Protocol(3pm) User Contributed Perl Documentation Protocol(3pm)
NAME
X11::Protocol - Perl module for the X Window System Protocol, version 11
SYNOPSIS
use X11::Protocol;
$x = X11::Protocol->new();
$win = $x->new_rsrc;
$x->CreateWindow($win, $x->root, 'InputOutput',
$x->root_depth, 'CopyFromParent',
($x_coord, $y_coord), $width,
$height, $border_w);
...
DESCRIPTION
X11::Protocol is a client-side interface to the X11 Protocol (see X(1)
for information about X11), allowing perl programs to display windows
and graphics on X11 servers.
A full description of the protocol is beyond the scope of this
documentation; for complete information, see the X Window System
Protocol, X Version 11, available as Postscript or *roff source from
"ftp://ftp.x.org", or Volume 0: X Protocol Reference Manual of O'Reilly
& Associates's series of books about X (ISBN 1-56592-083-X,
"http://www.oreilly.com"), which contains most of the same information.
DISCLAIMER
``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.'' -- Robert W.
Scheifler
BASIC METHODS
new
$x = X11::Protocol->new();
$x = X11::Protocol->new($display_name);
$x = X11::Protocol->new($connection);
$x = X11::Protocol->new($display_name, [$auth_type, $auth_data]);
$x = X11::Protocol->new($connection, [$auth_type, $auth_data]);
Open a connection to a server. $display_name should be an X display
name, of the form 'host:display_num.screen_num'; if no arguments are
supplied, the contents of the DISPLAY environment variable are used.
Alternatively, a pre-opened connection, of one of the
X11::Protocol::Connection classes (see X11::Protocol::Connection,
X11::Protocol::Connection::FileHandle,
X11::Protocol::Connection::Socket, X11::Protocol::Connection::UNIXFH,
X11::Protocol::Connection::INETFH,
X11::Protocol::Connection::UNIXSocket,
X11::Protocol::Connection::INETSocket) can be given. The authorization
data is obtained using X11::Auth or the second argument. If the display
is specified by $display_name, rather than $connection, a
choose_screen() is also performed, defaulting to screen 0 if the
'.screen_num' of the display name is not present. Returns the new
protocol object.
new_rsrc
$x->new_rsrc;
Returns a new resource identifier. A unique resource ID is required for
every object that the server creates on behalf of the client: windows,
fonts, cursors, etc. (IDs are chosen by the client instead of the server
for efficiency -- the client doesn't have to wait for the server to
acknowledge the creation before starting to use the object).
Note that the total number of available resource IDs, while large, is
finite. Beginning from the establishment of a connection, resource IDs
are allocated sequentially from a range whose size is server dependent
(commonly 2**21, about 2 million). If this limit is reached and the
server does not support the XC_MISC extension, subsequent calls to
new_rsrc will croak. If the server does support this extension, the
module will attempt to request a new range of free IDs from the server.
This should allow the program to continue, but it is an imperfect
solution, as over time the set of available IDs may fragment, requiring
increasingly frequent round-trip range requests from the server. For
long-running programs, the best approach may be to keep track of free
IDs as resources are destroyed. In the current version, however, no
special support is provided for this.
handle_input
$x->handle_input;
Get one chunk of information from the server, and do something with it.
If it's an error, handle it using the protocol object's handler
('error_handler' -- default is kill the program with an explanatory
message). If it's an event, pass it to the chosen event handler, or put
it in a queue if the handler is 'queue'. If it's a reply to a request,
save using the object's 'replies' hash for further processing.
atom_name
$name = $x->atom_name($atom);
Return the string corresponding to the atom $atom. This is similar to
the GetAtomName request, but caches the result for efficiency.
atom
$atom = $x->atom($name);
The inverse operation; Return the (numeric) atom corresponding to $name.
