NAME

PDF::Builder::Docs - additional documentation for Builder module

SOME SPECIAL NOTES

Software Development Kit

There are four levels of involvement with PDF::Builder. Depending on what you want to do, different kinds of installs are recommended.

1. Simply installing PDF::Builder as a prerequisite for running some other package. All you need to do is install the CPAN package for PDF::Builder, and it will load the .pm files into your Perl library. If the other package prereqs PDF::Builder, its installer may download and install PDF::Builder automatically.

2. You want to write a Perl program that uses PDF::Builder functions. In addition to installing PDF::Builder from CPAN, you will want documentation on it. Obtain a copy of the product from GitHub (https://github.com/PhilterPaper/Perl-PDF-Builder) or as a gzipped tar file from CPAN. This includes a utility to build (from POD) a library of HTML documents, as well as examples (examples/ directory) and contributed sample programs (contrib/ directory).

3. You want to modify PDF::Builder files. In addition to the CPAN and GitHub distributions, you may choose to keep a local Git repository for tracking your changes. Depending on whether or not your PDF::Builder copy is being used for production purposes, you may want to do your editing and testing in the Perl library installation (live) or in a different place. The "t" tests (t/ directory) and examples provide good regression tests to ensure that you haven't broken anything. If you do your editing on the live code, don't forget when done to copy the changes back into the master version you keep!

4. You want to contribute to the development of PDF::Builder. You will need a local Git repository (and a GitHub account), so that when you've got it all done, you can issue a "Pull Request" to bring it to our attention. We can't guarantee that your work will be incorporated into the project, but at least we will look at it. From time to time, a new CPAN version will be issued.

If you want to make substantial changes for public use, and can't come to a meeting of minds with us, you can even start your own GitHub project and register a new CPAN project (that's what we did, forking PDF::API2). Please don't just assume that we don't want your changes -- at least propose what you want to do in writing, so we can consider it. We're always looking for people to help out and expand PDF::Builder.

Strings (Character Text)

Perl, and hence PDF::Builder, use strings that support the full range of Unicode characters. When importing strings into a Perl program, for example by reading text from a file, you must be aware of what their character encoding is. Single-byte encodings (default is 'latin1'), represented as bytes of value 0x00 through 0xFF (0..255), will produce different results if you do something that depends on the encoding, such as sorting, searching, or comparing any two non-ASCII characters. This also applies to any characters (text) hard coded into the Perl program.

You can always decode the text from external encoding (ASCII, UTF-8, Latin-3, etc.) into the Perl (internal) UTF-8 multibyte encoding. This uses one to four bytes to represent each character. See pragma utf8 and module Encode for details about decoding text. Note that only TrueType fonts (ttfont) can make direct use of UTF-8-encoded text. Other font types (core, T1, etc.) can only use single-byte encoded text. If your text is ASCII, Latin-1, or CP-1252, you can just leave the Perl strings as the default single-byte encoding.

Then, there is the matter of encoding the output to match up with available font character sets. You're not actually translating the text on output, but are telling the output system (and Reader) what encoding the output byte stream represents, and what character glyphs they should generate.

If you confine your text to plain ASCII (0x00 .. 0x7F byte values) or even Latin-1 or CP-1252 (0x00 .. 0xFF byte values), you can use default (non-UTF-8) Perl strings and use the default output encoding (WinAnsiEncoding), which is more-or-less Windows CP-1252 (a superset in turn, of ISO-8859-1 Latin-1). If your text uses any other characters, you will need to be aware of what encoding your text strings are (in the Perl string and for declaring output glyph generation). See corefont, psfont, and ttfont in "FONT METHODS" for additional information.

Some Internal Details

Some of the following may be a bit scary or confusing to beginners, so don't be afraid to skip over it until you're ready for it...

Perl (and PDF::Builder) internally use strings which are either single-byte (ISO-8859-1/Latin-1) or multibyte UTF-8 encoded (there is an internal flag marking the string as UTF-8 or not). If you work strictly in ASCII or Latin-1 or CP-1252 (each a superset of the previous), you should be OK in not doing anything special about your string encoding. You can just use the default Perl single byte strings (internally marked as not UTF-8) and the default output encoding (WinAnsiEncoding).

