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RFC 1013 - X Window System Protocol, version 11: Alpha update April 1987
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RFC1013 - X Window System Protocol, version 11: Alpha update Ap
Network Working Group Robert W. Scheifler
Request for Comments: 1013 June 1987
X WINDOW SYSTEM PROTOCOL, VERSION 11
Alpha Update
April 1987
Copyright (c) 1986, 1987 Massachusetts Institute of Technology
X Window System is a trademark of M.I.T.
Status of this Memo
This RFC is distributed to the Internet community for information
only. It does not establish an Internet standard. The X window
system has been widely reviewed and tested. The internet community
is encouraged to experiment with it. Distribution of this memo is
unlimited (see copyright notice on page 2).
Permission to use, copy, modify, and distribute this document for any
purpose and without fee is hereby granted, provided that the above
copyright notice appear in all copies and that both that copyright
notice and this permission notice are retained, and that the name of
M.I.T. not be used in advertising or publicity pertaining to this
document without specific, written prior permission. M.I.T. makes no
representations about the suitability of this document or the
protocol defined in this document for any purpose. It is provided
"as is" without express or implied warranty.
Author: Robert W. Scheifler
Laboratory for Computer Science
545 Technology Square, Room 418
Cambridge, MA 02139
Contributors:
Dave Carver (Digital HPW)
Branko Gerovac (Digital HPW)
Jim Gettys (MIT/Project Athena, Digital)
Phil Karlton (Digital WSL)
Scott McGregor (Digital SSG)
Ram Rao (Digital UEG)
David Rosenthal (Sun)
Dave Winchell (Digital UEG)
Implementors of initial server who provided useful input:
Susan Angebranndt (Digital)
Raymond Drewry (Digital)
Todd Newman (Digital)
Invited reviewers who provided useful input:
Andrew Cherenson (Berkeley)
Burns Fisher (Digital)
Dan Garfinkel (HP)
Leo Hourvitz (Next)
Brock Krizan (HP)
David Laidlaw (Stellar)
Dave Mellinger (Interleaf)
Ron Newman (MIT)
John Ousterhout (Berkeley)
Andrew Palay (ITC CMU)
Ralph Swick (MIT)
Craig Taylor (Sun)
Jeffery Vroom (Stellar)
This document does not attempt to provide the rationale or pragmatics
required to fully understand the protocol or to place it in
perspective within a complete system. Knowledge of X Version 10
will certainly aid in understanding this document.
The protocol contains many management mechanisms that are not
intended for normal applications. Not all mechanisms are needed to
build a particular user interface. It is important to keep in mind
that the protocol is intended to provide mechanism, not policy.
This document does not attempt to define precise formats or bit
encodings.
-------------------------------------------------------------------
SECTION 1. TERMINOLOGY
Access control list
X maintains a list of hosts from which client programs may be
run. By default, only programs on the local host may use the
display, plus any hosts specified in an initial list read by
the server. This "access control list" can be changed by
clients on the local host. Some server implementations may
also implement other authorization mechanisms.
Active grab
A grab is "active" when the pointer or keyboard is actually
owned by the single grabbing client.
Ancestors
If W is an inferior of A, then A is an "ancestor" of W.
Atom
An "atom" is a unique id corresponding to a string name.
Atoms are used to identify properties, types, and selections.
Backing store
When a server maintains the contents of a window, the
off-screen saved pixels are known as a "backing store".
Bit gravity
When a window is resized, the contents of the window are
not necessarily discarded. It is possible to request the
server (though no guarantees are made) to relocate the
previous contents to some region of the window. This
attraction of window contents for some location of a window
is known as "bit gravity".
Bitmap
A "bitmap" is a pixmap of depth one.
Button grabbing
Buttons on the pointer may be passively "grabbed" by a
client. When the button is pressed, the pointer is then
actively grabbed by the client.
Byte order
For image (pixmap/bitmap) data, byte order is defined by
the server, and clients with different native byte ordering
must swap bytes as necessary. For all other parts of the
protocol, the byte order is defined by the client, and the
server swaps bytes as necessary.
Children
The "children" of a window are its first-level subwindows.
Client
An application program connects to the window system server
by some interprocess communication (IPC) path, such as a TCP
connection or a shared memory buffer. This program is the
window system server. More precisely, the client is the IPC
path itself; a program with multiple paths open to the server
is viewed as multiple clients by the protocol. Resource
lifetimes are controlled by connection lifetimes, not by
program lifetimes.
Clipping regions
In a graphics context, a bitmap or list of rectangles can
be specified to restrict output to a particular region of
the window. The image defined by the bitmap or rectangles
is called a "clipping region".
Color cell
An entry in a colormap is known as a "color cell". An entry
contains three values specifying red, green and blue
intensities. These values are always viewed as 16 bit
unsigned numbers, with zero being minimum intensity. The
values are scaled by the server to match the display
hardware. The components of a cell are coincident with
components of other cells in DirectColor and TrueColor
colormaps.
Colormap
A "colormap" consists of a set of color cells. A pixel value
indexes the color map to produce intensities to be displayed.
Depending on hardware limitations, one or more colormaps may
be installed at one time, such that windows associated with
those maps display with true colors.
Connection
The IPC path between the server and client program is known
as a "connection". A client program typically (but not
necessarily) has one connection to the server over which
requests and events are sent.
Containment
A window "contains" the pointer if the window is viewable and
the hotspot of the cursor is within a visible region of the
window or a visible region of one of its inferiors. The
border of the window is included as part of the window for
containment. The pointer is "in" a window if the window
contains the pointer but no inferior contains the pointer.
Coordinate system
The coordinate system has X horizontal and Y vertical, with
the origin [0, 0] at the upper left. Coordinates are
discrete, and in terms of pixels. Each window and pixmap has
its own coordinate system. For a window, the origin is at
the inside upper left, inside the border.
Cursor
A "cursor" is the visible shape of the pointer on a screen.
It consist of a hot spot, a source bitmap, a shape bitmap,
and a pair of colors. The cursor defined for a window
controls the visible appearance when the pinter is in that
window.
Depth
The "depth" of a window or pixmap is number of bits per pixel
it has. The depth of a gcontext is the depth of the root of
the gcontext.
Device
Keyboards, mice, tablets, track-balls, button boxes, etc. are
all collectively known as input "devices". The core protocol
only deals with two devices, "the keyboard" and "the
pointer".
Drawable
Both windows and pixmaps may be used as sources and
destinations in graphics operations. These are collectively
known as "drawables". However, an InputOnly window cannot be
used as a source or destination in a graphics operation.
Event
Clients are informed of information asynchronously via
"events". These events may be either asynchronously generated
from devices, or generated as side effects of client
requests. Events are grouped into types; events are never
sent to a client by the server unless the client has
specificially asked to be informed of that type of event,
but other clients can force events to be sent to other
clients. Events are typically reported relative to a window.
Event mask
Events are requested relative to a window. The set of event
types a client requests relative to a window described using
an "event mask".
Event sychronization
There are certain race conditions possible when
demultiplexing device events to clients (in particular
deciding where pointer and keyboard events should be sent
when in the middle of window management operations). The
event synchronization mechanism allows synchronous processing
of device events.
Event propagation
Device-related events "propagate" from the source window to
ancestor windows until some client has expressed interest in
handling that type of event, or until the event is discarded
explicitly.
Event source
The smallest window containing the pointer is the "source"
of a device related event.
Exposure event
Servers do not guarantee to preserve the contents of windows
when windows are obscured or reconfigur contents of regions
of windows have been lost.
Extension
Named "extensions" to the core protocol can be defined to
extend the system. Extension to output requests, resources,
and event types are all possible, and expected.
Font
A "font" is an array of glyphs (typically characters). The
protocol does no translation or interpretation of character
sets. The client simply indicates values used to index the
glyph array. A font contains additional metric information
to determine inter-glyph and inter-line spacing.
Glyph
A "glyph" is an image, typically of a character, in a font.
Grab
Keyboard keys, the keyboard, pointer buttons, the pointer,
and the server can be "grabbed" for exclusive use by a
client. In general, these facilities are not intended to be
used by normal applications, but are intended for various
input and window managers to implement various styles of
user interfaces.
Graphics context
Various information for graphics output is stored in "GC"'s,
such as foreground pixel, background pixel, line width,
clipping region, etc.
Hotspot
A cursor has an associated "hot spot" which defines a point
in the cursor that corresponds to the coordinates reported
for the pointer.
Identifier
Each resource has an "identifier", a unique value associated
with it that clients use to name the resource. An identifier
can be used over any connection to name the resource.
Inferiors
The "inferiors" of a window are all of the subwindows nested
below it: the children, the children's children, etc.
Input focus
The "input focus" is nominally where keyboard input goes.
Keyboard events are by default sent to the client expressing
interest on the window the pointer is in. This is said to be
a "real estate driven" input focus. It is also possible to
attach the keyboard input to a specific window; events will
then be sent to the appropriate client independent of the
pointer position.
Input manager
Control over keyboard input is typically provided by an
"input manager" client.
InputOnly window
A window that cannot be used for graphics requests.
InputOnly windows are "invisible", and can be used to control
such things as cursors, input event generation, and grabbing.
InputOutput window
The "normal" kind of opaque window, used for both input
and output.
Key grabbing
Keys on the keyboard may be passively "grabbed" by a client.
When the key is pressed, the keyboard is then actively
grabbed by the client.
Keyboard grabbing
A client can actively "grab" control of the keyboard, and key
events will be sent to that client rather than the client the
events would normally have been sent to.
Mapping
A window is said to be "mapped" if a map call has been
performed on it. Unmapped windows are never viewable or
visible.
Modifier keys
Shift, Control, Meta, Super, Hyper, ALT, Compose, Apple,
CapsLock, ShiftLock, and similar keys are called "modifier"
keys.
Obscures
Window A "obscures" window B if both are viewable
InputOutput windows and A is higher in the global stacking
order, and the rectangle defined by the outside edges of
intersects the rectangle defined by the outside edges of B.
Note the (fine) distinction with "occludes". Also note that
window borders are included in the calculation.
Occludes
Window A "occludes" window B if both are mapped and A is
higher in the global stacking order, and the rectangle
defined by the outside edges of A intersects the rectangle
defined by the outside edges of B. Note the (fine)
distinction with "obscures". Also note that window borders
are included in the calculation.
Padding
Some padding bytes are inserted in the data stream to
maintain alignment of the protocol requests on natural
boundaries. This increases ease of portability to some
machine architectures.
Parent window
If C is a child of P, then P is the "parent" of C.
Passive grab
Grabbing a key or button is a "passive" grab. The grab
activates when the key or button is actually pressed.
Pixel value
A "pixel" is an N-bit value, where N is the number of bit
planes used in a particular window or pixmap. For a window,
a pixel value indexes a colormap to derive an actual color
to be displayed.
Pixmap
A "pixmap" is a three dimensional array of bits. A pixmap
is normally thought of as a two dimensional array of pixels,
where each pixel can be a value from 0 to (2^N)-1, where N
is the depth (z axis) of the pixmap. A pixmap can also be
thought of as a stack of N bitmaps.
Plane mask
Graphics operations can be restricted to only affect a
subset of bit planes of a destination. A "plane mask" is
a bit mask describing which planes are to be modified, and
is stored in a graphics context.