This is similar to the InternAtom request, but caches the result.
choose_screen
$x->choose_screen($screen_num);
Indicate that you prefer to use a particular screen of the display. Per-
screen information, such as 'root', 'width_in_pixels', and 'white_pixel'
will be made available as
$x->{'root'}
instead of
$x->{'screens'}[$screen_num]{'root'}
SYMBOLIC CONSTANTS
Generally, symbolic constants used by the protocol, like
'CopyFromParent' or 'PieSlice' are passed to methods as strings, and
converted into numbers by the module. Their names are the same as those
in the protocol specification, including capitalization, but with
hyphens ('-') changed to underscores ('_') to look more perl-ish. If you
want to do the conversion yourself for some reason, the following
methods are available:
num
$num = $x->num($type, $str)
Given a string representing a constant and a string specifying what type
of constant it is, return the corresponding number. $type should be a
name like 'VisualClass' or 'GCLineStyle'. If the name is not recognized,
it is returned intact.
interp
$name = $x->interp($type, $num)
The inverse operation; given a number and string specifying its type,
return a string representing the constant.
You can disable interp() and the module's internal interpretation of
numbers by setting $x->{'do_interp'} to zero. Of course, this isn't very
useful, unless you have you own definitions for all the constants.
Here is a list of available constant types:
AccessMode, AllowEventsMode, AutoRepeatMode, BackingStore,
BitGravity, Bool, ChangePropertyMode, CirculateDirection,
CirculatePlace, Class, ClipRectangleOrdering, CloseDownMode,
ColormapNotifyState, CoordinateMode, CrossingNotifyDetail,
CrossingNotifyMode, DeviceEvent, DrawDirection, Error, EventMask,
Events, FocusDetail, FocusMode, GCArcMode, GCCapStyle, GCFillRule,
GCFillStyle, GCFunction, GCJoinStyle, GCLineStyle, GCSubwindowMode,
GrabStatus, HostChangeMode, HostFamily, ImageFormat,
InputFocusRevertTo, KeyMask, LedMode, MapState, MappingChangeStatus,
MappingNotifyRequest, PointerEvent, PolyShape, PropertyNotifyState,
Request, ScreenSaver, ScreenSaverAction, Significance, SizeClass,
StackMode, SyncMode, VisibilityState, VisualClass, WinGravity
SERVER INFORMATION
At connection time, the server sends a large amount of information about
itself to the client. This information is stored in the protocol object
for future reference. It can be read directly, like
$x->{'release_number'}
or, for object oriented True Believers, using a method:
$x->release_number
The method method also has a one argument form for setting variables,
but it isn't really useful for some of the more complex structures.
Here is an example of what the object's information might look like:
'connection' => X11::Connection::UNIXSocket(0x814526fd),
'byte_order' => 'l',
'protocol_major_version' => 11,
'protocol_minor_version' => 0,
'authorization_protocol_name' => 'MIT-MAGIC-COOKIE-1',
'release_number' => 3110,
'resource_id_base' => 0x1c000002,
'motion_buffer_size' => 0,
'maximum_request_length' => 65535, # units of 4 bytes
'image_byte_order' => 'LeastSiginificant',
'bitmap_bit_order' => 'LeastSiginificant',
'bitmap_scanline_unit' => 32,
'bitmap_scanline_pad' => 32,
'min_keycode' => 8,
'max_keycode' => 134,
'vendor' => 'The XFree86 Project, Inc',
'pixmap_formats' => {1 => {'bits_per_pixel' => 1,
'scanline_pad' => 32},
8 => {'bits_per_pixel' => 8,
'scanline_pad' => 32}},
'screens' => [{'root' => 43, 'width_in_pixels' => 800,
'height_in_pixels' => 600,
'width_in_millimeters' => 271,
'height_in_millimeters' => 203,
'root_depth' => 8,
'root_visual' => 34,
'default_colormap' => 33,
'white_pixel' => 0, 'black_pixel' => 1,
'min_installed_maps' => 1,
'max_installed_maps' => 1,
'backing_stores' => 'Always',
'save_unders' => 1,
'current_input_masks' => 0x58003d,
'allowed_depths' =>
[{'depth' => 1, 'visuals' => []},
{'depth' => 8, 'visuals' => [
{'visual_id' => 34, 'blue_mask' => 0,
