PDF::API2(3p)

NAME
PDF::API2 - Create, modify, and examine PDF files

SYNOPSIS
    use PDF::API2;

    # Create a blank PDF file
    $pdf = PDF::API2->new();

    # Open an existing PDF file
    $pdf = PDF::API2->open('some.pdf');

    # Add a blank page
    $page = $pdf->page();

    # Retrieve an existing page
    $page = $pdf->open_page($page_number);

    # Set the page size
    $page->size('Letter');

    # Add a built-in font to the PDF
    $font = $pdf->font('Helvetica-Bold');

    # Add an external TrueType font to the PDF
    $font = $pdf->font('/path/to/font.ttf');

    # Add some text to the page
    $text = $page->text();
    $text->font($font, 20);
    $text->position(200, 700);
    $text->text('Hello World!');

    # Save the PDF
    $pdf->save('/path/to/new.pdf');

INPUT/OUTPUT METHODS

  new
    my $pdf = PDF::API2->new(%options);

Create a new PDF.

The following options are available:

•   file

    If you will be saving the PDF to disk and already know the filename, you can include it here to open the file for writing immediately. "file" may also be a filehandle.

•   compress

    By default, most of the PDF will be compressed to save space. To turn this off (generally only useful for testing or debugging), set "compress" to 0.

  open
    my $pdf = PDF::API2->open('/path/to/file.pdf', %options);

Open an existing PDF file.

The following option is available:

•   compress

    By default, most of the PDF will be compressed to save space. To turn this off (generally only useful for testing or debugging), set "compress" to 0.

  save
    $pdf->save('/path/to/file.pdf');

Write the PDF to disk and close the file. A filename is optional if one was specified while opening or creating the PDF.

As a side effect, the document structure is removed from memory when the file is saved, so it will no longer be usable.

  close
    $pdf->close();

Close an open file (if relevant) and remove the object structure from memory.

PDF::API2 contains circular references, so this call is necessary in long-running processes to keep from running out of memory.

This will be called automatically when you save or stringify a PDF. You should only need to call it explicitly if you are reading PDF files and not writing them.

  from_string
    my $pdf = PDF::API2->from_string($pdf_string, %options);

Read a PDF document contained in a string.

The following option is available:

•   compress

    By default, most of the PDF will be compressed to save space. To turn this off (generally only useful for testing or debugging), set "compress" to 0.

  to_string
    my $string = $pdf->to_string();

Return the PDF document as a string.

As a side effect, the document structure is removed from memory when the string is created, so it will no longer be usable.

METADATA METHODS

  title
    $title = $pdf->title();
    $pdf = $pdf->title($title);

Get/set/clear the document's title.

  author
    $author = $pdf->author();
    $pdf = $pdf->author($author);

Get/set/clear the name of the person who created the document.

  subject
    $subject = $pdf->subject();
    $pdf = $pdf->subject($subject);

Get/set/clear the subject of the document.

  keywords
    $keywords = $pdf->keywords();
    $pdf = $pdf->keywords($keywords);

Get/set/clear a space-separated string of keywords associated with the document.

  creator
    $creator = $pdf->creator();
    $pdf = $pdf->creator($creator);

Get/set/clear the name of the product that created the document prior to its conversion to PDF.

  producer
    $producer = $pdf->producer();
    $pdf = $pdf->producer($producer);

Get/set/clear the name of the product that converted the original document to PDF.

PDF::API2 fills in this field when creating a PDF.

  created
    $date = $pdf->created();
    $pdf = $pdf->created($date);

Get/set/clear the document's creation date.

The date format is "D:YYYYMMDDHHmmSSOHH'mm", where "D:" is a static prefix identifying the string as a PDF date. The date may be truncated at any point after the year. "O" is one of "+", "-", or "Z", with the following "HH'mm" representing an offset from UTC.

When setting the date, "D:" will be prepended automatically if omitted.

  modified
    $date = $pdf->modified();
    $pdf = $pdf->modified($date);

Get/set/clear the document's modification date. The date format is as described in "created" above.

  info_metadata
    # Get all keys and values
    %info = $pdf->info_metadata();

    # Get the value of one key
    $value = $pdf->info_metadata($key);

    # Set the value of one key
    $pdf = $pdf->info_metadata($key, $value);

Get/set/clear a key in the document's information dictionary. The standard keys (title, author, etc.) have their own accessors, so this is primarily intended for interacting with custom metadata.

