title: get_cellmap() issue with DomPDF
body: <p>I'm working with DomPdf and trying to convert my file into pdf but facing a strange error given below</p>
  
  <p>I googled many times and read different forums but didn't get the reason for this error.</p>
  
  <p>Please help me guys. </p>
  
  <blockquote>
    <p>Fatal error: Uncaught Error: Call to a member function get_cellmap()
    on null in
    C:\xampp\htdocs\dom\dompdf\src\FrameReflower\TableCell.php:37 Stack
    trace: #0
    C:\xampp\htdocs\dom\dompdf\src\FrameDecorator\AbstractFrameDecorator.php(893):
    Dompdf\FrameReflower\TableCell->reflow(NULL) #1
    C:\xampp\htdocs\dom\dompdf\src\FrameReflower\TableRow.php(52):
    Dompdf\FrameDecorator\AbstractFrameDecorator->reflow() #2
    C:\xampp\htdocs\dom\dompdf\src\FrameDecorator\AbstractFrameDecorator.php(893):
    Dompdf\FrameReflower\TableRow->reflow(NULL) #3</p>
  </blockquote>
  
  <p>Code</p>
  
  <p>
  
  <pre><code>require_once './dompdf/autoload.inc.php';
  use Dompdf\Dompdf;
  
  $dompdf = new Dompdf();
  $dompdf-&gt;loadHtml(file_get_contents('./my-file.php'));
  
  $dompdf-&gt;setPaper('A4','landscape');
  $dompdf-&gt;render();
  
  $dompdf-&gt;stream('codexworld',array('Attachment'=&gt;0));
  </code></pre>
  
  <p>my-file.php</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
  
  &lt;head&gt;
  &lt;/head&gt;
  
  &lt;body&gt;
  
  &lt;div id="page-wrap"&gt;
  &lt;form method="post" action="save_view.php" novalidate=""&gt;   
  
  &lt;div id="header"&gt;
  
  &lt;h2 class="title" style="text-decoration: underline;font-size:2em;font-family: Brush Script Mt;"&gt;Pro Tech Diagnostics&lt;/h2&gt;
  &lt;!--            &lt;img id="image"  width="auto" src="images/Logo.png" alt="logo" height="60"/&gt;--&gt;
  &lt;div  class="adjust_contact"&gt;
  &lt;p&gt;26893 Bouquet Canyon Rd. Suite C204 Saugus, CA 91350&lt;/p&gt;
  &lt;div class="parent"&gt;
  
  &lt;p class="left"&gt;Phone # (818)644-1965&lt;/p&gt;
  &lt;p class="right"&gt;Fax # (661) 468-7504&lt;/p&gt;
  &lt;/div&gt;
  &lt;/div&gt;
  &lt;/div&gt;
  
  &lt;div id="identity"&gt;
  
  
  
  &lt;div id="header1"&gt;
  
  &lt;h3&gt;Customer Info&lt;/h3&gt;
  &lt;/div&gt;
  
  &lt;/div&gt;
  
  
  &lt;div style="clear:both"&gt;&lt;/div&gt;
  
  
  &lt;!--            &lt;textarea id="customer-title"&gt;Widget Corp.
  c/o Steve Widget&lt;/textarea&gt;--&gt;
  
  &lt;div id="customer"&gt; 
  &lt;div id="parent"&gt;
  
  &lt;table id="meta" style="overflow: wrap" class="left1"&gt;
  
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Name&lt;/td&gt;
  &lt;td&gt;
  &lt;input name="name" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;
  
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Address&lt;/td&gt;
  &lt;td&gt;
  &lt;input name="address" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Phone&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="phone" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;                
  
  
  &lt;/table&gt;
  
  
  
  &lt;table id="meta" style="overflow: wrap" class="right1"&gt;
  
  
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Invoice#&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="invoice" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;                
  
  &lt;tr&gt;
  
  &lt;td class="meta-head"&gt;Paid Date&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="date" type="text"/&gt;
  &lt;/td&gt;
  &lt;/tr&gt;
  
  
  &lt;/table&gt;                    
  &lt;/div&gt;
  &lt;/div&gt;
  
  
  &lt;!-----------------------3 columns Table Section-------------------------&gt;
  
  &lt;div id="identity"&gt;
  &lt;div id="header1-1"&gt;
  
  &lt;h3&gt;Vehicle Info&lt;/h3&gt;
  &lt;/div&gt;
  
  &lt;/div&gt;
  
  &lt;div class="Row"&gt;
  &lt;div class="Column"&gt;
  &lt;table id="meta" style="overflow: wrap" class="left1"&gt;
  
  &lt;span class="parent"&gt;
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Make:&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="make" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;
  
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Model:&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="model" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;
  &lt;/span&gt;
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Year:&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="year" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;                
  
  
  &lt;/table&gt;    
  
  &lt;/div&gt;&lt;!--1st table--&gt;
  
  
  &lt;div class="Column"&gt;
  &lt;table id="meta" style="overflow: wrap" class="left1"&gt;
  
  &lt;span class="parent"&gt;
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Vin #:&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="vin" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;
  
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Lic.#:&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="lic" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;
  &lt;/span&gt;
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Miles:&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="miles" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;                
  
  
  &lt;/table&gt;
  &lt;/div&gt;&lt;!--2nd table--&gt;
  
  &lt;div class="Column"&gt;
  
  &lt;table id="meta" style="overflow: wrap" class="left1"&gt;
  
  &lt;span class="parent"&gt;
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;Color:&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="color" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;
  
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;R.O. #:&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="ro" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;
  &lt;/span&gt;
  &lt;tr&gt;
  &lt;td class="meta-head"&gt;P.O. #:&lt;/td&gt;
  &lt;td&gt;
  &lt;input  required="required" name="po" type="text"/&gt;
  