'green_mask' => 0, 'red_mask' => 0,
'class' => 'PseudoColor',
'bits_per_rgb_value' => 6,
'colormap_entries' => 256},
{'visual_id' => 35, 'blue_mask' => 0xc0,
'green_mask' => 0x38, 'red_mask' => 0x7,
'class' => 'DirectColor',
'bits_per_rgb_value' => 6,
'colormap_entries' => 8}, ...]}]],
'visuals' => {34 => {'depth' => 8, 'class' => 'PseudoColor',
'red_mask' => 0, 'green_mask' => 0,
'blue_mask'=> 0, 'bits_per_rgb_value' => 6,
'colormap_entries' => 256},
35 => {'depth' => 8, 'class' => 'DirectColor',
'red_mask' => 0x7, 'green_mask' => 0x38,
'blue_mask'=> 0xc0, 'bits_per_rgb_value' => 6,
'colormap_entries' => 8}, ...}
'error_handler' => &\X11::Protocol::default_error_handler,
'event_handler' => sub {},
'do_interp' => 1
REQUESTS
request
$x->request('CreateWindow', ...);
$x->req('CreateWindow', ...);
$x->CreateWindow(...);
Send a protocol request to the server, and get the reply, if any. For
names of and information about individual requests, see below and/or the
protocol reference manual.
robust_req
$x->robust_req('CreateWindow', ...);
Like request(), but if the server returns an error, return the error
information rather than calling the error handler (which by default just
croaks). If the request succeeds, returns an array reference containing
whatever request() would have. Otherwise, returns the error type, the
major and minor opcodes of the failed request, and the extra error
information, if any. Note that even if the request normally wouldn't
have a reply, this method still has to wait for a round-trip time to see
whether an error occurred. If you're concerned about performance, you
should design your error handling to be asynchronous.
add_reply
$x->add_reply($sequence_num, \$var);
Add a stub for an expected reply to the object's 'replies' hash. When a
reply numbered $sequence_num comes, it will be stored in $var.
delete_reply
$x->delete_reply($sequence_num);
Delete the entry in 'replies' for the specified reply. (This should be
done after the reply is received).
send
$x->send('CreateWindow', ...);
Send a request, but do not wait for a reply. You must handle the reply,
if any, yourself, using add_reply(), handle_input(), delete_reply(), and
unpack_reply(), generally in that order.
unpack_reply
$x->unpack_reply('GetWindowAttributes', $data);
Interpret the raw reply data $data, according to the reply format for
the named request. Returns data in the same format as
"request($request_name, ...)".
This section includes only a short calling summary for each request; for
full descriptions, see the protocol standard. Argument order is usually
the same as listed in the spec, but you generally don't have to pass
lengths of strings or arrays, since perl keeps track. Symbolic constants
are generally passed as strings. Most replies are returned as lists, but
when there are many values, a hash is used. Lists usually come last;
when there is more than one, each is passed by reference. In lists of
multi-part structures, each element is a list ref. Parenthesis are
inserted in arg lists for clarity, but are optional. Requests are listed
in order by major opcode, so related requests are usually close
together. Replies follow the '=>'.
$x->CreateWindow($wid, $parent, $class, $depth, $visual, ($x, $y),
$width, $height, $border_width,
'attribute' => $value, ...)
$x->ChangeWindowAttributes($window, 'attribute' => $value, ...)
$x->GetWindowAttributes($window)
=>
('backing_store' => $backing_store, ...)
This is an example of a return value that is meant to be assigned to a
hash.
$x->DestroyWindow($win)
$x->DestroySubwindows($win)
$x->ChangeSaveSet($window, $mode)
$x->ReparentWindow($win, $parent, ($x, $y))
$x->MapWindow($win)
$x->MapSubwindows($win)
$x->UnmapWindow($win)
$x->UnmapSubwindows($win)
$x->ConfigureWindow($win, 'attribute' => $value, ...)
$x->CirculateWindow($win, $direction)
Note that this request actually circulates the subwindows of $win, not
the window itself.
