12
\fBAccess control list\fP
13
.IN "Access control list" "" "@DEF@"
15
X maintains a list of hosts from which client programs can be run.
17
only programs on the local host and hosts specified in an initial list read
18
by the server can use the display.
19
This access control list can be changed by clients on the local host.
20
Some server implementations can also implement other authorization mechanisms
21
in addition to or in place of this mechanism.
22
The action of this mechanism can be conditional based on the authorization
23
protocol name and data received by the server at connection setup.
28
.IN "Active grab" "" "@DEF@"
30
A grab is active when the pointer or keyboard is actually owned by the
31
single grabbing client.
36
.IN "Ancestors" "" "@DEF@"
38
If W is an inferior of A, then A is an ancestor of W.
45
An atom is a unique ID corresponding to a string name.
46
Atoms are used to identify properties, types, and selections.
51
.IN "Background" "" "@DEF@"
55
window can have a background, which is defined as a pixmap.
56
When regions of the window have their contents lost
58
the server automatically tiles those regions with the background.
63
.IN "Backing store" "" "@DEF@"
65
When a server maintains the contents of a window,
66
the pixels saved off-screen are known as a backing store.
71
.IN "Base font name" "" "@DEF@"
73
A font name used to select a family of fonts whose members may be encoded
79
fields of an XLFD name identify the charset of the font.
80
A base font name may be a full XLFD name, with all fourteen '-' delimiters,
81
or an abbreviated XLFD name containing only the first 12 fields of an XLFD name,
82
up to but not including
84
with or without the thirteenth '-', or a non-XLFD name.
85
Any XLFD fields may contain wild cards.
89
Xlib accepts from the client a list of one or more base font names
90
which select one or more font families.
91
They are combined with charset names obtained from the encoding of the locale
92
to load the fonts required to render text.
97
.IN "Bit" "gravity" "@DEF@"
99
When a window is resized,
100
the contents of the window are not necessarily discarded.
101
It is possible to request that the server relocate the previous contents
102
to some region of the window (though no guarantees are made).
103
This attraction of window contents for some location of
104
a window is known as bit gravity.
109
.IN "Bit" "plane" "@DEF@"
111
When a pixmap or window is thought of as a stack of bitmaps,
112
each bitmap is called a bit plane or plane.
117
.IN "Bitmap" "" "@DEF@"
119
A bitmap is a pixmap of depth one.
124
.IN "Border" "" "@DEF@"
128
window can have a border of equal thickness on all four sides of the window.
129
The contents of the border are defined by a pixmap,
130
and the server automatically maintains the contents of the border.
131
Exposure events are never generated for border regions.
135
\fBButton grabbing\fP
136
.IN "Button" "grabbing" "@DEF@"
138
Buttons on the pointer can be passively grabbed by a client.
139
When the button is pressed,
140
the pointer is then actively grabbed by the client.
145
.IN "Byte" "order" "@DEF@"
147
For image (pixmap/bitmap) data,
148
the server defines the byte order,
149
and clients with different native byte ordering must swap bytes as
151
For all other parts of the protocol,
152
the client defines the byte order,
153
and the server swaps bytes as necessary.
158
.IN "Character" "" "@DEF@"
160
A member of a set of elements used for the organization,
161
control, or representation of text (ISO2022, as adapted by XPG3).
162
Note that in ISO2022 terms, a character is not bound to a coded value
163
until it is identified as part of a coded character set.
167
\fBCharacter glyph\fP
168
.IN "Character glyph" "" "@DEF@"
170
The abstract graphical symbol for a character.
171
Character glyphs may or may not map one-to-one to font glyphs,
172
and may be context-dependent, varying with the adjacent characters.
173
Multiple characters may map to a single character glyph.
178
.IN "Character set" "" "@DEF@"
180
A collection of characters.
185
.IN "Charset" "" "@DEF@"
187
An encoding with a uniform, state-independent mapping from characters
189
A coded character set.
192
there can be a direct mapping from a charset to one font,
193
if the width of all characters in the charset is either one or two bytes.
194
A text string encoded in an encoding such as Shift-JIS cannot be passed
195
directly to the X server, because the text imaging requests accept only
196
single-width charsets (either 8 or 16 bits).
197
Charsets which meet these restrictions can serve as ``font charsets''.
198
Font charsets strictly speaking map font indices to font glyphs,
199
not characters to character glyphs.
201
Note that a single font charset is sometimes used as the encoding of a locale,
202
for example, ISO8859-1.
