+```
+
+instead of
+
+``` html
+
.
+```
+
+You can use the following code to achieve this result:
+
+``` php
+$writer->setImagesRoot('http://www.example.com');
+```
+
+#### Formula pre-calculation
+
+By default, this writer pre-calculates all formulas in the spreadsheet.
+This can be slow on large spreadsheets, and maybe even unwanted. You can
+however disable formula pre-calculation:
+
+``` php
+$writer = new \PhpOffice\PhpSpreadsheet\Writer\Html($spreadsheet);
+$writer->setPreCalculateFormulas(false);
+
+$writer->save("05featuredemo.htm");
+```
+
+#### Embedding generated HTML in a web page
+
+There might be a situation where you want to embed the generated HTML in
+an existing website. \PhpOffice\PhpSpreadsheet\Writer\Html provides
+support to generate only specific parts of the HTML code, which allows
+you to use these parts in your website.
+
+Supported methods:
+
+- generateHTMLHeader()
+- generateStyles()
+- generateSheetData()
+- generateHTMLFooter()
+
+Here's an example which retrieves all parts independently and merges
+them into a resulting HTML page:
+
+``` php
+generateHTMLHeader();
+?>
+
+
+?>
+
+-->
+
+
+generateSheetData();
+echo $writer->generateHTMLFooter();
+?>
+```
+
+#### Writing UTF-8 HTML files
+
+A HTML file can be marked as UTF-8 by writing a BOM file header. This
+can be enabled by using the following code:
+
+``` php
+$writer = new \PhpOffice\PhpSpreadsheet\Writer\Html($spreadsheet);
+$writer->setUseBOM(true);
+
+$writer->save("05featuredemo.htm");
+```
+
+#### Decimal and thousands separators
+
+See section \PhpOffice\PhpSpreadsheet\Writer\Csv how to control the
+appearance of these.
+
+## PDF
+
+PhpSpreadsheet allows you to write a spreadsheet into PDF format, for
+fast distribution of represented data.
+
+**PDF limitations** Please note that PDF file format has some limits
+regarding to styling cells, number formatting, ...
+
+### \PhpOffice\PhpSpreadsheet\Writer\Pdf
+
+PhpSpreadsheet’s PDF Writer is a wrapper for a 3rd-Party PDF Rendering
+library such as tcPDF, mPDF or DomPDF. You must now install a PDF
+rendering library yourself; but PhpSpreadsheet will work with a number
+of different libraries.
+
+Currently, the following libraries are supported:
+
+Library | Downloadable from | PhpSpreadsheet Internal Constant
+--------|-------------------------------------|---------------------------------
+tcPDF | https://github.com/tecnickcom/tcpdf | PDF_RENDERER_TCPDF
+mPDF | https://github.com/mpdf/mpdf | PDF_RENDERER_MPDF
+domPDF | https://github.com/dompdf/dompdf | PDF_RENDERER_DOMPDF
+
+The different libraries have different strengths and weaknesses. Some
+generate better formatted output than others, some are faster or use
+less memory than others, while some generate smaller .pdf files. It is
+the developers choice which one they wish to use, appropriate to their
+own circumstances.
+
+Before instantiating a Writer to generate PDF output, you will need to
+indicate which Rendering library you are using.
+
+``` php
+$rendererName = \PhpOffice\PhpSpreadsheet\Settings::PDF_RENDERER_MPDF;
+\PhpOffice\PhpSpreadsheet\Settings::setPdfRendererName($rendererName);
+```
+
+#### Writing a spreadsheet
+
+Once you have identified the Renderer that you wish to use for PDF
+generation, you can write a .pdf file using the following code:
+
+``` php
+$writer = new \PhpOffice\PhpSpreadsheet\Writer\Pdf($spreadsheet);
+$writer->save("05featuredemo.pdf");
+```
+
+Please note that \PhpOffice\PhpSpreadsheet\Writer\Pdf only outputs the
+first worksheet by default.
+
+#### Write all worksheets
+
+PDF files can contain one or more worksheets. If you want to write all
+sheets into a single PDF file, use the following code:
+
+``` php
+$writer->writeAllSheets();
+```
+
+#### Write a specific worksheet
+
+PDF files can contain one or more worksheets. Therefore, you can specify
+which sheet to write to PDF:
+
+``` php
+$writer->setSheetIndex(0);
+```
+
+#### Formula pre-calculation
+
+By default, this writer pre-calculates all formulas in the spreadsheet.
+This can be slow on large spreadsheets, and maybe even unwanted. You can
+however disable formula pre-calculation:
+
+``` php
+$writer = new \PhpOffice\PhpSpreadsheet\Writer\Pdf($spreadsheet);
+$writer->setPreCalculateFormulas(false);
+
+$writer->save("05featuredemo.pdf");
+```
+
+#### Decimal and thousands separators
+
+See section \PhpOffice\PhpSpreadsheet\Writer\Csv how to control the
+appearance of these.
