($xAxis->getShadowProperty(['size', 'sy']) !== null) {
-                $objWriter->writeAttribute('sy', $xAxis->getShadowProperty(['size', 'sy']));
-            }
-            if ($xAxis->getShadowProperty(['size', 'kx']) !== null) {
-                $objWriter->writeAttribute('kx', $xAxis->getShadowProperty(['size', 'kx']));
-            }
-            if ($xAxis->getShadowProperty('rotWithShape') !== null) {
-                $objWriter->writeAttribute('rotWithShape', $xAxis->getShadowProperty('rotWithShape'));
-            }
-
-            $objWriter->startElement("a:{$xAxis->getShadowProperty(['color', 'type'])}");
-            $objWriter->writeAttribute('val', $xAxis->getShadowProperty(['color', 'value']));
-            $objWriter->startElement('a:alpha');
-            $objWriter->writeAttribute('val', $xAxis->getShadowProperty(['color', 'alpha']));
-            $objWriter->endElement();
-            $objWriter->endElement();
-
-            $objWriter->endElement();
-        }
-
-        if ($xAxis->getSoftEdgesSize() !== null) {
-            $objWriter->startElement('a:softEdge');
-            $objWriter->writeAttribute('rad', $xAxis->getSoftEdgesSize());
-            $objWriter->endElement();
-        }
-
+        $this->writeGlow($objWriter, $xAxis);
+        $this->writeShadow($objWriter, $xAxis);
+        $this->writeSoftEdge($objWriter, $xAxis);
         $objWriter->endElement(); //effectList
+
         $objWriter->endElement(); //end spPr
 
         if ($id1 !== '0') {
@@ -1658,4 +1491,100 @@ class Chart extends WriterPart
 
         $objWriter->endElement();
     }
+
+    /**
+     * Write shadow properties.
+     *
+     * @param Axis|GridLines $xAxis
+     */
+    private function writeShadow(XMLWriter $objWriter, $xAxis): void
+    {
+        if ($xAxis->getShadowProperty('effect') === null) {
+            return;
+        }
+        /** @var string */
+        $effect = $xAxis->getShadowProperty('effect');
+        $objWriter->startElement("a:$effect");
+
+        if (is_numeric($xAxis->getShadowProperty('blur'))) {
+            $objWriter->writeAttribute('blurRad', Properties::pointsToXml((float) $xAxis->getShadowProperty('blur')));
+        }
+        if (is_numeric($xAxis->getShadowProperty('distance'))) {
+            $objWriter->writeAttribute('dist', Properties::pointsToXml((float) $xAxis->getShadowProperty('distance')));
+        }
+        if (is_numeric($xAxis->getShadowProperty('direction'))) {
+            $objWriter->writeAttribute('dir', Properties::angleToXml((float) $xAxis->getShadowProperty('direction')));
+        }
+        if ($xAxis->getShadowProperty('algn') !== null) {
+            $objWriter->writeAttribute('algn', $xAxis->getShadowProperty('algn'));
+        }
+        foreach (['sx', 'sy'] as $sizeType) {
+            $sizeValue = $xAxis->getShadowProperty(['size', $sizeType]);
+            if (is_numeric($sizeValue)) {
+                $objWriter->writeAttribute($sizeType, Properties::tenthOfPercentToXml((float) $sizeValue));
+            }
+        }
+        foreach (['kx', 'ky'] as $sizeType) {
+            $sizeValue = $xAxis->getShadowProperty(['size', $sizeType]);
+            if (is_numeric($sizeValue)) {
+                $objWriter->writeAttribute($sizeType, Properties::angleToXml((float) $sizeValue));
+            }
+        }
+        if ($xAxis->getShadowProperty('rotWithShape') !== null) {
+            $objWriter->writeAttribute('rotWithShape', $xAxis->getShadowProperty('rotWithShape'));
+        }
+
+        $objWriter->startElement("a:{$xAxis->getShadowProperty(['color', 'type'])}");
+        $objWriter->writeAttribute('val', $xAxis->getShadowProperty(['color', 'value']));
+        $alpha = $xAxis->getShadowProperty(['color', 'alpha']);
+        if (is_numeric($alpha)) {
+            $objWriter->startElement('a:alpha');
+            $objWriter->writeAttribute('val', Properties::alphaToXml((int) $alpha));
+            $objWriter->endElement();
+        }
+        $objWriter->endElement();
+
+        $objWriter->endElement();
+    }
+
+    /**
+     * Write glow properties.
+     *
+     * @param Axis|GridLines $yAxis
+     */
+    private function writeGlow(XMLWriter $objWriter, $yAxis): void
+    {
+        $size = $yAxis->getGlowProperty('size');
+        if (empty($size)) {
+            return;
+        }
+        $objWriter->startElement('a:glow');
+        $objWriter->writeAttribute('rad', Properties::pointsToXml((float) $size));
+        $objWriter->startElement("a:{$yAxis->getGlowProperty(['color', 'type'])}");
+        $objWriter->writeAttribute('val', (string) $yAxis->getGlowProperty(['color', 'value']));
+        $alpha = $yAxis->getGlowProperty(['color', 'alpha']);
+        if (is_numeric($alpha)) {
+            $objWriter->startElement('a:alpha');
+            $objWriter->writeAttribute('val', Properties::alphaToXml((int) $alpha));
+            $objWriter->endElement(); // alpha
+        }
+        $objWriter->endElement(); // color
+        $objWriter->endElement(); // glow
+    }
+
+    /**
+     * Write soft edge properties.