If you intend to use input from a variety of sources, you should consider decoding (converting) your text to UTF-8, which will provide an internally consistent representation (and your Perl code itself should be saved in UTF-8, in case you want to use any hard coded non-ASCII characters). In any string, non-ASCII characters (0x80 or higher) would be converted to the Perl UTF-8 internal representation, via $string = Encode::decode(MY_ENCODING, $input);. MY_ENCODING would be a string like 'latin1', 'cp-1252', 'utf8', etc. Similar capabilities are available for declaring a file to be in a certain encoding.

Be aware that if you use UTF-8 encoding for your text, that only TrueType font output (ttfont) can handle it directly. Corefont and Type1 output will require that the text will have to be converted back into a single-byte encoding (using Encode::encode), which may need to be declared with -encode (for corefont or psfont). If you have any characters not found in the selected single-byte encoding (but are found in the font itself), you will need to use automap to break up the font glyphs into 256 character planes, map such characters to 0x00 .. 0xFF in the appropriate plane, and switch between font planes as necessary.

Core and Type1 fonts (output) use the byte values in the string (single-byte encoding only!) and provide a byte-to-glyph mapping record for each plane. TrueType outputs a group of four hexadecimal digits representing the "CId" (character ID) of each character. The CId does not correspond to either the single-byte or UTF-8 internal representations of the characters.

The bottom line is that you need to know what the internal representation of your text is, so that the output routines can tell the PDF reader about it (via the PDF file). The text will not be translated upon output, but the PDF reader needs to know what the encoding in use is, so it knows what glyph to associate with each byte (or byte sequence).

By the way, it is recommended that you be using at least Perl 5.10 if you are going to be using any non-ASCII characters. Perl 5.8 may be a little unpredictable in handling such text.

PDF Versions Supported

When creating a PDF file using the functions in PDF::Builder, the output is marked as PDF 1.4. This does not mean that all PDF functionality up through 1.4 is supported! There are almost surely features missing as far back as the PDF 1.0 standard.

The big problem is when a PDF of version 1.5 or higher is imported or opened in PDF::Builder. If it contains content that is actually unsupported by this software, there is a chance that something will break. This does not guarantee that a PDF marked as "1.7" will go down in flames when read by PDF::Builder, or that a PDF written back out will break in a Reader, but the possibility is there. Much PDF writer software simply marks its output as the highest version of PDF at the time (usually 1.7), even if there is no content beyond, say, 1.2. There is some handling of PDF 1.5 items in PDF::Builder, such as cross reference streams, but support beyond 1.4 is very limited. All we can say is to be careful when handling PDFs whose version is above 1.4, and test thoroughly, as they may break at some point.

PDF::Builder includes a simple version control mechanism, where the initial PDF version to be output (default 1.4) can be set by the programmer. Input PDFs greater than 1.4 (current output level) will receive a warning (can be suppressed) that the output level will be raised to that level. The use of PDF features greater than the current output level will likewise trigger a warning that the output level is to be raised to the necessary level. If this is not desired, you should avoid using those PDF features which are higher than the desired PDF output level.

History

PDF::API2 was originally written by Alfred Reibenschuh, derived from Martin Hosken's Text::PDF via the Text::PDF::API wrapper. In 2009, Otto Hirr started the PDF::API3 fork, but it never went anywhere. In 2011, PDF::API2 maintenance was taken over by Steve Simms. In 2017, PDF::Builder was forked by Phil M. Perry, who desired a more aggressive schedule of new features and bug fixes than Simms was providing.

At Simms's request, the name of the new offering was changed from PDF::API4 to PDF::Builder, to reduce the chance of confusion due to parallel development. Perry's intent is to keep all internal methods as upwardly compatible with PDF::API2 as possible, although it is likely that there will be some drift (incompatibilities) over time. At least initially, any program written based on PDF::API2 should be convertable to PDF::Builder simply by changing "API2" anywhere it occurs to "Builder". See the KNOWN_INCOMP known incompatibilities file for further information.