Pointer
The "pointer" is the pointing device attached to the cursor,
and tracked on the screens.
Pointer grabbing
A client can actively "grab" control of the pointer, and
button and motion events will be sent to that client rather
than the client the events would normally have been sent to.
Pointing device
A "pointing device" is typically a mouse or tablet, or some
other device with effective dimensional motion. There is
only one visible cursor is defined by the core protocol,
and it tracks whatever pointing device is attached as the
pointer.
Property
Windows may have associated "properties", consisting of a
name, a type, a data format, and some data. The protocol
places no interpretation on properties, they are intended
as a general-purpose naming mechanism for clients. For
example, clients might share information such as resize
hints, program names, and icon formats with a window
manager via properties.
Property list
The "property list" of a window is the list of properties
that have been defined for the window.
Redirecting control
Window managers (or client programs) may wish to enforce
window layout policy in various ways. When a client
attempts to change the size or position of a window, the
operation may be "redirected" to a specified client,
rather than the operation actually being performed.
Reply
Information requested by a client program is sent back to
the client with a "reply". Both events and replys are
multipexed on the same connection. Most requests do not
generate replies.
Request
A command to the server is called a "request". It is a
single block of data sent over a connection.
Resource
Windows, pixmaps, cursors, fonts, graphics contexts, and
colormaps are known as "resources". They all have unique
identifiers associated with them for naming purposes. The
lifetime of a resource is bounded by the lifetime of the
connection over which the resource was created.
Root
The "root" of a pixmap or gcontext is the same as the root
of whatever drawable was used when the pixmap or gcontext
was created. The "root" of a window is the root window
under which the window was created.
Root window
Each screen has a "root window" covering it. It cannot be
reconfigured or unmapped, but otherwise acts as a full
fledged window. A root window has no parent.
Save set
The "save set" of a client is a list of other client's
windows which, if they are inferiors of one of the client's
windows at connection close, should not be destroyed, and
which should be remapped if it is unmapped. Save sets are
typically used by window managers to avoid lost windows if
the manager should terminate abnormally.
Screen
A server may provide several independent "screens", which
typically have physically independent monitors. This would
be the expected configuration when there is only a single
keyboard and pointer shared among the screens.
Server
The "server" provides the basic windowing mechanism. It
handles IPC connections from clients, demultipexes graphics
requests onto the screens, and multiplexes input back to the
appropriate clients.
Server grabbing
The server can be "grabbed" by a single client for exclusive
use. This prevents processing of any requests from other
client connections until the grab is complete. This is
typically only a transient state for such things as
rubber-banding and pop-up menus, or to execute requests
indivisibly.
Sibling
Children of the same parent window are known as "sibling"
windows.
Stacking order
Sibling windows may "stack" on top of each other. Windows
above both obscure and occlude lower windows. This is
similar to paper on a desk. The relationship between
sibling windows is known as the "stacking order".
Stipple
A "stipple pattern" is a bitmap that is used to tile a
region to serve as an additional clip mask for a fill
operation with the foreground color.
Tile
A pixmap can be replicated in two dimensions to "tile"
a region. The pixmap itself is also known as a "tile".
Timestamp
A time value, expressed in milliseconds, typically since
the last server reset. Timestamp values wrap around (after
about 49.7 days). The server, given its current time is
represented by timestamp T, always interprets timestamps
from clients by treating half of the timestamp space as
being earlier in time than T, and half of the timestamp
space as being later in time than T. One timestamp value
(named CurrentTime) is never generated by the server;
this value is reserved for use in requests to represent
the current server time.
Type
A type is an arbitrary atom used to identify the
interpretation of property data. Types are completely
uninterpreted by the server; they are solely for the
benefit of clients.
Unviewable
A window is "unviewable" if it is mapped but some ancestor is
unmapped.
Viewable
A window is "viewable" if it and all of its ancestors are
mapped. This does not imply that any portion of the window
is actually visible.
Visible
A region of a window is "visible" if someone looking at the
screen can actually "see" it: the window is viewable and the
region is not occluded by any other window.
Window gravity
When windows are resized, subwindows may be repositioned
automatically relative to some position in the window. This
attraction of a subwindow to some part of its parent is known
as "window gravity".
Window manager
Manipulation of windows on the screen, and much of the user
interface (policy) is typically provided by a "window
manager" client.
XYFormat
The data for a pixmap is said to be in "XYFormat" if it is
organized as a set of bitmaps representing individual bit
planes.
ZFormat
The data for a pixmap is said to be in "ZFormat" if it is
organized as a set of pixel values in scanline order.
SECTION 2. PROTOCOL FORMATS
Request Format
Every request contains an 8-bit "major" opcode, and a 16-bit length
field expressed in units of 4 bytes. Every request consists of 4
bytes of header containing the major opcode, the length field, and a
data byte) followed by zero or more additional bytes of data; the
length field defines the total length of the request, including the
header. The length field in a request must equal the minimum length
required to contain the request; if the specified length is smaller
or larger than the required length, an error is enerated. Unused
bytes in a request are not required to be zero. Major opcodes 128
through 255 are reserved for extensions. Extensions are intended
to contain multiple requests, so extension requests typically have
an additional minor opcode encoded in the "spare" data byte in the
request header, but the placement and interpretation of this minor
opcode, and all other fields in extension requests, are not defined
by the core protocol. Every request is implicitly assigned a sequence
number, starting with one,used in replies, errors, and events.
Reply Format
Every reply contains a 32-bit length field expressed in units of 4
bytes. Every reply consists of 32 bytes, followed by zero or more
additional bytes of data, as specified in the length field. Unused
bytes within a reply are not guaranteed to be zero. Every reply
also contains the least significant 16 bits of the sequence number
of the corresponding request.
Error Format
Error reports are 32 bytes long. Every error includes an 8-bit error
code. Error codes 128 through 255 are reserved for extensions. Every
error also includes the major and minor opcodes of the failed
request, and the least significant 16 bits of the sequence number of
the request. For the following errors (see Section 5), the failing
resource id is also returned: Colormap, Cursor, Drawable, Font,
GContext, IDChoice, Pixmap, and Window. For Atom errors, the failing
atom is returned. For Value errors, the failing value is returned.
Other core errors return no additional data. Unused bytes within
an error are not guaranteed to be zero.
Event Format
Events are 32 bytes long. Unused bytes within an event are not
guaranteed to be zero. Every event contains an 8-bit type code. The
most significant bit in this code is set if the event was generated
from a SendEvent request. Event codes 64 through 127 are reserved for
extensions, although the core protocol does not define a mechanism
for selecting interest in such events. Every core event (with the
exception of KeymapNotify) also contains the least significant 16
bits of the sequence number of the last request issued by the client
that was (or is currently being) processed by the server.
SECTION 3. SYNTAX
The syntax {...} encloses a set of alternatives.
The syntax [...] encloses a set of structure components.
In general, TYPEs are in upper case and AlternativeValues are
capitalized.
Requests in Section 10 are described in the following format:
RequestName
arg1: type1
...
argN: typeN
=>
result1: type1
...
resultM: typeM
Errors: kind1, ..., kindK
Description.
If no => is present in the description, then the request has no
reply (it is asynchronous), although errors may still be reported.
Events in Section 12 are described in the following format:
EventName
value1: type1
...
valueN: typeN
Description.
SECTION 4. COMMON TYPES
LISTofFOO
A type name of the form LISTofFOO means a counted list of elements
of type FOO; the size of the length field may vary (it is not
necessarily the same size as a FOO), in some cases may be implicit,
and is not fully specified in this document.
BITMASK and LISTofVALUE
The types BITMASK and LISTofVALUE are somewhat special. Various
requests contain arguments of the form:
value-mask: BITMASK
value-list: LISTofVALUE
used to allow the client to specify a subset of a heterogeneous
collection of "optional" arguments. The value-mask specifies which
arguments are to be provided; each such argument is assigned a unique
bit position. The representation of the BITMASK will typically
contain more bits than there are defined arguments; unused bits in
the value-mask must be zero (or the server generates a Value error).
The value-list contains one value for each one bit in the mask, from
least to most significant bit in the mask. Each value is represented
with 4 bytes, but the actual value occupies only the least
significant bytes as required; the values of the unused bytes do not
matter.
Or Types
A type of the form "T1 or ... or Tn" means the union of the indicated
types; a single-element type is given as the element without
enclosing braces.
DEVICE: 32-bit id (<class,model,manufacturer,unit> 8 bits each)
WINDOW: 32-bit id
PIXMAP: 32-bit id
CURSOR: 32-bit id
FONT: 32-bit id
GCONTEXT: 32-bit id
COLORMAP: 32-bit id
DRAWABLE: WINDOW or PIXMAP
ATOM: 32-bit id (top 3 bits guaranteed to be zero)
VISUALID: 32-bit id (top 3 bits guaranteed to be zero)
VALUE: 32-bit quantity (used only in LISTofVALUE)
INT8: 8-bit signed integer
INT16: 16-bit signed integer
INT32: 32-bit signed integer
CARD8: 8-bit unsigned integer
CARD16: 16-bit unsigned integer
CARD32: 32-bit unsigned integer
TIMESTAMP: CARD32
BITGRAVITY: {Forget, Static,
NorthWest, North, NorthEast,
West, Center, East,
SouthWest, South, SouthEast}
WINGRAVITY: {Unmap, Static,
NorthWest, North, NorthEast,
West, Center, East,
SouthWest, South, SouthEast}
BOOL: {True, False}
EVENT: {KeyPress, KeyRelease,
OwnerGrabButton,
ButtonPress, ButtonRelease, EnterWindow, LeaveWindow,
PointerMotion, PointerMotionHint,
Button1Motion, Button2Motion, Button3Motion,
Button4Motion, Button5Motion, ButtonMotion
Exposure, VisibilityChange,
StructureNotify, ResizeRedirect,
SubstructureNotify, SubstructureRedirect,
FocusChange,
PropertyChange, ColormapChange,
KeymapState}
POINTEREVENT: {ButtonPress, ButtonRelease, EnterWindow, LeaveWindow,
PointerMotion, PointerMotionHint,
Button1Motion, Button2Motion, Button3Motion,
Button4Motion, Button5Motion, ButtonMotion
KeymapState}
DEVICEEVENT: {KeyPress, KeyRelease,
ButtonPress, ButtonRelease,
PointerMotion,
Button1Motion, Button2Motion, Button3Motion,
Button4Motion, Button5Motion, ButtonMotion}
KEYCODE: CARD8
BUTTON: CARD8
KEYMASK: {Shift, CapsLock, Control, Mod1, Mod2, Mod3, Mod4, Mod5}
BUTMASK: {Button1, Button2, Button3, Button4, Button5}
KEYBUTMASK: KEYMASK or BUTMASK
STRING8: LISTofCARD8
STRING16: LISTofCHAR2B
CHAR2B: [byte1, byte2: CARD8]
POINT: [x, y: INT16]
RECTANGLE: [x, y: INT16,
width, height: CARD16]
ARC: [x, y: INT16,
width, height: CARD16,
angle1, angle2: INT16]
HOST: [family: {Internet, NS, ECMA, Datakit, DECnet}
address: LISTofCARD8]
The [x,y] coordinates of a RECTANGLE specify the upper left corner.
