Package gofpdf implements a PDF document generator with high level support for text, drawing and images.
##Features • Choice of measurement unit, page format and margins
• Page header and footer management
• Automatic page breaks, line breaks, and text justification
• Inclusion of JPEG, PNG, GIF and basic path-only SVG images
• Colors, gradients and alpha channel transparency
• Outline bookmarks
• Internal and external links
• TrueType, Type1 and encoding support
• Page compression
• Lines, Bézier curves, arcs, and ellipses
• Rotation, scaling, skewing, translation, and mirroring
• Clipping
• Document protection
• Layers
gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. However, support is provided to translate UTF-8 runes to code page encodings.
##Acknowledgments This package's code and documentation are closely derived from the FPDF library created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles and enhanced fill modes. Bruno Michel has provided valuable assistance with the code.
The FPDF website is http://www.fpdf.org/.
##License gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged above.
##Installation To install the package on your system, run
go get github.com/jung-kurt/gofpdf
Later, to receive updates, run
go get -u github.com/jung-kurt/gofpdf
##Quick Start The following Go code generates a simple PDF and writes it to standard output.
pdf := gofpdf.New("P", "mm", "A4", "")
pdf.AddPage()
pdf.SetFont("Arial", "B", 16)
pdf.Cell(40, 10, "Hello, world")
pdf.Output(os.Stdout)
See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples.
##Errors If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error().
##Conversion Notes This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ.
However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP.
##Example PDFs A side effect of running "go test" is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete.
Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename and summary.
##Nonstandard Fonts Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont().
In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example.
./makefont --embed --enc=../font/cp1252.map --dst=../font ../font/calligra.ttf
In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/.
##Roadmap • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided.
• Improve test coverage as reported by the coverage tool.