$x->GetGeometry($drawable)
=>
('root' => $root, ...)
$x->QueryTree($win)
=>
($root, $parent, @kids)
$x->InternAtom($name, $only_if_exists)
=>
$atom
$x->GetAtomName($atom)
=>
$name
$x->ChangeProperty($window, $property, $type, $format, $mode, $data)
$x->DeleteProperty($win, $atom)
$x->GetProperty($window, $property, $type, $offset, $length, $delete)
=>
($value, $type, $format, $bytes_after)
Notice that the value comes first, so you can easily ignore the rest.
$x->ListProperties($window)
=>
(@atoms)
$x->SetSelectionOwner($selection, $owner, $time)
$x->GetSelectionOwner($selection)
=>
$owner
$x->ConvertSelection($selection, $target, $property, $requestor, $time)
$x->SendEvent($destination, $propagate, $event_mask, $event)
The $event argument should be the result of a pack_event() (see
"EVENTS")
$x->GrabPointer($grab_window, $owner_events, $event_mask,
$pointer_mode, $keyboard_mode, $confine_to,
$cursor, $time)
=>
$status
$x->UngrabPointer($time)
$x->GrabButton($modifiers, $button, $grab_window, $owner_events,
$event_mask, $pointer_mode, $keyboard_mode,
$confine_to, $cursor)
$x->UngrabButton($modifiers, $button, $grab_window)
$x->ChangeActivePointerGrab($event_mask, $cursor, $time)
$x->GrabKeyboard($grab_window, $owner_events, $pointer_mode,
$keyboard_mode, $time)
=>
$status
$x->UngrabKeyboard($time)
$x->GrabKey($key, $modifiers, $grab_window, $owner_events,
$pointer_mode, $keyboard_mode)
$x->UngrabKey($key, $modifiers, $grab_window)
$x->AllowEvents($mode, $time)
$x->GrabServer
$x->UngrabServer
$x->QueryPointer($window)
=>
('root' => $root, ...)
$x->GetMotionEvents($start, $stop, $window)
=>
([$time, ($x, $y)], [$time, ($x, $y)], ...)
$x->TranslateCoordinates($src_window, $dst_window, $src_x, $src_y)
=>
($same_screen, $child, $dst_x, $dst_y)
$x->WarpPointer($src_window, $dst_window, $src_x, $src_y, $src_width,
$src_height, $dst_x, $dst_y)
$x->SetInputFocus($focus, $revert_to, $time)
$x->GetInputFocus
=>
($focus, $revert_to)
$x->QueryKeymap
=>
$keys
$keys is a bit vector, so you should use vec() to read it.
$x->OpenFont($fid, $name)
$x->CloseFont($font)
$x->QueryFont($font)
=>
('min_char_or_byte2' => $min_char_or_byte2,
...,
'min_bounds' =>
[$left_side_bearing, $right_side_bearing, $character_width, $ascent,
$descent, $attributes],
...,
'char_infos' =>
[[$left_side_bearing, $right_side_bearing, $character_width, $ascent,
$descent, $attributes],
...],
'properties' => {$prop => $value, ...}
)
$x->QueryTextExtents($font, $string)
=>
('draw_direction' => $draw_direction, ...)
$x->ListFonts($pattern, $max_names)
=>
@names
$x->ListFontsWithInfo($pattern, $max_names)
=>
({'name' => $name, ...}, {'name' => $name, ...}, ...)
The information in each hash is the same as the the information returned
by QueryFont, but without per-character size information. This request
is special in that it is the only request that can have more than one
reply. This means you should probably only use request() with it, not
send(), as the reply counting is complicated. Luckily, you never need
this request anyway, as its function is completely duplicated by other
requests.
$x->SetFontPath(@strings)
$x->GetFontPath
=>
@strings
$x->CreatePixmap($pixmap, $drawable, $depth, $width, $height)
$x->FreePixmap($pixmap)
$x->CreateGC($cid, $drawable, 'attribute' => $value, ...)
