widget/nsBaseDragService.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef nsBaseDragService_h__
   7 #define nsBaseDragService_h__
   8
   9 #include "nsIDragService.h"
  10 #include "nsIDragSession.h"
  11 #include "nsITransferable.h"
  12 #include "nsIDOMDocument.h"
  13 #include "nsIDOMDataTransfer.h"
  14 #include "nsCOMPtr.h"
  15 #include "nsRect.h"
  16 #include "nsPoint.h"
  17 #include "mozilla/RefPtr.h"
  18 #include "mozilla/dom/HTMLCanvasElement.h"
  19
  20 // translucency level for drag images
  21 #define DRAG_TRANSLUCENCY 0.65
  22
  23 class nsIContent;
  24 class nsIDOMNode;
  25 class nsIFrame;
  26 class nsPresContext;
  27 class nsIImageLoadingContent;
  28 class nsICanvasElementExternal;
  29
  30 namespace mozilla {
  31 namespace gfx {
  32 class SourceSurface;
  33 }
  34 }
  35
  36 /**
  37  * XP DragService wrapper base class
  38  */
  39
  40 class nsBaseDragService : public nsIDragService,
  41                           public nsIDragSession
  42 {
  43
  44 public:
  45   typedef mozilla::gfx::SourceSurface SourceSurface;
  46
  47   nsBaseDragService();
  48
  49   //nsISupports
  50   NS_DECL_ISUPPORTS
  51
  52   //nsIDragSession and nsIDragService
  53   NS_DECL_NSIDRAGSERVICE
  54   NS_DECL_NSIDRAGSESSION
  55
  56   void SetDragEndPoint(nsIntPoint aEndDragPoint) { mEndDragPoint = aEndDragPoint; }
  57
  58   uint16_t GetInputSource() { return mInputSource; }
  59
  60 protected:
  61   virtual ~nsBaseDragService();
  62
  63   /**
  64    * Draw the drag image, if any, to a surface and return it. The drag image
  65    * is constructed from mImage if specified, or aDOMNode if mImage is null.
  66    *
  67    * aRegion may be used to draw only a subset of the element. This region
  68    * should be supplied using x and y coordinates measured in css pixels
  69    * that are relative to the upper-left corner of the window.
  70    *
  71    * aScreenX and aScreenY should be the screen coordinates of the mouse click
  72    * for the drag. These are in global display pixels.
  73    *
  74    * On return, aScreenDragRect will contain the screen coordinates of the
  75    * area being dragged. This is used by the platform-specific part of the
  76    * drag service to determine the drag feedback. This rect will be in the
  77    * device pixels of the presContext.
  78    *
  79    * If there is no drag image, the returned surface will be null, but
  80    * aScreenDragRect will still be set to the drag area.
  81    *
  82    * aPresContext will be set to the nsPresContext used determined from
  83    * whichever of mImage or aDOMNode is used.
  84    */
  85   nsresult DrawDrag(nsIDOMNode* aDOMNode,
  86                     nsIScriptableRegion* aRegion,
  87                     int32_t aScreenX, int32_t aScreenY,
  88                     nsIntRect* aScreenDragRect,
  89                     mozilla::RefPtr<SourceSurface>* aSurface,
  90                     nsPresContext **aPresContext);
  91
  92   /**
  93    * Draw a drag image for an image node specified by aImageLoader or aCanvas.
  94    * This is called by DrawDrag.
  95    */
  96   nsresult DrawDragForImage(nsPresContext* aPresContext,
  97                             nsIImageLoadingContent* aImageLoader,
  98                             mozilla::dom::HTMLCanvasElement* aCanvas,
  99                             int32_t aScreenX, int32_t aScreenY,
 100                             nsIntRect* aScreenDragRect,
 101                             mozilla::RefPtr<SourceSurface>* aSurface);
 102
 103   /**
 104    * Convert aScreenX and aScreenY from CSS pixels into unscaled device pixels.
 105    */
 106   void
 107   ConvertToUnscaledDevPixels(nsPresContext* aPresContext,
 108                              int32_t* aScreenX, int32_t* aScreenY);
 109
 110   /**
 111    * If the drag image is a popup, open the popup when the drag begins.
 112    */
 113   void OpenDragPopup();
 114
 115   bool mCanDrop;
 116   bool mOnlyChromeDrop;
 117   bool mDoingDrag;
 118   // true if mImage should be used to set a drag image
 119   bool mHasImage;
 120   // true if the user cancelled the drag operation
 121   bool mUserCancelled;
 122
 123   uint32_t mDragAction;
 124   nsSize mTargetSize;
 125   nsCOMPtr<nsIDOMNode> mSourceNode;
 126   nsCOMPtr<nsIDOMDocument> mSourceDocument;       // the document at the drag source. will be null
 127                                                   //  if it came from outside the app.
 128   nsCOMPtr<nsIDOMDataTransfer> mDataTransfer;
 129
 130   // used to determine the image to appear on the cursor while dragging
 131   nsCOMPtr<nsIDOMNode> mImage;
 132   // offset of cursor within the image
 133   int32_t mImageX;
 134   int32_t mImageY;
 135
 136   // set if a selection is being dragged
 137   nsCOMPtr<nsISelection> mSelection;
 138
 139   // set if the image in mImage is a popup. If this case, the popup will be opened
 140   // and moved instead of using a drag image.
 141   nsCOMPtr<nsIContent> mDragPopup;
 142
 143   // the screen position where drag gesture occurred, used for positioning the
 144   // drag image when no image is specified. If a value is -1, no event was
 145   // supplied so the screen position is not known
 146   int32_t mScreenX;
 147   int32_t mScreenY;
 148
 149   // the screen position where the drag ended
 150   nsIntPoint mEndDragPoint;
 151
 152   uint32_t mSuppressLevel;
 153
 154   // The input source of the drag event. Possible values are from nsIDOMMouseEvent.
 155   uint16_t mInputSource;
 156 };
 157
 158 #endif // nsBaseDragService_h__