// =================================================================================
//	CDragItem.cp			©1995 J. Rodden, DD/MF & Associates. All rights reserved
// =================================================================================
// Mixin class to be used with anything that supports dragging of it's items.
// CDragItem encapsulates the characteristics of a dragable item.
//
// By using CDragItem and overriding AddFlavors and MakeDragRegion, you can
// (a) include as many flavors of an item as you want, (b) define your own outline
// to replace the generic rectangle that LDragTask provides, (c) arrange to send 
// drag data on demand by calling InstallDragSendData when adding flavors (and 
// installing null data in the drag) and overriding DoSendDragData for the object 
// being draged, and (d) override the drag manager's default behaviors for DragInput 
// and DragDrawing by calling InstallDragInput or InstallDragDrawing and overriding 
// DoDragInput or DoDragDrawing respectively.
// =================================================================================

#include "CDragItem.h"

// ============================================================================
//		€ AddFlavors
// ============================================================================
//	Add flavored items to the DragTask.

void
CDragItem::AddFlavors(DragReference inDragRef)
{
}


// ============================================================================
//		€ MakeDragRegion
// ============================================================================
//	Build the region outlining the items to be dragged

void
CDragItem::MakeDragRegion(
	DragReference	inDragRef,
	RgnHandle		inDragRegion)
{
	RgnHandle		theDragRgn = ::NewRgn();	// Make region containing item

  ::OpenRgn();
	SetLocalFrame();
	DrawDragRegion();							// Draw directly into the drag region
  ::CloseRgn (theDragRgn);

	OutlineRegion(theDragRgn);					// Carve out interior of region
	
	RgnHandle	extraRgn = ::NewRgn ();
	if (AddToDragRgn(extraRgn)) {				// provide hook to add another region
		OutlineRegion(extraRgn);
	  ::UnionRgn (extraRgn, theDragRgn, theDragRgn);
	}
  ::DisposeRgn (extraRgn);

	// Accumulate new regions in our total drag region
  ::UnionRgn (theDragRgn, inDragRegion, inDragRegion);
	
	// Tell Drag Manager about this item
  ::SetDragItemBounds (inDragRef, kItemRef, &(**theDragRgn).rgnBBox);
  ::DisposeRgn (theDragRgn);
}


// ============================================================================
//		€ SetLocalFrame
// ============================================================================
// Setup local frame (in global coords) for reference by drawing routines

void
CDragItem::SetLocalFrame (void)
{
}


// ============================================================================
//		€ DrawDragRegion
// ============================================================================
// Draw into the drag region, default does nothing

void
CDragItem::DrawDragRegion ()
{
}


// ============================================================================
//		€ AddToDragRgn
// ============================================================================
// Add a region to the drag region, default does nothing (automatically outlined)
//	return true to include changes to inDragRegion to total drag region.

Boolean
CDragItem::AddToDragRgn (RgnHandle inDragRegion)
{
	return false;
}

// ============================================================================
//		€ OutlineRegion
// ============================================================================
// Utility for obtaining the outline of a region

void
CDragItem::OutlineRegion(RgnHandle inRegion)
{
	RgnHandle	innerRgn = ::NewRgn();	// Carve out interior of region so
  ::CopyRgn (inRegion, innerRgn);		//   that it's just a one-pixel thick
  ::InsetRgn (innerRgn, 1, 1);			//   outline of the item
  ::DiffRgn (inRegion, innerRgn, inRegion);
  ::DisposeRgn (innerRgn);
}


// ============================================================================
//		€ DoDragSendData
// ============================================================================
//	Send the data associated with a particular drag item
//
//	This function gets called if you installed the optional DragSendDataProc
//	for this DropArea. In which case you should override this function
//	to provide the requested data by calling SetDragItemFlavorData.

void
CDragItem::DoDragSendData(
	FlavorType		inFlavor,
	ItemReference	inItemRef,
	DragReference	inDragRef)
{
}


// ============================================================================
//		€ DoDragInput
// ============================================================================
//	Modify the state of the mouse and modifier keys during a drag
//
//	This function gets called if you installed the optional DragInputProc
//	for this DropArea.

void
CDragItem::DoDragInput(
	Point			*ioMouse,
	Int16			*ioModifiers,
	DragReference	inDragRef)
{
}


