Invoked when the dragged image enters destination bounds or frame; delegate returns dragging operation to perform.
- macOS 10.0+
The object sending the message; use it to get details about the dragging operation.
Invoked when a dragged image enters the destination but only if the destination has registered for the pasteboard data type involved in the drag operation. Specifically, this method is invoked when the mouse pointer enters the destination’s bounds rectangle (if it is a view object) or its frame rectangle (if it is a window object).
This method must return a value that indicates which dragging operation the destination will perform when the image is released. In deciding which dragging operation to return, the method should evaluate the overlap between both the dragging operations allowed by the source (obtained from
sender with the
dragging method) and the dragging operations and pasteboard data types the destination itself supports.
If none of the operations is appropriate, this method should return
NSDrag (this is the default response if the method is not implemented by the destination). A destination will still receive
dragging even if
NSDrag is returned by this method.