Pass "undef" as the value in order to remove the key from the dictionary.

  xml_metadata
    $xml = $pdf->xml_metadata();
    $pdf = $pdf->xml_metadata($xml);

Get/set the document's XML metadata stream.

  version
    $version = $pdf->version($new_version);

Get/set the PDF version (e.g. 1.4).

  is_encrypted
    $boolean = $pdf->is_encrypted();

Returns true if the opened PDF is encrypted.

INTERACTIVE FEATURE METHODS

  outline
    $outline = $pdf->outlines();

Creates (if needed) and returns the document's outline tree, which is also known as its bookmarks or the table of contents, depending on the PDF reader.

To examine or modify the outline tree, see PDF::API2::Outline.

  open_action
    $pdf = $pdf->open_action($page, $location, @args);

Set the destination in the PDF that should be displayed when the document is opened.

$page may be either a page number or a page object. The other parameters are as described in PDF::API2::NamedDestination.

  page_layout
    $layout = $pdf->page_layout();
    $pdf = $pdf->page_layout($layout);

Get/set the page layout that should be used when the PDF is opened.

$layout is one of the following:

•   single_page (or undef)

    Display one page at a time.

•   one_column

    Display the pages in one column (a.k.a. continuous).

•   two_column_left

    Display the pages in two columns, with odd-numbered pages on the left.

•   two_column_right

    Display the pages in two columns, with odd-numbered pages on the right.

•   two_page_left

    Display two pages at a time, with odd-numbered pages on the left.

•   two_page_right

    Display two pages at a time, with odd-numbered pages on the right.

  page_mode
    # Get
    $mode = $pdf->page_mode();

    # Set
    $pdf = $pdf->page_mode($mode);

Get/set the page mode, which describes how the PDF should be displayed when opened.

$mode is one of the following:

•   none (or undef)

    Neither outlines nor thumbnails should be displayed.

•   outlines

    Show the document outline.

•   thumbnails

    Show the page thumbnails.

•   full_screen

    Open in full-screen mode, with no menu bar, window controls, or any other window visible.

•   optional_content

    Show the optional content group panel.

•   attachments

    Show the attachments panel.

  viewer_preferences
    # Get
    %preferences = $pdf->viewer_preferences();

    # Set
    $pdf = $pdf->viewer_preferences(%preferences);

Get or set PDF viewer preferences, as described in PDF::API2::ViewerPreferences.

PAGE METHODS

  page
     # Add a page to the end of the document
     $page = $pdf->page();

     # Insert a page before the specified page number
     $page = $pdf->page($page_number);

Returns a new page object. By default, the page is added to the end of the document. If you include an existing page number, the new page will be inserted in that position, pushing existing pages back.

If $page_number is -1, the new page is inserted as the second-last page; if $page_number is 0, the new page is inserted as the last page.

  open_page
    $page = $pdf->open_page($page_number);

Returns the PDF::API2::Page object of page $page_number, if it exists.

If $page_number is 0 or -1, it will return the last page in the document.

  import_page
    $page = $pdf->import_page($source_pdf, $source_page_num, $target_page_num);

Imports a page from $source_pdf and adds it to the specified position in $pdf.

If $source_page_num or $target_page_num is 0 or -1, the last page in the document is used.

Note: If you pass a page object instead of a page number for $target_page_num, the contents of the page will be merged into the existing page.

Example:

    my $pdf = PDF::API2->new();
    my $source = PDF::API2->open('source.pdf');

    # Add page 2 from the source PDF as page 1 of the new PDF
    my $page = $pdf->import_page($source, 2);

    $pdf->save('sample.pdf');

Note: You can only import a page from an existing PDF file.

  embed_page
    $xobject = $pdf->embed_page($source_pdf, $source_page_number);

Returns a Form XObject created by extracting the specified page from a $source_pdf.

This is useful if you want to transpose the imported page somewhat differently onto a page (e.g. two-up, four-up, etc.).

If $source_page_number is 0 or -1, it will return the last page in the document.