The primary interpretation of "large" characters in a STRING16 is
that they are composed of two bytes used to index a 2-D matrix;
hence the use of CHAR2B rather than CARD16. This corresponds to
the JIS/ISO method of indexing two-byte characters. It is expected
that most "large" fonts will be defined with two-byte matrix
indexing. For large fonts constructed with linear indexing, a
CHAR2B can be interpreted as a 16-bit number by treating byte1 as
the most significant byte; this means that clients should always
transmit such 16-bit character values most significant byte first,
as the server will never byte-swap CHAR2B quantities.
The length, format, and interpretation of a HOST address are specific
to the family.
SECTION 5. ERRORS
In general, when a request terminates with an error, the request has
no side effects (i.e., there is no partial execution). The only
requests for which this is not true are ChangeWindowAttributes,
ChangeGC, PolyText8, PolyText16, FreeColors, StoreColors, and
ChangeKeyboardControl.
The following error codes can be returned by the various requests:
Access
An attempt to grab a key/button combination already grabbed
by another client.
An attempt to free a colormap entry not allocated by the
client.
An attempt to store into a read-only or an unallocated
colormap entry.
An attempt to modify the access control list from other than
the local (or otherwise authorized) host.
An attempt to select an event type, that at most one client
can select at a time, when another client has already
selected it.
Alloc
The server failed to allocate the requested resource.
Note that this only covers allocation errors at a very coarse
level, and is not intended to (nor can it in practice hope
to) cover all cases of a server running out of allocation
space in the middle of service.
The semantics when a server runs out of allocation space are
left unspecified.
Atom
A value for an ATOM argument does not name a defined ATOM.
Colormap
A value for a COLORMAP argument does not name a defined
COLORMAP.
Cursor
A value for a CURSOR argument does not name a defined CURSOR.
Drawable
A value for a DRAWABLE argument does not name a defined
WINDOW or PIXMAP.
Font
A value for a FONT or <FONT or GCONTEXT> argument does not
name a defined FONT.
GContext
A value for a GCONTEXT argument does not name a defined
GCONTEXT.
IDChoice
The value chosen for a resource identifier is either not
included in the range assigned to the client, or is already
in use.
Implementation
The server does not implement some aspect of the request. A
server which generates this error for a core request is
deficient. As such, this error is not listed for any of the
requests, but clients should be prepared to receive such
errors, and handle or discard them.
Length
The length of a request is shorter or longer than that
required to minimally contain the arguments.
Match
An InputOnly window is used as a DRAWABLE.
Some argument (or pair of arguments) has the correct type and
range, but fails to "match" in some other way required by the
request.
Name
A font or color of the specified name does not exist.
Pixmap
A value for a PIXMAP argument does not name a defined PIXMAP.
Property
The requested property does not exist for the specified
window.
Request
The major or minor opcode does not specify a valid request.
Value
Some numeric value falls outside the range of values accepted
by the request. Unless a specific range is specified for an
argument, the full range defined by the argument's type is
accepted. Any argument defined as a set of alternatives can
generate this error.
Window
A value for a WINDOW argument does not name a defined WINDOW.
Note: the Atom, Colormap, Cursor, Drawable, Font, GContext, Pixmap,
and Window errors are also used when the argument type is extended
by union with a set of fixed alternatives, e.g.,<Window or
PointerRoot or None>.
SECTION 6. KEYBOARDS
Keycodes are always in the inclusive range [8,255].
For keyboards with both left-side and right-side modifier keys (e.g.,
Shift and Control), the mask bits in the protocol always define the
OR of the keys. If electronically distinguishable, they can have
separate up/down events generated, and clients that want to
distinguish can track the individual states manually.
<As part of the core we need to define a universal association
between keycaps and keycodes. A keycap is the graphical information
imprinted on a keyboard key, e.g., "$ 4", "T", "+ =".>
SECTION 7. POINTERS
Buttons are always numbered starting with one.
SECTION 8. PREDEFINED ATOMS
Predefined atoms are not strictly necessary, and may not be useful in
all environments, but will eliminate many InternAtom requests in most
applications. The core protocol imposes no semantics on these names,
except as they are used in FONTPROP structures (see QueryFont). Note
that upper/lower case matters.
BITMAP ICON_SIZE RGB_GREEN_MAP
COMMAND ITALIC_ANGLE RGB_RED_MAP
COPYRIGHT MAX_SPACE SECONDARY
CUT_BUFFER0 MIN_SPACE SIZE_HINTS
CUT_BUFFER1 NAME STRIKEOUT_ASCENT
CUT_BUFFER2 NORMAL_HINTS STRIKEOUT_DESCENT
CUT_BUFFER3 NORM_SPACE STRING
CUT_BUFFER4 PIXMAP SUBSCRIPT_X
CUT_BUFFER5 POINT_SIZE SUBSCRIPT_Y
CUT_BUFFER6 PRIMARY SUPERSCRIPT_X
CUT_BUFFER7 QUAD_WIDTH SUPERSCRIPT_Y
DEFAULT_CHAR RECTANGLE UNDERLINE_POSITION
END_SPACE RESIZE_HINT UNDERLINE_THICKNESS
FACE_NAME RESOLUTION WEIGHT
FAMILY_NAME RGB_BEST_MAP WINDOW
FONT_ASCENT RGB_BLUE_MAP WM_HINTS
FONT_DESCENT RGB_COLOR_MAP X_HEIGHT
ICON RGB_DEFAULT_MAP ZOOM_HINTS
ICON_NAME
SECTION 9. CONNECTION SETUP
For remote clients, the X protocol can be built on top of any
reliable byte stream. For TCP connections, displays on a given host
a numbered starting from 0, and the server for display N listens and
accepts connections on port 6000+N.
The client must send an initial byte of data to identify the byte
order to be employed. The value of the byte must be octal 102 or
154. The value 102 (ASCII uppercase B) means values are transmitted
most significant byte first, and value 154 (ASCII lowercase l) means
values are transmitted least significant byte first. Except where
explicitly noted in the protocol, all 16-bit and 32-bit quantities
sent by the client must be transmitted with this byte order, and all
16-bit and 32-bit quantities returned by the server will be
transmitted with this byte order.
Following the byte-order byte, the following information is sent by
the client at connection setup:
protocol-major-version: CARD16
protocol-minor-version: CARD16
authorization-protocol-name: STRING8
authorization-protocol-data: STRING8
The version numbers indicate what version of the protocol the
client expects the server to implement. See below for an
explanation. The authorization name indicates what
authorization protocol the client expects the server to use,
and the data is specific to that protocol. Specification of
valid authorization mechanisms is not part of the core X
protocol. It is hoped that eventually one authorization
protocol will be agreed upon. In the mean time, a server
that implements a different protocol than the client expects,
or a server that only implements the host-based mechanism,
will simply ignore this information.
Received by the client at connection setup:
success: BOOL
protocol-major-version: CARD16
protocol-minor-version: CARD16
length: CARD16
Length is the amount of additional data to follow, in units
of 4 bytes. The version numbers are an escape hatch in case
future revisions of the protocol are necessary. In general,
the major version would increment for incompatible changes,
and the minor version would increment for small upward
compatible changes. Barring changes, the major version
will be eleven, and the minor version will be zero. The
protocol version numbers returned indicate the protocol the
server actually supports. This might not equal the version
sent by the client. The server can (but need not) refuse
connections from clients that offer a different version
than the server supports. A server can (but need not)
support more than one version simultaneously.
Additional data received if authorization fails:
reason: STRING8
Additional data received if authorization is accepted:
vendor: STRING8
release-number: CARD32
resource-id-base, resource-id-mask: CARD32
image-byte-order: {LSBFirst, MSBFirst}
bitmap-format-scanline-unit: {8, 16, 32}
bitmap-format-scanline-pad: {8, 16, 32}
bitmap-format-bit-order: {LeastSignificant, MostSignificant}
pixmap-formats: LISTofFORMAT
roots: LISTofSCREEN
keyboard: DEVICE
pointer: DEVICE
motion-buffer-size: CARD32
maximum-request-length: CARD16
where
FORMAT: [depth: CARD8,
bits-per-pixel: {4, 8, 16, 24, 32}
scanline-pad: {8, 16, 32}]
SCREEN: [root: WINDOW
device: DEVICE
width-in-pixels, height-in-pixels: CARD16
width-in-millimeters,height-in-millimeters:CARD16
allowed-depths: LISTofDEPTH
root-depth: CARD8
root-visual: VISUALID
default-colormap: COLORMAP
white-pixel, black-pixel: CARD32
min-installed-maps, max-installed-maps: CARD16
backing-stores: {Never, WhenMapped, Always}
save-unders: BOOL
current-input-masks: SETofEVENT]
DEPTH: [depth: CARD8
visuals: LISTofVISUALTYPE]
VISUALTYPE: [visual-id: VISUALID
class: {StaticGray, StaticColor,
TrueColor,GrayScale, PseudoColor,
DirectColor}
red-mask, green-mask, blue-mask: CARD32
bits-per-rgb-value: CARD8
colormap-entries: CARD16]
Per server information:
The vendor string gives some indentification of the owner of the
server implementation. The semantics of the release-number is
controlled by the vendor.
The resource-id-mask contains a single contiguous set of bits (at
least 18); the client allocates resource ids by choosing a value
with (only) some subset of these bits set, and ORing it with
resource-id-base. Only values constructed in this way can be
used to name newly created resources over this connection.
Resource ids never have the top 3 bits set. The client is not
restricted to linear or contiguous allocation of resource ids.
Once an id has been freed, it can be reused, but this should not
be necessary. An id must be unique with respect to the ids of
all other resources, not just other resources of the same type.
Although the server is in general responsible for byte swapping
data to match the client, images are always transmitted and
received in formats (including byte order) specified by the
server. The byte order for images is given by image-byte-order,
and applies to each scanline unit in XYFormat (bitmap) format,
and to each pixel value in ZFormat.
A bitmap is represented in scanline order. Each scanline is padded
to a multiple of bits as given by bitmap-format-scanline-pad. The
pad bits are of arbitrary value. The scanline is quantized in
multiples of bits as given by bitmap-format-scanline-unit. Within
each unit, the leftmost bit in the bitmap is either the least or
most significant bit in the unit, as given by
bitmap-format-bit-order. If a pixmap is represented in XYFormat,
each plane is represented as a bitmap, and the planes appear from
most to least significant in bit order.
For each pixmap depth supported by some screen, pixmap-formats lists
the ZFormat used to represent images of that depth. In ZFormat, the
pixels are in scanline order, left to right within a scanline. The
number of bits used to hold each pixel is given by bits-per-pixel,
and may be larger than strictly required by the depth. When the
bits-per-pixel is 4, the order of nibbles in the byte is the same as
the image byte-order. Each scanline is padded to a multiple of bits
as given by scanline-pad.
How a pointing device roams the screens is up to the server
implementation, and is transparent to the protocol. No geometry
among screens is defined.
The server may retain the recent history of pointer motion, and to a
finer granularity than is reported by MotionNotify events. Such
history is available via the GetPointerMotions request. The
approximate size of the history buffer is given by
motion-buffer-size.