DETAILED NOTES ON METHODS

Preferences - set user display preferences

$pdf->preferences(%options)

Controls viewing preferences for the PDF.

Page Mode Options

-fullscreen

Full-screen mode, with no menu bar, window controls, or any other window visible.

-thumbs

Thumbnail images visible.

-outlines

Document outline visible.

Page Layout Options

-singlepage

Display one page at a time.

-onecolumn

Display the pages in one column.

-twocolumnleft

Display the pages in two columns, with oddnumbered pages on the left.

-twocolumnright

Display the pages in two columns, with oddnumbered pages on the right.

Viewer Options

-hidetoolbar

Specifying whether to hide tool bars.

-hidemenubar

Specifying whether to hide menu bars.

-hidewindowui

Specifying whether to hide user interface elements.

-fitwindow

Specifying whether to resize the document's window to the size of the displayed page.

-centerwindow

Specifying whether to position the document's window in the center of the screen.

-displaytitle

Specifying whether the window's title bar should display the document title taken from the Title entry of the document information dictionary.

-afterfullscreenthumbs

Thumbnail images visible after Full-screen mode.

-afterfullscreenoutlines

Document outline visible after Full-screen mode.

-printscalingnone

Set the default print setting for page scaling to none.

-simplex

Print single-sided by default.

-duplexflipshortedge

Print duplex by default and flip on the short edge of the sheet.

-duplexfliplongedge

Print duplex by default and flip on the long edge of the sheet.

Initial Page Options

-firstpage => [ $page, %options ]

Specifying the page (either a page number or a page object) to be displayed, plus one of the following options:

-fit => 1

Display the page designated by page, with its contents magnified just enough to fit the entire page within the window both horizontally and vertically. If the required horizontal and vertical magnification factors are different, use the smaller of the two, centering the page within the window in the other dimension.

-fith => $top

Display the page designated by page, with the vertical coordinate top positioned at the top edge of the window and the contents of the page magnified just enough to fit the entire width of the page within the window.

-fitv => $left

Display the page designated by page, with the horizontal coordinate left positioned at the left edge of the window and the contents of the page magnified just enough to fit the entire height of the page within the window.

-fitr => [ $left, $bottom, $right, $top ]

Display the page designated by page, with its contents magnified just enough to fit the rectangle specified by the coordinates left, bottom, right, and top entirely within the window both horizontally and vertically. If the required horizontal and vertical magnification factors are different, use the smaller of the two, centering the rectangle within the window in the other dimension.

-fitb => 1

Display the page designated by page, with its contents magnified just enough to fit its bounding box entirely within the window both horizontally and vertically. If the required horizontal and vertical magnification factors are different, use the smaller of the two, centering the bounding box within the window in the other dimension.

-fitbh => $top

Display the page designated by page, with the vertical coordinate top positioned at the top edge of the window and the contents of the page magnified just enough to fit the entire width of its bounding box within the window.

-fitbv => $left

Display the page designated by page, with the horizontal coordinate left positioned at the left edge of the window and the contents of the page magnified just enough to fit the entire height of its bounding box within the window.

-xyz => [ $left, $top, $zoom ]

Display the page designated by page, with the coordinates (left, top) positioned at the top-left corner of the window and the contents of the page magnified by the factor zoom. A zero (0) value for any of the parameters left, top, or zoom specifies that the current value of that parameter is to be retained unchanged.

Example

$pdf->preferences(
    -fullscreen => 1,
    -onecolumn => 1,
    -afterfullscreenoutlines => 1,
    -firstpage => [$page, -fit => 1],
);

info Example

%h = $pdf->info(
    'Author'       => "Alfred Reibenschuh",
    'CreationDate' => "D:20020911000000+01'00'",
    'ModDate'      => "D:YYYYMMDDhhmmssOHH'mm'",
    'Creator'      => "fredos-script.pl",
    'Producer'     => "PDF::Builder",
    'Title'        => "some Publication",
    'Subject'      => "perl ?",
    'Keywords'     => "all good things are pdf"
);
print "Author: $h{'Author'}\n";