207
.IN "Children" "" "@DEF@"
209
The children of a window are its first-level subwindows.
214
.IN "Class" "" "@DEF@"
216
Windows can be of different classes or types.
221
windows for further information about valid window types.
226
.IN "Client" "" "@DEF@"
228
An application program connects to the window system server by some
229
interprocess communication (IPC) path, such as a TCP connection or a
230
shared memory buffer.
231
This program is referred to as a client of the window system server.
233
the client is the IPC path itself.
234
A program with multiple paths open to the server is viewed as
235
multiple clients by the protocol.
236
Resource lifetimes are controlled by
237
connection lifetimes, not by program lifetimes.
241
\fBClipping region\fP
242
.IN "Clipping region" "" "@DEF@"
244
In a graphics context,
245
a bitmap or list of rectangles can be specified
246
to restrict output to a particular region of the window.
247
The image defined by the bitmap or rectangles is called a clipping region.
251
\fBCoded character\fP
252
.IN "Coded character" "" "@DEF@"
254
A character bound to a codepoint.
258
\fBCoded character set\fP
259
.IN "Coded character set" "" "@DEF@"
261
A set of unambiguous rules that establishes a character set
262
and the one-to-one relationship between each character of the set
263
and its bit representation.
264
(ISO2022, as adapted by XPG3)
265
A definition of a one-to-one mapping of a set of characters to a set of
271
.IN "Codepoint" "" "@DEF@"
273
The coded representation of a single character in a coded character set.
278
.IN "Colormap" "" "@DEF@"
280
A colormap consists of a set of entries defining color values.
281
The colormap associated with a window is used to display the contents of
282
the window; each pixel value indexes the colormap to produce an RGB value
283
that drives the guns of a monitor.
284
Depending on hardware limitations,
285
one or more colormaps can be installed at one time so
286
that windows associated with those maps display with true colors.
291
.IN "Connection" "" "@DEF@"
293
The IPC path between the server and client program is known as a connection.
294
A client program typically (but not necessarily) has one
295
connection to the server over which requests and events are sent.
300
.IN "Containment" "" "@DEF@"
302
A window contains the pointer if the window is viewable and the
303
hotspot of the cursor is within a visible region of the window or a
304
visible region of one of its inferiors.
305
The border of the window is included as part of the window for containment.
306
The pointer is in a window if the window contains the pointer
307
but no inferior contains the pointer.
311
\fBCoordinate system\fP
312
.IN "Coordinate system" "" "@DEF@"
314
The coordinate system has X horizontal and Y vertical,
315
with the origin [0, 0] at the upper left.
316
Coordinates are integral and coincide with pixel centers.
317
Each window and pixmap has its own coordinate system.
319
the origin is inside the border at the inside upper-left corner.
324
.IN "Cursor" "" "@DEF@"
326
A cursor is the visible shape of the pointer on a screen.
327
It consists of a hotspot, a source bitmap, a shape bitmap,
328
and a pair of colors.
329
The cursor defined for a window controls the visible
330
appearance when the pointer is in that window.
335
.IN "Depth" "" "@DEF@"
337
The depth of a window or pixmap is the number of bits per pixel it has.
338
The depth of a graphics context is the depth of the drawables it can be
339
used in conjunction with graphics output.
344
.IN "Device" "" "@DEF@"
346
Keyboards, mice, tablets, track-balls, button boxes, and so on are all
347
collectively known as input devices.
348
Pointers can have one or more buttons
349
(the most common number is three).
350
The core protocol only deals with two devices: the keyboard
356
.IN "DirectColor" "" "@DEF@"
359
is a class of colormap in which a pixel value is decomposed into three
360
separate subfields for indexing.
361
The first subfield indexes an array to produce red intensity values.
362
The second subfield indexes a second array to produce blue intensity values.
363
The third subfield indexes a third array to produce green intensity values.
364
The RGB (red, green, and blue) values in the colormap entry can be
370
.IN "Display" "" "@DEF@"
372
A server, together with its screens and input devices, is called a display.
375
.IN "Display" "structure"
376
structure contains all information about the particular display and its screens
377
as well as the state that Xlib needs to communicate with the display over a
378
particular connection.
383
.IN "Drawable" "" "@DEF@"
385
Both windows and pixmaps can be used as sources and destinations
386
in graphics operations.
387
These windows and pixmaps are collectively known as drawables.
390
window cannot be used as a source or destination in a
396
.IN "Encoding" "" "@DEF@"
398
A set of unambiguous rules that establishes a character set
399
and a relationship between the characters and their representations.