$x->ChangeGC($gc, 'attribute' => $value, ...)
$x->CopyGC($src, $dest, 'attribute', 'attribute', ...)
$x->SetDashes($gc, $dash_offset, (@dashes))
$x->SetClipRectangles($gc, ($clip_x_origin, $clip_y_origin),
$ordering, [$x, $y, $width, $height], ...)
$x->ClearArea($window, ($x, $y), $width, $height, $exposures)
$x->CopyArea($src_drawable, $dst_drawable, $gc, ($src_x, $src_y),
$width, $height, ($dst_x, $dst_y))
$x->CopyPlane($src_drawable, $dst_drawable, $gc, ($src_x, $src_y),
$width, $height, ($dst_x, $dst_y), $bit_plane)
$x->PolyPoint($drawable, $gc, $coordinate_mode,
($x, $y), ($x, $y), ...)
$x->PolyLine($drawable, $gc, $coordinate_mode,
($x, $y), ($x, $y), ...)
$x->PolySegment($drawable, $gc, ($x, $y) => ($x, $y),
($x, $y) => ($x, $y), ...)
$x->PolyRectangle($drawable, $gc,
[($x, $y), $width, $height], ...)
$x->PolyArc($drawable, $gc,
[($x, $y), $width, $height, $angle1, $angle2], ...)
$x->FillPoly($drawable, $gc, $shape, $coordinate_mode,
($x, $y), ...)
$x->PolyFillRectangle($drawable, $gc,
[($x, $y), $width, $height], ...)
$x->PolyFillArc($drawable, $gc,
[($x, $y), $width, $height, $angle1, $angle2], ...)
$x->PutImage($drawable, $gc, $depth, $width, $height,
($dst_x, $dst_y), $left_pad, $format, $data)
Currently, the module has no code to handle the various bitmap formats
that the server might specify. Therefore, this request will not work
portably without a lot of work.
$x->GetImage($drawable, ($x, $y), $width, $height, $plane_mask,
$format)
$x->PolyText8($drawable, $gc, ($x, $y),
($font OR [$delta, $string]), ...)
$x->PolyText16($drawable, $gc, ($x, $y),
($font OR [$delta, $string]), ...)
$x->ImageText8($drawable, $gc, ($x, $y), $string)
$x->ImageText16($drawable, $gc, ($x, $y), $string)
$x->CreateColormap($mid, $visual, $window, $alloc)
$x->FreeColormap($cmap)
$x->CopyColormapAndFree($mid, $src_cmap)
$x->InstallColormap($cmap)
$x->UninstallColormap($cmap)
$x->ListInstalledColormaps($window)
=>
@cmaps
$x->AllocColor($cmap, ($red, $green, $blue))
=>
($pixel, ($red, $green, $blue))
$x->AllocNamedColor($cmap, $name)
=>
($pixel, ($exact_red, $exact_green, $exact_blue),
($visual_red, $visual_green, $visual_blue))
$x->AllocColorCells($cmap, $colors, $planes, $contiguous)
=>
([@pixels], [@masks])
$x->AllocColorPlanes($cmap, $colors, ($reds, $greens, $blues),
$contiguous)
=>
(($red_mask, $green_mask, $blue_mask), @pixels)
$x->FreeColors($cmap, $plane_mask, @pixels)
$x->StoreColors($cmap, [$pixel, $red, $green, $blue, $do_mask], ...)
The 1, 2, and 4 bits in $do_mask are do-red, do-green, and do-blue.
$do_mask can be omitted, defaulting to 7, the usual case -- change the
whole color.
$x->StoreNamedColor($cmap, $pixel, $name, $do_mask)
$do_mask has the same interpretation as above, but is mandatory.
$x->QueryColors($cmap, @pixels)
=>
([$red, $green, $blue], ...)