+     *
+     * @param Axis|GridLines $yAxis
+     */
+    private function writeSoftEdge(XMLWriter $objWriter, $yAxis): void
+    {
+        $softEdgeSize = $yAxis->getSoftEdgesSize();
+        if (empty($softEdgeSize)) {
+            return;
+        }
+        $objWriter->startElement('a:softEdge');
+        $objWriter->writeAttribute('rad', Properties::pointsToXml((float) $softEdgeSize));
+        $objWriter->endElement(); //end softEdge
+    }
 }
diff --git a/tests/PhpSpreadsheetTests/Calculation/MergedCellTest.php b/tests/PhpSpreadsheetTests/Calculation/MergedCellTest.php
index 5e5aff6a..e6737b6d 100644
--- a/tests/PhpSpreadsheetTests/Calculation/MergedCellTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/MergedCellTest.php
@@ -100,7 +100,7 @@ class MergedCellTest extends TestCase
             $sheet->mergeCells($range);
             self::fail("Expected invalid merge range $range");
         } catch (SpreadException $e) {
-            self::assertSame('Merge must be set on a range of cells.', $e->getMessage());
+            self::assertSame('Merge must be on a valid range of cells.', $e->getMessage());
         }
     }
 
@@ -109,7 +109,8 @@ class MergedCellTest extends TestCase
         $spreadSheet = new Spreadsheet();
 
         $dataSheet = $spreadSheet->getActiveSheet();
-        $this->setBadRange($dataSheet, 'B1');
+        // TODO - Reinstate full validation and disallow single cell merging for version 2.0
+//        $this->setBadRange($dataSheet, 'B1');
         $this->setBadRange($dataSheet, 'Invalid');
         $this->setBadRange($dataSheet, '1');
         $this->setBadRange($dataSheet, 'C');
diff --git a/tests/PhpSpreadsheetTests/Chart/AxisGlowTest.php b/tests/PhpSpreadsheetTests/Chart/AxisGlowTest.php
index 88afef53..ad7fc776 100644
--- a/tests/PhpSpreadsheetTests/Chart/AxisGlowTest.php
+++ b/tests/PhpSpreadsheetTests/Chart/AxisGlowTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheetTests\Writer\Xlsx;
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
 
 use PhpOffice\PhpSpreadsheet\Chart\Chart;
 use PhpOffice\PhpSpreadsheet\Chart\DataSeries;
@@ -106,21 +106,21 @@ class AxisGlowTest extends AbstractFunctional
         );
         $yAxis = $chart->getChartAxisY();
         $xAxis = $chart->getChartAxisX();
-        $yAxis->setGlowProperties(10, 'FFFF00', 30, Properties::EXCEL_COLOR_TYPE_ARGB);
-        $expectedSize = 127000.0;
+        $yGlowSize = 10.0;
+        $yAxis->setGlowProperties($yGlowSize, 'FFFF00', 30, Properties::EXCEL_COLOR_TYPE_ARGB);
         $expectedGlowColor = [
             'type' => 'srgbClr',
             'value' => 'FFFF00',
-            'alpha' => '70000',
+            'alpha' => 30,
         ];
-        $yAxis->setSoftEdges(2.5);
-        $xAxis->setSoftEdges(5);
-        $expectedSoftEdgesY = '31750';
-        $expectedSoftEdgesX = '63500';
-        self::assertEquals($expectedSize, $yAxis->getGlowProperty('size'));
+        $softEdgesY = 2.5;
+        $yAxis->setSoftEdges($softEdgesY);
+        $softEdgesX = 5;
+        $xAxis->setSoftEdges($softEdgesX);
+        self::assertEquals($yGlowSize, $yAxis->getGlowProperty('size'));
         self::assertEquals($expectedGlowColor, $yAxis->getGlowProperty('color'));
-        self::assertEquals($expectedSoftEdgesY, $yAxis->getSoftEdgesSize());
-        self::assertEquals($expectedSoftEdgesX, $xAxis->getSoftEdgesSize());
+        self::assertEquals($softEdgesY, $yAxis->getSoftEdgesSize());
+        self::assertEquals($softEdgesX, $xAxis->getSoftEdgesSize());
 
         // Set the position where the chart should appear in the worksheet
         $chart->setTopLeftPosition('A7');
@@ -142,9 +142,9 @@ class AxisGlowTest extends AbstractFunctional
         $chart2 = $charts2[0];
         self::assertNotNull($chart2);
         $yAxis2 = $chart2->getChartAxisY();
-        self::assertEquals($expectedSize, $yAxis2->getGlowProperty('size'));
+        self::assertEquals($yGlowSize, $yAxis2->getGlowProperty('size'));
         self::assertEquals($expectedGlowColor, $yAxis2->getGlowProperty('color'));
-        self::assertEquals($expectedSoftEdgesY, $yAxis2->getSoftEdgesSize());
+        self::assertEquals($softEdgesY, $yAxis2->getSoftEdgesSize());
         $xAxis2 = $chart2->getChartAxisX();
         self::assertNull($xAxis2->getGlowProperty('size'));
         $reloadedSpreadsheet->disconnectWorksheets();
@@ -229,14 +229,14 @@ class AxisGlowTest extends AbstractFunctional
             $yAxisLabel  // yAxisLabel
         );
         $yAxis = $chart->getChartAxisX(); // deliberate
-        $yAxis->setGlowProperties(20, 'accent1', 20, Properties::EXCEL_COLOR_TYPE_SCHEME);
-        $expectedSize = 254000.0;
+        $yGlowSize = 20.0;
+        $yAxis->setGlowProperties($yGlowSize, 'accent1', 20, Properties::EXCEL_COLOR_TYPE_SCHEME);
         $expectedGlowColor = [
             'type' => 'schemeClr',
             'value' => 'accent1',
-            'alpha' => '80000',
+            'alpha' => 20,
         ];
-        self::assertEquals($expectedSize, $yAxis->getGlowProperty('size'));
+        self::assertEquals($yGlowSize, $yAxis->getGlowProperty('size'));
         self::assertEquals($expectedGlowColor, $yAxis->getGlowProperty('color'));
 