400
The character set does not have to be fixed to a finite pre-defined set of
402
The representations do not have to be of uniform length.
403
Examples are an ISO2022 graphic set, a state-independent
404
or state-dependent combination of graphic sets, possibly including control
405
sets, and the X Compound Text encoding.
407
In X, encodings are identified by a string
408
which appears as: the
412
components of an XLFD
413
name; the name of a charset of the locale for which a font could not be
414
found; or an atom which identifies the encoding of a text property or
415
which names an encoding for a text selection target type.
416
Encoding names should be composed of characters from the X Portable
422
.IN "Escapement" "" "@DEF@"
424
The escapement of a string is the distance in pixels in the
425
primary draw direction from the drawing origin to the origin of the next
426
character (that is, the one following the given string) to be drawn.
431
.IN "Event" "" "@DEF@"
433
Clients are informed of information asynchronously by means of events.
434
These events can be either asynchronously generated from devices or
435
generated as side effects of client requests.
436
Events are grouped into types.
437
The server never sends an event to a client unless the
438
client has specifically asked to be informed of that type of event.
439
However, clients can force events to be sent to other clients.
440
Events are typically reported relative to a window.
445
.IN "Event" "mask" "@DEF@"
447
Events are requested relative to a window.
448
The set of event types a client requests relative to a window is described
449
by using an event mask.
453
\fBEvent propagation\fP
454
.IN "Event" "propagation" "@DEF@"
456
Device-related events propagate from the source window to ancestor
457
windows until some client has expressed interest in handling that type
458
of event or until the event is discarded explicitly.
463
.IN "Event" "source" "@DEF@"
465
The deepest viewable window that the pointer is in is called
466
the source of a device-related event.
470
\fBEvent synchronization\fP
471
.IN "Event" "synchronization" "@DEF@"
473
There are certain race conditions possible when demultiplexing device
474
events to clients (in particular, deciding where pointer and keyboard
475
events should be sent when in the middle of window management
477
The event synchronization mechanism allows synchronous processing of
483
.IN "Event" "Exposure" "@DEF@"
485
Servers do not guarantee to preserve the contents of windows when
486
windows are obscured or reconfigured.
487
Exposure events are sent to clients to inform them when contents of regions
488
of windows have been lost.
493
.IN "Extension" "" "@DEF@"
495
Named extensions to the core protocol can be defined to extend the system.
496
Extensions to output requests, resources, and event types are all possible
502
.IN "Font" "" "@DEF@"
504
A font is an array of glyphs (typically characters).
505
The protocol does no translation or interpretation of character sets.
506
The client simply indicates values used to index the glyph array.
507
A font contains additional metric information to determine interglyph
508
and interline spacing.
513
.IN "Font glyph" "" "@DEF@"
515
The abstract graphical symbol for an index into a font.
520
.IN "Frozen events" "" "@DEF@"
522
Clients can freeze event processing during keyboard and pointer grabs.
529
GC is an abbreviation for graphics context.
530
See \fBGraphics context\fP.
535
.IN "Glyph" "" "@DEF@"
537
An identified abstract graphical symbol independent of any actual image.
539
An abstract visual representation of a graphic character,
540
not bound to a codepoint.
545
.IN "Glyph image" "" "@DEF@"
547
An image of a glyph, as obtained from a glyph representation displayed
548
on a presentation surface.
554
.IN "Grab" "" "@DEF@"
556
Keyboard keys, the keyboard, pointer buttons, the pointer,
557
and the server can be grabbed for exclusive use by a client.
559
these facilities are not intended to be used by normal applications
560
but are intended for various input and window managers to implement various
561
styles of user interfaces.
565
\fBGraphics context\fP
566
.IN "Graphics context" "" "@DEF@"
568
Various information for graphics output is stored in a graphics
569
context (GC), such as foreground pixel, background
570
pixel, line width, clipping region, and so on.
571
A graphics context can only
572
be used with drawables that have the same root and the same depth as
573
the graphics context.
578
.IN "Gravity" "" "@DEF@"
580
The contents of windows and windows themselves have a gravity,
581
which determines how the contents move when a window is resized.
582
See \fBBit gravity\fP and \fBWindow gravity\fP.
587
.IN "GrayScale" "" "@DEF@"
590
can be viewed as a degenerate case of
592
in which the red, green, and blue values in any given colormap entry
593
are equal and thus, produce shades of gray.