Maximum-request-length specifies the maximum length of a request, in
4-byte units, accepted by the server; i.e., this is the maximum value
that can appear in the length field of a request. Requests larger
than this generate a Length error, and the server will read and
simply discard the entire request. Maximum-request-length will
always be at least 4096 (i.e., requests of length up to and including
16384 bytes will be accepted by all servers).
Per screen information:
The allowed-depths specifies what pixmap and window depths are
supported. Pixmaps are supported for each depth listed, and windows
of that depth are supported if at least one visual type is listed for
the depth. A pixmap depth of one is always supported and listed, but
windows of depth one might not be supported. A depth of zero is
never listed, but zero-depth InputOnly windows are always supported.
Root-depth and root-visual specify the depth and visual type of the
root window. Width-in-pixels and height-in-pixels specify the size
of the root window (which cannot be changed). The class of the root
window is always InputOutput. Width-in-millimeters and
height-in-millimeters can be used to determine the physical size and
the aspect ratio.
The default-colormap is the one initially associated with the root
window. Clients with minimal color requirements creating windows of
the same depth as the root may want to allocate from this map by
default.
Black-pixel and white-pixel can be used in implementing a
"monochrome" application. These pixel values are for permanently
allocated entries in the default-colormap; the actual RGB values may
be settable on some screens.
The border of the root window is initially a pixmap filled with the
black-pixel. The initial background of the root window is a pixmap
filled with some unspecified two-color pattern using black-pixel and
white-pixel.
Min-installed-maps specifies the number of maps that can be
guaranteed to installed simultaneously (with InstallColormap),
regardless of the number of entries allocated in each map.
Max-installed-maps specifies the maximum number of maps that might
possibly be installed simultaneously, depending on their
allocations. For the typical case of a single hardware colormap,
both values will be one.
Backing-stores indicates when the server supports backing stores for
this screen, although it may be storage limited in the number of
windows it can support at once. If save-unders is True, then the a
server can support the save-under mode in CreateWindow and
ChangeWindowAttributes, although again it may be storage limited.
The current-input-events is what GetWindowAttributes would return for
the all-event-masks for the root window.
Per visual-type information:
A given visual type might be listed for more than one depth, or for
more than one screen.
For PseudoColor, a pixel value indexes a colormap to produce
independent RGB values; the RGB values can be changed dynamically.
GrayScale is treated the same as PseudoColor, except which primary
drives the screen is undefined, so the client should always store
the same value for red, green, and blue in colormaps. For
DirectColor, a pixel value is decomposed into separate RGB
subfields, and each subfield separately indexes the colormap for
the corresponding value; The RGB values can be changed dynamically.
TrueColor is treated the same as DirectColor, except the colormap
has predefined read-only RGB values, which are server-dependent,
but provide (near-)linear ramps in each primary. StaticColor is
treated the same as PseudoColor, except the colormap has
predefined read-only RGB values, which are server-dependent.
StaticGray is treated the same as StaticColor, except the red,
green, and blue values are equal for any single pixel value,
resulting in shades of gray. StaticGray with a two-entry colormap
can be thought of as "monochrome".
The red-mask, green-mask, and blue-mask are only defined for
DirectColor and TrueColor; each has one contiguous set of bits, with
no intersections.
The bits-per-rgb-value specifies the log base 2 of the approximate
number of distinct color values (individually) of red, green, and
blue. Actual RGB values are always passed in the protocol within a
16-bit spectrum.
The colormap-entries defines the number of available colormap entries
in a newly created colormap. For DirectColor and TrueColor, this
will usually be the size of an individual pixel subfield.
SECTION 10. REQUESTS
CreateWindow
wid, parent: WINDOW
class: {InputOutput, InputOnly, CopyFromParent}
depth: CARD8
visual: VISUALID or CopyFromParent
x, y: INT16
width, height, border-width: CARD16
value-mask: BITMASK
value-list: LISTofVALUE
Errors: IDChoice, Window, Pixmap, Colormap, Cursor, Match,
Value, Alloc
Creates an unmapped window, and assigns the identifier wid
to it.
A class of CopyFromParent means the class is taken from the
parent. A depth of zero for class InputOutput or
CopyFromParent means the depth is taken from the parent.
A visual of CopyFromParent means the visual type is taken
from the parent. For class InputOutput, the visual type
and depth must be a combination supported for the screen
(else a Match error); the depth need not be the same as the
parent, but the parent must not be of class InputOnly (else
a Match error). For class InputOnly, the depth must be
zero (else a Match error), and the visual must be one
supported for the screen (else a Match error), but the
parent may have any depth and class.
The server essentially 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 (as a source or destination for
graphics requests). InputOnly and InputOutput windows act
identically in other respects (properties, grabs, input
control, and so on).
The window is placed on top in the stacking order with
respect to siblings. The x and y coordinates are relative
to the parent's origin, and specify the position of the upper
left outer corner of the window (not the origin). The width
and height specify the inside size, not including the border,
and must be non-zero. The border-width for an InputOnly
window must be zero (else a Match error).
The value-mask and value-list specify attributes of the
window that are to be explicitly initialized. The possible
values are:
background-pixmap: PIXMAP or None or ParentRelative
background-pixel: CARD32
border-pixmap: PIXMAP or CopyFromParent
border-pixel: CARD32
bit-gravity: BITGRAVITY
win-gravity: WINGRAVITY
backing-store: {NotUseful, WhenMapped, Always}
backing-bit-planes: CARD32
backing-pixel: CARD32
save-under: BOOL
event-mask: SETofEVENT
do-not-propagate-mask: SETofDEVICEEVENT
override-redirect: BOOL
colormap: COLORMAP or CopyFromParent
cursor: CURSOR or None
The default values, when attributes are not explicitly
initialized, are:
background-pixmap: None
border-pixmap: CopyFromParent
bit-gravity: Forget
win-gravity: NorthWest
backing-store: NotUseful
backing-bit-planes: all ones
backing-pixel: zero
save-under: False
event-mask: {} (empty set)
do-not-propagate-mask: {} (empty set)
override-redirect: False
colormap: CopyFromParent
cursor: None
Only the following attributes are defined for InputOnly
windows: win-gravity, event-mask, do-not-propagate-mask,
and cursor. It is a Match error to specify any other
attributes for InputOnly windows.
If background-pixmap is given, it overrides the default
background-pixel. The background pixmap and the window must
have the same root and the same depth (else a Match error).
Any size pixmap can be used, although some sizes may be
faster than others. If background None is specifed, the
window has no defined background. If background
ParentRelative is specified, the parent's background is
used, but the window must have the same depth as the parent
(else a Match error); if the parent has background None,
then the window will also have background None. A copy
of the parent's background is not made; the parent's
background is reexamined each time the window background is
required. If background-pixel is given, it overrides the
default and any background-pixmap given, and a pixmap of
undefined size filled with background-pixel is used for the
background. For a ParentRelative background, the
background tile origin always aligns with the parent's
background tile origin; otherwise the background tile
origin is always the window origin.
When regions of the window are exposed and the server has
not retained the contents, the server automatically tiles
the regions with the window's background unless the window
has a background of None, in which case the previous screen
contents are simply left in place. Exposure events are then
generated for the regions, even if the background is None.
The border tile origin is always the same as the background
tile origin. If border-pixmap is given, it overrides the
default border-pixel. The border pixmap and the window must
have the same root and the same depth (else a Match error).
Any size pixmap can be used, although some sizes may faster
than others. If CopyFromParent is given, the parent's border
pixmap is copied (subsequent changes to the parent do not
affect the child), but the window must have the same depth
as the parent (else a Match error). If border-pixel is
given, it overrides the default and any border-pixmap given,
and a pixmap of undefined size filled with border-pixel is
used for the border.
Output to a window is always clipped to the inside of the
window, so that the border is never affected.
The bit-gravity defines which region of the window should be
retained if the window is resized, and win-gravity defines
how the window should be repositioned if the parent is
resized; see ConfigureWindow.
A backing-store of WhenMapped advises the server that
maintaining contents of obscured regions when the window
is mapped would be beneficial. A backing-store of Always
advises the server that maintaining contents even when the
window is unmapped would be beneficial. Note that, even if
the window is larger than its parent, the server should
maintain complete contents, not just the region within the
parent boundaries. If the server maintains contents,
Exposure events will not be generated, but the server may
stop maintaining contents at any time. A value of NotUseful
advises the server that maintaining contents is unnecessary,
although a server may still choose to maintain contents.
Backing-bit-planes indicates (with one bits) which bit
planes of the window hold dynamic data that must be preserved
in backing-stores. Backing-pixel specifies what value to use
in planes not covered by backing-bit-planes. The server is
free to only save the specified bit planes in the
backing-store, and regenerate the remaining planes with the
specified pixel value.
If save-under is True, the server is advised that, when
this window is mapped, saving the contents of windows it
obscures would be beneficial.
The event-mask defines which events the client is interested
in for this window (or, for some event types, inferiors of
the window). The do-not-propagate-mask defines which events
should not be propagated to ancestor windows when no client
has the event type selected in this window.
Override-redirect specifies whether map and configure
request on this window should override a SubstructureRedirect
on the parent, typically to inform a window manager not to
tamper with the window.
The colormap specifies the colormap, that best reflects the
"true" colors of the window. Servers capable of supporting
hardware colormaps may use this information, and window
managers may use it for InstallColormap requests. The
colormap must have the same visual type as the window
(else a match error). If CopyFromParent is specified, the
parents's colormap is copied (subsequent changes to the
parent do not affect the child), but the window must have
the same visual type as the parent (else a Match error) an
the parent must not have a colormap of None (else a Match
error).
If a cursor is specified, it will be used whenever the
pointer is in the window. If None is specified, the
parent's cursor will be used when the pointer is in the
window, and any change in the parent's cursor will
cause an immediate change in the display cursor.
This request generates a CreateNotify event.
The background and border pixmaps and the cursor may be
freed immediately if no further explicit references to
them are to be made.
Subsequent drawing into the background or border pixmap has
an undefined effect on the window state; the server might or
might not make a copy of the pixmap.
ChangeWindowAttributes
window: WINDOW
value-mask: BITMASK
value-list: LISTofVALUE
Errors: Window, Pixmap, Colormap, Cursor, Match, Value,
Access
The value-mask and value-list specify which attributes are
to be changed. The values and restrictions are the same
as for CreateWindow.
Changing the background does not cause the window contents
to be changed. Setting the border, or changing the
background such that border tile origin changes, causes the
border to be repainted. Changing the background of a root
window to None or ParentRelative restores the default
background pixmap. Changing the border of a root window to
CopyFromParent restores the default border pixmap.
Changing the back-store of an obsecured window to
WhenMapped or Always, or changing the backing-bit-planes,
backing-pixel, or save-under of a mapped window, may have
no immediate effect.
Multiple clients can select input on the same window; their
event-masks are disjoint. When an event is generated it
will be reported to all interested clients. However, at
most one client at a time can select for
SubstructureRedirect, at most one client at a time can
select for ResizeRedirectr, and at most one client at a
time can select for ButtonPress.
There is only one do-not-propagate-mask for a window, not
one per client.
Changing the colormap of a window (i.e., defining a new map,
not changing the contents of the existing map) generates a
ColormapNorify event. Changing the colormap os a visible
window may have no immediate effect on the screen; see
InstallColormap.
