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// IconWell.h
//
// Free software created 1 Feb 1992
// by Paul Burchard <burchard@math.utah.edu>.
//
// This class creates a well for drag-and-drop of icons. It conforms to the
// target-action paradigm of Controls and so may be configured easily in IB.
// In communicating with other objects it works via its stringValue, a
// TAB-separated list of the complete path names of the file(s) represented by
// the icon. Double-clicks open the files; either via the IconWell's delegate,
// if present, or via WorkSpace otherwise. (Actually, incomplete path names
// work, as long as the icon doesn't depend on the absolute path name, and
// except that you can't double-click to open such an icon.) The delegate also
// receives notice when an icon is about to be dragged out in case the file
// needs to be prepared in any way.
//
// To avoid circularity, if an action message is received from the target, our
// action is not sent back to it.
//
// While IconWells may be dropped into an app in IB like any other Control, two
// things must be present in the NIB file to support their function: (1) the
// opaque white 48 x 48 image "Blank.tiff"; (2) one IconWellControl object
// for each Window in which IconWells appear, created with
// [[IconWellControl alloc] initWindow:theWindow];
// (you don't have to do anything else with it).
//
// The appearance of the IconWell may be set with the setBezeled: and
// setBordered: methods. The setHoldOnDrag: method determines whether dragging
// out of the well is a "copy" or "move" operation; i.e., whether or not the
// icon should remain in the well after it has been successfully dragged out.
// Defaults: bezeled, no border, hold on drag. Dragging and dropping can be
// selectively disabled with the setDraggable:droppable: method.
//
// To implement a different file-opening procedure, create an object with an
// - (int)openFile:(const char *)fullPath ok:(int *)flag;
// method (see Speaker/Listener class documentation for details), and connect
// it up as the IconWell's delegate in IB. Similarly, to intercept drag-outs
// and prep files as needed, implement a method like this:
// - (int)prepFile:(const char *)fullPath ok:(int *)flag;
//
//
// NOTES ON IMPLEMENTATION:
//
// The design of this class is a bit convoluted because drag-and-drop is not
// implemented in a truly robust or object-oriented way in NeXTstep 2.0. You
// have to arrange things just so.
//
// One problem is that WorkSpace handles drag-and-drop messages window by
// window; there is no view-level interface yet in NeXTstep. A Listener which
// has registered to get all the remote msgs for a window sends them to a
// single delegate. It is this delegate, then (an IconWellControl object in
// this scheme), which must delegate these messages to the individual accepting
// views.
//
// The scheme used here is enabled just by initializing an IconWellControl for
// each Window; all organizing between IconWells and, IconWellControls, and
// Listeners is then done automatically. Presumably, the features of the
// IconWellControl class could be built into the Window class itself in a
// future version of NeXTstep.
//
// Another problem is that WorkSpace is tied up while the drop operation is
// being completed. This means that WorkSpace services (such as getting the
// correct icon for a path) are not available for the IconWell methods that
// handle drag-and-drop messages. Thus, low-level PostScript calls are needed
// for some operations.
//
// TO DO:
//
// Use custom ActionCell subclass so background gray can be set.
//
#import <appkit/Control.h>
@interface IconWell : Control
{
id delegate;
id iconPath;
char iconName[512];
BOOL isDropping;
BOOL isDragging;
BOOL isDraggable;
BOOL isDroppable;
BOOL isHoldOnDrag;
NXEvent dragFromEvent;
}
+ initialize;
+ wellListFor:aWindow;
- initFrame:(const NXRect *)frameRect;
- free;
- windowChanged:newWindow;
- setBezeled:(BOOL)flag;
- (BOOL)isBezeled;
- setBordered:(BOOL)flag;
- (BOOL)isBordered;
- setHoldOnDrag:(BOOL)flag;
- (BOOL)isHoldOnDrag;
- setDraggable:(BOOL)dragFlag droppable:(BOOL)dropFlag;
- (BOOL)isDraggable;
- (BOOL)isDroppable;
- (const char *)stringValue;
- setStringValue:(const char *)aString;
- takeStringValueFrom:sender;
- clear:sender;
- (BOOL)acceptsFirstMouse;
- mouseDown:(NXEvent *)theEvent;
- mouseDragged:(NXEvent *)theEvent;
- mouseUp:(NXEvent *)theEvent;
- (int)iconEntered:(int)windowNum at:(double)x :(double)y
iconWindow:(int)iconWindowNum iconX:(double)iconX iconY:(double)iconY
iconWidth:(double)iconWidth iconHeight:(double)iconHeight
pathList:(char *)pathList;
- (int)iconMovedTo:(double)x :(double)y;
- (int)iconExitedAt:(double)x :(double)y;
- (int)iconReleasedAt:(double)x :(double)y ok:(int *)flag;
- (int)openFile:(const char *)fullPath ok:(int *)flag;
- (int)prepFile:(const char *)fullPath ok:(int *)flag;
- setDelegate:anObject;
- delegate;
@end
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.