594
The gray values can be changed dynamically.
598
\fBHost Portable Character Encoding\fP
599
.IN "Host Portable Character Encoding" "" "@DEF@"
601
The encoding of the X Portable Character Set on the host.
602
The encoding itself is not defined by this standard,
603
but the encoding must be the same in all locales supported by Xlib on the host.
604
If a string is said to be in the Host Portable Character Encoding,
605
then it only contains characters from the X Portable Character Set,
606
in the host encoding.
611
.IN "Hotspot" "" "@DEF@"
613
A cursor has an associated hotspot, which defines the point in the
614
cursor corresponding to the coordinates reported for the pointer.
619
.IN "Identifier" "" "@DEF@"
621
An identifier is a unique value associated with a resource
622
that clients use to name that resource.
623
The identifier can be used over any connection to name the resource.
628
.IN "Inferiors" "" "@DEF@"
630
The inferiors of a window are all of the subwindows nested below it:
631
the children, the children's children, and so on.
636
.IN "Input" "focus" "@DEF@"
638
The input focus is usually a window defining the scope for processing
640
If a generated keyboard event usually would be reported to this window
641
or one of its inferiors,
642
the event is reported as usual.
643
Otherwise, the event is reported with respect to the focus window.
644
The input focus also can be set such that all keyboard events are discarded
645
and such that the focus window is dynamically taken to be the root window
646
of whatever screen the pointer is on at each keyboard event.
651
.IN "Input" "manager" "@DEF@"
653
Control over keyboard input is typically provided by an input manager
654
client, which usually is part of a window manager.
658
\fBInputOnly window\fP
659
.IN "Window" "InputOnly" "@DEF@"
663
window is a window that cannot be used for graphics requests.
665
windows are invisible and are used to control such things as cursors,
666
input event generation, and grabbing.
670
windows as inferiors.
674
\fBInputOutput window\fP
675
.IN "Window" "InputOutput" "@DEF@"
679
window is the normal kind of window that is used for both input and output.
681
windows can have both
685
windows as inferiors.
689
\fBInternationalization\fP
690
.IN "Internationalization" "" "@DEF@"
692
The process of making software adaptable to the requirements
693
of different native languages, local customs, and character string encodings.
694
Making a computer program adaptable to different locales
695
without program source modifications or recompilation.
700
.IN "ISO2022" "" "@DEF@"
702
ISO standard for code extension techniques for 7-bit and 8-bit coded
708
.IN "Key" "grabbing" "@DEF@"
710
Keys on the keyboard can be passively grabbed by a client.
711
When the key is pressed,
712
the keyboard is then actively grabbed by the client.
716
\fBKeyboard grabbing\fP
717
.IN "Keyboard" "grabbing" "@DEF@"
719
A client can actively grab control of the keyboard, and key events
720
will be sent to that client rather than the client the events would
721
normally have been sent to.
726
.IN "Keysym" "" "@DEF@"
728
An encoding of a symbol on a keycap on a keyboard.
733
.IN "Latin-1" "" "@DEF@"
735
The coded character set defined by the ISO8859-1 standard.
739
\fBLatin Portable Character Encoding\fP
740
.IN "Latin Portable Character Encoding" "" "@DEF@"
742
The encoding of the X Portable Character Set using the Latin-1 codepoints
743
plus ASCII control characters.
744
If a string is said to be in the Latin Portable Character Encoding,
745
then it only contains characters from the X Portable Character Set,
751
.IN "Locale" "" "@DEF@"
753
The international environment of a computer program defining the ``localized''
754
behavior of that program at run-time.
755
This information can be established from one or more sets of localization data.
756
ANSI C defines locale-specific processing by C system library calls.
757
See ANSI C and the X/Open Portability Guide specifications for more details.
758
In this specification, on implementations that conform to the ANSI C library,
759
the ``current locale'' is the current setting of the LC_CTYPE
762
Associated with each locale is a text encoding. When text is processed
763
in the context of a locale, the text must be in the encoding of the locale.
764
The current locale affects Xlib in its:
767
Encoding and processing of input method text
769
Encoding of resource files and values
771
Encoding and imaging of text strings
773
Encoding and decoding for inter-client text communication
779
.IN "Locale name" "" "@DEF@"
781
The identifier used to select the desired locale for the host C library
782
and X library functions.
783
On ANSI C library compliant systems,
784
the locale argument to the
791
.IN "Localization" "" "@DEF@"
793
The process of establishing information within a computer system specific
794
to the operation of particular native languages, local customs
795
and coded character sets.