XMP XML example

$xml = $pdf->xmpMetadata();
print "PDFs Metadata reads: $xml\n";
$xml=<<EOT;
<?xpacket begin='' id='W5M0MpCehiHzreSzNTczkc9d'?>
<?adobe-xap-filters esc="CRLF"?>
<x:xmpmeta
  xmlns:x='adobe:ns:meta/'
  x:xmptk='XMP toolkit 2.9.1-14, framework 1.6'>
    <rdf:RDF
      xmlns:rdf='http://www.w3.org/1999/02/22-rdf-syntax-ns#'
      xmlns:iX='http://ns.adobe.com/iX/1.0/'>
        <rdf:Description
          rdf:about='uuid:b8659d3a-369e-11d9-b951-000393c97fd8'
          xmlns:pdf='http://ns.adobe.com/pdf/1.3/'
          pdf:Producer='Acrobat Distiller 6.0.1 for Macintosh'></rdf:Description>
        <rdf:Description
          rdf:about='uuid:b8659d3a-369e-11d9-b951-000393c97fd8'
          xmlns:xap='http://ns.adobe.com/xap/1.0/'
          xap:CreateDate='2004-11-14T08:41:16Z'
          xap:ModifyDate='2004-11-14T16:38:50-08:00'
          xap:CreatorTool='FrameMaker 7.0'
          xap:MetadataDate='2004-11-14T16:38:50-08:00'></rdf:Description>
        <rdf:Description
          rdf:about='uuid:b8659d3a-369e-11d9-b951-000393c97fd8'
          xmlns:xapMM='http://ns.adobe.com/xap/1.0/mm/'
          xapMM:DocumentID='uuid:919b9378-369c-11d9-a2b5-000393c97fd8'/></rdf:Description>
        <rdf:Description
          rdf:about='uuid:b8659d3a-369e-11d9-b951-000393c97fd8'
          xmlns:dc='http://purl.org/dc/elements/1.1/'
          dc:format='application/pdf'>
            <dc:description>
              <rdf:Alt>
                <rdf:li xml:lang='x-default'>Adobe Portable Document Format (PDF)</rdf:li>
              </rdf:Alt>
            </dc:description>
            <dc:creator>
              <rdf:Seq>
                <rdf:li>Adobe Systems Incorporated</rdf:li>
              </rdf:Seq>
            </dc:creator>
            <dc:title>
              <rdf:Alt>
                <rdf:li xml:lang='x-default'>PDF Reference, version 1.6</rdf:li>
              </rdf:Alt>
            </dc:title>
        </rdf:Description>
    </rdf:RDF>
</x:xmpmeta>
<?xpacket end='w'?>
EOT

$xml = $pdf->xmpMetadata($xml);
print "PDF metadata now reads: $xml\n";

FONT METHODS

Core Fonts

Core fonts are limited to single byte encodings. You cannot use UTF-8 or other multibyte encodings with core fonts. The default encoding for the core fonts is WinAnsiEncoding (roughly the CP-1252 superset of ISO-8859-1). See the -encode option below to change this encoding. See PDF::Builder::Resource::Font automap method for information on accessing more than 256 glyphs in a font, using planes, although there is no guarantee that future changes to font files will permit consistent results.

Note that core fonts use fixed lists of expected glyphs, along with metrics such as their widths. This may not exactly match up with whatever local font file is used by the PDF reader. It's usually pretty close, but many cases have been found where the list of glyphs is different between the core fonts and various local font files, so be aware of this.

To allow UTF-8 text and extended glyph counts, you should consider replacing your use of core fonts with TrueType (.ttf) and OpenType (.otf) fonts. There are tools, such as FontForge, which can do a fairly good (though, not perfect) job of converting a Type1 font library to OTF.

Examples:

$font1 = $pdf->corefont('Times-Roman', -encode => 'latin2');
$font2 = $pdf->corefont('Times-Bold');
$font3 = $pdf->corefont('Helvetica');
$font4 = $pdf->corefont('ZapfDingbats');

Valid %options are:

-encode

Changes the encoding of the font from its default. Notice that the encoding (not the entire font's glyph list) is shown in a PDF object (record), listing 256 glyphs associated with this encoding (and that are available in this font).

