| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |
Arguments: window-or-widget
Returns an object from the specified window or widget that is suitable
for placing onto the clipboard, or nil
if no
suitable object is found. This function is called by copy-command, which does
the actual placing of the object onto the clipboard. An application
could call either function, or add methods to either in order to
extend the clipboard functionality.
window-or-widget should be an instance of a
basic-pane
subclass or a dialog-item
subclass.
If a copy was done, then a second value is returned that indicates the
clipboard format that is appropriate for the copied object on the
underlying platform's system-wide clipboard. This will be one of the
keywords :text
, :rich-text
, or
:pixmap
. The Windows clipboard knows how to hold
one value of each of its clipboard formats simultaneously.
The default method returns the object returned by calling selected-object, plus
:text
as the second value. The methods for bitmap-pane
and
drawable-pane
return a pixmap that is created by calling get-pixmap on the window, plus
:pixmap
as the second value. The method for
rich-edit-pane
returns the selected text as a rich text string, plus
:rich-text
as the second value. The method for
dialog-item
simply calls copy-selection on the window of the dialog-item
if the
widget is currently on a parent window.
An anomaly: When called on a rich-edit-pane
in Windows, it is
copy-selection
rather than copy-command that actually places
the object onto the clipboard. This is due to a problem with mapping
the Common Graphics behavior onto the Windows clipboard and rich-edit
APIs. In this case, both the rich text string and the plain text
string are placed onto the clipboard, with the rich text string being
topmost on the lisp clipboard stack.
An application could add methods for additional widget or window
classes if you would like to call copy-selection (or copy-command) on the
selected widget or window without regard to its class, letting it
handle the command if it knows how. To do this for a widget (rather
than a window), you could specialize on the dialog-item
subclass if you will
only call copy-selection on the widget; if
you might instead pass the widget's associated window, then you would need to
specialize on the widget-window
subclass. Doing so
requires subclassing both the dialog-item
class and the widget-window
class,
and associating the two subclasses together with a trivial widget-device method.
cut-selection does what this function does and also deletes the returned object from the window or widget. See also paste-selection.
In releases prior to 7.0, this function passed its action to the lowest selected descendent child window of the specified window, though some applications may not desire such automatic redirection. The functions focus-component, get-focus, or selected-window may be useful for finding a suitable widget or window to pass to this function. Earlier releases also returned the window where the copy was actually done as the first value, and the copied object as the second value.
See cg-clipboard.htm.
Copyright (c) 1998-2016, Franz Inc. Oakland, CA., USA. All rights reserved.
This page was not revised from the 8.1 page.
Created 2010.1.21.
| Allegro CL version 8.2 Unrevised from 8.1 to 8.2. 8.1 version |