801
.IN "Mapped window" "" "@DEF@"
803
A window is said to be mapped if a map call has been performed on it.
804
Unmapped windows and their inferiors are never viewable or visible.
809
.IN "Modifier keys" "" "@DEF@"
811
Shift, Control, Meta, Super, Hyper, Alt, Compose, Apple, CapsLock,
812
ShiftLock, and similar keys are called modifier keys.
817
.IN "Monochrome" "" "@DEF@"
819
Monochrome is a special case of
821
in which there are only two colormap entries.
826
.IN "Multibyte" "" "@DEF@"
828
A character whose codepoint is stored in more than one byte;
829
any encoding which can contain multibyte characters;
830
text in a multibyte encoding.
831
The ``char *'' null-terminated string datatype in ANSI C.
832
Note that references in this document to multibyte strings
833
imply only that the strings \fImay\fP contain multibyte characters.
838
.IN "Obscure" "" "@DEF@"
840
A window is obscured if some other window obscures it.
841
A window can be partially obscured and so still have visible regions.
842
Window A obscures window B if both are viewable
844
windows, if A is higher in the global stacking order,
845
and if the rectangle defined by the outside
846
edges of A intersects the rectangle defined by the outside edges of B.
847
Note the distinction between obscures and occludes.
848
Also note that window borders are included in the calculation.
853
.IN "Occlude" "" "@DEF@"
855
A window is occluded if some other window occludes it.
856
Window A occludes window B if both are mapped,
857
if A is higher in the global stacking order,
858
and if the rectangle defined by the outside edges of A intersects the rectangle defined
859
by the outside edges of B.
860
Note the distinction between occludes and obscures.
861
Also note that window borders are included in the calculation
864
windows never obscure other windows but can occlude other windows.
869
.IN "Padding" "" "@DEF@"
871
Some padding bytes are inserted in the data stream to maintain
872
alignment of the protocol requests on natural boundaries.
873
This increases ease of portability to some machine architectures.
878
.IN "Window" "parent" "@DEF@"
880
If C is a child of P, then P is the parent of C.
885
.IN "Passive grab" "" "@DEF@"
887
Grabbing a key or button is a passive grab.
888
The grab activates when the key or button is actually pressed.
893
.IN "Pixel value" "" "@DEF@"
895
A pixel is an N-bit value,
896
where N is the number of bit planes used in a particular window or pixmap
897
(that is, is the depth of the window or pixmap).
898
A pixel in a window indexes a colormap to derive an actual color to be
904
.IN "Pixmap" "" "@DEF@"
909
A pixmap is a three-dimensional array of bits.
910
A pixmap is normally thought of as a two-dimensional array of pixels,
911
where each pixel can be a value from 0 to %2 sup N %\-1,
912
and where N is the depth (z axis) of the pixmap.
913
A pixmap can also be thought of as a stack of N bitmaps.
914
A pixmap can only be used on the screen that it was created in.
919
.IN "Plane" "" "@DEF@"
921
When a pixmap or window is thought of as a stack of bitmaps, each
922
bitmap is called a plane or bit plane.
927
.IN "Plane" "mask" "@DEF@"
929
Graphics operations can be restricted to only affect a subset of bit
930
planes of a destination.
931
A plane mask is a bit mask describing which planes are to be modified.
932
The plane mask is stored in a graphics context.
937
.IN "Pointer" "" "@DEF@"
939
The pointer is the pointing device currently attached to the cursor
940
and tracked on the screens.
944
\fBPointer grabbing\fP
945
.IN "Pointer" "grabbing" "@DEF@"
947
A client can actively grab control of the pointer.
948
Then button and motion events will be sent to that client
949
rather than the client the events would normally have been sent to.
953
\fBPointing device\fP
954
.IN "Pointing device" "" "@DEF@"
956
A pointing device is typically a mouse, tablet, or some other
957
device with effective dimensional motion.
958
The core protocol defines only one visible cursor,
959
which tracks whatever pointing device is attached as the pointer.
964
.IN "POSIX" "" "@DEF@"
966
Portable Operating System Interface, ISO/IEC 9945-1 (IEEE Std 1003.1).
970
\fBPOSIX Portable Filename Character Set\fP
971
.IN "POSIX Portable Filename Character Set" "" "@DEF@"
973
The set of 65 characters which can be used in naming files on a POSIX-compliant
974
host that are correctly processed in all locales.