Changing the cursor of a root window to None restores the
default cursor.
The order in which attributes are verified and altered is
server dependent. If an error is generated, a subset of
the attributes may have been altered.
GetWindowAttributes
window: WINDOW
=>
visual: VISUALID
class: {InputOutput, InputOnly}
bit-gravity: BITGRAVITY
win-gravity: WINGRAVITY
backing-store: {NotUseful, WhenMapped, Always}
backing-bit-planes: CARD32
backing-pixel: CARD32
save-under: BOOL
colormap: COLORMAP or None
map-is-installed: BOOL
map-state: {Unmapped, Unviewable, Viewable}
all-event-masks, your-event-mask: SETofEVENT
do-not-propagate-mask: SETofDEVICEEVENT
override-redirect: BOOL
Errors: Window
Returns current attributes of the window. All-event-masks
is the inclusive-OR of all event masks selected on the
window by clients. Your-event-mask is the event mask
selected by the querying client.
DestroyWindow
window: WINDOW
Errors: Window
If the argument window is mapped, an UnmapWindow request is
performed automatically. The window and all inferiors are
then destroyed, and a DestroyNotify event is generated for
each window, in order from the argument window downwards,
with unspecified order among siblings at each level.
Normal exposure processing on formerly obscured windows is
performed.
If the window is a root window, this request has no effect.
DestroySubwindows
window: WINDOW
Errors: Window
Performs a DestroyWindow on all children of the window, in
bottom to top stacking order.
ChangeSaveSet
window: WINDOW
mode: {Insert, Delete}
Errors: Window, Match, Value
Adds or removes the specified window from the client's
"save-set". The window must have been created by some other
client (else a Match error). The use of the save-set is
described in Section 11.
Windows are removed automatically from the save-set by the
server when they are destroyed.
ReparentWindow
window, parent: WINDOW
x, y: INT16
Errors: Window, Match
If the window is mapped, an UnmapWindow request is
performed automatically first. The window is then removed
from its current position in the hierarchy, and is inserted
as a child of the specified parent. The x and y coordinates
are relative to the parent's origin, and specify the new
position of the upper left outer corner of the window. The
window is placed on top in the stacking order with respect
to siblings. A ReparentNotify event is then generated. The
override-redirect attribute of the window is passed on in
this event; a value of True indicates that a window manager
should not tamper with this window. Finally, if the window
was originally mapped, a MapWindow request is performed
automatically.
Normal exposure processing on formerly obscured windows is
performed. The server might not generate exposure events for
regions from the initial unmap that are immediately obscured
by the final map.
A Match error is generated if the new parent is not on the
same screen as the old parent, or if the new parent is the
window itself or an inferior of the window, or if the window
has a ParentRelative background and the new parent is not
the same depth as the window.
MapWindow
window: WINDOW
Errors: Window
If the window is already mapped, this request has no effect.
If the override-redirect attribute of the window is False and
some other client has selected SubstructureRedirect on the
parent, then a MapRequest event is generated, but the window
remains unmapped. Otherwise, the window is mapped and a
MapNotify event is generated.
If the window is now viewable and its contents had been
discarded, then the window is tiled with its background (if
no background is defined the existing screen contents are not
altered) and one or more exposure events are generated. If a
backing-store has been maintained while the window was
unmapped, no exposure events are generated. If a
backing-store will now be maintained, a full-window exposure
is always generated; otherwise only visible regions may be
reported. Similar tiling and exposure take place for any
newly viewable inferiors.
MapSubwindows
window: WINDOW
Errors: Window
Performs a MapWindow request on all unmapped children of the
window, in top to bottom stacking order.
UnmapWindow
window: WINDOW
Errors: Window
If the window is already unmapped, this request has no
effect. Otherwise, the window is unmapped and an UnmapNotify
event is generated. Normal exposure processing on formerly
obscured windows is performed.
UnmapSubwindows
window: WINDOW
Errors: Window
Performs an UnmapWindow request on all mapped children of the
window, in bottom to top stacking order.
ConfigureWindow
window: WINDOW
value-mask: BITMASK
value-list: LISTofVALUE
Errors: Window, Match, Value
Changes the configuration of the window. The value-mask and
value-list specify which values are to be given. The
possible values are:
x: INT16
y: INT16
width: CARD16
height: CARD16
border-width: CARD16
sibling: WINDOW
stack-mode: {Above, Below, TopIf, BottomIf, Opposite}
The x and y coordinates are relative to the parent's origin,
and specify the position of the upper left outer corner of
the window. The width and height specify the inside size,
not including the border, and must be non-zero. It is a
Match error to attempt to make the border-width of an
InputOnly window non-zero.
If the override-redirect attribute of the window is False
and some other client has selected SubstructureRedirect on
the parent, then a ConfigureRequest event is generated, and
no further processing is performed. Otherwise, the following
is performed.
If some other client has selected ResizeRedirect on the
window and the width or height of the window is being
changed, then a ResizeRequest event is generated, and the
current width and height are used instead in the following.
The geometry of the window is changed as specified and the
window is restacked among siblings as described below, and a
ConfigureNotify event is generated. If the width or height
of the window has actually changed, then children of the
window are affected as described below.
Exposure processing is performed on formerly obscured
windows.
Changing the width or height of the window causes its
contents to be moved or lost, depending on the bit-gravity of
the window, and causes children to be reconfigured, depending
on their win-gravity. For a change of width and height of W
and H, we define the [x, y] pairs:
NorthWest: [0, 0]
North: [W/2, 0]
NorthEast: [W, 0]
West: [0, H/2]
Center: [W/2, H/2]
East: [W, H/2]
SouthWest: [0, H]
South: [W/2, H]
SouthEast: [W, H]
When a window with one of these bit-gravities is resized, the
corresponding pair defines the change in position of each
pixel in the window. When a window with one of these
win-gravities has its parent window resized, the
corresponding pair defines the change in position of the
window within the parent. When a window is so repositioned,
a GravityNotify event is generated.
A gravity of Static indicates that the contents or origin
should not move relative to the origin of the root window. If
the change in size of the window is coupled with a change in
position of [X, Y], then for bit-gravity the change in
position of each pixel is [-X, -Y], and for win-gravity the
change in position of a child when its parent is so resized
is [-X, -Y]. Note that Static gravity still only takes
effect when the width or height of the window is changed, not
when the window is simply moved.
A bit-gravity of Forget indicates that the window contents
are always discarded after a size change; the window is tiled
with its background (if no background is defined, the
existing screen contents are not altered) and one or more
exposure events are generated. A server may also ignore the
specified bit-gravity and use Forget instead.
A win-gravity of Unmap is like NorthWest, but the child is
also unmapped when the parent is resized, and an UnmapNotify
event is generated.
If a sibling and a stack-mode is specified, the window is
restacked as follows:
Above: window is placed just above sibling
Below: window is placed just below sibling
TopIf: if sibling occludes window, then window is placed
at the top of the stack
BottomIf: if window occludes sibling, then window is
placed at the bottom of the stack
Opposite: if sibling occludes window, then window is
placed at the top of the stack, else if window
occludes sibling, then window is placed at the
bottom of the stack
If a stack-mode is specified but no sibling is specified, the
window is restacked as follows:
Above: window is placed at the top of the stack
Below: window is placed at the bottom of the stack
TopIf: if any sibling occludes window, then window is
placed at the top of the stack
BottomIf: if window occludes any sibling, then window is
placed at the bottom of the stack
Opposite: if any sibling occludes window, then window is
placed at the top of the stack, else if window
occludes any sibling, then window is placed at
the bottom of the stack
It is a Match error if a sibling is specified without a
stack-mode, or if the window is not actually a sibling.
Note that the computations for BottomIf, TopIf, and Opposite
are performed with respect to the window's final geometry
(as controlled by the other arguments to the request), not
its initial geometry.
CirculateWindow
window: WINDOW
direction: {RaiseLowest, LowerHighest}
Errors: Window, Value
If some other client has selected SubstructureRedirect on the
window, then a CirculateRequest event is generated, and no
further processing is performed. Otherwise, the following is
performed, and then a CirculateNotify event is generated if
the window is actually restacked.
For RaiseLowest, raises the lowest mapped child (if any) that
is occluded by another child to the top of the stack. For
LowerHighest, lowers the highest mapped child (if any) that
occludes another child to the bottom of the stack. Exposure
processing is performed on formerly obscured windows.
GetGeometry
drawable: DRAWABLE
=>
root: WINDOW
depth: CARD8
x, y: INT16
width, height, border-width: CARD16
Errors: Drawable
Returns the root and (current) geometry of the drawable.
Depth is the number of bits per pixel for the object.
X, y, and border-width will always be zero for pixmaps.
For a window, the x and y coordinates specify the upper
left outer corner of the window relative to its parent's
origin, and the width and height specify the inside size
(not including the border).
It is legal to pass an InputOnly window as a drawable to
this request.
QueryTree
window: WINDOW
=>
root: WINDOW
parent: WINDOW or None
children: LISTofWINDOW
Errors: Window
Returns the root, the parent, and children of the window.
The children are listed in bottom-to-top stacking order.
InternAtom
name: STRING8
only-if-exists: BOOL
=>
atom: ATOM or None
Errors: Value, Alloc
Returns the atom for the given name. If only-if-exists is
False, then the atom is created if it does not exist. The
string should use the ASCII encoding, and upper/lower case
matters.
The lifetime of an atom is not tied to the interning client.
Atoms remained defined until server reset (see Section 11).
GetAtomName
atom: ATOM
=>
name: STRING8
Errors: Atom
Returns the name for the given atom.
ChangeProperty
window: WINDOW
property, type: ATOM
format: {8, 16, 32}
mode: {Replace, Prepend, Append}
data: LISTofINT8 or LISTofINT16 or LISTofINT32
Errors: Window, Atom, Value, Match, Alloc
Alters the property for the specified window. The type is
uninterpreted by the server. The format specifies whether
the data should be viewed as a list of 8-bit, 16-bit, or
32-bit quantities, so that the server can correctly
byte-swap as necessary.
If mode is Replace, the previous property value is discarded.
If the mode is Prepend or Append, then the type and format
must match the existing property value (else a Match error);
if the property is undefined, it is treated as defined with
the correct type and format with zero-length data. For
Prepend, the data is tacked on to the beginning of the
existing data, and for Append it is tacked on to the
end of the existing data.
Generates a PropertyNotify event on the window.
The lifetime of a property is not tied to the storing client.
Properties remain until explicitly deleted, or the window is
destroyed, or until server reset (see Section 11).
The maximum size of a property is server dependent.
DeleteProperty
window: WINDOW
property: ATOM
Errors: Window, Atom
Deletes the property from the specified window if the
property exists. Generates a PropertyNotify event on the
window unless the property does not exist.
GetProperty
window: WINDOW
property: ATOM
type: ATOM or AnyPropertyType
long-offset, long-length: CARD32
delete: BOOL
=>
type: ATOM
format: {8, 16, 32}
bytes-after: CARD32
value: LISTofINT8 or LISTofINT16 or LISTofINT32
Errors: Window, Atom, Property, Match, Value
If the specified property does not exist for the specifed
window, a Property error is generated. Otherwise, if type
AnyPropertyType is specified, (part of) the property is
returned regardless of its type; if a type is specified,
(part of) the property is returned only if its type equals
the specified type (else a Match error). The actual type
and format of the property are returned.