         // Set the position where the chart should appear in the worksheet
@@ -259,7 +259,7 @@ class AxisGlowTest extends AbstractFunctional
         $chart2 = $charts2[0];
         self::assertNotNull($chart2);
         $yAxis2 = $chart2->getChartAxisX(); // deliberate
-        self::assertEquals($expectedSize, $yAxis2->getGlowProperty('size'));
+        self::assertEquals($yGlowSize, $yAxis2->getGlowProperty('size'));
         self::assertEquals($expectedGlowColor, $yAxis2->getGlowProperty('color'));
         $xAxis2 = $chart2->getChartAxisY(); // deliberate
         self::assertNull($xAxis2->getGlowProperty('size'));
diff --git a/tests/PhpSpreadsheetTests/Chart/AxisShadowTest.php b/tests/PhpSpreadsheetTests/Chart/AxisShadowTest.php
new file mode 100644
index 00000000..d6f122ef
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Chart/AxisShadowTest.php
@@ -0,0 +1,184 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
+
+use PhpOffice\PhpSpreadsheet\Chart\Chart;
+use PhpOffice\PhpSpreadsheet\Chart\DataSeries;
+use PhpOffice\PhpSpreadsheet\Chart\DataSeriesValues;
+use PhpOffice\PhpSpreadsheet\Chart\Legend as ChartLegend;
+use PhpOffice\PhpSpreadsheet\Chart\PlotArea;
+use PhpOffice\PhpSpreadsheet\Chart\Properties;
+use PhpOffice\PhpSpreadsheet\Chart\Title;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx as XlsxReader;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Writer\Xlsx as XlsxWriter;
+use PhpOffice\PhpSpreadsheetTests\Functional\AbstractFunctional;
+
+class AxisShadowTest extends AbstractFunctional
+{
+    public function readCharts(XlsxReader $reader): void
+    {
+        $reader->setIncludeCharts(true);
+    }
+
+    public function writeCharts(XlsxWriter $writer): void
+    {
+        $writer->setIncludeCharts(true);
+    }
+
+    public function testGlowY(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $worksheet = $spreadsheet->getActiveSheet();
+        $worksheet->fromArray(
+            [
+                ['', 2010, 2011, 2012],
+                ['Q1', 12, 15, 21],
+                ['Q2', 56, 73, 86],
+                ['Q3', 52, 61, 69],
+                ['Q4', 30, 32, 0],
+            ]
+        );
+
+        // Set the Labels for each data series we want to plot
+        //     Datatype
+        //     Cell reference for data
+        //     Format Code
+        //     Number of datapoints in series
+        //     Data values
+        //     Data Marker
+        $dataSeriesLabels = [
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$B$1', null, 1), // 2010
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$C$1', null, 1), // 2011
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$D$1', null, 1), // 2012
+        ];
+        // Set the X-Axis Labels
+        //     Datatype
+        //     Cell reference for data
+        //     Format Code
+        //     Number of datapoints in series
+        //     Data values
+        //     Data Marker
+        $xAxisTickValues = [
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$A$2:$A$5', null, 4), // Q1 to Q4
+        ];
+        // Set the Data values for each data series we want to plot
+        //     Datatype
+        //     Cell reference for data
+        //     Format Code
+        //     Number of datapoints in series
+        //     Data values
+        //     Data Marker
+        $dataSeriesValues = [
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$B$2:$B$5', null, 4),
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$C$2:$C$5', null, 4),
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$D$2:$D$5', null, 4),
+        ];
+
+        // Build the dataseries
+        $series = new DataSeries(
+            DataSeries::TYPE_AREACHART, // plotType
+            DataSeries::GROUPING_PERCENT_STACKED, // plotGrouping
+            range(0, count($dataSeriesValues) - 1), // plotOrder
+            $dataSeriesLabels, // plotLabel
+            $xAxisTickValues, // plotCategory
+            $dataSeriesValues          // plotValues
+        );
+
+        // Set the series in the plot area
+        $plotArea = new PlotArea(null, [$series]);
+        // Set the chart legend
+        $legend = new ChartLegend(ChartLegend::POSITION_TOPRIGHT, null, false);
+
+        $title = new Title('Test %age-Stacked Area Chart');
+        $yAxisLabel = new Title('Value ($k)');
+
+        // Create the chart
+        $chart = new Chart(
+            'chart1', // name
+            $title, // title
+            $legend, // legend
+            $plotArea, // plotArea
+            true, // plotVisibleOnly
+            DataSeries::EMPTY_AS_GAP, // displayBlanksAs
+            null, // xAxisLabel
+            $yAxisLabel  // yAxisLabel
+        );
+        $yAxis = $chart->getChartAxisY();
+        $expectedY = [
+            'effect' => 'outerShdw',
+            'algn' => 'tl',
+            'blur' => 5,
+            'direction' => 45,
+            'distance' => 3,
+            'rotWithShape' => 0,
+            'color' => [
+                'type' => Properties::EXCEL_COLOR_TYPE_STANDARD,
+                'value' => 'black',
+                'alpha' => 40,
+            ],
+        ];
+        foreach ($expectedY as $key => $value) {