984
.IN "Property" "" "@DEF@"
986
Windows can have associated properties that consist of a name, a type,
987
a data format, and some data.
988
The protocol places no interpretation on properties.
989
They are intended as a general-purpose naming mechanism for clients.
990
For example, clients might use properties to share information such as resize
991
hints, program names, and icon formats with a window manager.
996
.IN "Property list" "" "@DEF@"
998
The property list of a window is the list of properties that have
999
been defined for the window.
1004
.IN "PseudoColor" "" "@DEF@"
1007
is a class of colormap in which a pixel value indexes the colormap entry to
1008
produce an independent RGB value;
1009
that is, the colormap is viewed as an array of triples (RGB values).
1010
The RGB values can be changed dynamically.
1015
.IN "Rectangle" "" "@DEF@"
1017
A rectangle specified by [x,y,w,h] has an infinitely thin
1018
outline path with corners at [x,y], [x+w,y], [x+w,y+h], and [x, y+h].
1019
When a rectangle is filled,
1020
the lower-right edges are not drawn.
1023
nothing would be drawn.
1025
a single pixel would be drawn.
1029
\fBRedirecting control\fP
1030
.IN "Redirecting control" "" "@DEF@"
1032
Window managers (or client programs) may enforce window layout
1033
policy in various ways.
1034
When a client attempts to change the size or position of a window,
1035
the operation may be redirected to a specified client
1036
rather than the operation actually being performed.
1041
.IN "Reply" "" "@DEF@"
1043
Information requested by a client program using the X protocol
1044
is sent back to the client with a reply.
1045
Both events and replies are multiplexed on the same connection.
1046
Most requests do not generate replies,
1047
but some requests generate multiple replies.
1052
.IN "Request" "" "@DEF@"
1054
A command to the server is called a request.
1055
It is a single block of data sent over a connection.
1060
.IN "Resource" "" "@DEF@"
1062
Windows, pixmaps, cursors, fonts, graphics contexts, and colormaps are
1064
They all have unique identifiers associated with them for naming purposes.
1065
The lifetime of a resource usually is bounded by the lifetime of the
1066
connection over which the resource was created.
1071
.IN "RGB values" "" "@DEF@"
1073
RGB values are the red, green, and blue intensity values that are used
1075
These values are always represented as 16-bit, unsigned numbers, with 0
1076
the minimum intensity and 65535 the maximum intensity.
1077
The X server scales these values to match the display hardware.
1082
.IN "Root" "" "@DEF@"
1084
The root of a pixmap or graphics context is the same as the root
1085
of whatever drawable was used when the pixmap or GC was created.
1086
The root of a window is the root window under which the window was created.
1091
.IN "Window" "root" "@DEF@"
1093
Each screen has a root window covering it.
1094
The root window cannot be reconfigured or unmapped,
1095
but otherwise it acts as a full-fledged window.
1096
A root window has no parent.
1101
.IN "Save set" "" "@DEF@"
1103
The save set of a client is a list of other clients' windows that,
1104
if they are inferiors of one of the client's windows at connection
1105
close, should not be destroyed and that should be remapped
1106
if currently unmapped.
1107
Save sets are typically used by window managers to avoid
1108
lost windows if the manager should terminate abnormally.
1113
.IN "Scanline" "" "@DEF@"
1115
A scanline is a list of pixel or bit values viewed as a horizontal
1116
row (all values having the same y coordinate) of an image, with the
1117
values ordered by increasing the x coordinate.
1121
\fBScanline order\fP
1122
.IN "Scanline" "order" "@DEF@"
1124
An image represented in scanline order contains scanlines ordered by
1125
increasing the y coordinate.
1130
.IN "Screen" "" "@DEF@"
1132
A server can provide several independent screens,
1133
which typically have physically independent monitors.
1134
This would be the expected configuration when there is only a single keyboard
1135
and pointer shared among the screens.
1138
.IN "Screen" "structure"
1139
structure contains the information about that screen
1140
and is linked to the
1142
.IN "Display" "structure"
1148
.IN "Selection" "" "@DEF@"
1150
A selection can be thought of as an indirect property with dynamic
1152
That is, rather than having the property stored in the X server,
1153
it is maintained by some client (the owner).
1154
A selection is global and is thought of as belonging to the user
1155
and being maintained by clients,
1156
rather than being private to a particular window subhierarchy
1157
or a particular set of clients.
1158
When a client asks for the contents of
1159
a selection, it specifies a selection target type,
1160
which can be used to control the transmitted representation of the contents.