-dokern

Enables kerning if data is available.

Note: even though these are called "core" fonts, they are not shipped with PDF::Builder, but are expected to be found on the machine with the PDF reader. Most core fonts are installed with a PDF reader, and thus are not coordinated with PDF::Builder. PDF::Builder does ship with core font metrics files (width, glyph names, etc.), but these cannot be guaranteed to be in sync with what the PDF reader has installed!

See also PDF::Builder::Resource::Font::CoreFont.

PS Fonts

PS (T1) fonts are limited to single byte encodings. You cannot use UTF-8 or other multibyte encodings with T1 fonts. The default encoding for the T1 fonts is WinAnsiEncoding (roughly the CP-1252 superset of ISO-8859-1). See the -encode option below to change this encoding. See PDF::Builder::Resource::Font automap method for information on accessing more than 256 glyphs in a font, using planes, although there is no guarantee that future changes to font files will permit consistent results. Note: many Type1 fonts are limited to 256 glyphs, but some are available with more than 256 glyphs. Still, a maximum of 256 at a time are usable.

psfont accepts both ASCII (.pfa) and binary (.pfb) Type1 glyph files. Font metrics can be supplied in either ASCII (.afm) or binary (.pfm) format, as can be seen in the examples given below. It is possible to use .pfa with .pfm and .pfb with .afm if that's what's available. The ASCII and binary files have the same content, just in different formats.

To allow UTF-8 text and extended glyph counts in one font, you should consider replacing your use of Type1 fonts with TrueType (.ttf) and OpenType (.otf) fonts. There are tools, such as FontForge, which can do a fairly good (though, not perfect) job of converting your font library to OTF.

Examples:

$font1 = $pdf->psfont('Times-Book.pfa', -afmfile => 'Times-Book.afm');
$font2 = $pdf->psfont('/fonts/Synest-FB.pfb', -pfmfile => '/fonts/Synest-FB.pfm');

Valid %options are:

-encode

Changes the encoding of the font from its default. Notice that the encoding (not the entire font's glyph list) is shown in a PDF object (record), listing 256 glyphs associated with this encoding (and that are available in this font).

-afmfile

Specifies the location of the ASCII font metrics file (.afm). It may be used with either an ASCII (.pfa) or binary (.pfb) glyph file.

-pfmfile

Specifies the location of the binary font metrics file (.pfm). It may be used with either an ASCII (.pfa) or binary (.pfb) glyph file.

-dokern

Enables kerning if data is available.

Note: these T1 (Type1) fonts are not shipped with PDF::Builder, but are expected to be found on the machine with the PDF reader. Most PDF readers do not install T1 fonts, and it is up to the user of the PDF reader to install the needed fonts.

See also PDF::Builder::Resource::Font::Postscript.

TrueType Fonts

Warning: BaseEncoding is not set by default for TrueType fonts, so text in the PDF isn't searchable (by the PDF reader) unless a ToUnicode CMap is included. A ToUnicode CMap is included by default (-unicodemap set to 1) by PDF::Builder, but allows it to be disabled (for performance and file size reasons) by setting -unicodemap to 0. This will produce non-searchable text, which, besides being annoying to users, may prevent screen readers and other aids to disabled users from working correctly!

Examples:

$font1 = $pdf->ttfont('Times.ttf');
$font2 = $pdf->ttfont('Georgia.otf');

Valid %options are:

-encode

Changes the encoding of the font from its default (WinAnsiEncoding).

Note that for a single byte encoding (e.g., 'latin1'), you are limited to 256 characters defined for that encoding. 'automap' does not work with TrueType. If you want more characters than that, use 'utf8' encoding with a UTF-8 encoded text string.

-isocmap

Use the ISO Unicode Map instead of the default MS Unicode Map.

-unicodemap

If 1 (default), output ToUnicode CMap to permit text searches and screen readers. Set to 0 to save space by not including the ToUnicode CMap, but text searching and screen reading will not be possible.