+            $yAxis->setShadowProperty($key, $value);
+        }
+        foreach ($expectedY as $key => $value) {
+            self::assertEquals($value, $yAxis->getShadowProperty($key), $key);
+        }
+        $xAxis = $chart->getChartAxisX();
+        $expectedX = [
+            'effect' => 'outerShdw',
+            'algn' => 'bl',
+            'blur' => 6,
+            'direction' => 315,
+            'distance' => 3,
+            'rotWithShape' => 0,
+            'size' => [
+                'sx' => null,
+                'sy' => 254,
+                'kx' => -94,
+                'ky' => null,
+            ],
+            'color' => [
+                'type' => Properties::EXCEL_COLOR_TYPE_ARGB,
+                'value' => 'FF0000',
+                'alpha' => 20,
+            ],
+        ];
+        foreach ($expectedX as $key => $value) {
+            $xAxis->setShadowProperty($key, $value);
+        }
+        foreach ($expectedX as $key => $value) {
+            self::assertEquals($value, $xAxis->getShadowProperty($key), $key);
+        }
+
+        // Set the position where the chart should appear in the worksheet
+        $chart->setTopLeftPosition('A7');
+        $chart->setBottomRightPosition('H20');
+
+        // Add the chart to the worksheet
+        $worksheet->addChart($chart);
+
+        /** @var callable */
+        $callableReader = [$this, 'readCharts'];
+        /** @var callable */
+        $callableWriter = [$this, 'writeCharts'];
+        $reloadedSpreadsheet = $this->writeAndReload($spreadsheet, 'Xlsx', $callableReader, $callableWriter);
+        $spreadsheet->disconnectWorksheets();
+
+        $sheet = $reloadedSpreadsheet->getActiveSheet();
+        $charts2 = $sheet->getChartCollection();
+        self::assertCount(1, $charts2);
+        $chart2 = $charts2[0];
+        self::assertNotNull($chart2);
+        $yAxis2 = $chart2->getChartAxisY();
+        foreach ($expectedY as $key => $value) {
+            self::assertEquals($value, $yAxis2->getShadowProperty($key), $key);
+        }
+        $xAxis2 = $chart2->getChartAxisX();
+        foreach ($expectedX as $key => $value) {
+            self::assertEquals($value, $xAxis2->getShadowProperty($key), $key);
+        }
+
+        $reloadedSpreadsheet->disconnectWorksheets();
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32CatAxValAxTest.php b/tests/PhpSpreadsheetTests/Chart/Charts32CatAxValAxTest.php
similarity index 99%
rename from tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32CatAxValAxTest.php
rename to tests/PhpSpreadsheetTests/Chart/Charts32CatAxValAxTest.php
index af33baa1..268ee094 100644
--- a/tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32CatAxValAxTest.php
+++ b/tests/PhpSpreadsheetTests/Chart/Charts32CatAxValAxTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheetTests\Writer\Xlsx;
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
 
 use PhpOffice\PhpSpreadsheet\Chart\Axis;
 use PhpOffice\PhpSpreadsheet\Chart\Chart;
diff --git a/tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32ColoredAxisLabelTest.php b/tests/PhpSpreadsheetTests/Chart/Charts32ColoredAxisLabelTest.php
similarity index 98%
rename from tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32ColoredAxisLabelTest.php
rename to tests/PhpSpreadsheetTests/Chart/Charts32ColoredAxisLabelTest.php
index 71b8da28..71cda504 100644
--- a/tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32ColoredAxisLabelTest.php
+++ b/tests/PhpSpreadsheetTests/Chart/Charts32ColoredAxisLabelTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheetTests\Writer\Xlsx;
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
 
 use PhpOffice\PhpSpreadsheet\Reader\Xlsx as XlsxReader;
 use PhpOffice\PhpSpreadsheet\RichText\RichText;
diff --git a/tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32ScatterTest.php b/tests/PhpSpreadsheetTests/Chart/Charts32ScatterTest.php
similarity index 99%
rename from tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32ScatterTest.php
rename to tests/PhpSpreadsheetTests/Chart/Charts32ScatterTest.php
index 76389727..d79cba6f 100644
--- a/tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32ScatterTest.php
+++ b/tests/PhpSpreadsheetTests/Chart/Charts32ScatterTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheetTests\Writer\Xlsx;
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
 
 use PhpOffice\PhpSpreadsheet\Reader\Xlsx as XlsxReader;
 use PhpOffice\PhpSpreadsheet\RichText\RichText;
diff --git a/tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32XmlTest.php b/tests/PhpSpreadsheetTests/Chart/Charts32XmlTest.php
similarity index 98%
rename from tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32XmlTest.php
rename to tests/PhpSpreadsheetTests/Chart/Charts32XmlTest.php
index 9b32518a..a193ca7d 100644
--- a/tests/PhpSpreadsheetTests/Writer/Xlsx/Charts32XmlTest.php
+++ b/tests/PhpSpreadsheetTests/Chart/Charts32XmlTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheetTests\Writer\Xlsx;
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
 
 use PhpOffice\PhpSpreadsheet\Chart\Properties;
 use PhpOffice\PhpSpreadsheet\Reader\Xlsx as XlsxReader;
