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SaWMan

SaWMan Screen Tiling Demo DirectFB proudly presents SaWMan, the Shared application and Window Manager, as a co-development of Royal Philips and Denis Oliver Kropp. You'll find some informative pages about it in this presentation...

Introduction

SaWMan is a new window manager module for use with DirectFB. Its main difference to the default module is that it allows one process to be an application and window manager, implementing all kinds of diversity, while SaWMan is only the working horse.

On its own, SaWMan will behave similar to the default window manager, but as soon as there's an application manager, SaWMan will do synchronous RPCs to that application in relevant functions of the window manager module. That means it switches to the process and continues after it has completed the requested call and returned a result. The data which those calls operate on is already in shared memory, e.g. a window configuration.

The application manager can hook itself into several operations with this, e.g. it can forbid or modify requested window configurations right before they're actually applied by SaWMan.

For non-desktop and especially non-pointer environments like TVs, it is important to provide a simple and convenient layout and focus management. The layout of all windows can be completely overridden by the application manager, e.g. to implement a screen tiling mode.

The integration of application management allows easy definition and handling of application specific constraints. The manager has a list of applications identified by their name. Launching applications is usually initiated by the application manager itself, e.g. based on global keys grabbed by an input only window. However, the public SaWMan interfaces provide a way to send launch/shutdown requests from any application to the application manager.

While the key grabbing only provides asynchronous notification about keys which are then handled in the manager's main loop, SaWMan provides a hook to let the manager basically filter every single input event in a synchronous way, similar to the window configuration. Critical operations like layout and focus switching are best done in this callback.

For more information you can check the more or less documented header files in the include/ directory, or have a look at 'testman' - a minimal example of a manager implementation in the samples/ directory. You'll also find a small test program called 'testrun' which demonstrates launching of applications from another application.

Running testman

Once you have a session running after setting the option "wm = sawman" you'll notice that there's nothing new, except the old window manager hacks (builtin keys) are gone.

However, if you start 'testman' from the samples/ directory, you'll see windows being tiled on the screen, unless these windows have the DWCAPS_NODECORATION flag, e.g. LiTE and XDirectFB use that.

You can try running "df_andi --dfb:force-windowed" or even simply run df_window.

Hitting F9 cycles the focus through managed windows.
F10 would switch layout modes, but there's only one implemented in the test code.
F11 switches between "smooth software" or "standard (hw/sw)" scaling (for windows only).

The smooth scaling algorithms have also been developed in the scope of this project.

Using testrun

The command "testrun " will start/stop an application.

Available in the test code are:

  • Penguins: df_andi --dfb:mode=640x480,force-windowed
  • Windows: df_windows


directfb.org / Platform / SaWMan