+
+## Generating Excel files from templates (read, modify, write)
+
+Readers and writers are the tools that allow you to generate Excel files
+from templates. This requires less coding effort than generating the
+Excel file from scratch, especially if your template has many styles,
+page setup properties, headers etc.
+
+Here is an example how to open a template file, fill in a couple of
+fields and save it again:
+
+``` php
+$spreadsheet = \PhpOffice\PhpSpreadsheet\IOFactory::load('template.xlsx');
+
+$worksheet = $spreadsheet->getActiveSheet();
+
+$worksheet->getCell('A1')->setValue('John');
+$worksheet->getCell('A2')->setValue('Smith');
+
+$writer = \PhpOffice\PhpSpreadsheet\IOFactory::createWriter($spreadsheet, 'Xls');
+$writer->save('write.xls');
+```
+
+Notice that it is ok to load an xlsx file and generate an xls file.
diff --git a/docs/topics/reading-files.md b/docs/topics/reading-files.md
index f7120253..7d103118 100644
--- a/docs/topics/reading-files.md
+++ b/docs/topics/reading-files.md
@@ -451,7 +451,7 @@ by available disk space. This means that we wouldn’t ordinarily be able
to read all the rows from a very large CSV file that exceeded those
limits, and save it as an Xls or Xlsx file. However, by using Read
Filters to read the CSV file in “chunks” (using the chunkReadFilter
-Class that we defined in section REF \_Ref275604563 \r \p 5.3 above),
+Class that we defined in [the above section](#reading-only-specific-columns-and-rows-from-a-file-read-filters),
and the setSheetIndex() method of the \$reader, we can split the CSV
file across several individual worksheets.
diff --git a/docs/topics/recipes.md b/docs/topics/recipes.md
index 167893d9..20fd2a46 100644
--- a/docs/topics/recipes.md
+++ b/docs/topics/recipes.md
@@ -5,8 +5,8 @@ Please note that these do NOT offer complete documentation on specific
PhpSpreadsheet API functions, but just a bump to get you started. If you
need specific API functions, please refer to the API documentation.
-For example, REF \_Ref191885321 \w \h 4.4.7 REF \_Ref191885321
-\h Setting a worksheet's page orientation and size covers setting a page
+For example, [setting a worksheet's page orientation and size
+](#setting-a-worksheets-page-orientation-and-size) covers setting a page
orientation to A4. Other paper formats, like US Letter, are not covered
in this document, but in the PhpSpreadsheet API documentation.
@@ -119,9 +119,9 @@ in an English version of Microsoft Office Excel, and PhpSpreadsheet
handles all formulae internally in this format. This means that the
following rules hold:
-- Decimal separator is '.' (period)
-- Function argument separator is ',' (comma)
-- Matrix row separator is ';' (semicolon)
+- Decimal separator is `.` (period)
+- Function argument separator is `,` (comma)
+- Matrix row separator is `;` (semicolon)
- English function names must be used
This is regardless of which language version of Microsoft Office Excel
@@ -132,15 +132,15 @@ will take care of displaying the formula according the applications
language. Translation is taken care of by the application!
The following line of code writes the formula
-'=IF(C4>500,"profit","loss")' into the cell B8. Note that the
-formula must start with "=" to make PhpSpreadsheet recognise this as a
+`=IF(C4>500,"profit","loss")` into the cell B8. Note that the
+formula must start with `=` to make PhpSpreadsheet recognise this as a
formula.
``` php
$spreadsheet->getActiveSheet()->setCellValue('B8','=IF(C4>500,"profit","loss")');
```
-If you want to write a string beginning with an "=" character to a
+If you want to write a string beginning with an `=` character to a
cell, then you should use the setCellValueExplicit() method.
``` php
@@ -159,7 +159,7 @@ $formula = $spreadsheet->getActiveSheet()->getCell('B8')->getValue();
```
If you need the calculated value of a cell, use the following code. This
-is further explained in REF \_Ref191885372 \w \h \* MERGEFORMAT 4.4.35.
+is further explained in [the calculation engine](./calculation-engine.md).
``` php
$value = $spreadsheet->getActiveSheet()->getCell('B8')->getCalculatedValue();
diff --git a/docs/topics/worksheets.md b/docs/topics/worksheets.md
new file mode 100644
index 00000000..60453d9c
--- /dev/null
+++ b/docs/topics/worksheets.md
@@ -0,0 +1,130 @@
+# Worksheets
+
+A worksheet is a collection of cells, formulae, images, graphs, etc. It
+holds all data necessary to represent a spreadsheet worksheet.