Example:

    my $pdf = PDF::API2->new();
    my $source = PDF::API2->open('source.pdf');
    my $page = $pdf->page();

    # Import Page 2 from the source PDF
    my $object = $pdf->embed_page($source, 2);

    # Add it to the new PDF's first page at 1/2 scale
    my ($x, $y) = (0, 0);
    $page->object($object, $x, $y, 0.5);

    $pdf->save('sample.pdf');

Note: You can only import a page from an existing PDF file.

  page_count
    $integer = $pdf->page_count();

Return the number of pages in the document.

  page_labels
    $pdf = $pdf->page_labels($page_number, %options);

Describes how pages should be numbered beginning at the specified page number.

    # Generate a 30-page PDF
    my $pdf = PDF::API2->new();
    $pdf->page() for 1..30;

    # Number pages i to v, 1 to 20, and A-1 to A-5, respectively
    $pdf->page_labels(1, style => 'roman');
    $pdf->page_labels(6, style => 'decimal');
    $pdf->page_labels(26, style => 'decimal', prefix => 'A-');

    $pdf->save('sample.pdf');

The following options are available:

•   style

    One of "decimal" (standard decimal arabic numerals), "Roman" (uppercase roman numerals), "roman" (lowercase roman numerals), "Alpha" (uppercase letters), or "alpha" (lowercase letters).

    There is no default numbering style. If omitted, the page label will be just the prefix (if set) or an empty string.

•   prefix

    The label prefix for pages in this range.

•   start

    An integer (default: 1) representing the first value to be used in this page range.

  default_page_size
    # Set
    $pdf->default_page_size($size);

    # Get
    @rectangle = $pdf->default_page_size()

Set the default physical size for pages in the PDF. If called without arguments, return the coordinates of the rectangle describing the default physical page size.

See "Page Sizes" in PDF::API2::Page for possible values.

  default_page_boundaries
    # Set
    $pdf->default_page_boundaries(%boundaries);

    # Get
    %boundaries = $pdf->default_page_boundaries();

Set default prepress page boundaries for pages in the PDF. If called without arguments, returns the coordinates of the rectangles describing each of the supported page boundaries.

See the equivalent "page_boundaries" method in PDF::API2::Page for details.

FONT METHODS

  font
    my $font = $pdf->font($name, %options)

Add a font to the PDF. Returns the font object, to be used by PDF::API2::Content.

The font $name is either the name of one of the standard 14 fonts (e.g. Helvetica) or the path to a font file.

    my $pdf = PDF::API2->new();
    my $font1 = $pdf->font('Helvetica-Bold');
    my $font2 = $pdf->font('/path/to/ComicSans.ttf');
    my $page = $pdf->page();
    my $content = $page->text();

    $content->position(1 * 72, 9 * 72);
    $content->font($font1, 24);
    $content->text('Hello, World!');

    $content->position(0, -36);
    $content->font($font2, 12);
    $content->text('This is some sample text.');

    $pdf->save('sample.pdf');

The path can be omitted if the font file is in the current directory or one of the directories returned by "font_path".

TrueType (ttf/otf), Adobe PostScript Type 1 (pfa/pfb), and Adobe Glyph Bitmap Distribution Format (bdf) fonts are supported.

The following %options are available:

•   format

    The font format is normally detected automatically based on the file's extension. If you're using a font with an atypical extension, you can set "format" to one of "truetype" (TrueType or OpenType), "type1" (PostScript Type 1), or "bitmap" (Adobe Bitmap).

•   kerning

    Kerning (automatic adjustment of space between pairs of characters) is enabled by default if the font includes this information. Set this option to false to disable.

•   afm_file (PostScript Type 1 fonts only)

    Specifies the location of the font metrics file.

•   pfm_file (PostScript Type 1 fonts only)

    Specifies the location of the printer font metrics file. This option overrides the -encode option.

•   embed (TrueType fonts only)

    Fonts are embedded in the PDF by default, which is required to ensure that they can be viewed properly on a device that doesn't have the font installed. Set this option to false to prevent the font from being embedded.

  synthetic_font
    $font = $pdf->synthetic_font($base_font, %options)

Create and return a new synthetic font object. See PDF::API2::Resource::Font::SynFont for details.

  font_path
    @directories = PDF::API2->font_path()

Return the list of directories that will be searched (in order) in addition to the current directory when you add a font to a PDF without including the full path to the font file.

  add_to_font_path
    @directories = PDF::API2->add_to_font_path('/my/fonts', '/path/to/fonts');

Add one or more directories to the list of paths to be searched for font files.

