In human–computer interfaces , the X keyboard extension or XKB is a part of the X Window System that extends the ability to control the keyboard over what is offered by the X Window System core protocol , and allows to use multiple keyboard layouts .
18-461: Its main features are: XKB is composed of two parts: a server extension and a client library. Modern versions of Xlib contain XKB, which is active by default. Client programs not using this extension can deactivate it before connecting with the server, or can simply work normally as the extension simulates the core protocol by default. XKB is also used by Wayland compositors and kmscon . XKB allows
36-416: A client to deactivate some of them and to be informed when a bell is rung. XKB allows a client to query the physical shape of the keyboard, including the shapes of individual keys. In particular, keys are arranged into sections, possibly rotated (as an example, the numeric keypad is typically considered a section). Within a section, keys are arranged into rows. Keys and sections have a geometry, which comprise
54-425: A keyboard behave like a keyboard of a different language. In this context, the set of characters that is generated by the keyboard is called a group , and a keyboard can switch to a different group at any time. XKB defines some group selectors (which are simply called groups in the specification). As with modifiers, a group selector can be associated with a key, but can also be latched or locked. The behavior of
72-551: A modifier to be locked or latched , other than being in its regular state. Normally, a modifier is active exactly when it is pressed, like the Shift . However, a modifier may also be locked, like the Caps Lock modifier. When a modifier is locked, it remains active until it is explicitly deactivated. An intermediate condition between regular and locked is the latched state: When a modifier is latched, it remains active, but only until
90-413: A part of the control, but is specified by attaching actions to these keys. The above two controls are Boolean : they are either active or not. The PerKeyRepeat is a control that is not Boolean. Namely, it is a mask that says which keys are in autorepeat mode. According to the specification, non-Boolean controls are "always active": that means that they always depends on a set of parameters (in this case,
108-468: A point set S in N dimensions is the box with the smallest measure ( area , volume , or hypervolume in higher dimensions) within which all the points lie. When other kinds of measure are used, the minimum box is usually called accordingly, e.g., "minimum-perimeter bounding box". The minimum bounding box of a point set is the same as the minimum bounding box of its convex hull , a fact which may be used heuristically to speed up computation. In
126-430: The keyboard indicators (LEDs). In particular, XKB provides symbolic names for indicators, which allows binding indicators to keyboard activity and checking which indicators are actually present on the keyboard. XKB also improves upon the core protocol's handling of bells ; the core protocol only supports one bell, and the only action a client can perform is to ring the bell. XKB supports multiple named bells and allows
144-495: The Wikimedia System Administrators, please include the details below. Request from 172.68.168.236 via cp1112 cp1112, Varnish XID 967177174 Upstream caches: cp1112 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 10:44:56 GMT Bounding box In geometry , the minimum bounding box or smallest bounding box (also known as the minimum enclosing box or smallest enclosing box ) for
162-409: The approximate outline of the key, its bounding box , and the precise form. Other than keys, the geometry also includes doodads , which are elements on the keyboard that are not keys. The overall shape of the keyboard is a doodad. Information provided about doodads includes their color and any text printed on them (including the font used). Xlib Too Many Requests If you report this error to
180-517: The burden of input event processing from client applications to the X server. However, the actions that can be associated with keys are limited to the following: Moreover, there are some actions related to devices that are available if the server supports the X Input extension . The X keyboard extension is incompatible with core keyboard handling and as a result several modifier keys are not working or require workarounds inside emulated environments such as VNC or Xephyr . XKB allows better handling of
198-404: The check of the actual intersection (because it only requires comparisons of coordinates), it allows quickly excluding checks of the pairs that are far apart. The arbitrarily oriented minimum bounding box is the minimum bounding box, calculated subject to no constraints as to the orientation of the result. Minimum bounding box algorithms based on the rotating calipers method can be used to find
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#1732790696669216-519: The keyboard depends on a number of parameters that can be changed by the clients. These parameters are called controls . For example, the SlowKey control can be used to ignore short keypresses. Another control is the MouseKeys , which makes some keypresses to simulate mouse movements. The control only indicates whether this simulation is active or not; which keys produce the movement is not considered
234-425: The latter as well as the optimal compromise between accuracy and CPU time are available. In the case where an object has its own local coordinate system , it can be useful to store a bounding box relative to these axes, which requires no transformation as the object's own transformation changes. In digital image processing , the bounding box is merely the coordinates of the rectangular border that fully encloses
252-518: The mask), but that there is no single bit that can be used to deactivate the effects of the control completely. Other than being Boolean or non-Boolean, controls also classifies as affecting the behavior of the server and affecting the behavior of the client library. The two above are server controls. Client library controls affect the translation of a keycode or a sequence of keycodes into a string ( XLookupString ) and event delivery. XKB allows for associating actions with key presses, which moves some of
270-416: The minimum-area or minimum-perimeter bounding box of a two-dimensional convex polygon in linear time, and of a three-dimensional point set in the time it takes to construct its convex hull followed by a linear-time computation. A three-dimensional rotating calipers algorithm can find the minimum-volume arbitrarily-oriented bounding box of a three-dimensional point set in cubic time. Matlab implementations of
288-419: The next non-modifier key is pressed. XKB allows a client application to explicitly latch or lock a modifier. Moreover, an application can bind a key press or release to a modifier state change. This way, a modifier may automatically become latched or locked whenever a key is pressed or released. XKB allows for the keyboard to switch between any of four different character groups. This is usually done for making
306-406: The points in S . Axis-aligned minimal bounding boxes are used as an approximate location of an object in question and as a very simple descriptor of its shape. For example, in computational geometry and its applications when it is required to find intersections in the set of objects, the initial check is the intersections between their MBBs. Since it is usually a much less expensive operation than
324-475: The two-dimensional case it is called the minimum bounding rectangle . The axis-aligned minimum bounding box (or AABB ) for a given point set is its minimum bounding box subject to the constraint that the edges of the box are parallel to the (Cartesian) coordinate axes. It is the Cartesian product of N intervals each of which is defined by the minimal and maximal value of the corresponding coordinate for
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