Class: XlibObj::Window::Property

Inherits:
Object
  • Object
show all
Defined in:
lib/window/property.rb

Instance Method Summary collapse

Constructor Details

#initialize(window, name) ⇒ Property

Returns a new instance of Property.



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# File 'lib/window/property.rb', line 12

def initialize(window, name)
  @window = window
  @name = name
  @atom = Atom.new(window.display, name)
end

Instance Method Details

#delete ⇒ Object 



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# File 'lib/window/property.rb', line 77

def delete
  Xlib.XDeleteProperty(@window.display.to_native, @window.to_native, @atom.to_native)
end

#get ⇒ Object 



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# File 'lib/window/property.rb', line 18

def get
  return unless @atom.exists?

  data_offset     = 0
  data_max_length = 2**16  # multiple of 32 bit
  allow_deleted   = false  # don't retrieve deleted properties
  requested_type  = Xlib::AnyPropertyType

  # response data
  pointer     = FFI::MemoryPointer.new :pointer
  item_type   = FFI::MemoryPointer.new :Atom
  item_width  = FFI::MemoryPointer.new :int
  item_count  = FFI::MemoryPointer.new :ulong
  cutoff_data = FFI::MemoryPointer.new :ulong

  # do and validate the request
  status = Xlib.XGetWindowProperty(
    @window.display.to_native, @window.to_native, @atom.to_native,
    data_offset, data_max_length, allow_deleted, requested_type,
    item_type, item_width, item_count, cutoff_data, pointer
  )

  return unless status == 0

  return if pointer.read_pointer.null? # property is not set for the window

  # extract response data
  item_type = Atom.new(@window.display, item_type.read_int).name
  item_width = item_width.read_int
  item_count = item_count.read_int

  return if item_count == 0

  # get the property's value
  bytes = read_bytes(pointer, item_width, item_count)
  items = bytes_to_items(bytes, item_type, item_count)

  return if items.empty?

  items_to_objects(items, item_type)
end

#set(value, type = nil) ⇒ Object 



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# File 'lib/window/property.rb', line 60

def set(value, type = nil)
  objects = value.is_a?(Array) ? value : [value]
  item_type = type || type_from_objects(objects)
  items = objects_to_items(objects, item_type)
  item_width = width_from_type(item_type)
  bytes = items_to_bytes(items, item_type)
  item_count = item_type[-6..-1] == 'STRING' ? bytes.size : items.size

  Xlib.XChangeProperty(
    @window.display.to_native, @window.to_native, @atom.to_native,
    Atom.new(@window.display, item_type).to_native, item_width,
    Xlib::PropModeReplace, bytes, item_count)
  Xlib::X.flush(@window.display)

  self
end