Returns the font search path.

  set_font_path
    @directories = PDF::API2->set_font_path('/my/fonts', '/path/to/fonts');

Replace the existing font search path. This should only be necessary if you need to remove a directory from the path for some reason, or if you need to reorder the list.

Returns the font search path.

GRAPHICS METHODS

  image
    $object = $pdf->image($file, %options);

Import a supported image type and return an object that can be placed as part of a page's content:

    my $pdf = PDF::API2->new();
    my $page = $pdf->page();

    my $image = $pdf->image('/path/to/image.jpg');
    $page->object($image, 100, 100);

    $pdf->save('sample.pdf');

$file may be either a file name, a filehandle, or a GD::Image object.

See "place" in PDF::API2::Content for details about placing images on a page once they're imported.

The image format is normally detected automatically based on the file's extension. If passed a filehandle, image formats GIF, JPEG, and PNG will be detected based on the file's header.

If the file has an atypical extension or the filehandle is for a different kind of image, you can set the "format" option to one of the supported types: "gif", "jpeg", "png", "pnm", or "tiff".

Note: PNG images that include an alpha (transparency) channel go through a relatively slow process of splitting the image into separate RGB and alpha components as is required by images in PDFs. If you're having performance issues, install PDF::API2::XS or Image::PNG::Libpng to speed this process up by an order of magnitude; either module will be used automatically if available.

  barcode
    $object = $pdf->barcode($format, $code, %options);

Generate and return a barcode that can be placed as part of a page's content:

    my $pdf = PDF::API2->new();
    my $page = $pdf->page();

    my $barcode = $pdf->barcode('ean13', '0123456789012');
    $page->object($barcode, 100, 100);

    $pdf->save('sample.pdf');

$format can be one of "codabar", "code128", "code39" (a.k.a. 3 of 9), "ean128", "ean13", or "itf" (a.k.a. interleaved 2 of 5).

$code is the value to be encoded. Start and stop characters are only required when they're not static (e.g. for Codabar).

The following options are available:

•   bar_width

    The width of the smallest bar or space in points (72 points = 1 inch).

    If you're following a specification that gives bar width in mils (thousandths of an inch), use this conversion: "$points = $mils / 1000 * 72".

•   bar_height

    The base height of the barcode in points.

•   bar_extend

    If present, bars for non-printing characters (e.g. start and stop characters) will be extended downward by this many points, and printing characters will be shown below their respective bars.

    This is enabled by default for EAN-13 barcodes.

•   caption

    If present, this value will be printed, centered, beneath the barcode, and should be a human-readable representation of the barcode.

•   font

    A font object (created by "font") that will be used to print the caption, or the printable characters when "bar_extend" is set.

    Helvetica will be used by default.

•   font_size

    The size of the font used for printing the caption or printable characters.

    The default will be calculated based on the barcode size, if "bar_extend" is set, or 10 otherwise.

•   quiet_zone

    A margin, in points, that will be place before the left and bottom edges of the barcode (including the caption, if present). This is used to help barcode scanners tell where the barcode begins and ends.

    The default is the width of one encoded character.

•   bar_overflow

    Shrinks the horizontal width of bars by this amount in points to account for ink spread when printing.

    The default is 0.01 points.

•   color

    Draw bars using this color, which may be any value accepted by "fillcolor" in PDF::API2::Content.

    The default is black.

  colorspace
    $colorspace = $pdf->colorspace($type, @arguments);

Colorspaces can be added to a PDF to either specifically control the output color on a particular device (spot colors, device colors) or to save space by limiting the available colors to a defined color palette (web-safe palette, ACT file).

Once added to the PDF, they can be used in place of regular hex codes or named colors:

    my $pdf = PDF::API2->new();
    my $page = $pdf->page();
    my $content = $page->graphics();

    # Add colorspaces for a spot color and the web-safe color palette
    my $spot = $pdf->colorspace('spot', 'PANTONE Red 032 C', '#EF3340');
    my $web = $pdf->colorspace('web');

    # Fill using the spot color with 100% coverage
    $content->fill_color($spot, 1.0);

    # Stroke using the first color of the web-safe palette
    $content->stroke_color($web, 0);

    # Add a rectangle to the page
    $content->rectangle(100, 100, 200, 200);
    $content->paint();

    $pdf->save('sample.pdf');

The following types of colorspaces are supported

•   spot

        my $spot = $pdf->colorspace('spot', $tint, $alt_color);

    Spot colors are used to instruct a device (usually a printer) to use or emulate a particular ink color ($tint) for parts of the document. An $alt_color is provided for devices (e.g. PDF viewers) that don't know how to produce the named color. It can either be an approximation of the color in RGB, CMYK, or HSV formats, or a wildly different color (e.g. 100% magenta, %0F00) to make it clear if the spot color isn't being used as expected.

