PDF Export in OpenOffice.org
Originally, PDF export in OpenOffice.org was limited to three levels of quality, whose exact differences were obscure to most users. But that was many releases ago. The latest versions of OpenOffice.org provide, for no cost, most of the features available in Acrobat Standard for $299 -- to say nothing of a few features that even Acrobat Pro Extended does not include even at $699. The problem for many people is knowing what options they might want, especially since the wording of the dialog window is sloppy in a couple of places.
For some reason, OpenOffice.org has two Export items listed in the File menu: plain Export and Export to PDF. Which you choose is irrelevant: if you choose PDF as the format in Export, the same PDF Options dialog window opens as when you choose Export to PDF.
The dialog window is divided into five tabs: General, Initial View, User Interface, Links, and Security. Generally, the defaults are reasonable selections, so, if you prefer, the most you have to choose is the range of pages to print. However, the options are worth understanding for those occasions when you need more control over the PDF creation process.
The General Tab
The General tab contains settings that determine the general structure of the PDF document that you are creating.
In the first section of the tab, you set which pages of the original document will be included in the PDF. The default is All, but you can also export the pages currently selected in the original, or designate a range of pages. In setting a range, you can include single page numbers, a range of pages separated by a hyphen (for example, 7-10), or a list of single pages or ranges, with each item separated by a semi-colon (for example, 1; 7-10.
If you want to minimize the size of the PDF file, you can reduce space by your selections in the Image section of the tab. You can reduce the size of JPEG images by selecting an image quality expressed as a percentage, or a general resolution for all images, expressed in dots per inch.
However, be aware that there is a trade off when you reduce image quality. The lower the JPEG setting, the more "noise" that is introduced into the displayed image. If the PDF will be printed by users, then you want a resolution of at least 200dpi, if not 300. If you are not willing to make these trade offs, then use the Lossless setting.
The General tab also contains a number of other unorganized settings. For instance, you can choose whether you want the PDF to include bookmarks, comments (notes), or blank pages from the original.
You can also choose the variant of PDF format you want: PDF/A-1a, which is a standard for long-term document preservation; Tagged PDF, which marks the structure of the PDF export so it can be viewed on devices that otherwise could not open it properly; or Hybrid, which is a large file that contains both PDF and Open Document Format versions of the original file and is useful if you are using the Sun PDF Import extension to edit PDF files. However, unless you have a specific need, you can ignore all these choices.
Yet another formatting choice is to make the PDF export a form that users can fill in. Here, you can select the format in which you will receive data from each form that readers fill.
The Initial View Tab
The Initial View tab lists options for what readers will see when they open the PDF. In the Panes section, you can choose whether only the page is visible, or whether bookmarks or thumbnails are also available, as well as the first page to display. Usually, of course, a PDF opens on the first page, but you might decide to skip over the table of contents and front matter so that readers can start to read at once.
You also have a choice of Magnification -- that is, the size of the displayed page. If you select Default, then pages will be displayed without any zoom. Alternatively, you can choose to fit the page(s) displayed to fit the window or its width, or to ensure that everything is visible. But the most useful option is to set an exact zoom, so you know exactly what readers will see.
Other options on the Initial View tab determine what pages the reader sees. The Default setting leaves this formatting choice to the PDF browser used, while Single page displays only one page. By contrast, Continuous shows pages, one at a time, in a vertical column, while continuous facing shows two pages at a time beside each other. Single page is probably the most popular page layout, but you might opt for Continuous facing if you a diagram that occupies two pages.
The User Interface Tab
Depending on the PDF viewer you use, the settings on the User Interface tab may not have much effect. For instance, if you use XPDF, the options to set bookmark levels is irrelevant, because XPDF does not display bookmarks.
However, assuming that your PDF viewer has the controls mentioned on the tab, you have several groups of user interface options. To start with, you can set the size and placement of the windows. You can adjust the window to fit the initial view settings, center the window on the screen, display the window in full screen mode, and include the document title. In addition, you can hide the menu, toolbar, or other window controls, although in most cases there seems no reason to do so. Hiding these items does give more space to display the PDF, but if you want to maximize the display, why not just set the PDF to open in full-screen mode instead of removing controls that users might want?
When you create a PDF from an Impress file, you have the option of enabling transition effects. Practically speaking, this option turns the PDF into a presentation that can run without OpenOffice.org -- a handy means of making sure that anyone can view it.
The fourth pane on the User Interface tab is for the bookmarks that display, but appears to be broken in OpenOffice.org 3.2, the latest version as I write. The usage also appears to be confused, because, from the mention of levels of bookmarks, the pane is not talking about the bookmarks you enter from the OpenOffice.org's Insert menu -- which have no levels -- but the heading styles that you use in outline numbering, which include up to ten levels. This bug is a nuisance, because bookmarks are used in PDFs to provide a table of contents. However, when it is fixed, I advise setting the levels to three at the most, so as not to produce unnecessary clutter.
The Links tab
The only people likely to need the settings on the Links tab are those making a set of inter-connected PDFs. If you are one of them, be aware that, on this pane, "bookmarks" is used as a synonym for hyperlinks, and does not refer to headings or actual bookmarks.
When you produce inter-connected PDFs, you will want to select Export bookmarks as named destinations and Convert document references to PDF targets so that you can refer to the bookmarks in other documents. Furthermore, you will want to make all URLs relative to the filesystem, so that they function when the PDF exports are transferred to another document.
Another consideration is how links open. If you select Default, then you leave it to the PDF viewer's settings. Alternatively, you can set the links to open in the PDF viewer, or in a web browser. Which you choose depends whether the links are to other PDFs -- in which case, opening in the PDF viewer makes sense -- or to web pages -- in which case, opening in the web browser is the obvious choice.
The Security Tab
Security in PDFs is extremely low. A web search will quickly give you several means of bypassing both encryption and permissions, including many free software options.
All the same, you might be professionally required to write a PDF with security settings. If that happens, in OpenOffice.org you can encrypt the password so that only those with the password (or a way of bypassing it) can read the PDF. Note that this option is not the same as digital encryption, and can even be set and left blank.
Another set of security options is to limit what users can do without a password. For example, you can keep users from printing, or restrict them to printing only in low resolution. You can forbid users to make any changes, or allow them limited ability, such as rotating pages, filling in form fields, or adding comments, or from anything except extracting pages. Others options include whether content can be copied, or accessed by accessibility tools like Orca.
Just remember, though, that all these options are easily sidestepped. All you can really do is guard the PDF from people with limited knowledge or initiative.
Saving and Other Considerations
When you are content with all the settings, click the Export button at the bottom of the Window dialog. A file saving dialog opens, set to the same directory as the original file or, if the original is unsaved, to ~/.openoffice.org/3/user/gallery -- which you will almost certainly wish to change.
The only feature I really miss in the current PDF Export document is the ability to open the new export as soon as it is made. Otherwise, if OpenOffice.org does not supply the feature I need, than pdftk or the Sun PDF Import extension almost certainly will. There may be one or two tools in the proprietary Acrobat packages that advanced users will miss, but, for the most part, today you can create and edit PDFs using free software just as well as you can with proprietary software.
-- Bruce Byfield (nanday)
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