wxOSX: Add support for wxDropSource icons.

The wxDropSource has API for icons of different dnd states indication.
But it is not supported at all on cocoa. No icons at all on OSX.
Now add the proper support for this API.

Author: 徐扬斌

include/wx/dnd.h

@@ -95,7 +95,6 @@ class WXDLLIMPEXP_CORE wxDropSourceBase
     // give the default feedback
     virtual bool GiveFeedback(wxDragResult WXUNUSED(effect)) { return false; }
 
-protected:
     const wxCursor& GetCursor(wxDragResult res) const
     {
         if ( res == wxDragCopy )
@@ -105,7 +104,8 @@ class WXDLLIMPEXP_CORE wxDropSourceBase
         else
             return m_cursorStop;
     }
-
+	
+protected:
     // the data we're dragging
     wxDataObject *m_data;
 

include/wx/osx/cocoa/private/dnd.h

@@ -0,0 +1,36 @@
+#include "wx/wxprec.h"
+
+#if wxUSE_DRAG_AND_DROP || wxUSE_CLIPBOARD
+
+#ifndef WX_PRECOMP
+#include "wx/object.h"
+#endif
+
+#include "wx/dnd.h"
+
+#include "wx/osx/private.h"
+#include "wx/osx/private/datatransfer.h"
+
+@interface DropSourceDelegate : NSObject<NSDraggingSource>
+{
+    BOOL dragFinished;
+    int resultCode;
+    wxDropSource* impl;
+
+    // Flags for drag and drop operations (wxDrag_* ).
+    int m_dragFlags;
+    NSImage* m_copy_cursor;
+    NSImage* m_move_cursor;
+    NSImage* m_none_cursor;
+}
+
+- (void)setImplementation:(nonnull wxDropSource *)dropSource flags:(int)flags;
+- (BOOL)finished;
+- (NSDragOperation)code;
+- (NSDragOperation)draggingSession:(nonnull NSDraggingSession *)session sourceOperationMaskForDraggingContext:(NSDraggingContext)context;
+- (void)draggedImage:(nonnull NSImage *)anImage movedTo:(NSPoint)aPoint;
+- (void)draggedImage:(nonnull NSImage *)anImage endedAt:(NSPoint)aPoint operation:(NSDragOperation)operation;
+- (nullable NSImage*)cursorForStatus:(wxDragResult)status;
+@end
+
+#endif

src/osx/cocoa/dnd.mm

@@ -17,6 +17,7 @@
 #endif
 
 #include "wx/dnd.h"
+#include "wx/osx/cocoa/private/dnd.h"
 #include "wx/clipbrd.h"
 #include "wx/filename.h"
 
@@ -268,24 +269,6 @@ wxDragResult NSDragOperationToWxDragResult(NSDragOperation code)
     return wxDragNone;
 }
 
-@interface DropSourceDelegate : NSObject<NSDraggingSource>
-{
-    BOOL dragFinished;
-    int resultCode;
-    wxDropSource* impl;
-
-    // Flags for drag and drop operations (wxDrag_* ).
-    int m_dragFlags;
-}
-
-- (void)setImplementation:(wxDropSource *)dropSource flags:(int)flags;
-- (BOOL)finished;
-- (NSDragOperation)code;
-- (NSDragOperation)draggingSession:(nonnull NSDraggingSession *)session sourceOperationMaskForDraggingContext:(NSDraggingContext)context;
-- (void)draggedImage:(NSImage *)anImage movedTo:(NSPoint)aPoint;
-- (void)draggedImage:(NSImage *)anImage endedAt:(NSPoint)aPoint operation:(NSDragOperation)operation;
-@end
-
 @implementation DropSourceDelegate
 
 - (id)init
@@ -296,6 +279,9 @@ - (id)init
         resultCode = NSDragOperationNone;
         impl = 0;
         m_dragFlags = wxDrag_CopyOnly;
+        m_copy_cursor = nil;
+        m_move_cursor = nil;
+        m_none_cursor = nil;
     }
     return self;
 }
@@ -397,6 +383,42 @@ - (void)draggedImage:(NSImage *)anImage endedAt:(NSPoint)aPoint operation:(NSDra
     dragFinished = YES;
 }
 
+- (NSImage*)cursorForStatus:(wxDragResult)status
+{
+    NSImage* cursor_img = nil;
+    switch(status){
+    case wxDragCopy:
+        cursor_img = m_copy_cursor;
+        break;
+    case wxDragMove:
+        cursor_img = m_move_cursor;
+        break;
+    default:
+        cursor_img = m_none_cursor;
+        break;
+    }
+    if (cursor_img != nil)
+        return cursor_img;
+
+	wxCursor indicate_cursor = impl->GetCursor(status);
+	
+	if (indicate_cursor.IsOk()) {
+		NSCursor *cursor = (NSCursor*)indicate_cursor.GetHCURSOR();
+		cursor_img = [[cursor image] retain];
+        switch(status){
+        case wxDragCopy:
+            m_copy_cursor = cursor_img;
+            break;
+        case wxDragMove:
+            m_move_cursor = cursor_img;
+            break;
+        default:
+            m_none_cursor = cursor_img;
+            break;
+        }
+	}
+	return cursor_img;
+}
 @end
 
 wxDropTarget::wxDropTarget( wxDataObject *data )

src/osx/cocoa/window.mm

@@ -37,6 +37,9 @@
 #if wxUSE_DRAG_AND_DROP
     #include "wx/dnd.h"
     #include "wx/clipbrd.h"
+    #ifdef __WXOSX_MAC__
+    #include "wx/osx/cocoa/private/dnd.h"
+    #endif
 #endif
 
 #if wxUSE_TOOLTIPS
@@ -1374,6 +1377,22 @@ When dragging the bottom part of the DND sample ("Drag text from here!")
         default :
             break;
     }
+	if (!entered){
+		NSView* the_view = viewImpl->GetWXWidget();
+		[sender enumerateDraggingItemsWithOptions:NSDraggingItemEnumerationConcurrent forView:the_view 
+			classes:[NSArray arrayWithObject:[NSPasteboardItem class]] searchOptions:nil 
+			usingBlock:^(NSDraggingItem *draggingItem, NSInteger idx, BOOL *stop) {
+                           wxUnusedVar(idx);
+						   NSRect theFrame = draggingItem.draggingFrame;
+						   DropSourceDelegate* drop_src_delegate = sender.draggingSource;
+						   NSImage* newDragImage = [drop_src_delegate cursorForStatus:result];
+                           if (newDragImage != nil){
+                               NSRect newFrame = NSMakeRect(theFrame.origin.x, theFrame.origin.y, newDragImage.size.width, newDragImage.size.height);
+						       [draggingItem setDraggingFrame:newFrame contents:newDragImage];
+                           }
+						   *stop = NO;
+					   }];	
+	}
     return nsresult;
 }