Nested compositing window managers

Abstract

Compositing is currently the prevalent rendering paradigm for window managers. It applies off-screen drawing of managed windows with final image composition by the window manager itself. In this context, a compositing system is presented, enabling the concurrent presence of multiple window managers, being arbitrarily nested while facilitating switch managers on-the-fly. Two distinct managers are implemented, 2d desktop and custom 3d book, that can be freely combined into nested hierarchies. To allow such nesting two extensions are introduced. Firstly, the compositing process is turned to a rendering pipeline with window managers directly in-the-loop, with an imaging model combining diverse geometries. Secondly, to facilitate focus control in such geometric spaces, a cascaded pointing translation process is implemented, enabling geometric mapping of pointing events across nested window managers. The entire compositing system is implemented in a custom widget toolkit named sprint (in C++ with OpengGL and shaders) that is publicly available. © 2014 Springer International Publishing.