-dokern

Enables kerning if data is available.

-noembed

Disables embedding of the font file.

CJK Fonts

Examples:

$font = $pdf->cjkfont('korean');
$font = $pdf->cjkfont('traditional');

Valid %options are:

-encode

Changes the encoding of the font from its default.

See also PDF::Builder::Resource::CIDFont::CJKFont

Synthetic Fonts

Warning: BaseEncoding is not set by default for these fonts, so text in the PDF isn't searchable (by the PDF reader) unless a ToUnicode CMap is included. A ToUnicode CMap is included by default (-unicodemap set to 1) by PDF::Builder, but allows it to be disabled (for performance and file size reasons) by setting -unicodemap to 0. This will produce non-searchable text, which, besides being annoying to users, may prevent screen readers and other aids to disabled users from working correctly!

Examples:

$cf  = $pdf->corefont('Times-Roman', -encode => 'latin1');
$sf  = $pdf->synfont($cf, -slant => 0.85);  # compressed 85%
$sfb = $pdf->synfont($cf, -bold => 1);      # embolden by 10em
$sfi = $pdf->synfont($cf, -oblique => -12); # italic at -12 degrees

Valid %options are:

-slant

Slant/expansion factor (0.1-0.9 = slant, 1.1+ = expansion).

-oblique

Italic angle (+/-)

-bold

Emboldening factor (0.1+, bold = 1, heavy = 2, ...)

-space

Additional character spacing in ems (0-1000)

-caps

0 for normal text, 1 for small caps. Note that not all lower case letters appear to have small caps equivalents defined for them. These include, but are not limited to, 'n U+0149, fi ligature U+FB01, fl ligature U+FB02, German eszet (sharp s) U+00DF, and doubtless others. In such cases, you may want to consider replacing these ligatures with separate characters: '+n, f+i, f+l, s+s, etc.

See also PDF::Builder::Resource::Font::SynFont

IMAGE METHODS

TIFF Images

Note that the Graphics::TIFF support library does not currently permit a filehandle for $file.

PDF::Builder will use the Graphics::TIFF support library for TIFF functions, if it is available, unless explicitly told not to. Your code can test whether Graphics::TIFF is available by examining $tiff->usesLib() or $pdf->LA_GT().

= -1

Graphics::TIFF is installed, but your code has specified -nouseGT, to not use it. The old, pure Perl, code (buggy!) will be used instead, as if Graphics::TIFF was not installed.

= 0

Graphics::TIFF is not installed. Not all systems are able to successfully install this package, as it requires libtiff.a.

= 1

Graphics::TIFF is installed and is being used.

Options:

-nouseGT => 1

Do not use the Graphics::TIFF library, even if it's available. Normally you would want to use this library, but there may be cases where you don't, such as when you want to use a file handle instead of a name.

-silent => 1

Do not give the message that Graphics::TIFF is not installed. This message will be given only once, but you may want to suppress it, such as during t-tests.

PNG Images

PDF::Builder will use the Image::PNG::Libpng support library for PNG functions, if it is available, unless explicitly told not to. Your code can test whether Image::PNG::Libpng is available by examining $png->usesLib() or $pdf->LA_IPL().

= -1

Image::PNG::Libpng is installed, but your code has specified -nouseIPL, to not use it. The old, pure Perl, code (slower and less capable) will be used instead, as if Image::PNG::Libpng was not installed.

= 0

Image::PNG::Libpng is not installed. Not all systems are able to successfully install this package, as it requires libpng.a.

= 1

Image::PNG::Libpng is installed and is being used.

Options:

-nouseIPL => 1

Do not use the Image::PNG::Libpng library, even if it's available. Normally you would want to use this library, when available, but there may be cases where you don't.

-silent => 1

Do not give the message that Image::PNG::Libpng is not installed. This message will be given only once, but you may want to suppress it, such as during t-tests.

-notrans => 1

No transparency -- ignore tRNS chunk if provided, ignore Alpha channel if provided.

cpanm PDF::Builder

perl -MCPAN -e shell
install PDF::Builder