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PL/PDF version 2.1.0

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We use the PL/PDF package to produce PDF documents that can be mailed on request to APEX web site users. The PDF contents will usually be a version of something that was displayed on screen, for example a list of answers to a questionnaire. Version 2.1.0 of PL/PDF has recently become available and we’ve just upgraded our development and production systems.

PL/PDF does quite a good job of converting simple text or tabular data into reasonable-looking PDFs, but it
takes some work to produce more complicated documents, and it lacks the ability to convert an HTML document directly into a PDF.

Pound sign (£)

The FAQs on the PL/PDF web site state that the default decoding cp1252 does not include a pound sign, but that one can be displayed using unistr(‘0a3’) or chr(49827).

We found those characters display a capital L with a line crossing it, rather than a real pound sign. I wrote a procedure to print every Unicode character just to make sure there wasn’t some other encoding for a real pound sign – but there wasn’t. Instead we had to use an TrueType embedded font rather than one of the built-in fonts.

TrueType Fonts

One of the least friendly aspects of previous PL/PDF versions was the procedure for using TrueType embedded fonts, which involved running a command line program to generate an Adobe Font Metrics (AFM) file, then using SQL*Loader with custom control files to load two tables, and finally running a stored procedure. It took me most of a day’s work to do this for a single TrueType font file, and the resulting embedded font was unusable – it produced a blank document. I never had the time or the inclination to try again. Version 2.1.0 has fixed that – it includes a graphical application (PL/PDF v2.1.0 TTF Loader) that does all the work automatically. In 5 minutes I managed to install all 4 Arial TrueType fonts in a usable form. I had to specify utf16 encoding and unicode in the graphical interface (our Oracle NLS_CHARACTERSET=AL32UTF8, NLS_NCHAR_CHARACTERSET=AL16UTF16).

It’s not immediately obvious how to use the embedded TrueType fonts. They first have to be loaded with a user-defined alias using the numerical value of an ID field in a PL/PDF table; plpdf_ttf_add.ID. The value of the ID is derived from an Oracle sequence so it can vary with the server it is running on – in order to avoid hard-coding it we had to write a procedure to find the ID corresponding to a given font name.

Once loaded, TrueType fonts can be referred to by their aliases. However, the different font styles are each in different TrueType files, and it seems they must therefore have different font names when used in PL/PDF, so the built-in PL/PDF method for specifying font styles won’t work. Eg to print in ArialMT bold, instead of specifying font ‘ArialMT’ and style ‘B’, you need to specify font ‘Arial-BoldMT’ and style NULL.

Other PL/SQL anomalies

These were seen in earlier versions – we’ve not yet had time to retest with version 2.1.0:

  • The left margin setting procedure appears not to work; to produce a left indent we have to add spaces to the output text.
  • The expected width of text to be printed as reported by the GetTextWidth function is sometimes wrong (by a constant factor) – we need to declare a variable to hold an empirically determined “fudge factor” that we multiply every result from GetTextWidth by.
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Written by Roger

28 April, 2009 at 12:40 pm

Posted in Uncategorized

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