1161
For example, if the selection is ``the last thing the user clicked on,''
1162
and that is currently an image, then the target type might specify
1163
whether the contents of the image should be sent in XY format or
1166
The target type can also be used to control the class of
1167
contents transmitted; for example,
1168
asking for the ``looks'' (fonts, line
1169
spacing, indentation, and so forth) of a paragraph selection, rather than the
1170
text of the paragraph.
1171
The target type can also be used for other
1173
The protocol does not constrain the semantics.
1178
.IN "Server" "" "@DEF@"
1180
The server, which is also referred to as the X server,
1181
provides the basic windowing mechanism.
1182
It handles IPC connections from clients,
1183
multiplexes graphics requests onto the screens,
1184
and demultiplexes input back to the appropriate clients.
1188
\fBServer grabbing\fP
1189
.IN "Server" "grabbing" "@DEF@"
1191
The server can be grabbed by a single client for exclusive use.
1192
This prevents processing of any requests from other client connections until
1193
the grab is completed.
1194
This is typically only a transient state for such things as rubber-banding,
1195
pop-up menus, or executing requests indivisibly.
1199
\fBShift sequence\fP
1200
.IN "Shift sequence" "" "@DEF@"
1202
ISO2022 defines control characters and escape sequences
1203
which temporarily (single shift) or permanently (locking shift) cause a
1204
different character set to be in effect (``invoking'' a character set).
1209
.IN "Sibling" "" "@DEF@"
1211
Children of the same parent window are known as sibling windows.
1215
\fBStacking order\fP
1216
.IN "Stacking order" "" "@DEF@"
1218
Sibling windows, similar to sheets of paper on a desk,
1219
can stack on top of each other.
1220
Windows above both obscure and occlude lower windows.
1221
The relationship between sibling windows is known as the stacking order.
1225
\fBState-dependent encoding\fP
1226
.IN "State-dependent encoding" "" "@DEF@"
1228
An encoding in which an invocation of a charset can apply to multiple
1229
characters in sequence.
1230
A state-dependent encoding begins in an ``initial state''
1231
and enters other ``shift states'' when specific ``shift sequences''
1232
are encountered in the byte sequence.
1234
this means use of locking shifts, not single shifts.
1238
\fBState-independent encoding\fP
1239
.IN "State-independent encoding" "" "@DEF@"
1241
Any encoding in which the invocations of the charsets are fixed,
1242
or span only a single character.
1244
this means use of at most single shifts, not locking shifts.
1249
.IN "StaticColor" "" "@DEF@"
1252
can be viewed as a degenerate case of
1254
in which the RGB values are predefined and read-only.
1259
.IN "StaticGray" "" "@DEF@"
1262
can be viewed as a degenerate case of
1264
in which the gray values are predefined and read-only.
1265
The values are typically linear or near-linear increasing ramps.
1270
.IN "Status" "" "@DEF@"
1272
Many Xlib functions return a success status.
1273
If the function does not succeed,
1274
however, its arguments are not disturbed.
1279
.IN "Stipple" "" "@DEF@"
1281
A stipple pattern is a bitmap that is used to tile a region to serve
1282
as an additional clip mask for a fill operation with the foreground
1288
\fBSTRING encoding\fP
1289
.IN "STRING encoding" "" "@DEF@"
1291
Latin-1, plus tab and newline.
1294
\fBString Equivalence\fP
1295
.IN "String Equivalence" "" "@DEF@"
1297
Two ISO Latin-1 STRING8 values are considered equal if they are the same
1298
length and if corresponding bytes are either equal or are equivalent as
1299
follows: decimal values 65 to 90 inclusive (characters ``A'' to ``Z'') are
1300
pairwise equivalent to decimal values 97 to 122 inclusive
1301
(characters ``a'' to ``z''), decimal values 192 to 214 inclusive
1302
(characters ``A grave'' to ``O diaeresis'') are pairwise equivalent to decimal
1303
values 224 to 246 inclusive (characters ``a grave'' to ``o diaeresis''),
1304
and decimal values 216 to 222 inclusive (characters ``O oblique'' to ``THORN'')
1305
are pairwise equivalent to decimal values 246 to 254 inclusive
1306
(characters ``o oblique'' to ``thorn'').
1311
.IN "Tile" "" "@DEF@"
1313
A pixmap can be replicated in two dimensions to tile a region.
1314
The pixmap itself is also known as a tile.
