WinCairo port is a WebKit port for Windows, which is fully Open Source and redistributable unlike AppleWin port. It is using ​Cairo for the graphics backend, ​libcurl for the network backend. It supports only 64 bit.

Installing Development Tools

You need CMake, Perl, Python, Ruby, gperf, the latest Windows 10 SDK and Visual Studio 2022 to build WinCairo port. The easiest way to install some tools is using ​Chocolatey,

choco install -y ActivePerl python ruby git gperf

choco install cmake doesn't configure your PATH. A switch is needed.

choco install -y cmake --installargs 'ADD_CMAKE_TO_PATH=System'

WinCairo supports CMake Ninja generator and CMake Visual Studio generator. Ninja is optional.

choco install -y ninja

You might need more tools if you want to develop WebKit.

choco install -y svn patch diffutils

Or, you can follow the part of ​AppleWin port's instructions to install the necessary developer tools, and check out the WebKit code.

Building WinCairo

Start "x64 Native Tools Command Prompt for VS 2022".

Change the directory to the top source directory. Some environment variables should be set.

set WEBKIT_LIBRARIES=%cd%\WebKitLibraries\win
set WEBKIT_OUTPUTDIR=%cd%\WebKitBuild

Invoke build-webkit to start building.

perl Tools/Scripts/build-webkit --wincairo --release

Ensure you don't have GCC in your PATH, otherwise CMake is going to use GCC and builds will fail.

build-webkit automatically downloads the latest WebKitRequirements from GitHub. It checks the latest WebKitRequirements every time you invoke. I'd like to recommend to use --skip-library-update for incremental build to speed up.

python Tools\Scripts\update-webkit-wincairo-libs.py
perl Tools\Scripts\build-webkit --wincairo --release --skip-library-update

The build succeeded if you got WebKit is now built message. Run your MiniBrowser.

WebKitBuild/Release/bin64/MiniBrowser.exe

Building from within Visual Studio

Start "x64 Native Tools Command Prompt for VS 2022".

perl Tools/Scripts/build-webkit --wincairo --release --no-ninja --generate-project-only

Some environment variables should be propagated to Visual Studio.

set WEBKIT_LIBRARIES=%cd%\WebKitLibraries\win
set WEBKIT_OUTPUTDIR=%cd%\WebKitBuild

If you are behind http proxy, you need more environment variables for libcurl.

set http_proxy=http://proxy.example.com:8080/
set https_proxy=%http_proxy%
set no_proxy=localhost,127.0.0.1

Open the generated solution file by devenv.

devenv WebKitBuild\Release\WebKit.sln

Build "MiniBrowser" project.

Debugging WinCairo

• Debugging With Visual Studio.
• ​Logging in WebKit

Required Libraries

You will get required libraries downloaded automatically when you perform a build-webkit --wincairo. The source code is hosted in: ​https://github.com/WebKitForWindows/WebKitRequirements

Running the tests

Install XAMPP. XAMPP should be installed in the default install path (c:\xampp).

choco install -y XAMPP-74

Install required Python and Ruby modules.

pip install pywin32
gem install webrick

If Apache service is running, stop it.

net stop apache2.4

Some extensions need to be registered as CGI. Modify the following commands for your Perl an Python paths, and run them as administrator.

reg add HKEY_CLASSES_ROOT\.pl\Shell\ExecCGI\Command /ve /d "c:\xampp\perl\bin\perl.exe -T"
reg add HKEY_CLASSES_ROOT\.cgi\Shell\ExecCGI\Command /ve /d "c:\xampp\perl\bin\perl.exe -T"
reg add HKEY_CLASSES_ROOT\.py\Shell\ExecCGI\Command /ve /d "c:\Python39\python.exe -X utf8"

You need openssl.exe in your PATH to run wpt server. XAMPP contains openssl.exe in C:\xampp\apache\bin directory. Append the directory to your PATH.

Open a command prompt as administrator because http tests need to run Apache service. Set some environment variables.

set WEBKIT_LIBRARIES=%cd%\WebKitLibraries\win
set WEBKIT_OUTPUTDIR=%cd%\WebKitBuild
set WEBKIT_TESTFONTS=%cd%\Tools\WebKitTestRunner\fonts
set DUMPRENDERTREE_TEMP=%TEMP%

Invoke run-webkit-tests.

# for WebKit1
python Tools/Scripts/run-webkit-tests --release --wincairo -1
# for WebKit2
python Tools/Scripts/run-webkit-tests --release --wincairo

You can use Docker to run LayoutTests by mounting the host directory.

docker run -it --rm --cpu-count=8 --memory=16g -v %cd%:c:\repo -w c:\repo webkitdev/msbuild

If you are using Japanese Windows, some layout tests fails due to form control size differences. GetStockObject(DEFAULT_GUI_FONT) returns MS UI Gothic on it. Remove GUIFont.Facename of HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\GRE_Initialize. And, replace MS UI Gothic with Microsoft Sans Serif in HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\FontSubstitutes\MS Shell Dlg.

If http tests fail as flaky failures due to the socket count limit, increase the user port range. See ​Bug 224523

netsh int ipv4 set dynamicport tcp start=1025 num=64511

Download build artifacts from Buildbot

• Go to ​WinCairo-64-bit-WKL-Release-Build Buildbot builder page.
• Click any "Build #" which is green.
• Click "> stdio" of "transfer-to-s3".
• You can find "S3 URL" in the console log.
• Download the zip.
• Download the corresponding release of WebKitRequirements. ​https://github.com/WebKitForWindows/WebKitRequirements/releases

• Unpack them, copy all DLL of WinCairoRequirements to the directory of MiniBrowser.exe
• Install the latest ​vc_redist.x64.exe of Microsoft Visual C++ Redistributable for Visual Studio

Compile WinCairo with Clang

clang-cl builds isn't supported anymore, see ​Bug 171618.

clang-cl has a problem for /MP support. ​https://reviews.llvm.org/D52193 It's recommended to use Ninja with clang-cl. Install clang-cl and Ninja.

choco install llvm ninja -y

Open Visual Studio Command Prompt, and invoke the following commands.

set CC=clang-cl
set CXX=clang-cl
perl Tools\Scripts\build-webkit --release --wincairo --ninja

clang-cl builds are experimental, see ​Bug 171618 for the current status.