$x->LookupColor($cmap, $name)
=>
(($exact_red, $exact_green, $exact_blue),
($visual_red, $visual_green, $visual_blue))
$x->CreateCursor($cid, $source, $mask,
($fore_red, $fore_green, $fore_blue),
($back_red, $back_green, $back_blue),
($x, $y))
$x->CreateGlyphCursor($cid, $source_font, $mask_font,
$source_char, $mask_char,
($fore_red, $fore_green, $fore_blue),
($back_red, $back_green, $back_blue))
$x->FreeCursor($cursor)
$x->RecolorCursor($cursor, ($fore_red, $fore_green, $fore_blue),
($back_red, $back_green, $back_blue))
$x->QueryBestSize($class, $drawable, $width, $height)
=>
($width, $height)
$x->QueryExtension($name)
=>
($major_opcode, $first_event, $first_error)
If the extension is not present, an empty list is returned.
$x->ListExtensions
=>
(@names)
$x->ChangeKeyboardMapping($first_keycode, $keysysms_per_keycode,
@keysyms)
$x->GetKeyboardMapping($first_keycode, $count)
=>
($keysysms_per_keycode, [$keysym, ...], [$keysym, ...], ...)
$x->ChangeKeyboardControl('attribute' => $value, ...)
$x->GetKeyboardControl
=>
('global_auto_repeat' => $global_auto_repeat, ...)
$x->Bell($percent)
$x->ChangePointerControl($do_acceleration, $do_threshold,
$acceleration_numerator,
$acceleration_denominator, $threshold)
$x->GetPointerControl
=>
($acceleration_numerator, $acceleration_denominator, $threshold)
$x->SetScreenSaver($timeout, $interval, $prefer_blanking,
$allow_exposures)
$x->GetScreenSaver
=>
($timeout, $interval, $prefer_blanking, $allow_exposures)
$x->ChangeHosts($mode, $host_family, $host_address)
$x->ListHosts
=>
($mode, [$family, $host], ...)
$x->SetAccessControl($mode)
$x->SetCloseDownMode($mode)
$x->KillClient($resource)
$x->RotateProperties($win, $delta, @props)
$x->ForceScreenSaver($mode)
$x->SetPointerMapping(@map)
=>
$status
$x->GetPointerMapping
=>
@map
$x->SetModifierMapping(@keycodes)
=>
$status
$x->GetModiferMapping
=>
@keycodes
$x->NoOperation($length)
$length specifies the length of the entire useless request, in four byte
units, and is optional.
EVENTS
To receive events, first set the 'event_mask' attribute on a window to
indicate what types of events you desire (see "pack_event_mask"). Then,
set the protocol object's 'event_handler' to a subroutine reference that
will handle the events. Alternatively, set 'event_handler' to 'queue',
and retrieve events using dequeue_event() or next_event(). In both
cases, events are returned as a hash. For instance, a typical
MotionNotify event might look like this:
%event = ('name' => 'MotionNotify', 'sequence_number' => 12,
'state' => 0, 'event' => 58720256, 'root' => 43,
'child' => None, 'same_screen' => 1, 'time' => 966080746,
'detail' => 'Normal', 'event_x' => 10, 'event_y' => 3,
'code' => 6, 'root_x' => 319, 'root_y' => 235)
pack_event_mask
$mask = $x->pack_event_mask('ButtonPress', 'KeyPress', 'Exposure');
Make an event mask (suitable as the 'event_mask' of a window) from a
list of strings specifying event types.
unpack_event_mask
@event_types = $x->unpack_event_mask($mask);
The inverse operation; convert an event mask obtained from the server
into a list of names of event categories.
dequeue_event
%event = $x->dequeue_event;
If there is an event waiting in the queue, return it.
next_event
%event = $x->next_event;
Like Xlib's XNextEvent(), this function is equivalent to
$x->handle_input until %event = dequeue_event;
pack_event
$data = $x->pack_event(%event);
Given an event in hash form, pack it into a string. This is only useful
as an argument to SendEvent().
unpack_event
%event = $x->unpack_event($data);
The inverse operation; given the raw data for an event (32 bytes),
unpack it into hash form. Normally, this is done automatically.