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/ChartsOpenpyxlTest.php b/tests/PhpSpreadsheetTests/Chart/ChartsOpenpyxlTest.php
similarity index 98%
rename from tests/PhpSpreadsheetTests/Reader/Xlsx/ChartsOpenpyxlTest.php
rename to tests/PhpSpreadsheetTests/Chart/ChartsOpenpyxlTest.php
index a7343af5..7fcc2e90 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xlsx/ChartsOpenpyxlTest.php
+++ b/tests/PhpSpreadsheetTests/Chart/ChartsOpenpyxlTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheetTests\Writer\Xlsx;
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
 
 use PhpOffice\PhpSpreadsheet\Reader\Xlsx as XlsxReader;
 use PHPUnit\Framework\TestCase;
diff --git a/tests/PhpSpreadsheetTests/Reader/Xlsx/ChartsTitleTest.php b/tests/PhpSpreadsheetTests/Chart/ChartsTitleTest.php
similarity index 97%
rename from tests/PhpSpreadsheetTests/Reader/Xlsx/ChartsTitleTest.php
rename to tests/PhpSpreadsheetTests/Chart/ChartsTitleTest.php
index 3d881ecf..5a929c62 100644
--- a/tests/PhpSpreadsheetTests/Reader/Xlsx/ChartsTitleTest.php
+++ b/tests/PhpSpreadsheetTests/Chart/ChartsTitleTest.php
@@ -1,6 +1,6 @@
 <?php
 
-namespace PhpOffice\PhpSpreadsheetTests\Reader\Xlsx;
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
 
 use PhpOffice\PhpSpreadsheet\Chart\Title;
 use PhpOffice\PhpSpreadsheet\IOFactory;
diff --git a/tests/PhpSpreadsheetTests/Chart/GridlinesShadowGlowTest.php b/tests/PhpSpreadsheetTests/Chart/GridlinesShadowGlowTest.php
new file mode 100644
index 00000000..04ca7c31
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Chart/GridlinesShadowGlowTest.php
@@ -0,0 +1,187 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
+
+use PhpOffice\PhpSpreadsheet\Chart\Chart;
+use PhpOffice\PhpSpreadsheet\Chart\DataSeries;
+use PhpOffice\PhpSpreadsheet\Chart\DataSeriesValues;
+use PhpOffice\PhpSpreadsheet\Chart\GridLines;
+use PhpOffice\PhpSpreadsheet\Chart\Legend as ChartLegend;
+use PhpOffice\PhpSpreadsheet\Chart\PlotArea;
+use PhpOffice\PhpSpreadsheet\Chart\Properties;
+use PhpOffice\PhpSpreadsheet\Chart\Title;
+use PhpOffice\PhpSpreadsheet\Reader\Xlsx as XlsxReader;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Writer\Xlsx as XlsxWriter;
+use PhpOffice\PhpSpreadsheetTests\Functional\AbstractFunctional;
+
+class GridlinesShadowGlowTest extends AbstractFunctional
+{
+    public function readCharts(XlsxReader $reader): void
+    {
+        $reader->setIncludeCharts(true);
+    }
+
+    public function writeCharts(XlsxWriter $writer): void
+    {
+        $writer->setIncludeCharts(true);
+    }
+
+    public function testGlowY(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $worksheet = $spreadsheet->getActiveSheet();
+        $worksheet->fromArray(
+            [
+                ['', 2010, 2011, 2012],
+                ['Q1', 12, 15, 21],
+                ['Q2', 56, 73, 86],
+                ['Q3', 52, 61, 69],
+                ['Q4', 30, 32, 0],
+            ]
+        );
+
+        // Set the Labels for each data series we want to plot
+        //     Datatype
+        //     Cell reference for data
+        //     Format Code
+        //     Number of datapoints in series
+        //     Data values
+        //     Data Marker
+        $dataSeriesLabels = [
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$B$1', null, 1), // 2010
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$C$1', null, 1), // 2011
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$D$1', null, 1), // 2012
+        ];
+        // Set the X-Axis Labels
+        //     Datatype
+        //     Cell reference for data
+        //     Format Code
+        //     Number of datapoints in series
+        //     Data values
+        //     Data Marker
+        $xAxisTickValues = [
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$A$2:$A$5', null, 4), // Q1 to Q4
+        ];
+        // Set the Data values for each data series we want to plot
+        //     Datatype
+        //     Cell reference for data
+        //     Format Code
+        //     Number of datapoints in series
+        //     Data values
+        //     Data Marker
+        $dataSeriesValues = [
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$B$2:$B$5', null, 4),
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$C$2:$C$5', null, 4),
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$D$2:$D$5', null, 4),
+        ];
+
+        // Build the dataseries
+        $series = new DataSeries(
+            DataSeries::TYPE_LINECHART, // plotType
+            DataSeries::GROUPING_PERCENT_STACKED, // plotGrouping
+            range(0, count($dataSeriesValues) - 1), // plotOrder
+            $dataSeriesLabels, // plotLabel
+            $xAxisTickValues, // plotCategory
+            $dataSeriesValues          // plotValues
+        );
+
+        // Set the series in the plot area
+        $plotArea = new PlotArea(null, [$series]);
+        // Set the chart legend
+        $legend = new ChartLegend(ChartLegend::POSITION_TOPRIGHT, null, false);
+
+        $title = new Title('Test %age-Stacked Area Chart');
+        $yAxisLabel = new Title('Value ($k)');
+        $majorGridlines = new GridLines();
+        $majorGlowSize = 10.0;