// ============================================================================
//		€ DoDragDrawing
// ============================================================================
//	Draw the items for a drag in progress
//
//	This function gets called if you installed the optional DragDrawingProc
//	for this DropArea.

void
CDragItem::DoDragDrawing(
	DragRegionMessage	inMessage,
	RgnHandle			inShowRgn,
	Point				inShowOrigin,
	RgnHandle			inHideRgn,
	Point				inHideOrigin,
	DragReference 		inDragRef)
{
}


// ============================================================================
// € Install Callback Functions					   Install Callback Functions €
// ============================================================================
//	Install SendData, DragInput, and DragDrawing Handlers for the Drag Manager
//
//	We use a single handler for each of the Drag and Drop operations.
//	With the Drag Manager, you can register handlers globally or for specific
//	windows. With PowerPlant, we want to have separate handlers for each
//	dragable object.

// ============================================================================
//		€ InstallDragSendData
// ============================================================================

void
CDragItem::InstallDragSendData(DragReference inDragRef)
{
	OSErr	err;

	DragSendDataUPP	theDragSendDataUPP = NewDragSendDataProc(HandleDragSendData);

	err = ::SetDragSendProc( inDragRef, theDragSendDataUPP, this);
	ThrowIfOSErr_(err);
}


// ============================================================================
//		€ InstallDragInput
// ============================================================================

void
CDragItem::InstallDragInput(DragReference inDragRef)
{
	OSErr	err;

	DragInputUPP	theDragInputUPP = NewDragInputProc(HandleDragInput);

	err = ::SetDragInputProc( inDragRef, theDragInputUPP, this);
	ThrowIfOSErr_(err);
}


// ============================================================================
//		€ InstallDragDrawing
// ============================================================================

void
CDragItem::InstallDragDrawing(DragReference inDragRef)
{
	OSErr	err;

	DragDrawingUPP	theDragDrawingUPP = NewDragDrawingProc(HandleDragDrawing);

	err = ::SetDragDrawingProc( inDragRef, theDragDrawingUPP, this);
	ThrowIfOSErr_(err);
}


// ===========================================================================
// € Static Callback Functions					   Static Callback Functions €
// ===========================================================================

// ============================================================================
//		€ HandleDragSendData
// ============================================================================
//	Drag Manager callback for sending the data for an item that is part
//	of an accepted drag and drop

pascal OSErr
CDragItem::HandleDragSendData(
	FlavorType		inFlavor,
	void			*inRefCon,
	ItemReference	inItemRef,
	DragReference	inDragRef)
{
	OSErr	err = noErr;

	Try_ {
		((CDragItem*) inRefCon)->DoDragSendData(inFlavor, inItemRef,
													inDragRef);
	}
	
	Catch_(inErr) {
		err = inErr;
	} EndCatch_
	
	return err;
}


// ============================================================================
//		€ HandleDragInput
// ============================================================================
//	Drag Manager callback for manipulating the mouse and modifier keys
//	during a drag

pascal OSErr
CDragItem::HandleDragInput(
	Point			*ioMouse,
	Int16			*ioModifiers,
	void			*inRefCon,
	DragReference	inDragRef)
{
	OSErr	err = noErr;

	Try_ {
		((CDragItem*) inRefCon)->DoDragInput(ioMouse, ioModifiers,
													inDragRef);
	}
	
	Catch_(inErr) {
		err = inErr;
	} EndCatch_
	
	return err;
}


// ============================================================================
//		€ HandleDragDrawing
// ============================================================================
//	Drag Manager callback for drawing the items during a drag

pascal OSErr
CDragItem::HandleDragDrawing(
	DragRegionMessage	inMessage,
	RgnHandle			inShowRgn,
	Point				inShowOrigin,
	RgnHandle			inHideRgn,
	Point				inHideOrigin,
	void				*inRefCon,
	DragReference		inDragRef)
{
	OSErr	err = noErr;

	Try_ {
		((CDragItem*) inRefCon)->DoDragDrawing(inMessage,
												inShowRgn, inShowOrigin,
												inHideRgn, inHideOrigin,
												inDragRef);
	}
	
	Catch_(inErr) {
		err = inErr;
	} EndCatch_
	
	return err;
}