EXTENSIONS
Protocol extensions add new requests, event types, and error types to
the protocol. Support for them is compartmentalized in modules in the
X11::Protocol::Ext:: hierarchy. For an example, see
X11::Protocol::Ext::SHAPE. You can tell if the module has loaded an
extension by looking at
$x->{'ext'}{$extension_name}
If the extension has been initialized, this value will be an array
reference, [$major_request_number, $first_event_number,
$first_error_number, $obj], where $obj is an object containing
information private to the extension.
init_extension
$x->init_extension($name);
Initialize an extension: query the server to find the extension's
request number, then load the corresponding module. Returns 0 if the
server does not support the named extension, or if no module to
interface with it exists.
init_extensions
$x->init_extensions;
Initialize protocol extensions. This does a ListExtensions request, then
calls init_extension() for each extension that the server supports.
WRITING EXTENSIONS
Internally, the X11::Protocol module is table driven. All an extension
has to do is to add new add entries to the protocol object's tables. An
extension module should "use X11::Protocol", and should define an new()
method
X11::Protocol::Ext::NAME
->new($x, $request_num, $event_num, $error_num)
where $x is the protocol object and $request_num, $event_num and
$error_num are the values returned by QueryExtension().
The new() method should add new types of constant like
$x->{'ext_const'}{'ConstantType'} = ['Constant', 'Constant', ...]
and set up the corresponding name to number translation hashes like
$x->{'ext_const_num'}{'ConstantType'} =
{make_num_hash($x->{'ext_const'}{'ConstantType'})}
Event names go in
$x->{'ext_const'}{'Events'}[$event_number]
while specifications for event contents go in
$x->{'ext_event'}[$event_number]
each element of which is either "[\&unpack_sub, \&pack_sub]" or
"[$pack_format, $field, $field, ...]", where each $field is 'name',
"['name', 'const_type']", or "['name', ['special_name_for_zero',
'special_name_for_one']]", where 'special_name_for_one' is optional.
Finally,
$x->{'ext_request'}{$major_request_number}
should be an array of arrays, with each array either "[$name, \&packit]"
or "[$name, \&packit, \&unpackit]", and
$x->{'ext_request_num'}{$request_name}
should be initialized with "[$minor_num, $major_num]" for each request
the extension defines. For examples of code that does all of this, look
at X11::Protocol::Ext::SHAPE.
X11::Protocol exports several functions that might be useful in
extensions (note that these are not methods).
padding
$p = padding $x;
Given an integer, compute the number need to round it up to a multiple
of 4. For instance, padding(5) is 3.
pad
$p = pad $str;
Given a string, return the number of extra bytes needed to make a
multiple of 4. Equivalent to "padding(length($str))".
padded
$data = pack(padded($str), $str);
Return a format string, suitable for pack(), for a string padded to a
multiple of 4 bytes. For instance, "pack(padded('Hello'), 'Hello')"
gives "Hello\0\0\0".
hexi
$str = hexi $n;
Format a number in hexidecimal, and add a "0x" to the front.
make_num_hash
%hash = make_num_hash(['A', 'B', 'C']);
Given a reference to a list of strings, return a hash mapping the
strings onto numbers representing their position in the list, as used by
"$x->{'ext_const_num'}".
BUGS
This module is too big (~2500 lines), too slow (10 sec to load on a slow
machine), too inefficient (request args are copied several times), and
takes up too much memory (3000K for basicwin).
If you have more than 65535 replies outstanding at once, sequence
numbers can collide.
The protocol is too complex.
AUTHOR
Stephen McCamant <SMCCAM@cpan.org>.
SEE ALSO
perl(1), X(1), X11::Keysyms, X11::Protocol::Ext::SHAPE,
X11::Protocol::Ext::BIG_REQUESTS, X11::Protocol::Ext::XC_MISC,
X11::Protocol::Ext::DPMS, X11::Protocol::Ext::XFree86_Misc, X11::Auth, X
Window System Protocol (X Version 11), Inter-Client Communications
Conventions Manual, X Logical Font Description Conventions.
perl v5.34.0 2022-10-13 Protocol(3pm)
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