+        $majorGridlines->setGlowProperties($majorGlowSize, 'FFFF00', 30, Properties::EXCEL_COLOR_TYPE_ARGB);
+        $softEdgeSize = 2.5;
+        $majorGridlines->setSoftEdges($softEdgeSize);
+        $expectedGlowColor = [
+            'type' => 'srgbClr',
+            'value' => 'FFFF00',
+            'alpha' => 30,
+        ];
+        self::assertEquals($majorGlowSize, $majorGridlines->getGlowProperty('size'));
+        self::assertEquals($majorGlowSize, $majorGridlines->getGlowSize());
+        self::assertEquals($expectedGlowColor['value'], $majorGridlines->getGlowColor('value'));
+        self::assertEquals($expectedGlowColor, $majorGridlines->getGlowProperty('color'));
+        self::assertEquals($softEdgeSize, $majorGridlines->getSoftEdgesSize());
+
+        $minorGridlines = new GridLines();
+        $expectedShadow = [
+            'effect' => 'outerShdw',
+            'algn' => 'tl',
+            'blur' => 4,
+            'direction' => 45,
+            'distance' => 3,
+            'rotWithShape' => 0,
+            'color' => [
+                'type' => Properties::EXCEL_COLOR_TYPE_STANDARD,
+                'value' => 'black',
+                'alpha' => 40,
+            ],
+        ];
+        foreach ($expectedShadow as $key => $value) {
+            $minorGridlines->setShadowProperty($key, $value);
+        }
+        foreach ($expectedShadow as $key => $value) {
+            self::assertEquals($value, $minorGridlines->getShadowProperty($key), $key);
+        }
+
+        // Create the chart
+        $chart = new Chart(
+            'chart1', // name
+            $title, // title
+            $legend, // legend
+            $plotArea, // plotArea
+            true, // plotVisibleOnly
+            DataSeries::EMPTY_AS_GAP, // displayBlanksAs
+            null, // xAxisLabel
+            $yAxisLabel,  // yAxisLabel
+            null, // xAxis
+            null, // yAxis
+            $majorGridlines,
+            $minorGridlines
+        );
+        $majorGridlines2 = $chart->getMajorGridlines();
+        self::assertEquals($majorGlowSize, $majorGridlines2->getGlowProperty('size'));
+        self::assertEquals($expectedGlowColor, $majorGridlines2->getGlowProperty('color'));
+        self::assertEquals($softEdgeSize, $majorGridlines2->getSoftEdgesSize());
+        $minorGridlines2 = $chart->getMinorGridlines();
+        foreach ($expectedShadow as $key => $value) {
+            self::assertEquals($value, $minorGridlines2->getShadowProperty($key), $key);
+        }
+
+        // Set the position where the chart should appear in the worksheet
+        $chart->setTopLeftPosition('A7');
+        $chart->setBottomRightPosition('H20');
+
+        // Add the chart to the worksheet
+        $worksheet->addChart($chart);
+
+        /** @var callable */
+        $callableReader = [$this, 'readCharts'];
+        /** @var callable */
+        $callableWriter = [$this, 'writeCharts'];
+        $reloadedSpreadsheet = $this->writeAndReload($spreadsheet, 'Xlsx', $callableReader, $callableWriter);
+        $spreadsheet->disconnectWorksheets();
+
+        $sheet = $reloadedSpreadsheet->getActiveSheet();
+        $charts2 = $sheet->getChartCollection();
+        self::assertCount(1, $charts2);
+        $chart2 = $charts2[0];
+        self::assertNotNull($chart2);
+        $majorGridlines3 = $chart2->getMajorGridlines();
+        self::assertEquals($majorGlowSize, $majorGridlines3->getGlowProperty('size'));
+        self::assertEquals($expectedGlowColor, $majorGridlines3->getGlowProperty('color'));
+        self::assertEquals($softEdgeSize, $majorGridlines3->getSoftEdgesSize());
+        $minorGridlines3 = $chart->getMinorGridlines();
+        foreach ($expectedShadow as $key => $value) {
+            self::assertEquals($value, $minorGridlines3->getShadowProperty($key), $key);
+        }
+
+        $reloadedSpreadsheet->disconnectWorksheets();
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Chart/MultiplierTest.php b/tests/PhpSpreadsheetTests/Chart/MultiplierTest.php
new file mode 100644
index 00000000..35161ff7
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Chart/MultiplierTest.php
@@ -0,0 +1,157 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
+
+use PhpOffice\PhpSpreadsheet\Chart\Chart;
+use PhpOffice\PhpSpreadsheet\Chart\DataSeries;
+use PhpOffice\PhpSpreadsheet\Chart\DataSeriesValues;
+use PhpOffice\PhpSpreadsheet\Chart\Legend as ChartLegend;
+use PhpOffice\PhpSpreadsheet\Chart\PlotArea;
+use PhpOffice\PhpSpreadsheet\Chart\Properties;
+use PhpOffice\PhpSpreadsheet\Chart\Title;
+use PhpOffice\PhpSpreadsheet\Shared\File;
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Writer\Xlsx as XlsxWriter;
+use PHPUnit\Framework\TestCase;
+
+class MultiplierTest extends TestCase
+{
+    public function testMultiplier(): void
+    {
+        $spreadsheet = new Spreadsheet();
+        $worksheet = $spreadsheet->getActiveSheet();
+        $worksheet->fromArray(
+            [
+                ['', 2010, 2011, 2012],
+                ['Q1', 12, 15, 21],
+                ['Q2', 56, 73, 86],
+                ['Q3', 52, 61, 69],
+                ['Q4', 30, 32, 0],
+            ]
+        );
+
+        // Set the Labels for each data series we want to plot
