Hadli, Manjunath wrote: > Hello, > I am trying to grasp some basic concpets of DirectFB as part of a > detailed study I am doing on DirectFb for some of our products. You can see > me as an avtive contributor thereafter. > > On the outset, it looked to me for a multi desktop kind of scenario, multiple > screens can be used. Am I right in saying this? To be more clear on the > matter, I list down my understanding and throw up a few questions: > > Understanding: > 1. A screen is a collection of layers( hardware) and a surface chain can be > associated with each layer. > 2. There can be multiple screens and each of these screen represent a > different collection of layers like a computer with 2 desktops. > 3. Display modes can be set through the main interface - IDitectFB. > > Questions: > 1. If a screen is like a desktop, the modes and resolutions should be an > attribute of the screen. In directFb I see them as methods of the topmost > object IDirecFB. How can I set independent resolutions to different screens? > 2. How can I setup an extended desktop scenario?
The Screen in DirectFB is a logical group of hardware components rather than a screen in terms of a display. A screen can have multiple outputs with different encoders behind that can take the composed image from one or more hardware mixers combining hardware layers. Layers -> Mixers -> Encoders -> Outputs A Screen describes the whole group and the possible combinations, where parts can be left out, e.g. not providing outputs or their configuration, or not providing mixers but just encoder settings like PAL/NTSC or HD resolutions with digital outputs. For example, you can choose in a mixer configuration which of the connected layers you want to display. When there are two completely independent paths without any possibility of e.g. moving one layer from one mixer to another, you have two distinct "screen objects" in DirectFB, otherwise you just have two encoders or two outputs or both. Display modes are set at encoder level. The video mode setting in IDirectFB is just a legacy method to control the size of the primary display layer, which can be selected per application not dealing with different layers at all. It's a simplification of the API for simple application like games. The primary surface abstraction should be ignored by sophisticated applications. Better make use of the display layers and their configurations in conjunction with the settings of the screen(s). -- Best regards, Denis Oliver Kropp .------------------------------------------. | DirectFB - Hardware accelerated graphics | | http://www.directfb.org/ | "------------------------------------------" _______________________________________________ directfb-users mailing list directfb-users@directfb.org http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-users
