On Sat, 2020-06-06 at 08:18 -0300, Sleep wrote: > Thank you very much Adam, I have written a small diagram as an > exercise, > I would appreciate if someone could tell me if this is correct: > > Display -> is ------> +---------------+ > | | Server and | > V | Input Devices | > contains +---------------+ > | > V > Screens > | > V > and a > | > V > Screen -------------+ > | | > V V > contains contains +-------- which uses colors from > | | | ^ > V | V | > Visuals <----+ | Colormap* (and only one) images** > ^ | | ^ ^ > | | | | | > from | | is associated with <--- contains > ^ | +----------- \____ ^ > | | \ \ | > Visual are associated with <- Windows -> contains -> Window > ^ ^ > | | > +-----------------------------------------is associated with
The left side of this is pretty good. The right side isn't wrong, but maybe... incomplete? Windows don't necessarily contain images. There are two kinds of windows, InputOnly and InputOutput. InputOnly windows are often used as targets for mouse clicks or IPC. All windows have a geometry and can receive events, but only InputOutput Windows have pixels; attempting to draw to an InputOnly Window will fail, even though its subregion of the parent InputOutput window might be valid. An InputOnly window can not be the parent of an InputOutput window. Colormaps are server resources the same way Windows are, in general the client may create its own Colormaps or Windows and manipulate them how it likes. In particular, just as there is a predefined root Window for each screen, there is a predefined Colormap associated with that root Window. For TrueColor Visuals, said Colormap is read-only, and is effectively the gamma correction ramp. For PseudoColor visuals, the Colormap is a traditional color palette, where the pixel value directly determines all of R G and B at once. You describe the server as "containing" both Visuals and Windows, but they're not really the same kind of relationship. It might be better to say a server "supports" a set of Visuals. Visuals are not dynamic, they may not be created destroyed or modified by any client, they are defined up-front by the server. They are a description of what kinds of Window are supported. (Similarly, Formats describe what kinds of Pixmap are supported.) - ajax _______________________________________________ xorg@lists.x.org: X.Org support Archives: http://lists.freedesktop.org/archives/xorg Info: https://lists.x.org/mailman/listinfo/xorg Your subscription address: %(user_address)s