•   web

        my $web = $pdf->colorspace('web');

    The web-safe color palette is a historical collection of colors that was used when many display devices only supported 256 colors.

•   act

        my $act = $pdf->colorspace('act', $filename);

    An Adobe Color Table (ACT) file provides a custom palette of colors that can be referenced by PDF graphics and text drawing commands.

•   device

        my $devicen = $pdf->colorspace('device', @colorspaces);

    A device-specific colorspace allows for precise color output on a given device (typically a printing press), bypassing the normal color interpretation performed by raster image processors (RIPs).

    Device colorspaces are also needed if you want to blend spot colors:

        my $pdf = PDF::API2->new();
        my $page = $pdf->page();
        my $content = $page->graphics();

        # Create a two-color device colorspace
        my $yellow = $pdf->colorspace('spot', 'Yellow', '%00F0');
        my $spot = $pdf->colorspace('spot', 'PANTONE Red 032 C', '#EF3340');
        my $device = $pdf->colorspace('device', $yellow, $spot);

        # Fill using a blend of 25% yellow and 75% spot color
        $content->fill_color($device, 0.25, 0.75);

        # Stroke using 100% spot color
        $content->stroke_color($device, 0, 1);

        # Add a rectangle to the page
        $content->rectangle(100, 100, 200, 200);
        $content->paint();

        $pdf->save('sample.pdf');

  egstate
    $resource = $pdf->egstate();

Creates and returns a new extended graphics state object, described in PDF::API2::ExtGState.

BACKWARD COMPATIBILITY
Code written using PDF::API2 should continue to work unchanged for the life of most long-term-stable (LTS) server distributions. Specifically, it should continue working for versions of Perl that were released within the past five years (the typical support window for LTS releases) plus six months (allowing plenty of time for package freezes prior to release).

In PDF::API2, method names, options, and functionality change over time. Functionality that's documented (not just in source code comments) should continue working for the same time period of five years and six months, though deprecation warnings may be added. There may be exceptions if your code happens to rely on bugs that get fixed, including when a method in PDF::API2 is changed to more closely follow the PDF specification.

Occasional breaking changes may be unavoidable or deemed small enough in scope to be worth the benefit of making the change instead of keeping the old behavior. These will be noted in the Changes file as items beginning with the phrase "Breaking Change".

Undocumented features, unreleased code, features marked as experimental, and underlying data structures may change at any time. An exception is for features that were previously released and documented, which should continue to work for the above time period after the documentation is removed.

Before migrating to a new LTS server version, it's recommended that you upgrade to the latest version of PDF::API2, "use warnings", and check your server logs for deprecation messages after exercising your code. Once these are resolved, it should be safe to use future PDF::API2 releases during that LTS support window.

If your code uses a PDF::API2 method that isn't documented here, it has probably been deprecated. Search for it in the Migration section below to find its replacement.

MIGRATION
Use this section to bring your existing code up to date with current method names and options. If you're not getting a deprecation warning, this is optional, but still recommended.

For example, in cases where a method was simply renamed, the old name will be set up as an alias for the new one, which can be maintained indefinitely. The main benefit of switching to the new name is to make it easier to find the appropriate documentation when you need it.

new(-compress => 0)
new(-file => $filename)
    Remove the hyphen from the option names.

new() with any options other than "compress" or "file"
    Replace with calls to "INTERACTIVE FEATURE METHODS". See the deprecated "preferences" method for particular option names.

finishobjects
saveas
update
    Replace with "save".

end
release
    Replace with "close".

open_scalar
openScalar
    Replace with "from_string".

stringify
    Replace with "to_string".

info
    Each of the hash keys now has its own accessor. See "METADATA METHODS".