+        //     Datatype
+        //     Cell reference for data
+        //     Format Code
+        //     Number of datapoints in series
+        //     Data values
+        //     Data Marker
+        $dataSeriesLabels = [
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$B$1', null, 1), // 2010
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$C$1', null, 1), // 2011
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$D$1', null, 1), // 2012
+        ];
+        // Set the X-Axis Labels
+        //     Datatype
+        //     Cell reference for data
+        //     Format Code
+        //     Number of datapoints in series
+        //     Data values
+        //     Data Marker
+        $xAxisTickValues = [
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_STRING, 'Worksheet!$A$2:$A$5', null, 4), // Q1 to Q4
+        ];
+        // Set the Data values for each data series we want to plot
+        //     Datatype
+        //     Cell reference for data
+        //     Format Code
+        //     Number of datapoints in series
+        //     Data values
+        //     Data Marker
+        $dataSeriesValues = [
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$B$2:$B$5', null, 4),
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$C$2:$C$5', null, 4),
+            new DataSeriesValues(DataSeriesValues::DATASERIES_TYPE_NUMBER, 'Worksheet!$D$2:$D$5', null, 4),
+        ];
+
+        // Build the dataseries
+        $series = new DataSeries(
+            DataSeries::TYPE_AREACHART, // plotType
+            DataSeries::GROUPING_PERCENT_STACKED, // plotGrouping
+            range(0, count($dataSeriesValues) - 1), // plotOrder
+            $dataSeriesLabels, // plotLabel
+            $xAxisTickValues, // plotCategory
+            $dataSeriesValues          // plotValues
+        );
+
+        // Set the series in the plot area
+        $plotArea = new PlotArea(null, [$series]);
+        // Set the chart legend
+        $legend = new ChartLegend(ChartLegend::POSITION_TOPRIGHT, null, false);
+
+        $title = new Title('Test %age-Stacked Area Chart');
+        $yAxisLabel = new Title('Value ($k)');
+
+        // Create the chart
+        $chart = new Chart(
+            'chart1', // name
+            $title, // title
+            $legend, // legend
+            $plotArea, // plotArea
+            true, // plotVisibleOnly
+            DataSeries::EMPTY_AS_GAP, // displayBlanksAs
+            null, // xAxisLabel
+            $yAxisLabel  // yAxisLabel
+        );
+        $xAxis = $chart->getChartAxisX();
+        $expectedX = [
+            'effect' => 'outerShdw',
+            'algn' => 'bl',
+            'blur' => 6,
+            'direction' => 315,
+            'distance' => 3,
+            'rotWithShape' => 0,
+            'size' => [
+                'sx' => null,
+                'sy' => 254,
+                'kx' => -94,
+                'ky' => null,
+            ],
+            'color' => [
+                'type' => Properties::EXCEL_COLOR_TYPE_ARGB,
+                'value' => 'FF0000',
+                'alpha' => 20,
+            ],
+        ];
+        $expectedXmlX = [
+            '<a:outerShdw ',
+            ' algn="bl"',
+            ' blurRad="76200"',
+            ' dir="18900000"',
+            ' dist="38100"',
+            ' rotWithShape="0"',
+            ' sy="25400000"',
+            ' kx="-5640000"',
+            '<a:srgbClr val="FF0000">',
+            '<a:alpha val="80000"/>',
+        ];
+        $expectedXmlNoX = [
+            ' sx=',
+            ' ky=',
+        ];
+        foreach ($expectedX as $key => $value) {
+            $xAxis->setShadowProperty($key, $value);
+        }
+        // Set the position where the chart should appear in the worksheet
+        $chart->setTopLeftPosition('A7');
+        $chart->setBottomRightPosition('H20');
+
+        // Add the chart to the worksheet
+        $worksheet->addChart($chart);
+
+        $writer = new XlsxWriter($spreadsheet);
+        $writer->setIncludeCharts(true);
+        $writerChart = new XlsxWriter\Chart($writer);
+        $data = $writerChart->writeChart($chart);
+
+        // confirm that file contains expected tags
+        foreach ($expectedXmlX as $expected) {
+            self::assertSame(1, substr_count($data, $expected), $expected);
+        }
+        foreach ($expectedXmlNoX as $expected) {
+            self::assertSame(0, substr_count($data, $expected), $expected);
+        }
+        $spreadsheet->disconnectWorksheets();
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Chart/ShadowPresetsTest.php b/tests/PhpSpreadsheetTests/Chart/ShadowPresetsTest.php
new file mode 100644
index 00000000..58c024c1
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Chart/ShadowPresetsTest.php
@@ -0,0 +1,183 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Chart;
+
+use PhpOffice\PhpSpreadsheet\Chart\Axis;
+use PhpOffice\PhpSpreadsheet\Chart\GridLines;
+use PhpOffice\PhpSpreadsheet\Chart\Properties;
+use PHPUnit\Framework\TestCase;
+
+class ShadowPresetsTest extends TestCase
+{
+    public function testGridlineShadowPresets(): void
+    {
+        $gridlines = new GridLines();
+        $gridlines->setShadowProperties(17);