Define the following values:
N = actual length of the stored property in bytes
(even if the format is 16 or 32)
I = 4 * long-offset
T = N - I
L = MINIMUM(T, 4 * long-length)
A = N - (I + L)
The returned value starts at byte index I in the property
(indexing from 0), and its length in bytes is L. It is a
Value error if long-offset is given such that L is negative.
The value of bytes-after is A, giving the number of trailing
unread bytes in the stored property.
If delete is True and bytes-after is zero, the property is
also deleted from the window and a PropertyNotify event is
generated on the window.
RotateProperties
window: WINDOW
delta: INT8
properties: LISTofATOM
Errors: Window, Atom, Match
If the property names in the list are viewed as being
numbered starting from zero, and there are N property names
in the list, then the value associated with property name I
becomes the value associated with property name (I + delta)
mod N, for all I from zero to N - 1. The effect is to rotate
the states by delta places around the virtual ring of
property names (right for positive delta, left for negative
delta).
A PropertyNotify event is generated for each property, in the
order listed.
If an atom occurs more than once in the list or no property
with that name is defined for the window, a Match error is
generated. If an Atom or Match error is generated, no
properties are changed.
ListProperties
window: WINDOW
=>
atoms: LISTofATOM
Errors: Window
Returns the atoms of properties currently defined on the
window.
SetSelectionOwner
selection: ATOM
owner: WINDOW or None
time: TIMESTAMP or CurrentTime
Error: Atom, Window
Changes the owner and last-change time of the specifed
selection. The request has no effect if the specified time
is earlier than the current last-change time of the specified
selection or is later than the current server time;
otherwise, the last-change time is set to the specified time,
with CurrentTime replaced by the current server time.
If the new owner is not the same as the current owner of the
selection, and the current owner is a window, then the
current owner is sent a SelectClear event.
If the owner of a selection is a window, and the window is
later destroyed, the owner of the selection automatically
reverts to None, but the last-change time is not affected.
The selection atom is uninterpreted by the server.
Selections are global to the server.
GetSelectionOwner
selection: ATOM
=>
owner: WINDOW or None
Errors: Atom
Returns the current owner of the specified selection, if any.
ConvertSelection
selection, target: ATOM
property: ATOM or None
requestor: WINDOW
time: TIMESTAMP or CurrentTime
Error: Atom, Window
If the specified selection is owned by a window, the server
sends a SelectionRequest event to the owner. If no owner for
the specified selection exists, the server generates a
SelectionNotify event to the requestor with property None.
The arguments are passed on unchanged in either event.
SendEvent
destination: WINDOW or PointerWindow or InputFocus
propagate: BOOL
event-mask: SETofEVENT
event: <normal-event-format>
Errors: Window, Value
If PointerWindow is specified, destination is replaced with
the window that the pointer is in. If InputFocus is
specified, then if the focus window contains the pointer,
destination is replaced with the window that the pointer is
in, and otherwise destination is replaced with the focus
window.
If propagate is False, then the event is sent to every client
selecting on destination any of the event types in
event-mask.
If propagate is True and no clients have selected on
destination any of the event types in event-mask, then
destination is replaced with the closest ancestor of
destination for which some client has selected a type in
event-mask and no intervening window has that type in its
do-not-propagate-mask. If no such window exists, or if the
window is an ancestor of the focus window and InputFocus was
originally specified sent to any clients. Otherwise, the
event is reported to every client selecting on the final
destination any of the types specified in event-mask.
The event code must be one of the core events, or one of
the events defined by an extension, so that the server can
correctly byte swap the contents as necessary. The
contents of the event are otherwise unaltered and unchecked
by the server except to force on the most significant bit
of the event code.
Active grabs are ignored for this request.
GrabPointer
grab-window: WINDOW
owner-events: BOOL
event-mask: SETofPOINTEREVENT
pointer-mode, keyboard-mode: {Synchronous, Asynchronous}
confine-to: WINDOW or None
cursor: CURSOR or None
time: TIMESTAMP or CurrentTime
=>
status: {Success, AlreadyGrabbed, Frozen, InvalidTime,
NotViewable}
Errors: Cursor, Window, Value
Actively grabs control of the pointer. Further pointer
events are only reported to the grabbing client. The
request overrides any active pointer grab by this client.
Event-mask is always augmented to include ButtonPress and
ButtonRelease. If owner-events is False, all generated
pointer events are reported with respect to grab-window,
and are only reported if selected by event-mask. If
owner-events is True, then if a generated pointer event
would normally be reported to this client, it is reported
normally; otherwise the event is reported with respect to
the grab-window, and is only reported if selected by
event-mask. For either value of owner-events, unreported
events are simply discarded.
Pointer-mode controls further processing of pointer events,
and keyboard-mode controls further processing of keyboard
events. If the mode is Asynchronous, event processing
continues normally; if the device is currently frozen by
this client, then processing of events for the device is
resumed. If the mode is Synchronous, the device (as seen
via the protocol) appears to freeze, and no further events
for that device are generated by the server until the
grabbing client issues a releasing AllowEvents request.
Actual device changes are not lost while the device is
frozen; they are simply queued for later processing.
If a cursor is specified, then it is displayed regardless
of what window the pointer is in. If no cursor is
specified, then when the pointer is in grab-window or one
of its subwindows, the normal cursor for that window is
displayed, and otherwise the cursor for grab-window is
displayed.
If a confine-to window is specified, then the pointer
will be restricted to stay contained in that window.
The confine-to window need have no relationship to the
grab-window. If the pointer is not initially in the
confine-to window, then it is warped automatically to
the closest edge (and enter/leave events generated
normally) just before the grab activates. If the
confine-to window is subsequently reconfigured, the
pointer will be warped automatically as necessary to keep
it contained in the window.
This request generates EnterNotify and LeaveNotify events.
The request fails with status AlreadyGrabbed if the
pointer is actively grabbed by some other client. The
request fails with status Frozen if the pointer is frozen
by an active grab of another client. The request fails
with status NotViewable if grab-window or
confine-to window is not viewable. The request fails with
status InvalidTime if the specified time is earlier than
the last-pointer-grab time or later than the current
server time; otherwise the last-pointer-grab time is set
to the specified time, with CurrentTime replaced by the
current server time.
UngrabPointer
time: TIMESTAMP or CurrentTime
Releases the pointer if this client has it actively
grabbed (from either GrabPointer or GrabButton or from a
normal button press), and releases any queued events. The
request has no effect if the specified time is earlier
than the last-pointer-grab time or is later than the
current server time.
This request generates EnterNotify and LeaveNotify events.
An UngrabPointer is performed automatically if the event
window or confine-to window for an active pointer grab
becomes not viewable.
GrabButton
modifiers: SETofKEYMASK or AnyModifier
button: BUTTON or AnyButton
grab-window: WINDOW
owner-events: BOOL
event-mask: SETofPOINTEREVENT
pointer-mode, keyboard-mode: {Synchronous, Asynchronous}
confine-to: WINDOW or None
cursor: CURSOR or None
Errors: Cursor, Window, Value, Access
This request establishes a passive grab. In the future,
if the specified button is pressed when the specified
modifier keys are down (and no other buttons or modifier
keys are down), and grab-window contains the pointer,
and the confine-to window (if any) is viewable, and these
constraints are not satisfied for any ancestor, then the
pointer is actively grabbed as described in GrabPointer,
the last-pointer-grab time is set to the time at which
the button was pressed (as transmitted in the ButtonPress
event), and the ButtonPress event is reported. The
interpretation of the remaining arguments is as for
GrabPointer. The active grab is terminated automatically
when all buttons are released (independent of the state
of modifier keys).
A modifiers of AnyModifier is equivalent to issuing the
request for all possible modifier combinations. A
button of AnyButton is equivalent to issuing the request
for all possible buttons.
An Access error is generated if some other client has
already issued a GrabButton with the same button/key
combination on the same window. When using AnyModifier
or AnyButton, the request fails completely (no grabs are
established) if there is a combination. The request has
no effect on an active grab.
UngrabButton
modifiers: SETofKEYMASK or AnyModifier
button: BUTTON or AnyButton
grab-window: WINDOW
Errors: Window
Releases the passive button/key combination on the
specified window if it was grabbed by this client. A
modifiers of AnyModifier is equivalent to issuing the
request for all possible modifier combinations. A
button of AnyButton is equivalent to issuing the request
for all possible buttons. Has no effect on an active
grab.
ChangeActivePointerGrab
event-mask: SETofPOINTEREVENT
cursor: CURSOR or None
time: TIMESTAMP or CurrentTime
Errors: Cursor
Changes the specified dynamic parameters if the pointer
is actively grabbed by the client and the specified time
is no earlier than the last-pointer-grab time and no
later than the current server time. The interpretation
of event-mask and cursor are as in GrabPointer. The
event-mask is always augmented to include ButtonPress
and ButtonRelease. Has no effect on the passive
parameters of a GrabButton.
GrabKeyboard
grab-window: WINDOW
owner-events: BOOL
pointer-mode, keyboard-mode: {Synchronous, Asynchronous}
time: TIMESTAMP or CurrentTime
=>
status: {Success, AlreadyGrabbed, Frozen, InvalidTime,
NotViewable}
Errors: Window, Value
Actively grabs control of the keyboard. Further key
events are reported only to the grabbing client. The
request overrides any active keyboard grab by this
client.
If owner-events is False, all generated key events are
reported with respect to grab-window. If owner-events is
True, then if a generated key event would normally be
reported to this client, it is reported normally;
otherwise the event is reported with respect to the
grab-window. Both KeyPress and KeyRelease events are
always reported, independent of any event selection made
by the client.
Pointer-mode controls further processing of pointer
events, and keyboard-mode controls further processing of
keyboard events. If the mode is Asynchronous, event
processing continues normally; if the device is currently
frozen by this client, then processing of events for the
device is resumed. If the mode is Synchronous, the
device (as seen via the protocol) appears to freeze, and
no further events for that device are generated by the
server until the grabbing client issues a releasing
AllowEvents request. Actual device changes are not lost
while the device is frozen; they are simply queued for
later processing.
This request generates FocusIn and FocusOut events.
The request fails with status AlreadyGrabbed if the
keyboard is actively grabbed by some other client. The
request fails with status Frozen if the keyboard is
frozen by an active grab of another client. The request
fails with status NotViewable if grab-window is not
viewable. The request fails with status InvalidTime if
the specified time is earlier than the last-keyboard-grab
time or later than the current server time; otherwise the
last-keyboard-grab time is set to the specified time,
with CurrentTime replaced by the current server time.
UngrabKeyboard
time: TIMESTAMP or CurrentTime
Releases the keyboard if this client has it actively
grabbed (from either GrabKeyboard or GrabKey), and
releases any queued events. The request has no effect
if the specified time is earlier than the
last-keyboard-grab time or is later than the current
server time.
This request generates FocusIn and FocusOut events.
An UngrabKeyboard is performed automatically if the event
window for an active keyboard grab becomes not viewable.
