An object to be dragged
A string to be dragged or
A plist of formats and objects to be dragged
A function or
A list of operation keywords allowed for the dragged objects
drag-pane-object initiates a dragging operation from within the pane
. It can only be called from within the button
:press or button
:motion callbacks of the
of an output-pane.
plist is a property list of additional format/value pairs to make available. The currently supported formats are as described for set-drop-object-supported-formats. You can make more than one format available simultaneously.
provides a graphical image for use during the dragging operation on Cocoa. If
is supplied, then it should be a function of one argument. It might be called to provide an image for use during the dragging operation. The function
should return three values: a image object, an x offset and a y offset. The x and y offsets are the position within the image where the mouse should be located. If the image is
is not supplied then a default image is generated. If the x or y offsets are
nil or not returned then the image is positioned with the mouse at its center point. The image that is returned by
is freed automatically in the end of dragging operation. It must be a new image, and cannot be reused.
should be a list of operation keywords that the pane will allow the target application to perform. The operation keywords are
:link as described for the effect in drop-object-drop-effect. If certain platform-specific modifier keys are pressed, then some of the operations will be ignored.
The return value
indicates which operation was performed by the application where the dragged object was dropped. The value will be
:none if the object was not dropped anywhere or dragging was abandoned (for example, by the user hitting the
Escape key). If
:move, then you should update the data structures in your application to remove the object that was dragged.
drag-pane-object is not supported on X11/Motif. See simple-pane for information about drop callbacks.
:image is supplied in
, the dragging mechanism automatically frees the image object as if by free-image when it no longer needs it.
CAPI User Guide and Reference Manual (Macintosh version) - 25 Feb 2015