+        $expectedShadow = [
+            'effect' => 'innerShdw',
+            'distance' => 4,
+            'direction' => 270,
+            'blur' => 5,
+        ];
+        foreach ($expectedShadow as $key => $value) {
+            self::assertEquals($gridlines->getShadowProperty($key), $value, $key);
+        }
+    }
+
+    public function testGridlineShadowPresetsWithArray(): void
+    {
+        $gridlines = new GridLines();
+        $gridlines->setShadowProperties(20);
+        $expectedShadow = [
+            'effect' => 'outerShdw',
+            'blur' => 6,
+            'direction' => 315,
+            'size' => [
+                'sx' => null,
+                'sy' => 0.23,
+                'kx' => -20,
+                'ky' => null,
+            ],
+            'algn' => 'bl',
+            'rotWithShape' => '0',
+        ];
+        foreach ($expectedShadow as $key => $value) {
+            self::assertEquals($gridlines->getShadowProperty($key), $value, $key);
+        }
+    }
+
+    public function testAxisShadowPresets(): void
+    {
+        $axis = new Axis();
+        $axis->setShadowProperties(9);
+        $expectedShadow = [
+            'effect' => 'outerShdw',
+            'blur' => 4,
+            'distance' => 3,
+            'direction' => 225,
+            'algn' => 'br',
+            'rotWithShape' => '0',
+        ];
+        foreach ($expectedShadow as $key => $value) {
+            self::assertEquals($axis->getShadowProperty($key), $value, $key);
+        }
+    }
+
+    public function testAxisShadowPresetsWithChanges(): void
+    {
+        $axis = new Axis();
+        $axis->setShadowProperties(
+            9, // preset
+            'FF0000', // colorValue
+            'srgbClr', // colorType
+            20, // alpha
+            6, // blur
+            30, // direction
+            4, // distance
+        );
+        $expectedShadow = [
+            'effect' => 'outerShdw',
+            'blur' => 6,
+            'distance' => 4,
+            'direction' => 30,
+            'algn' => 'br',
+            'rotWithShape' => '0',
+            'color' => [
+                'value' => 'FF0000',
+                'type' => 'srgbClr',
+                'alpha' => 20,
+            ],
+        ];
+        foreach ($expectedShadow as $key => $value) {
+            self::assertEquals($axis->getShadowProperty($key), $value, $key);
+        }
+    }
+
+    public function testGridlinesShadowPresetsWithChanges(): void
+    {
+        $gridline = new GridLines();
+        $gridline->setShadowProperties(
+            9, // preset
+            'FF0000', // colorValue
+            'srgbClr', // colorType
+            20, // alpha
+            6, // blur
+            30, // direction
+            4, // distance
+        );
+        $expectedShadow = [
+            'effect' => 'outerShdw',
+            'blur' => 6,
+            'distance' => 4,
+            'direction' => 30,
+            'algn' => 'br',
+            'rotWithShape' => '0',
+            'color' => [
+                'value' => 'FF0000',
+                'type' => 'srgbClr',
+                'alpha' => 20,
+            ],
+        ];
+        foreach ($expectedShadow as $key => $value) {
+            self::assertEquals($gridline->getShadowProperty($key), $value, $key);
+        }
+    }
+
+    public function testOutOfRangePresets(): void
+    {
+        $axis = new Axis();
+        $axis->setShadowProperties(99);
+        $expectedShadow = [
+            'presets' => Properties::SHADOW_PRESETS_NOSHADOW,
+            'effect' => null,
+            'color' => [
+                'type' => Properties::EXCEL_COLOR_TYPE_STANDARD,
+                'value' => 'black',
+                'alpha' => 40,
+            ],
+            'size' => [
+                'sx' => null,
+                'sy' => null,
+                'kx' => null,
+                'ky' => null,
+            ],
+            'blur' => null,
+            'direction' => null,
+            'distance' => null,
+            'algn' => null,
+            'rotWithShape' => null,
+        ];
+        foreach ($expectedShadow as $key => $value) {
+            self::assertEquals($value, $axis->getShadowProperty($key), $key);
+        }
+    }
+
+    public function testOutOfRangeGridlines(): void
+    {
+        $gridline = new GridLines();
+        $gridline->setShadowProperties(99);
+        $expectedShadow = [
+            'presets' => Properties::SHADOW_PRESETS_NOSHADOW,
+            'effect' => null,
+            'color' => [
+                'type' => Properties::EXCEL_COLOR_TYPE_STANDARD,
+                'value' => 'black',
+                'alpha' => 40,
+            ],
+            'size' => [
+                'sx' => null,
+                'sy' => null,
+                'kx' => null,
+                'ky' => null,
+            ],
+            'blur' => null,
+            'direction' => null,
+            'distance' => null,
+            'algn' => null,
+            'rotWithShape' => null,
+        ];
+        foreach ($expectedShadow as $key => $value) {
+            self::assertEquals($value, $gridline->getShadowProperty($key), $key);
+        }
+    }
+}