Drag & drop implementation at GHOST level (only OSX for now)

The dragging sequence is performed in four phases:
 
- Start sequence (GHOST_kEventDraggingEntered) that tells a drag'n'drop operation has started. Already gives the object data type, and the entering mouse location

- Update mouse position (GHOST_kEventDraggingUpdated) sent upon each mouse move until the drag'n'drop operation stops, to give the updated mouse position.
Useful to highlight a potential destination, and update the status (through GHOST_setAcceptDragOperation) telling if the object can be dropped at the current cursor position.

- Abort drag'n'drop sequence (GHOST_kEventDraggingExited) sent when the user moved the mouse outside the window.

- Send the dropped data (GHOST_kEventDraggingDropDone)

- Outside of the normal sequence, dropped data can be sent (GHOST_kEventDraggingDropOnIcon). This can happen when the user drops an object on the application icon. (Also used in OSX to pass the filename of the document the user doubled-clicked in the finder)

Note that the event handler is responsible for freeing the received data.
And the mouse position is sent directly in blender client coordinates (y=0 at bottom)

The GHOST_setAcceptDragOperation(TRUE) call must be placed before the user drops the object for it to be accepted.

Current handled data types :
- Text string
- Array of filenames (full paths)
- Bitmap image (not implemented yet)

1 files changed, 30 insertions, 0 deletions

diff --git a/intern/ghost/GHOST_Types.h b/intern/ghost/GHOST_Types.h
index e98e58740ad..5c888e218d8 100644
--- a/intern/ghost/GHOST_Types.h
+++ b/intern/ghost/GHOST_Types.h
@@ -167,6 +167,12 @@ typedef enum {
 	GHOST_kEventWindowUpdate,
 	GHOST_kEventWindowSize,
 	GHOST_kEventWindowMove,
+	
+	GHOST_kEventDraggingEntered,
+	GHOST_kEventDraggingUpdated,
+	GHOST_kEventDraggingExited,
+	GHOST_kEventDraggingDropDone,
+	GHOST_kEventDraggingDropOnIcon,
 
 	GHOST_kEventTimer,
 
@@ -368,6 +374,30 @@ typedef struct {
 } GHOST_TEventWheelData;
 
 
+typedef enum {
+	GHOST_kDragnDropTypeUnknown =0,
+	GHOST_kDragnDropTypeFilenames, /*Array of strings representing file names (full path) */
+	GHOST_kDragnDropTypeString, /* Unformatted text UTF-8 string */
+	GHOST_kDragnDropTypeBitmap /*Bitmap image data */
+} GHOST_TDragnDropTypes;
+
+typedef struct {
+	/** The x-coordinate of the cursor position. */
+	GHOST_TInt32 x;
+	/** The y-coordinate of the cursor position. */
+	GHOST_TInt32 y;
+	/** The dropped item type */
+	GHOST_TDragnDropTypes dataType;
+	/** The "dropped content" */
+	GHOST_TEventDataPtr data;
+} GHOST_TEventDragnDropData;
+
+typedef struct {
+	int count;
+	GHOST_TUns8 **strings;
+} GHOST_TStringArray;
+
+
 /* original patch used floats, but the driver return ints and uns. We will calibrate in view, no sense on doing conversions twice */
 /* as all USB device controls are likely to use ints, this is also more future proof */
 //typedef struct {