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 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 #ifndef nsBaseDragService_h__

 #define nsBaseDragService_h__

 #include "nsIDragService.h"

 #include "nsIDragSession.h"

 #include "nsITransferable.h"

 #include "nsIDOMDocument.h"

 #include "nsIDOMDataTransfer.h"

 #include "nsCOMPtr.h"

 #include "nsRect.h"

 #include "nsPoint.h"

 #include "mozilla/RefPtr.h"

 #include "mozilla/dom/HTMLCanvasElement.h"

 // translucency level for drag images

 #define DRAG_TRANSLUCENCY 0.65

 class nsIContent;

 class nsIDOMNode;

 class nsIFrame;

 class nsPresContext;

 class nsIImageLoadingContent;

 class nsICanvasElementExternal;

 namespace mozilla {

 namespace gfx {

 class SourceSurface;

 }

 }

 /**

  * XP DragService wrapper base class

  */

 class nsBaseDragService : public nsIDragService,

                           public nsIDragSession

 {

 public:

   typedef mozilla::gfx::SourceSurface SourceSurface;

   nsBaseDragService();

   virtual ~nsBaseDragService();

   //nsISupports

   NS_DECL_ISUPPORTS

   //nsIDragSession and nsIDragService

   NS_DECL_NSIDRAGSERVICE

   NS_DECL_NSIDRAGSESSION

   void SetDragEndPoint(nsIntPoint aEndDragPoint) { mEndDragPoint = aEndDragPoint; }

   uint16_t GetInputSource() { return mInputSource; }

 protected:

   /**

    * Draw the drag image, if any, to a surface and return it. The drag image

    * is constructed from mImage if specified, or aDOMNode if mImage is null.

    *

    * aRegion may be used to draw only a subset of the element. This region

    * should be supplied using x and y coordinates measured in css pixels

    * that are relative to the upper-left corner of the window.

    *

    * aScreenX and aScreenY should be the screen coordinates of the mouse click

    * for the drag. These are in global display pixels.

    *

    * On return, aScreenDragRect will contain the screen coordinates of the

    * area being dragged. This is used by the platform-specific part of the

    * drag service to determine the drag feedback. This rect will be in the

    * device pixels of the presContext.

    *

    * If there is no drag image, the returned surface will be null, but

    * aScreenDragRect will still be set to the drag area.

    *

    * aPresContext will be set to the nsPresContext used determined from

    * whichever of mImage or aDOMNode is used.

    */

   nsresult DrawDrag(nsIDOMNode* aDOMNode,

                     nsIScriptableRegion* aRegion,

                     int32_t aScreenX, int32_t aScreenY,

                     nsIntRect* aScreenDragRect,

                     mozilla::RefPtr<SourceSurface>* aSurface,

                     nsPresContext **aPresContext);

   /**

    * Draw a drag image for an image node specified by aImageLoader or aCanvas.

    * This is called by DrawDrag.

    */

   nsresult DrawDragForImage(nsPresContext* aPresContext,

                             nsIImageLoadingContent* aImageLoader,

                             mozilla::dom::HTMLCanvasElement* aCanvas,

                             int32_t aScreenX, int32_t aScreenY,

                             nsIntRect* aScreenDragRect,

                             mozilla::RefPtr<SourceSurface>* aSurface);

   /**

    * Convert aScreenX and aScreenY from CSS pixels into unscaled device pixels.

    */

   void

   ConvertToUnscaledDevPixels(nsPresContext* aPresContext,

                              int32_t* aScreenX, int32_t* aScreenY);

   /**

    * If the drag image is a popup, open the popup when the drag begins.

    */

   void OpenDragPopup();

   bool mCanDrop;

   bool mOnlyChromeDrop;

   bool mDoingDrag;

   // true if mImage should be used to set a drag image

   bool mHasImage;

   // true if the user cancelled the drag operation

   bool mUserCancelled;

   uint32_t mDragAction;

   nsSize mTargetSize;

   nsCOMPtr<nsIDOMNode> mSourceNode;

   nsCOMPtr<nsIDOMDocument> mSourceDocument;       // the document at the drag source. will be null

                                                   //  if it came from outside the app.

   nsCOMPtr<nsIDOMDataTransfer> mDataTransfer;

   // used to determine the image to appear on the cursor while dragging

   nsCOMPtr<nsIDOMNode> mImage;

   // offset of cursor within the image 

   int32_t mImageX;

   int32_t mImageY;

   // set if a selection is being dragged

   nsCOMPtr<nsISelection> mSelection;

   // set if the image in mImage is a popup. If this case, the popup will be opened

   // and moved instead of using a drag image.

   nsCOMPtr<nsIContent> mDragPopup;

   // the screen position where drag gesture occurred, used for positioning the

   // drag image when no image is specified. If a value is -1, no event was

   // supplied so the screen position is not known

   int32_t mScreenX;

   int32_t mScreenY;

   // the screen position where the drag ended

   nsIntPoint mEndDragPoint;

   uint32_t mSuppressLevel;

   // The input source of the drag event. Possible values are from nsIDOMMouseEvent.

   uint16_t mInputSource;

 };

 #endif // nsBaseDragService_h__