Get the Chromium depot_tools via the instructions. This provides the gclient utility needed below and many other tools needed for PDFium development.
Also install Python, Subversion, and Git and make sure they're in your path.
PDFium uses the same build tool as Chromium:
Please refer to Chromium's Visual Studio set up for requirements and instructions on build environment configuration.
Run set DEPOT_TOOLS_WIN_TOOLCHAIN=0, or set that variable in your global environment.
Compilation is done through Ninja, not Visual Studio.
The default architecture for Windows, Linux, and Mac is "x64". On Windows, "x86" is also supported. GN parameter "target_cpu = "x86"" can be used to override the default value. If you specify Android build, the default CPU architecture will be "arm".
It is expected that there are still some places lurking in the code which will not function properly on big-endian architectures. Bugs and/or patches are welcome, however providing this support is not a priority at this time.
Run: download_from_google_storage --config and follow the authentication instructions. Note that you must authenticate with your @google.com credentials. Enter "0" if asked for a project-id.
Once you've done this, the toolchain will be installed automatically for you in the Generate the build files step below.
The toolchain will be in depot_tools\win_toolchain\vs_files\<hash>, and windbg can be found in depot_tools\win_toolchain\vs_files\<hash>\win_sdk\Debuggers.
If you want the IDE for debugging and editing, you will need to install it separately, but this is optional and not needed for building PDFium.
The name of the top-level directory does not matter. In our examples, we use "repo". This directory must not have been used before by gclient config as each directory can only house a single gclient configuration.
mkdir repo cd repo gclient config --unmanaged https://pdfium.googlesource.com/pdfium.git gclient sync cd pdfium
Additional build dependencies need to be installed by running the following from the pdfium directory.
./build/install-build-deps.sh
We use GN to generate the build files and Ninja to execute the build files. Both of these are included with the depot_tools checkout.
PDFium may be built either with or without JavaScript support, and with or without XFA forms support. Both of these features are enabled by default. Also note that the XFA feature requires JavaScript.
Configuration is done by executing gn args <directory> to configure the build. This will launch an editor in which you can set the following arguments. By convention, <directory> should be named out/foo, and some tools / test support code only works if one follows this convention. A typical <directory> name is out/Debug.
use_goma = true # Googlers only. Make sure goma is installed and running first. is_debug = true # Enable debugging features. # Set true to enable experimental Skia backend. pdf_use_skia = false # Set true to enable experimental Skia backend (paths only). pdf_use_skia_paths = false pdf_enable_xfa = true # Set false to remove XFA support (implies JS support). pdf_enable_v8 = true # Set false to remove Javascript support. pdf_is_standalone = true # Set for a non-embedded build. is_component_build = false # Disable component build (must be false) clang_use_chrome_plugins = false # Currently must be false.
For sample applications like pdfium_test to build, one must set pdf_is_standalone = true.
To use the Skia backend, one must set use_cxx11 = false which will build the entire project with C++14.
When complete the arguments will be stored in <directory>/args.gn, and GN will automatically use the new arguments to generate build files. Should your files fail to generate, please double-check that you have set use_sysroot as indicated above.
You can build the sample program by running: ninja -C <directory> pdfium_test You can build the entire product (which includes a few unit tests) by running: ninja -C <directory> pdfium_all.
The pdfium_test program supports reading, parsing, and rasterizing the pages of a .pdf file to .ppm or .png output image files (Windows supports two other formats). For example: <directory>/pdfium_test --ppm path/to/myfile.pdf. Note that this will write output images to path/to/myfile.pdf.<n>.ppm. Run pdfium_test --help to see all the options.
There are currently several test suites that can be run:
It is possible the tests in the testing directory can fail due to font differences on the various platforms. These tests are reliable on the bots. If you see failures, it can be a good idea to run the tests on the tip-of-tree checkout to see if the same failures appear.
The public/ directory contains header files for the APIs available for use by embedders of PDFium. We endeavor to keep these as stable as possible.
Outside of the public/ directory, code may change at any time, and embedders should not directly call these routines.
Code coverage reports for PDFium can be generated in Linux development environments. Details can be found here.
Chromium provides code coverage reports for PDFium here. PDFium is located in third_party/pdfium in Chromium's source code. This includes code coverage from PDFium's fuzzers.
Valgrind and other profiling tools do not work correctly with the standard build setup that PDFium uses. You will need to add ro_segment_workaround_for_valgrind=true to args.gn to get symbols to correctly appear.
The current health of the source tree can be found here.
There are several mailing lists that are setup:
Note, the Reviews and Bugs lists are typically read-only.
We use this bug tracker, but for security bugs, please use Chromium's security bug template and add the "Cr-Internals-Plugins-PDF" label.
For contributing code, we will follow Chromium's process as much as possible. The main exceptions are: