1selection(3) User Contributed Perl Documentation selection(3)
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6 Tk::Selection - Manipulate the X selection
7
9 $widget->SelectionOption?(args)?
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12 This command provides an interface to the X selection mechanism and
13 implements the full selection functionality described in the X Inter-
14 Client Communication Conventions Manual (ICCCM).
15 The widget object used to invoke the methods below determines which
17 display is used to access the selection. In order to avoid conflicts
18 with selection methods of widget classes (e.g. Text) this set of
19 methods uses the prefix Selection. The following methods are currently
20 supported:
21 $widget->SelectionClear?(-selection=>selection)?
23 If selection exists anywhere on $widget's display, clear it so that
24 no window owns the selection anymore. Selection specifies the X
25 selection that should be cleared, and should be an atom name such
26 as PRIMARY or CLIPBOARD; see the Inter-Client Communication
27 Conventions Manual for complete details. Selection defaults to
28 PRIMARY. Returns an empty string.
29 $widget->SelectionGet?(?-selection=>selection?,?-type=>type?)?
31 Retrieves the value of selection from $widget's display and returns
32 it as a result. Selection defaults to PRIMARY.
33 Type specifies the form in which the selection is to be returned
35 (the desired ``target'' for conversion, in ICCCM terminology), and
36 should be an atom name such as STRING or FILE_NAME; see the Inter-
37 Client Communication Conventions Manual for complete details. Type
38 defaults to STRING. The selection owner may choose to return the
39 selection in any of several different representation formats, such
40 as STRING, ATOM, INTEGER, etc. (this format is different than the
41 selection type; see the ICCCM for all the confusing details).
42 If format is not STRING then things get messy, the following
44 description is from the Tcl/Tk man page as yet incompetely
45 translated for the perl version - it is misleading at best.
46 If the selection is returned in a non-string format, such as
48 INTEGER or ATOM, the SelectionGet converts it to a list of perl
49 values: atoms are converted to their textual names, and anything
50 else is converted integers.
51 A goal of the perl port is to provide better handling of different
53 formats than Tcl/Tk does, which should be possible given perl's
54 wider range of ``types''. Although some thought went into this in
55 very early days of perl/Tk what exactly happens is still "not quite
56 right" and subject to change.
57 $widget->SelectionHandle(?-selection=>selection?,?-type=>type?,?-format=>format?
59 callback)
60 Creates a handler for selection requests, such that callback will
61 be executed whenever selection is owned by $widget and someone
62 attempts to retrieve it in the form given by type (e.g. type is
63 specified in the selection get command). Selection defaults to
64 PRIMARY, type defaults to STRING, and format defaults to STRING.
65 If callback is an empty string then any existing handler for
66 $widget, type, and selection is removed.
67 When selection is requested, $widget is the selection owner, and
69 type is the requested type, callback will be executed with two
70 additional arguments. The two additional arguments are offset and
71 maxBytes: offset specifies a starting character position in the
72 selection and maxBytes gives the maximum number of bytes to
73 retrieve. The command should return a value consisting of at most
74 maxBytes of the selection, starting at position offset. For very
75 large selections (larger than maxBytes) the selection will be
76 retrieved using several invocations of callback with increasing
77 offset values. If callback returns a string whose length is less
78 than maxBytes, the return value is assumed to include all of the
79 remainder of the selection; if the length of callback's result is
80 equal to maxBytes then callback will be invoked again, until it
81 eventually returns a result shorter than maxBytes. The value of
82 maxBytes will always be relatively large (thousands of bytes).
83 If callback returns an error (e.g. via die) then the selection
85 retrieval is rejected just as if the selection didn't exist at all.
86 The format argument specifies the representation that should be
88 used to transmit the selection to the requester (the second column
89 of Table 2 of the ICCCM), and defaults to STRING. If format is
90 STRING, the selection is transmitted as 8-bit ASCII characters
91 (i.e. just in the form returned by command).
92 If format is not STRING then things get messy, the following
94 description is from the Tcl/Tk man page as yet untranslated for the
95 perl version - it is misleading at best.
96 If format is ATOM, then the return value from command is divided
98 into fields separated by white space; each field is converted to
99 its atom value, and the 32-bit atom value is transmitted instead of
100 the atom name. For any other format, the return value from command
101 is divided into fields separated by white space and each field is
102 converted to a 32-bit integer; an array of integers is transmitted
103 to the selection requester.
104 The format argument is needed only for compatibility with many
106 selection requesters, except Tcl/Tk. If Tcl/Tk is being used to
107 retrieve the selection then the value is converted back to a string
108 at the requesting end, so format is irrelevant.
109 A goal of the perl port is to provide better handling of different
111 formats than Tcl/Tk does, which should be possible given perl's
112 wider range of ``types''. Although some thought went into this in
113 very early days of perl/Tk what exactly happens is still "not quite
114 right" and subject to change.
115 $widget->SelectionOwner?(-selection=>selection)?
117 SelectionOwner returns the window in this application that owns
118 selection on the display containing $widget, or an empty string if
119 no window in this application owns the selection. Selection
120 defaults to PRIMARY.
121 $widget->SelectionOwn?(?-command=>callback?,?-selection=>selection?)?
123 SelectionOwn causes $widget to become the new owner of selection on
124 $widget's display, returning an empty string as result. The
125 existing owner, if any, is notified that it has lost the selection.
126 If callback is specified, it will be executed when some other
127 window claims ownership of the selection away from $widget.
128 Selection defaults to PRIMARY.
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131 clear, format, handler, ICCCM, own, selection, target, type
132perl v5.32.0 2020-07-28 selection(3)