attribute to a colormap or to CopyFromParent (default).
If you set the colormap to CopyFromParent, the parent window's colormap is copied and used by its child. However, the child window must have the same visual type as the parent, or a BadMatch error results. The parent window must not have a colormap of None, or a BadMatcherror results. The colormap is copied by sharing the colormap object between the child and parent, not by making a complete copy of the colormap contents. Subsequent changes to the parent window's colormap attribute do not affect the child window.
3.2.10. Cursor Attribute
The cursor attribute specifies which cursor is to be used when the pointer is in the InputOutput or InputOnly window. You can set the cursor to a cursor or None (default).
If you set the cursor to None, the parent's cursor is used when the pointer is in the InputOutput or InputOnly window, and any change in the parent's cursor will cause an immediate change in the displayed cursor. By calling XFreeCursor, the cursor can be freed immediately as long as no further explicit reference to it is made.
3.3. Creating Windows
Xlib provides basic ways for creating windows, and toolkits often supply higher-level functions specifically for creating and placing top-level windows, which are discussed in the appropriate toolkit documentation. If you do not use a toolkit, however, you must provide some standard information or hints for the window manager by using the Xlib inter-client communication functions (see chapter 14).
If you use Xlib to create your own top-level windows (direct children of the root window), you must observe the following rules so that all applications interact reasonably across the different styles of window management:
- You must never fight with the window manager for the size or placement of your top-level window.
- You must be able to deal with whatever size window you get, even if this means that your application just prints a message like "Please make me bigger" in its window.
- You should only attempt to resize or move top-level windows in direct response to a user request. If a request to change the size of a top-level window fails, you must be prepared to live with what you get. You are free to resize or move the children of top-level windows as necessary. (Toolkits often have facilities for automatic relayout.)
- If you do not use a toolkit that automatically sets standard window properties, you should set these properties for top-level windows before mapping them.
For further information, see chapter 14 and the Inter-Client Communication Conventions Manual.
XCreateWindow is the more general function that allows you to set specific window attributes when you create a window. XCreateSimpleWindow creates a window that inherits its attributes from its parent window.
The X server acts as if InputOnly windows do not exist for the purposes of graphics requests, exposure processing, and VisibilityNotify events. An InputOnly window cannot be used as a drawable (that is, as a source or destination for graphics requests). InputOnly and InputOutput windows act identically in other respects (properties, grabs, input control, and so on). Extension packages can define other classes of windows.
To create an unmapped window and set its window attributes, use XCreateWindow.
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