Package gofpdf implements a PDF document generator with high level support for text, drawing and images.
- 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, TIFF 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
- Document protection
- Charting facility
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. In particular, languages that require more than one code page such as Chinese, Japanese, and Arabic are not currently supported. This is explained in issue 109. However, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs.
To install the package on your system, run
go get github.com/jung-kurt/gofpdf
Later, to receive updates, run
go get -u -v github.com/jung-kurt/gofpdf/...
The following Go code generates a simple PDF file.
pdf := gofpdf.New("P", "mm", "A4", "") pdf.AddPage() pdf.SetFont("Arial", "B", 16) pdf.Cell(40, 10, "Hello, world") err := pdf.OutputFileAndClose("hello.pdf")
See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples.
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().
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.
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().
Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory and if the third argument to ComparePDFFiles() in internal/example/example.go is true. (By default it is false.) The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples.
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 Google Fonts and DejaVu Fonts.
The draw2d package is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode.
gofpdf is a global community effort and you are invited to make it even better.
If you have implemented a new feature or corrected a problem, please consider
contributing your change to the project. A contribution that does not directly
pertain to the core functionality of gofpdf should be placed in its own
directory directly beneath the
Here are guidelines for making submissions. Your change should
- be compatible with the MIT License
- be properly documented
- be formatted with
- include an example in fpdf_test.go if appropriate
- conform to the standards of golint and
go vet, that is,
go vet .should not generate any warnings
- not diminish test coverage
Pull requests work nicely as a means of contributing your changes.
gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below.
- 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.