IF01401
Clipboard
The
clipboard is a software program that is used for short-term storage of data as
it is transferred between documents or applications, via copy and paste
operations. It is most commonly a part of a GUI environment and is usually
implemented as an anonymous, temporary block of memory that can be accessed from
most or all programs within the environment.
Basic
Clipboard functions
The
semantics of the clipboard facility varies from one operating environment to
another, and can also vary between versions of the same system. They can
sometimes be changed programmatically or by user preference. This can lead to
user frustration when switching between environments with different clipboard
semantics particularly as copy and paste operations often become embedded in the
user's muscle memory.
Most
environments support a single clipboard transaction. Each cut or copy overwrites
the previous contents. Normally paste operations copy the contents, leaving the
contents available in the clipboard for further pasting operations.
Clipboard data formats
Early
implementations of the clipboard stored data as plain text without
meta-information such as typeface, type style or color. More recent
implementations support the multiple flavors of data; a flavor is a type of
data, allowing complex data structures to be stored. These range from styled
text formats such as RTF or HTML, through a variety of bitmap and vector image
formats to complex data types like spreadsheets and database entries.
For example
cutting a range of cells in a spreadsheet and then pasting them into another
sheet may preserve the underlying formulae and data, and may even translate
intra-cell references, so that a "SUM(...)" calculation on a sub-range of the
cells is converted to refer to the newly pasted copies of those cells.
Not all
applications can interpret every flavor that a clipboard supports. Often
applications will attempt to translate complex formats into simpler ones they
can handle. Many text editors, for example, translate structured data from the
clipboard into plain text. This is a common way for users to convert small
selections of data into plain text for various purposes.
Clipboard Management
Modern GUIs
often provide a clipboard manager which supports multiple cut and paste
transactions. In this model the clipboard is treated as a stack or scrap book,
with new cuts and copies being placed added to the top of the list of recent
transations. The standard paste operation copies the most recent transaction,
while specialized pastes provide access to the other stored transactions. These
managers generally also provide a window that displays the transaction history
and allows the user to select earlier copies, edit them, change their format and
even search amongst them.
Most
environments do not save the clipboard contents to any persistent storage - when
a user logs out or reboots his or her system the clipboard contents are cleared
and forgotten.
Operating System Specific Clipboards
Microsoft Windows
In some
versions of the Microsoft Windows operating system, the contents of the
clipboard can be viewed at any time by using the Clipboard Viewer (Clipbook
Viewer in Windows XP) application (clipbrd.exe). In older versions of Windows
the common practice was to open a copy of the "Notepad" or "Wordpad" editor, and
paste into that. Often these operations are available from the "Edit" pull down
menu and they may be available via a context menu, usually accessible by
context-clicking in the window or dialog entry that is to be cut from or pasted
into.
The
standard Windows keybindings are:
Ctrl-c to
copy data onto the clipboard
Ctrl-x to
cut data to the clipboard
Ctrl-v to
paste data from the clipboard
The
Clipbook Viewer was removed entirely in Windows Vista.
Did this Article Give you the
Information You Were Looking For?
If you found this information useful,
please