    For custom keys or if you prefer to give the key names as variables (e.g. as part of a loop), use "info_metadata".

infoMetaAttributes
    Use "info_metadata" without arguments to get a list of currently-set keys in the Info dictionary (including any custom keys). This is slightly different behavior from calling "infoMetaAttributes" without arguments, which always returns the standard key names and any defined custom key names, whether or not they're present in the PDF.

    Calling "infoMetaAttributes" with arguments defines the list of Info keys that are supported by the deprecated "info" method. You can now just call "info_metadata" with a standard or custom key and value.

xmpMetadata
    Replace with "xml_metadata". Note that, when called with an argument, "xml_metadata" returns the PDF object rather than the value, to line up with most other PDF::API2 accessors.

isEncrypted
    Replace with "is_encrypted".

outlines
    Replace with "outline".

preferences
    This functionality has been split into a few methods, aligning more closely with the underlying PDF structure. See the documentation for each of the methods for revised option names.

    •   -fullscreen, -thumbs, -outlines

        Call "page_mode".

    •   -singlepage, -onecolumn, -twocolumnleft, -twocolumnright

        Call "page_layout".

    •   -hidetoolbar, -hidemenubar, -hidewindowui, -fitwindow, -centerwindow, -displaytitle, -righttoleft, -afterfullscreenthumbs, -afterfullscreenoutlines, -printscalingnone, -simplex, -duplexfliplongedge, -duplexflipshortedge

        Call "viewer_preferences".

    •   -firstpage

        Call "open_action".

openpage
    Replace with "open_page".

importpage
    Replace with "import_page".

importPageIntoForm
    Replace with "embed_page".

pages
    Replace with "page_count".

pageLabel
    Replace with "page_labels". Remove hyphens from the argument names. Add "style => 'decimal'" if there wasn't a "-style" argument.

mediabox
cropbox
bleedbox
trimbox
artbox
    Replace with "default_page_boundaries". If using page size aliases (e.g. "letter" or "A4"), check to ensure that the alias is still supported (you'll get an error if it isn't).

synfont
    Replace with "synthetic_font".

addFontDirs
    Replace with "add_to_font_path".

corefont
    Replace with "font". Note that "font" requires that the font name be an exact, case-sensitive match. The full list can be found in "STANDARD FONTS" in PDF::API2::Resource::Font::CoreFont.

ttfont
    Replace with "font". Replace "-noembed => 1" with "embed => 0".

bdfont
    Replace with "font".

psfont
    Replace with "font". Rename options "-afmfile" and "-pfmfile" to "afm_file" and "pfm_file".

    Note that Adobe has announced that their products no longer support Postscript Type 1 fonts, effective early 2023. They recommend using TrueType or OpenType fonts instead.

cjkfont
unifont
    These are old methods from back when Unicode was still new and poorly supported. Replace them with calls to "font" using a TrueType or OpenType font that has the characters you need.

    If you're successfully using one of these two methods and feel they shouldn't be deprecated, please contact me with your use case.

image_gd
image_gif
image_jpeg
image_png
image_pnm
image_tiff
    Replace with "image".

xo_code128
xo_codabar
xo_2of5int
xo_3of9
xo_ean13
    Replace with "barcode". Replace arguments as follows:

    •   "-color": "color"

    •   "-fnsz": "font_size"

    •   "-font": "font"

    •   "-lmzn": "bar_extend"

    •   "-ofwt": "bar_overflow"

    •   "-quzn": "quiet_zone"

    •   "-zone": "bar_height"

        These options are simple renames.

    •   "-mils": "bar_width"

        This requires a conversion from mils to points. The "bar_width" documentation has sample code to do the conversion.

    •   "-ean"

        Specify "ean128" as the barcode format instead of "code128".

colorspace_act
colorspace_web
colorspace_separation
colorspace_devicen
    Replace with "colorspace".

colorspace_hue
    This is deprecated because I wasn't able to find a corresponding standard. Please contact me if you're using it, to avoid having it be removed in a future release.

default
    The optional changes in default behavior have all been deprecated.

    Replace "pageencaps" with calls to "save" and "restore" when embedding or superimposing a page onto another, if needed.

    "nounrotate" and "copyannots" will continue to work until better options are available, but should not be used in new code.

AUTHOR
PDF::API2 is developed and maintained by Steve Simms, with patches from numerous contributors who are credited in the Changes file.

It was originally written by Alfred Reibenschuh, extending code written by Martin Hosken.

LICENSE
This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.