+
+When you load a workbook from a spreadsheet file, it will be loaded with
+all its existing worksheets (unless you specified that only certain
+sheets should be loaded). When you load from non-spreadsheet files (such
+as a CSV or HTML file) or from spreadsheet formats that don't identify
+worksheets by name (such as SYLK), then a single worksheet called
+"WorkSheet1" will be created containing the data from that file.
+
+When you instantiate a new workbook, PhpSpreadsheet will create it with
+a single worksheet called "WorkSheet1".
+
+The `getSheetCount()` method will tell you the number of worksheets in
+the workbook; while the `getSheetNames()` method will return a list of
+all worksheets in the workbook, indexed by the order in which their
+"tabs" would appear when opened in MS Excel (or other appropriate
+Spreadsheet program).
+
+Individual worksheets can be accessed by name, or by their index
+position in the workbook. The index position represents the order that
+each worksheet "tab" is shown when the workbook is opened in MS Excel
+(or other appropriate Spreadsheet program). To access a sheet by its
+index, use the `getSheet()` method.
+
+``` php
+// Get the second sheet in the workbook
+// Note that sheets are indexed from 0
+$spreadsheet->getSheet(1);
+```
+
+If you don't specify a sheet index, then the first worksheet will be
+returned.
+
+Methods also exist allowing you to reorder the worksheets in the
+workbook.
+
+To access a sheet by name, use the `getSheetByName()` method, specifying
+the name of the worksheet that you want to access.
+
+``` php
+// Retrieve the worksheet called 'Worksheet 1'
+$spreadsheet->getSheetByName('Worksheet 1');
+```
+
+Alternatively, one worksheet is always the currently active worksheet,
+and you can access that directly. The currently active worksheet is the
+one that will be active when the workbook is opened in MS Excel (or
+other appropriate Spreadsheet program).
+
+``` php
+// Retrieve the current active worksheet
+$spreadsheet->getActiveSheet();
+```
+
+You can change the currently active sheet by index or by name using the
+`setActiveSheetIndex()` and `setActiveSheetIndexByName()` methods.
+
+## Adding a new Worksheet
+
+You can add a new worksheet to the workbook using the `createSheet()`
+method of the `Spreadsheet` object. By default, this will be created as
+a new "last" sheet; but you can also specify an index position as an
+argument, and the worksheet will be inserted at that position, shuffling
+all subsequent worksheets in the collection down a place.
+
+``` php
+$spreadsheet->createSheet();
+```
+
+A new worksheet created using this method will be called
+"Worksheet<n>" where "<n>" is the lowest number possible to
+guarantee that the title is unique.
+
+Alternatively, you can instantiate a new worksheet (setting the title to
+whatever you choose) and then insert it into your workbook using the
+addSheet() method.
+
+``` php
+// Create a new worksheet called "My Data"
+$myWorkSheet = new \PhpOffice\PhpSpreadsheet\Worksheet($spreadsheet, 'My Data');
+
+// Attach the "My Data" worksheet as the first worksheet in the Spreadsheet object
+$spreadsheet->addSheet($myWorkSheet, 0);
+```
+
+If you don't specify an index position as the second argument, then the
+new worksheet will be added after the last existing worksheet.
+
+## Copying Worksheets
+
+Sheets within the same workbook can be copied by creating a clone of the
+worksheet you wish to copy, and then using the addSheet() method to
+insert the clone into the workbook.
+
+``` php
+$clonedWorksheet = clone $spreadsheet->getSheetByName('Worksheet 1');
+$clonedWorksheet->setTitle('Copy of Worksheet 1')
+$spreadsheet->addSheet($clonedWorksheet);
+```
+
+You can also copy worksheets from one workbook to another, though this
+is more complex as PhpSpreadsheet also has to replicate the styling
+between the two workbooks. The addExternalSheet() method is provided for
+this purpose.
+
+ $clonedWorksheet = clone $spreadsheet1->getSheetByName('Worksheet 1');
+ $spreadsheet->addExternalSheet($clonedWorksheet);
+
+In both cases, it is the developer's responsibility to ensure that
+worksheet names are not duplicated. PhpSpreadsheet will throw an
+exception if you attempt to copy worksheets that will result in a
+duplicate name.
+
+## Removing a Worksheet
+
+You can delete a worksheet from a workbook, identified by its index
+position, using the removeSheetByIndex() method
+
+``` php
+$sheetIndex = $spreadsheet->getIndex(
+ $spreadsheet->getSheetByName('Worksheet 1')
+);
+$spreadsheet->removeSheetByIndex($sheetIndex);
+```
+
+If the currently active worksheet is deleted, then the sheet at the
+previous index position will become the currently active sheet.