GrabKey
key: KEYCODE or AnyNonModifier
modifiers: SETofKEYMASK or AnyModifier
grab-window: WINDOW
owner-events: BOOL
pointer-mode, keyboard-mode: {Synchronous, Asynchronous}
Errors: Window, Value, Access
This request establishes a passive grab on the keyboard.
In the future, if the specified key (which can itself be a
modifier key) is pressed when the specified modifier keys
are down (and no other modifier keys are down), and the
KeyPress event would be generated in grab-window or one of
its inferiors, and these constraints are not satisfied for
any ancestor, then the keyboard is actively grabbed as
described in GrabKeyboard, the last-keyboard-grab time is
transmitted in set to the time at which the key was
pressed (as in the KeyPress event), and the KeyPress
event is reported. The interpretation of the remaining
arguments is as for GrabKeyboard. The active grab is
terminated automatically when the specified key has been
released (independent of the state of the modifier keys).
A modifiers of AnyModifier is equivalent to issuing the
request for all possible modifier combinations. A key of
AnyNonModifier is equivalent to issuing the request for
all possible non-modifier key codes.
An Access error is generated if some other client has
issued a GrabKey with the same key combination on the
same window. When using AnyModifier or AnyNonModifier,
the request fails completely (no grabs are established)
if there is a conflicting grab for any combination.
UngrabKey
key: KEYCODE or AnyNonModifier
modifiers: SETofKEYMASK or AnyModifier
grab-window: WINDOW
Errors: Window
Releases the key combination on the specified window if it
was grabbed by this client. A modifiers of AnyModifier is
equivalent to issuing the request for all possible
modifier combinations. A key of AnyNonModifier is
equivalent to issuing the request for all possible
non-modifier key codes. Has no effect on an active grab.
AllowEvents
mode: {AsyncPointer, SyncPointer, ReplayPointer,
AsyncKeyboard, SyncKeyboard, ReplayKeyboard}
time: TIMESTAMP or CurrentTime
Errors: Value
Releases some queued events if the client has caused a
device to freeze. The request has no effect if the
specified time is earlier than the last-grab time of the
most recent active grab for the client, or if the
specified time is later than the current server time.
For AsyncPointer, if the pointer is frozen by the client,
pointer event processing continues normally. If the
pointer is frozen twice by the client on behalf of two
separate grabs, AsyncPointer "thaws" for both.
AsyncPointer has no effect if the pointer is not frozen
by the client, but the pointer need not be grabbed by
the client.
For SyncPointer, if the pointer is frozen and actively
grabbed by the client, pointer event processing continues
normally until the next ButtonPress or ButtonRelease event
is reported to the client, at which time the pointer again
appears to freeze. However if the reported event causes
the pointer grab to be released, then the pointer does not
freeze. SyncPointer has no effect if the pointer is not
frozen by the client, or if the pointer is not grabbed by
the client.
For ReplayPointer, if the pointer is actively grabbed by
the client and is frozen as the result of an event having
been sent to the client (either from the activation of a
GrabButton, or from a previous AllowEvents with mode
SyncPointer, but not from a GrabPointer), then the pointer
grab is released and that event is completely reprocessed,
but this time ignoring any passive grabs at or above
(towards the root) the grab-window of the grab just
released. The request has no effect if the pointer is
not grabbed by the client, or if the pointer is not
frozen as the result of an event.
For AsyncKeyboard, if the keyboard is frozen by the
client, keyboard event processing continues normally. If
the pointer is frozen twice by the client on behalf of
two separate grabs, AsyncPointer "thaws" for both.
AsyncKeyboard has no effect if the keyboard is not
frozen by the client, but the keyboard need not be
grabbed by the client.
For SyncKeyboard, if the keyboard is frozen and actively
grabbed by the client, keyboard event processing
continues normally until the next KeyPress or KeyRelease
event is reported to the client, at which time the
keyboard again appears to freeze. However if the
reported event causes the keyboard grab to be released,
then the keyboard does not freeze. SyncKeyboard has no
effect if the keyboard is not frozen by the client, or
if the keyboard is not grabbed by the client.
For ReplayKeyboard, if the keyboard is actively grabbed
by the client and is frozen as the result of an event
having been sent to the client (either from the
activation of a GrabKey, or from a previous AllowEvents
with mode SyncKeyboard, but not from a GrabKeyboard),
then the keyboard grab is released and that event is
completely reprocessed, but this time ignoring any passive
grabs at or above (towards the root) the grab-window of
the grab just released. The request has no effect if the
keyboard is not grabbed by the client, or if the keyboard
is notfrozen as the result of an event.
AsyncPointer, SyncPointer, and Replay Pointer have no
effect on processing of keyboard events. AsyncKeyboard,
SyncKeyboard, and ReplayKeyboard have no effect on
processing of pointer events.
It is possible for both a pointer grab and a keyboard grab
to be active simultaneously (by the same or different
clients). If a device is frozen on behalf of either grab,
no event processing is performed for the device. It is
possible for a single device to be frozen due to both
grabs. In this case, the freeze must be released on
behalf of both grabs before events can again be
processed.
GrabServer
Disables processing of requests and close-downs on all
other connections (than the one this request arrived on).
UngrabServer
Restarts processing of requests and close-downs on other
connections.
QueryPointer
window: WINDOW
=>
root: WINDOW
child: WINDOW or None
same-screen: BOOL
root-x, root-y, win-x, win-y: INT16
mask: SETofKEYBUTMASK
Errors: Window
The root window the pointer is currently on, and pointer
coordinates relative to the root's origin, are returned.
If same-screen is False, then the pointer is not on the
same screen as the argument window, and child is None and
win-x and win-y are zero. If same-screen is True, then
win-x and win-y are the pointer coordinates relative to
the argument window's origin, and child is the child
containing the pointer, if any. The current state of the
modifier keys and the buttons are also returned.
GetMotionEvents
start, stop: TIMESTAMP or CurrentTime
window: WINDOW
=>
events: LISTofTIMECOORD
where
TIMECOORD: {x, y: CARD16
time: TIMESTAMP}
Error: Window
Returns all events in the motion history buffer that fall
between the specified start and stop times (inclusive)
and that have coordinates that lie within (including
borders) the specified window at its present placement.
The x and y coordinates are reported relative to the
origin of the window.
TranslateCoordinates
src-window, dst-window: WINDOW
src-x, src-y: INT16
=>
same-screen: BOOL
child: WINDOW or None
dst-x, dst-y: INT16
Errors: Window
The src-x and src-y coordinates are taken relative to
src-window's origin, and returned as dst-x and dst-y
coordinates relative to dst-window's origin. If
same-screen is False, then src-window and dst-window are
on different screens, and dst-x and dst-y are zero. If
the coordinates are contained in a mapped child of
dst-window, then that child is returned.
WarpPointer
src-window: WINDOW or None
dst-window: WINDOW
src-x, src-y: INT16
src-width, src-height: CARD16
dst-x, dst-y: INT16
Errors: Window
Moves the pointer to [dst-x, dst-y] relative to
dst-window's origin. If src-window is None, the move is
independent of the current pointer position, but if a
window is specified, the move only takes place if the
pointer is currently contained in a visible portion of
the specified rectangle of the src-window.
The src-x and src-y coordinates are relative to
src-window's origin. If src-height is zero, it is
replaced with the current height of src-window minus
src-y. If src-width is zero, it is replaced with the
current width of src-window minus src-x.
This request cannot be used to move the pointer outside
the confine-to window of an active pointer grab; an
attempt will only move the pointer as far as the closest
edge of the confine-to window.
SetInputFocus
focus: WINDOW or PointerRoot or None
revert-to: {Parent, PointerRoot, None}
time: TIMESTAMP or CurrentTime
Errors: Window, Value
Changes the input focus and the last-focus-change time.
The request has no effect if the specified time is earlier
than the current last-focus-change time or is later than
the current server time; otherwise, the last-focus-change
time is set to the specified time, with CurrentTime
replaced by the current server time.
If None is specified as the focus, all keyboard events are
discarded until a new focus window is set. In this case,
therevert-to argument is ignored.
If a window is specified as the focus, it becomes the
keyboard's focus window. If a generated keyboard event
would normally be reported to this window or one of its
inferiors, the event is reported normally; otherwise, the
event is reported with respect to the focus window.
If PointerRoot is specified as the focus, the focus
window is dynamically taken to be the root window of
whatever screen the pointer is on at each keyboard event.
In this case, the revert-to argument is ignored.
This request generates FocusIn and FocusOut events.
If the focus window becomes not viewable, the new focus
window depends on the revert-to argument. If revert-to
is Parent, the focus reverts to the parent (or the
closest viewable ancestor) and the new revert-to value is
take to be None. If revert-to is PointerRoot or None,
the focus reverts to that value. When the focus reverts,
FocusIn and FocusOut events are generated, but the
last-focus-change time is not affected.
GetInputFocus
=>
focus: WINDOW or PointerRoot or None
revert-to: {Parent, PointerRoot, None}
Returns the current focus state.
QueryKeymap
=>
keys: LISTofCARD8
Returns a bit vector for the keyboard; each one bit
indicates that the corresponding key is currently pressed.
The vector is represented as 32 bytes. Byte N (from 0)
contains the bits for keys 8N to 8N+7, with the least
significant bit in the byte representing key 8N.
OpenFont
fid: FONT
name: STRING8
Errors: IDChoice, Name, Alloc
Loads the specified font, if necessary, and associates
identifier fid with it. The font can be used as a source
for any drawable. The font name should use the ASCII
encoding, and upper/lower case does not matter.
CloseFont
font: FONT
Errors: Font
Deletes the association between the resource id and the
font. The font itself will be freed when no other
resource references it.
QueryFont
font: FONT or GCONTEXT
=>
font-info: FONTINFO
char-infos: LISTofCHARINFO
where
FONTINFO: [draw-direction: {LeftToRight, RightToLeft}
min-char-or-byte2,max-char-or-byte2:CARD16
min-byte1, max-byte1: CARD8
all-chars-exist: BOOL
default-char: CARD16
min-bounds: CHARINFO
max-bounds: CHARINFO
font-ascent: INT16
font-descent: INT16
properties: LISTofFONTPROP]
FONTPROP: [name: ATOM
value: INT32 or CARD32]
CHARINFO: [left-side-bearing: INT16
right-side-bearing: INT16
character-width: INT16
ascent: INT16
descent: INT16
attributes: CARD16]
Errors: Font
Returns logical information about a font.
The draw-direction is essentially just a hint, indicating
whether most char-infos have a positive (LeftToRight) or a
negative (RightToLeft) character-width metric. The core
protocol defines no support for vertical text.
If min-byte1 and max-byte1 are both zero, then
min-char-or-byte2 specifies the linear character index
corresponding to the first elementb of char-infos, and
max-char-or-byte2 specifies the linear character index of
the last element. If either min-byte1 or max-byte1 are
non-zero, then both min-char-or-byte2 and
max-char-or-byte2 will be less than 256, and the two-byte
character index values corresponding to char-infos element
N (counting from 0) are
byte1 = N/D + min-byte1
byte2 = N\D + min-char-or-byte2
where
D = max-char-or-byte2 - min-char-or-byte2 + 1
/ = integer division
\ = integer modulus
If char-infos has length zero, then min-bounds and
max-bounds will be identical, and the effective
char-infos is one filled with this char-info, of length
L = D * (max-byte1 - min-byte1 + 1)
That is, all glyphs in the specified linear or matrix
range have the same information, as given by min-bounds
(and max-bounds). If all-chars-exist is True, then all
characters in char-infos have non-zero bounding boxes.
