Module: Tk::Selection

Defined in:
lib/ffi-tk/command/selection.rb

Overview

This command provides a Tcl interface to the X selection mechanism and implements the full selection functionality described in the X Inter-Client Communication Conventions Manual (ICCCM).

Note that for management of the CLIPBOARD selection (see below), the clipboard command may also be used.

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.clear(options = {}) ⇒ Object

If selection exists anywhere on window’s display, clear it so that no window owns the selection anymore. Selection specifies the X selection that should be cleared, and should be an atom name such as PRIMARY or CLIPBOARD; see the Inter-Client Communication Conventions Manual for complete details. Selection defaults to PRIMARY and window defaults to “.”.



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# File 'lib/ffi-tk/command/selection.rb', line 33

def clear(options = {})
  Tk.execute_only(:selection, :clear, options.to_tcl_options)
end

.get(options = {}) ⇒ Object

Retrieves the value of selection from window’s display and returns it as a result. Selection defaults to PRIMARY and window defaults to “.”. Type specifies the form in which the selection is to be returned (the desired “target” for conversion, in ICCCM terminology), and should be an atom name such as STRING or FILE_NAME; see the Inter-Client Communication Conventions Manual for complete details. Type defaults to STRING. The selection owner may choose to return the selection in any of several different representation formats, such as STRING, UTF8_STRING, ATOM, INTEGER, etc. (this format is different than the selection type; see the ICCCM for all the confusing details). If the selection is returned in a non-string format, such as INTEGER or ATOM, the selection command converts it to string format as a collection of fields separated by spaces: atoms are converted to their textual names, and anything else is converted to hexadecimal integers. Note that selection get does not retrieve the selection in the UTF8_STRING format unless told to.



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# File 'lib/ffi-tk/command/selection.rb', line 55

def get(options = {})
  Tk.execute(:selection, :get, options.to_tcl_options).to_s
end

.handle(window, options = {}, &command) ⇒ Object

Creates a handler for selection requests, such that command will be executed whenever selection s is owned by window and someone attempts to retrieve it in the form given by type t (e.g. t is specified in the selection get command). S defaults to PRIMARY, t defaults to STRING, and f defaults to STRING. If command is an empty string then any existing handler for window, t, and s is removed. Note that when the selection is handled as type STRING it is also automatically handled as type UTF8_STRING as well.

When selection is requested, window is the selection owner, and type is the requested type, command will be executed as a Tcl command with two additional numbers appended to it (with space separators). The two additional numbers are offset and maxChars: offset specifies a starting character position in the selection and maxChars gives the maximum number of characters to retrieve. The command should return a value consisting of at most maxChars of the selection, starting at position offset. For very large selections (larger than maxChars) the selection will be retrieved using several invocations of command with increasing offset values. If command returns a string whose length is less than maxChars, the return value is assumed to include all of the remainder of the selection; if the length of command’s result is equal to maxChars then command will be invoked again, until it eventually returns a result shorter than maxChars. The value of maxChars will always be relatively large (thousands of characters). If command returns an error then the selection retrieval is rejected just as if the selection did not exist at all. The format argument specifies the representation that should be used to transmit the selection to the requester (the second column of Table 2 of the ICCCM), and defaults to STRING.

If format is STRING, the selection is transmitted as 8-bit ASCII characters (i.e. just in the form returned by command, in the system encoding; the UTF8_STRING format always uses UTF-8 as its encoding).

If format is ATOM, then the return value from command is divided into fields separated by white space; each field is converted to its atom value, and the 32-bit atom value is transmitted instead of the atom name. For any other format, the return value from command is divided into fields separated by white space and each field is converted to a 32-bit integer; an array of integers is transmitted to the selection requester.

The format argument is needed only for compatibility with selection requesters that do not use Tk. If Tk is being used to retrieve the selection then the value is converted back to a string at the requesting end, so format is irrelevant.



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# File 'lib/ffi-tk/command/selection.rb', line 106

def handle(window, options = {}, &command)
  command = register_command(:selection_handle, &command)
  Tk.execute_only(options.to_tcl_options, window, command)
end

.own(window = None, options = {}, &command) ⇒ Object

The first form of selection own returns the path name of the window in this application that owns selection on the display containing window, or an empty string if no window in this application owns the selection. Selection defaults to PRIMARY and window defaults to “.”.



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# File 'lib/ffi-tk/command/selection.rb', line 115

def own(window = None, options = {}, &command)
  if window == None
    Tk.execute(:selection, :own)
  elsif window.is_a?(Hash)
    options = window

    if cmd = (options[:command] || command)
      command = register_command(:selection_own, &cmd)
      Tk.execute(:selection, :own, {command: command}.merge(options).to_tcl_options)
    else
      Tk.execute(:selection, :own, options.to_tcl_options)
    end
  else
    Tk.execute(:selection, :own, options.to_tcl_options, window)
  end
end

Instance Method Details

#selection_clear(options = {}) ⇒ Object 



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# File 'lib/ffi-tk/command/selection.rb', line 9

def selection_clear(options = {})
  Selection.clear({displayof: self}.merge(options))
end

#selection_get(options = {}) ⇒ Object 



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# File 'lib/ffi-tk/command/selection.rb', line 13

def selection_get(options = {})
  Selection.get({displayof: self}.merge(options))
end

#selection_handle(options = {}, &command) ⇒ Object 



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# File 'lib/ffi-tk/command/selection.rb', line 17

def selection_handle(options = {}, &command)
  Selection.handle(self, options, &command)
end

#selection_own(options, &command) ⇒ Object 



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# File 'lib/ffi-tk/command/selection.rb', line 21

def selection_own(options, &command)
  Selection.own(self, options, &command)
end