About Arbortext Styler > General Reference Information > Differences in Output Support > Print/PDF Output via XSL-FO
Print/PDF Output via XSL-FO
The FOSI and XSL-FO print engines are on sustained support and do not receive enhancements or maintenance fixes. PTC ALD is the recommended engine for print/PDF output.
For information on how to set the print engine for your environment, see Logic for Print/Preview Engine Selection.
Area in UI
Text category
Shading activated for a block element via the Shading field will apply background color to the whole block. With the FOSI and PTC ALD print engines shading applies only to individual lines of text in the block.
Elements that are shaded can only be split across page boundaries in XSL-FO output when deepcontentsplitting is active.
Breaks category
If an element is set to start a new page set, and the Page number field is set to Initial, the first page will always be a recto (odd) page regardless of the settings in the Start new field. This may result in a blank page at the end of the previous section.
In FOSI and PTC ALD output, the type of first page output will always follow the value of the Start new field, even if the page number is set to Initial.
If an element is set to start a new page set, and its style is set to Definition List, you will see composition pipeline errors as shown below when you attempt to publish the document via the XSL-FO engine, and the element in question will likely show the terms overlapping the definitions in output.
No content area defined for formatting object fo:block, output may not be properly formatted
Expecting 'fo:page-sequence' but found 'fo:block' which is not a valid child of 'fo:root'
To overcome this, either do not start a new page set on a definition list element or use either the FOSI or the PTC ALD engine for print/PDF output.
Run-in styling is not supported.
Generated text category
Generated text configured for a property set will be resolved to the contexts/conditions that reference the property set when the stylesheet is exported.
Side by side category
If Placement is Right, the value of Horizontal offset is ignored when determining the left edge of the right aligned element. The XSL-FO engine uses the left indent and first line indent settings on the Indent category instead.
When Horizontal gap is greater than zero, the position of the following content is determined by adding the values of both Horizontal gap and the indent settings to the adjacent edge of the aligned element.
Values specified in em are not permitted in the Horizontal offset, Width, and Horizontal gap fields. If such a size is used, XSL-FO will treat 1em as 1pc.
PDF tags category
This is disabled for a stylesheet set to generate PDF via XSL-FO. You must use the PTC ALD engine to generate tagged PDF output or alternate text for graphics/links.
Tables of Contents list
PDF bookmarks in PDFs generated using the XSL-FO engine will always consist of the number followed by the title contents, irrespective of any other content that may be associated with the title when it is displayed in a table of contents. All formatting details associated with the context in the TOC are ignored when using the XSL-FO engine. See description of PDF bookmarks in Tables of Contents List for further information.
The FOSI engine incorporates formatting information associated with the context in the TOC when generating PDF bookmarks.
Page Sets list
In the Page types category, when the Double sided option is selected, a setting of Same as other pages in the Blank pages field will output the page type specified for even pages.
Unequal column widths are not supported.
Page Regions list
The main content flow region must be the same width for all pages.
The main content flow region may only be rotated by 90 degrees.
Graphics for a region background may not be extracted via XPath.
Region borders will not be output.
An Underlaid regions avoid this region setting will be ignored.
A Clip region at page edge setting will be ignored.
Independent horizontal and vertical scaling of graphics is not supported.
Custom Tables list
Styling for the element used as an anonymous cell in a custom table is ignored. One of the following methods could be used instead:
1. Putting the styling on an element within the cell that wraps all the content (if such exists)
2. Specifying explicitly in the custom table model all the elements that can be cells
The Shrink graphics to fit option is not supported. You must publish via the PTC ALD engine to use this feature.
Default dpi differences between Windows and Unix mean that graphics may appear cropped in XSL-FO output generated via a Solaris or Linux PE server. To get results equivalent to that produced in a Windows environment, set defaultscreendpi=96 on the Unix machine.  
Rotated content in table cells is always formatted on one line. You may see very tall cells if their content is rotated 90° or 180°.
Publish via the PTC ALD engine if you need your content to break across lines.