The default-char specifies the character that will be
used when an undefined or non-existent character is used.
Note that default-char is a CARD16 (not CHAR2B); for a
font using two-byte matrix format, the default-char has
byte1 in the most significant byte, and byte2 in the
least significant byte. If the default-char itself
specifies an undefined or non-existent character, then
no printing is performed for an undefined or non-existent
character.
The min-bounds and max-bounds contain the minimum and
maximum values of each individual CHARINFO component over
all char-infos (ignoring non-existent characters). The
bounding box of the font, i.e., the smallest rectangle
enclosing the shape obtained by superimposing all
characters at the same origin [x,y], has its upper left
coordinate at
[x + min-bounds.left-side-bearing, y - max-bounds.
ascent] with a width of
max-bounds.right-side-bearing - min-bounds.
left-side-bearing and a height of
max-bounds.ascent + max-bounds.descent
The font-ascent is the logical extent of the font above
the baseline, for determining line spacing. Specific
characters may extend beyond this. The font-descent is
the logical extent of the font at or below the baseline,
for determining line spacing. Specific characters may
extend beyond this. If the baseline is at Y-coordinate
y, then the logical extent of the font is inclusive
between the Y-coordinate values (y - font-ascent) and
(y + font-descent - 1).
A font is not guaranteed to have any properties. Whether
a property value is signed or unsigned must be derived
from a prior knowledge of the property. When possible,
fonts should have at least the following properties (note
that the trailing colon is not part of the name, and that
upper/lower case matters).
MIN_SPACE: CARD32
The minimum interword spacing, in pixels.
NORM_SPACE: CARD32
The normal interword spacing, in pixels.
MAX_SPACE: CARD32
The maximum interword spacing, in pixels
SUBSCRIPT_X: INT32
SUBSCRIPT_Y: INT32
Offsets from the character origin where subscripts
should begin, in pixels. If the origin is at [x,y],
then subscripts should begin at [x + SubscriptX,
y + SubscriptY].
UNDERLINE_POSITION: INT32
Y offset from the baseline to the top of an underline,
in pixels. If the baseline is Y-coordinate y, then
the top of the underline is at (y +
UnderlinePosition).
UNDERLINE_THICKNESS: CARD32
Thickness of the underline, in pixels.
STRIKEOUT_ASCENT: INT32
STRIKEOUT_DESCENT: INT32
Vertical extents for boxing or voiding characters, in
pixels. If the baseline is at Y-coordinate y, then
the top of the strikeout box is at (y -
StrikeoutAscent), and the height of the box is
(StrikeoutAscent + StrikeoutDescent).
ITALIC_ANGLE: INT32
The angle of characters in the font, in degrees
scaled by 64, relative to the three-oclock position
from the character origin, with positive indicating
counterclockwise motion (as in Arc requests).
X_HEIGHT: INT32
"1 ex" as in TeX, but expressed in units of pixels.
Often the height of lowercase x.
QUAD_WIDTH: INT32
"1 em" as in TeX, but expressed in units of pixels.
Often the width of the digits 0-9.
WEIGHT: CARD32
The weight or boldness of the font, expressed as a
value between 0 and 1000.
POINT_SIZE: CARD32
The point size, expressed in 1/10ths, of this font at
the ideal resolution. There are 72.27 points to the
inch.
RESOLUTION: CARD32
The number of pixels per point, expressed in 1/100ths,
at which this font was created.
For a character origin at [x,y], the bounding box of a
character,i.e., the smallest rectangle enclosing the
character's shape, described in terms of CHARINFO
components, is a rectangle with its upper left corner at
[x + left-side-bearing, y - ascent]
with a width of
right-side-bearing - left-side-bearing
and a height of
ascent + descent
and the origin for the next character is defined to be
[x + character-width, y]
Note that the baseline is logically viewed as being just
below non-descending characters (when descent is zero,
only pixels with Y-coordinates less than y are drawn),
and that the origin is logically viewed as being
coincident with the left edge of a non-kerned character
(when left-side-bearing is zero, no pixels with
X-coordinate less than x are drawn).
Note that CHARINFO metric values can be negative.
A non-existent character is represented with all CHARINFO
components zero.
The interpretation of the per-character attributes field
is undefined by the core protocol.
QueryTextExtents
font: FONT or GCONTEXT
items: STRING16
=>
draw-direction: {LeftToRight, RightToLeft}
font-ascent: INT16
font-descent: INT16
overall-ascent: INT16
overall-descent: INT16
overall-width: INT32
overall-left: INT32
overall-right: INT32
Errors: Font
Returns the logical extents of the specified string of
characters in the specified font. Draw-direction,
font-ascent, and font-descent are as described in
QueryFont. Overall-ascent is the maximum of the ascent
metrics of all characters in the string, and
overall-descent is the maximum of the descent metrics.
Overall-width is the sum of the character-width metrics
of all characters in the string. For each character in
the string, let W be the sum of the character-width
metrics of all characters preceding it in the string,
let L be the left-side-bearing metric of the character
plus W, and let R be the right-side-bearing metric of
the character plus W. Overall-left is the minimum L of
all characters in the string, and overall-right is the
maximum R.
For fonts defined with linear indexing rather than
two-byte matrix indexing, the server will interpret each
CHAR2B as a 16-bit number that has been transmitted most
significant byte first (i.e., byte1 of the CHAR2B is
taken as the most significant byte).
If the font has no defined default-char, then undefined
characters in the string are taken to have all zero
metrics.
ListFonts
pattern: STRING8
max-names: CARD16
=>
names: LISTofSTRING8
Returns a list of length at most max-names, of names of
fonts matching the pattern. The pattern should use the
ASCII encoding, and upper/lower case does not matter.
In the pattern, the '?' character (octal value 77) will
match any single character, and the character '*' (octal
value 52) will match any number of characters. The
returned names are in lower case.
ListFontsWithInfo
pattern: STRING8
max-names: CARD16
=>
fonts: LISTofFONTDATA
where
FONTDATA: [name: STRING8
info: FONTINFO]
FONTINFO: <same type definition as in QueryFont>
Like ListFonts, but also returns information about each
font. The information returned for each font is
identical to what QueryFont would return (except that the
per-character metrics are not returned).
SetFontPath
path: LISTofSTRING8
Errors: Value
Defines the search path for font lookup. There is only one
search path per server, not one per client. The
interpretation of the strings is operating system dependent,
but they are intended to specify directories to be
searched in the order listed.
Setting the path to the empty list restores the default
path defined for the server.
As a side-effect of executing this request, the server
is guaranteed to flush all cached information about fonts
for which there currently are no explicit resource ids
allocated.
The meaning of an error from this request is system
specific.
GetFontPath
=>
path: LISTofSTRING8
Returns the current search path for fonts.
CreatePixmap
pid: PIXMAP
drawable: DRAWABLE
depth: CARD8
width, height: CARD16
Errors: IDChoice, Drawable, Value, Alloc
Creates a pixmap, and assigns the identifier pid to it.
Width and height must be non-zero. Depth must be one of
the depths supported by root of the specified drawable.
The initial contents of the pixmap are undefined.
It is legal to pass an InputOnly window as a drawable to
this request.
FreePixmap
pixmap: PIXMAP
Errors: Pixmap
Deletes the association between the resource id and the
pixmap. The pixmap storage will be freed when no other
resource references it.
CreateGC
cid: GCONTEXT
drawable: DRAWABLE
value-mask: BITMASK
value-list: LISTofVALUE
Errors: IDChoice, Drawable, Pixmap, Font, Match, Value, Alloc
Creates a graphics context, and assigns the identifier cid to
it. The gcontext can be used with any destination drawable
having the same root and depth as the specified drawable.
The value-mask and value-list specify which components are to
be explicitly initialized. The context components are:
alu-function: {Clear, And, AndReverse, Copy, AndInverted,
Noop, Xor, Or, Nor, Equiv, Invert,
OrReverse, CopyInverted, OrInverted,
Nand, Set}
plane-mask: CARD32
foreground: CARD32
background: CARD32
line-width: CARD16
line-style: {Solid, OnOffDash, DoubleDash}
cap-style: {NotLast, Butt, Round, Projecting}
join-style: {Miter, Round, Bevel}
fill-style: {Solid, Tiled, OpaqueStippled, Stippled}
fill-rule: {EvenOdd, Winding}
arc-mode: {Chord, PieSlice}
tile: PIXMAP
stipple: PIXMAP
tile-stipple-x-origin: INT16
tile-stipple-y-origin: INT16
font: FONT
subwindow-mode: {ClipByChildren, IncludeInferiors}
graphics-exposures: BOOL
clip-x-origin: INT16
clip-y-origin: INT16
clip-mask: PIXMAP or None
dash-offset: CARD16
dash-list: CARD8
In graphics operations, given a source and destination pixel,
the result is computed bitwise on corresponding bits of the
pixels. That is, a boolean operation is performed in each
bit plane. The plane-mask restricts the operation to a subset
of planes. That is, the result is
((src FUNC dst) AND plane-mask) OR (dst AND (NOT plane-mask))
Range checking is not performed on the values for foreground,
background, or plane-mask; they are simply truncated to the
appropriate number of bits.
The meanings of the alu-functions are:
Clear 0
And src AND dst
AndReverse src AND (NOT dst)
Copy src
AndInverted (NOT src) AND dst
NoOp dst
Xor src XOR dst
Or src OR dst
Nor (NOT src) AND (NOT dst)
Equiv (NOT src) XOR dst
Invert NOT dst
OrReverse src OR (NOT dst)
CopyInverted NOT src
OrInverted (NOT src) OR dst
NAnd (NOT src) OR (NOT dst)
Set 1
Line-width is measured in pixels and can be greater than or
equal to one (a "wide" line) or the special value zero (a
"thin" line).
Wide lines are drawn centered on the path described by the
graphics request. Unless otherwise specified by the join or
cap style, the bounding box of a wide line with endpoints
[x1, y1], [x2, y2], and width w is a rectangle with vertices
at the following real coordinates:
[x1-(w*sn/2), y1+(w*cs/2)], [x1+(w*sn/2), y1-(w*cs/2)],
[x2-(w*sn/2), y2+(w*cs/2)], [x2+(w*sn/2), y2-(w*cs/2)]
where sn is the sine of the angle of the line and cs is the
cosine of the angle of the line. A pixel is part of the line
(and hence drawn) if the center of the pixel is fully inside
the bounding box (which is viewed as having infinitely thin
edges). If the center of the pixel is exactly on the
bounding box, it is part of the line if and only if the
interior is immediately to its right (x increasing
direction). Pixels with centers on a horizontal edge are a
special case and are part of the line if and only if the
interior is immediately below (y increasing direction).
Note that this description is a mathematical model
describing the pixels that are drawn for a wide line and
does not imply that trigonometry is required to implement
such a model. Real or fixed point arithmetic is
recommended for computing the corners