  &lt;/td&gt;
  &lt;/tr&gt;                
  
  
  &lt;/table&gt;
  &lt;/div&gt;&lt;!--3rd table--&gt;
  
  &lt;/div&gt;&lt;!--End 3 column table row--&gt;
  
  
  
  
  
  
  &lt;table id="items" style="overflow: wrap; margin-top: 100px;"&gt;
  
  &lt;tr&gt;
  &lt;th  colspan="6"&gt;Descryption&lt;/th&gt;
  
  &lt;th&gt;Hrs&lt;/th&gt;
  &lt;th colspan="1"&gt;Amount&lt;/th&gt;
  &lt;/tr&gt;
  
  &lt;tr class="item-row"&gt;
  &lt;td colspan="6" class="item-name"&gt;
  &lt;textarea style="padding-bottom: 300px;" name="description" rows="12" cols="5"&gt;&lt;/textarea&gt;
  &lt;p style="font-weight: bold"&gt;*******All Parts Supplied By Shop*******&lt;/p&gt;
  &lt;/td&gt;
  
  
  &lt;td&gt;
  &lt;input  name="hrs" type="text"/&gt;
  
  &lt;/td&gt;
  
  &lt;td colspan="5"&gt;
  
  &lt;input required="required" name="amount" type="text"/&gt;
  &lt;/td&gt;
  &lt;/tr&gt;
  
  
  &lt;tr&gt;
  &lt;td colspan="4"&gt;Technician #: 81 (Miguel A.)&lt;/td&gt;
  &lt;td style="border: none;" colspan="2"&gt;Labor Hrs:&lt;/td&gt;
  &lt;td colspan="1"&gt;&lt;input placeholder="0"  name="labourHrs" type="text"/&gt;&lt;/td&gt;
  &lt;td colspan="1"&gt;&lt;/td&gt;
  &lt;/tr&gt;
  
  &lt;tr&gt;
  &lt;td colspan="2"&gt;Labor Rate (Per Hr):&lt;/td&gt;
  &lt;td  colspan="2"&gt;&lt;input placeholder="60" required="required" name="labourRate" type="text"/&gt;&lt;/td&gt;
  &lt;td style="border: none;" colspan="2"&gt;Labor Price:&lt;/td&gt;
  &lt;td colspan="1"&gt;&lt;input placeholder="0"  name="labourPrice" type="text"/&gt;&lt;/td&gt;
  &lt;td colspan="1"&gt;&lt;/td&gt;
  &lt;/tr&gt;
  
  &lt;tr&gt;
  &lt;td style="border: none;" colspan="4"&gt;&lt;/td&gt;
  &lt;td style="border: none;" colspan="2"&gt;Total&lt;/td&gt;
  &lt;td colspan="1"&gt;&lt;/td&gt;
  &lt;td colspan="1"&gt;&lt;input  placeholder="0"  name="total" type="text"/&gt;&lt;/td&gt;
  &lt;/tr&gt;
  
  &lt;tr&gt;
  &lt;td style="border: none" colspan="4"&gt;&lt;/td&gt;
  &lt;td colspan="3"&gt;Grand Total&lt;/td&gt;
  &lt;td colspan="1"&gt;&lt;input  placeholder="$0.00"  name="gTotal" type="text"/&gt;&lt;/td&gt;
  &lt;/tr&gt;
  
  
  &lt;tr&gt;
  &lt;td colspan="4"&gt;Signature Approval:&lt;/td&gt;
  &lt;td colspan="4"&gt;&lt;/td&gt;
  &lt;/tr&gt;
  
  &lt;tr&gt;
  &lt;td style="border: none" colspan="4"&gt;&lt;/td&gt;
  &lt;td style="border-right: none;" colspan="4"&gt;Paid&lt;/td&gt;
  &lt;/tr&gt;
  
  &lt;tr class="no-border"&gt;
  &lt;td colspan="4"&gt;&lt;/td&gt;
  &lt;td&gt;&lt;/td&gt; 
  &lt;td &gt;Yes&lt;input type="checkbox" name="one" value="Yes( &amp;#10003; )"&gt;&lt;/td&gt;
  &lt;td&gt;No ( )&lt;input type="checkbox" name="two" value="No( &amp;#10003; )"&gt;&lt;/td&gt;
  &lt;td&gt;P.O. ( )&lt;input type="checkbox" name="three" value="P.O( &amp;#10003; )"&gt;&lt;/td&gt;
  &lt;/tr&gt;
  
  &lt;tr&gt;
  
  &lt;td colspan="8"&gt;
  &lt;p style="font-size: 10px"&gt;Not responsible for loss by fire or theft or any other cause beyond our control. I hereby authorize the above repair work to be done with the necessary material &amp; grant
  permission to operate equipment for purpose of testing and inspection. An express mechanic's lien is acknowledged to secure the amount of repairs. I agree to pay
  the payment in full no later than 30 days after work has been completed. After 30 days, a 1.4% monthly charge will be added to the outstanding balance.
  &lt;/p&gt;
  &lt;/td&gt;
  &lt;/tr&gt;
  
  
  &lt;/table&gt;
  
  
  &lt;/div&gt;
  &lt;h2 style="text-decoration: underline;font-style: italic;text-align: center; font-weight: bold;font-family: Brush Script Mt;"&gt;
  Thanks for Your Business
  &lt;/h2&gt;
  &lt;input name="submit" class="submit" type="submit" value="Submit"/&gt;
  
  &lt;/form&gt;
  
  &lt;/body&gt;
  
  &lt;/html&gt;
  </code></pre>