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/ContentParent.h"
  19 #include "mozilla/dom/HTMLCanvasElement.h"
  20 #include "nsTArray.h"
  21 #include "Units.h"
  22
  23 // translucency level for drag images
  24 #define DRAG_TRANSLUCENCY 0.65
  25
  26 class nsIContent;
  27 class nsIDOMNode;
  28 class nsPresContext;
  29 class nsIImageLoadingContent;
  30
  31 namespace mozilla {
  32 namespace gfx {
  33 class SourceSurface;
  34 } // namespace gfx
  35 } // namespace mozilla
  36
  37 /**
  38  * XP DragService wrapper base class
  39  */
  40
  41 class nsBaseDragService : public nsIDragService,
  42                           public nsIDragSession
  43 {
  44
  45 public:
  46   typedef mozilla::gfx::SourceSurface SourceSurface;
  47
  48   nsBaseDragService();
  49
  50   //nsISupports
  51   NS_DECL_ISUPPORTS
  52
  53   //nsIDragSession and nsIDragService
  54   NS_DECL_NSIDRAGSERVICE
  55   NS_DECL_NSIDRAGSESSION
  56
  57   void SetDragEndPoint(nsIntPoint aEndDragPoint)
  58   {
  59     mEndDragPoint = mozilla::LayoutDeviceIntPoint::FromUnknownPoint(aEndDragPoint);
  60   }
  61   void SetDragEndPoint(mozilla::LayoutDeviceIntPoint aEndDragPoint)
  62   {
  63     mEndDragPoint = aEndDragPoint;
  64   }
  65
  66   uint16_t GetInputSource() { return mInputSource; }
  67
  68   int32_t TakeChildProcessDragAction();
  69
  70 protected:
  71   virtual ~nsBaseDragService();
  72
  73   /**
  74    * Called from nsBaseDragService to initiate a platform drag from a source
  75    * in this process.  This is expected to ensure that StartDragSession() and
  76    * EndDragSession() get called if the platform drag is successfully invoked.
  77    */
  78   virtual nsresult InvokeDragSessionImpl(nsIArray* aTransferableArray,
  79                                          nsIScriptableRegion* aDragRgn,
  80                                          uint32_t aActionType) = 0;
  81
  82   /**
  83    * Draw the drag image, if any, to a surface and return it. The drag image
  84    * is constructed from mImage if specified, or aDOMNode if mImage is null.
  85    *
  86    * aRegion may be used to draw only a subset of the element. This region
  87    * should be supplied using x and y coordinates measured in css pixels
  88    * that are relative to the upper-left corner of the window.
  89    *
  90    * aScreenPosition should be the screen coordinates of the mouse click
  91    * for the drag. These are in CSS pixels.
  92    *
  93    * On return, aScreenDragRect will contain the screen coordinates of the
  94    * area being dragged. This is used by the platform-specific part of the
  95    * drag service to determine the drag feedback. This rect will be in the
  96    * device pixels of the presContext.
  97    *
  98    * If there is no drag image, the returned surface will be null, but
  99    * aScreenDragRect will still be set to the drag area.
 100    *
 101    * aPresContext will be set to the nsPresContext used determined from
 102    * whichever of mImage or aDOMNode is used.
 103    */
 104   nsresult DrawDrag(nsIDOMNode* aDOMNode,
 105                     nsIScriptableRegion* aRegion,
 106                     mozilla::CSSIntPoint aScreenPosition,
 107                     mozilla::LayoutDeviceIntRect* aScreenDragRect,
 108                     RefPtr<SourceSurface>* aSurface,
 109                     nsPresContext **aPresContext);
 110
 111   /**
 112    * Draw a drag image for an image node specified by aImageLoader or aCanvas.
 113    * This is called by DrawDrag.
 114    */
 115   nsresult DrawDragForImage(nsPresContext *aPresContext,
 116                             nsIImageLoadingContent* aImageLoader,
 117                             mozilla::dom::HTMLCanvasElement* aCanvas,
 118                             mozilla::LayoutDeviceIntRect* aScreenDragRect,
 119                             RefPtr<SourceSurface>* aSurface);
 120
 121   /**
 122    * Convert aScreenPosition from CSS pixels into unscaled device pixels.
 123    */
 124   mozilla::LayoutDeviceIntPoint
 125   ConvertToUnscaledDevPixels(nsPresContext* aPresContext,
 126                              mozilla::CSSIntPoint aScreenPosition);
 127
 128   /**
 129    * If the drag image is a popup, open the popup when the drag begins.
 130    */
 131   void OpenDragPopup();
 132
 133   /**
 134    * Free resources contained in DataTransferItems that aren't needed by JS.
 135    */
 136   void DiscardInternalTransferData();
 137
 138   // Returns true if a drag event was dispatched to a child process after
 139   // the previous TakeDragEventDispatchedToChildProcess() call.
 140   bool TakeDragEventDispatchedToChildProcess()
 141   {
 142     bool retval = mDragEventDispatchedToChildProcess;
 143     mDragEventDispatchedToChildProcess = false;
 144     return retval;
 145   }
 146
 147   bool mCanDrop;
 148   bool mOnlyChromeDrop;
 149   bool mDoingDrag;
 150   // true if mImage should be used to set a drag image
 151   bool mHasImage;
 152   // true if the user cancelled the drag operation
 153   bool mUserCancelled;
 154
 155   bool mDragEventDispatchedToChildProcess;
 156
 157   uint32_t mDragAction;
 158   uint32_t mDragActionFromChildProcess;
 159
 160   nsSize mTargetSize;
 161   nsCOMPtr<nsIDOMNode> mSourceNode;
 162   nsCOMPtr<nsIDOMDocument> mSourceDocument;       // the document at the drag source. will be null
 163                                                   //  if it came from outside the app.
 164   nsContentPolicyType mContentPolicyType;         // the contentpolicy type passed to the channel
 165                                                   // when initiating the drag session
 166   nsCOMPtr<nsIDOMDataTransfer> mDataTransfer;
 167
 168   // used to determine the image to appear on the cursor while dragging
 169   nsCOMPtr<nsIDOMNode> mImage;
 170   // offset of cursor within the image
 171   mozilla::CSSIntPoint mImageOffset;
 172
 173   // set if a selection is being dragged
 174   nsCOMPtr<nsISelection> mSelection;
 175
 176   // set if the image in mImage is a popup. If this case, the popup will be opened
 177   // and moved instead of using a drag image.
 178   nsCOMPtr<nsIContent> mDragPopup;
 179
 180   // the screen position where drag gesture occurred, used for positioning the
 181   // drag image.
 182   mozilla::CSSIntPoint mScreenPosition;
 183
 184   // the screen position where the drag ended
 185   mozilla::LayoutDeviceIntPoint mEndDragPoint;
 186
 187   uint32_t mSuppressLevel;
 188
 189   // The input source of the drag event. Possible values are from nsIDOMMouseEvent.
 190   uint16_t mInputSource;
 191
 192   nsTArray<RefPtr<mozilla::dom::ContentParent>> mChildProcesses;
 193 };
 194
 195 #endif // nsBaseDragService_h__