Skia Graphics Engine
The Skia Graphics Engine is an open-source graphics library written in C++. Skia Inc. originally developed the library; Google acquired it in 2005, and then released the software as open source licensed under the New BSD free software license.
Now known as Skia, the library is used in Google Chrome, Chrome OS, Chromium OS, Mozilla Firefox, Mozilla Thunderbird, Android, Firefox OS, and Flutter. The Skia library is also present on the BlackBerry PlayBook, though the extent of its usage is unclear.
Skia has several back-ends, including one for CPU-based software rasterization, one for PDF output, and one for GPU-accelerated OpenGL. Partially implemented back-ends are also available for OpenGL ES, OpenVG, SVG, and Adobe SWF. Skia is most similar in purpose to Cairo or Pathfinder rather than to other more elaborate infrastructures like Qt that provide their own widgets etc.
Mark Kilgard and Jeff Bolz explain the internals of Skia in the following terms:
Since then, Skia has added support for the proposed NV path rendering OpenGL vendor extension.
