LibreOffice uses its own GUI and rendering toolkit called VCL that works across every major PC platform and even a few mobile platforms. On Linux it provides backends for Gtk and Qt. To make use of modern graphics hardware the LibreOffice project decided to add a cross-platform backend that still provides support for different GUI toolkits.
Using OpenGL allows us to improve the performance of our rendering by moving the work from the CPU to the mostly unused GPU. It also provides us with fast image scaling allowing us to use better scaling algorithms while still supporting fast scrolling. Together with the fact that OpenGL allows us to innovate without being limited by the ancient rendering APIs provided by different systems, makes porting our rendering toolkit to OpenGL an attractive option.
Come and see how the LibreOffice embraced this challenge and implemented the new VCL OpenGL backend that is being shipped in LibreOffice 4.4.
Markus is studying Mathematics at the Karlsruhe Institue for Techonoology and works part time on LibreOffice for Collabora. He mainly concentrates on LibreOffice calc and charts and in recent times the OpenGL support. He also maintains the LibreOffice cppunit version and is a co-maintainer of mdds, ixion and orcus. In his free time he likes to travel and see interesting new places.