1319
.IN "Timestamp" "" "@DEF@"
1321
A timestamp is a time value expressed in milliseconds.
1322
It is typically the time since the last server reset.
1323
Timestamp values wrap around (after about 49.7 days).
1324
The server, given its current time is represented by timestamp T,
1325
always interprets timestamps from clients by treating half
1326
of the timestamp space as being earlier in time than T
1327
and half of the timestamp space as being later in time than T.
1328
One timestamp value, represented by the constant
1330
is never generated by the server.
1331
This value is reserved for use in requests to represent the current server time.
1336
.IN "TrueColor" "" "@DEF@"
1339
can be viewed as a degenerate case of
1341
in which the subfields in the pixel value directly encode the corresponding RGB
1343
That is, the colormap has predefined read-only RGB values.
1344
The values are typically linear or near-linear increasing ramps.
1349
.IN "Type" "" "@DEF@"
1351
A type is an arbitrary atom used to identify the interpretation of property
1353
Types are completely uninterpreted by the server.
1354
They are solely for the benefit of clients.
1355
X predefines type atoms for many frequently used types,
1356
and clients also can define new types.
1361
.IN "Viewable" "" "@DEF@"
1363
A window is viewable if it and all of its ancestors are mapped.
1364
This does not imply that any portion of the window is actually visible.
1365
Graphics requests can be performed on a window when it is not
1366
viewable, but output will not be retained unless the server is maintaining
1372
.IN "Visible" "" "@DEF@"
1374
A region of a window is visible if someone looking at the screen can
1375
actually see it; that is, the window is viewable and the region is not occluded
1376
by any other window.
1381
.IN "Whitespace" "" "@DEF@"
1383
Any spacing character.
1384
On implementations that conform to the ANSI C library,
1385
whitespace is any character for which
1391
\fBWindow gravity\fP
1392
.IN "Window" "gravity" "@DEF@"
1394
When windows are resized,
1395
subwindows may be repositioned automatically relative to some position in the
1397
This attraction of a subwindow to some part of its parent is known
1402
\fBWindow manager\fP
1403
.IN "Window" "manager" "@DEF@"
1405
Manipulation of windows on the screen and much of the user interface
1406
(policy) is typically provided by a window manager client.
1410
\fBX Portable Character Set\fP
1411
.IN "X Portable Character Set" "" "@DEF@"
1413
A basic set of 97 characters which are assumed to exist in all
1414
locales supported by Xlib. This set contains the following characters:
1421
!"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~
1422
<space>, <tab>, and <newline>
1428
This is the left/lower half (also called the G0 set)
1429
of the graphic character set of ISO8859-1 plus <space>, <tab>, and <newline>.
1430
It is also the set of graphic characters in 7-bit ASCII plus the same
1431
three control characters.
1432
The actual encoding of these characters on the host is system dependent;
1433
see the Host Portable Character Encoding.
1438
.IN "XLFD" "" "@DEF@"
1440
The X Logical Font Description Conventions that define a standard syntax
1441
for structured font names.
1446
.IN "XY format" "" "@DEF@"
1448
The data for a pixmap is said to be in XY format if it is organized as
1449
a set of bitmaps representing individual bit planes with the planes
1450
appearing from most-significant to least-significant bit order.
1455
.IN "Z format" "" "@DEF@"
1457
The data for a pixmap is said to be in Z format if it is organized as
1458
a set of pixel values in scanline order.
1463
ANSI Programming Language - C: ANSI X3.159-1989, December 14, 1989.
1465
Draft Proposed Multibyte Extension of ANSI C, Draft 1.1, November 30,
1466
1989, SC22/C WG/SWG IPSJ/ITSCJ Japan.
1468
ISO2022: Information processing - ISO 7-bit and 8-bit coded character
1469
sets - Code extension techniques.
1471
ISO8859-1: Information processing - 8-bit single-byte coded graphic
1472
character sets - Part 1: Latin alphabet No. 1.
1474
POSIX: Information Technology - Portable Operating System Interface (POSIX) -
1475
Part 1: System Application Program Interface (API) [C Language],
1478
Text of ISO/IEC/DIS 9541-1, Information Processing - Font Information
1479
Interchange - Part 1: Architecture.
1481
X/Open Portability Guide, Issue 3, December 1988 (XPG3), X/Open Company,
1482
Ltd, Prentice-Hall, Inc. 1989. ISBN 0-13-685835-8.
1483
(See especially Volume 3: XSI Supplementary Definitions.)
added
removed
specs/libX11/glossary
