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 "nsCOMPtr.h"
  14 #include "nsRect.h"
  15 #include "nsPoint.h"
  16 #include "nsString.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
  36 namespace dom {
  37 class DataTransfer;
  38 class Selection;
  39 } // namespace dom
  40 } // namespace mozilla
  41
  42 /**
  43  * XP DragService wrapper base class
  44  */
  45
  46 class nsBaseDragService : public nsIDragService,
  47                           public nsIDragSession
  48 {
  49
  50 public:
  51   typedef mozilla::gfx::SourceSurface SourceSurface;
  52
  53   nsBaseDragService();
  54
  55   //nsISupports
  56   NS_DECL_ISUPPORTS
  57
  58   //nsIDragSession and nsIDragService
  59   NS_DECL_NSIDRAGSERVICE
  60   NS_DECL_NSIDRAGSESSION
  61
  62   void SetDragEndPoint(nsIntPoint aEndDragPoint)
  63   {
  64     mEndDragPoint = mozilla::LayoutDeviceIntPoint::FromUnknownPoint(aEndDragPoint);
  65   }
  66   void SetDragEndPoint(mozilla::LayoutDeviceIntPoint aEndDragPoint)
  67   {
  68     mEndDragPoint = aEndDragPoint;
  69   }
  70
  71   uint16_t GetInputSource() { return mInputSource; }
  72
  73   int32_t TakeChildProcessDragAction();
  74
  75 protected:
  76   virtual ~nsBaseDragService();
  77
  78   /**
  79    * Called from nsBaseDragService to initiate a platform drag from a source
  80    * in this process.  This is expected to ensure that StartDragSession() and
  81    * EndDragSession() get called if the platform drag is successfully invoked.
  82    */
  83   virtual nsresult InvokeDragSessionImpl(nsIArray* aTransferableArray,
  84                                          nsIScriptableRegion* aDragRgn,
  85                                          uint32_t aActionType) = 0;
  86
  87   /**
  88    * Draw the drag image, if any, to a surface and return it. The drag image
  89    * is constructed from mImage if specified, or aDOMNode if mImage is null.
  90    *
  91    * aRegion may be used to draw only a subset of the element. This region
  92    * should be supplied using x and y coordinates measured in css pixels
  93    * that are relative to the upper-left corner of the window.
  94    *
  95    * aScreenPosition should be the screen coordinates of the mouse click
  96    * for the drag. These are in CSS pixels.
  97    *
  98    * On return, aScreenDragRect will contain the screen coordinates of the
  99    * area being dragged. This is used by the platform-specific part of the
 100    * drag service to determine the drag feedback. This rect will be in the
 101    * device pixels of the presContext.
 102    *
 103    * If there is no drag image, the returned surface will be null, but
 104    * aScreenDragRect will still be set to the drag area.
 105    *
 106    * aPresContext will be set to the nsPresContext used determined from
 107    * whichever of mImage or aDOMNode is used.
 108    */
 109   nsresult DrawDrag(nsIDOMNode* aDOMNode,
 110                     nsIScriptableRegion* aRegion,
 111                     mozilla::CSSIntPoint aScreenPosition,
 112                     mozilla::LayoutDeviceIntRect* aScreenDragRect,
 113                     RefPtr<SourceSurface>* aSurface,
 114                     nsPresContext **aPresContext);
 115
 116   /**
 117    * Draw a drag image for an image node specified by aImageLoader or aCanvas.
 118    * This is called by DrawDrag.
 119    */
 120   nsresult DrawDragForImage(nsPresContext *aPresContext,
 121                             nsIImageLoadingContent* aImageLoader,
 122                             mozilla::dom::HTMLCanvasElement* aCanvas,
 123                             mozilla::LayoutDeviceIntRect* aScreenDragRect,
 124                             RefPtr<SourceSurface>* aSurface);
 125
 126   /**
 127    * Convert aScreenPosition from CSS pixels into unscaled device pixels.
 128    */
 129   mozilla::LayoutDeviceIntPoint
 130   ConvertToUnscaledDevPixels(nsPresContext* aPresContext,
 131                              mozilla::CSSIntPoint aScreenPosition);
 132
 133   /**
 134    * If the drag image is a popup, open the popup when the drag begins.
 135    */
 136   void OpenDragPopup();
 137
 138   /**
 139    * Free resources contained in DataTransferItems that aren't needed by JS.
 140    */
 141   void DiscardInternalTransferData();
 142
 143   // Returns true if a drag event was dispatched to a child process after
 144   // the previous TakeDragEventDispatchedToChildProcess() call.
 145   bool TakeDragEventDispatchedToChildProcess()
 146   {
 147     bool retval = mDragEventDispatchedToChildProcess;
 148     mDragEventDispatchedToChildProcess = false;
 149     return retval;
 150   }
 151
 152   bool mCanDrop;
 153   bool mOnlyChromeDrop;
 154   bool mDoingDrag;
 155   // true if mImage should be used to set a drag image
 156   bool mHasImage;
 157   // true if the user cancelled the drag operation
 158   bool mUserCancelled;
 159
 160   bool mDragEventDispatchedToChildProcess;
 161
 162   uint32_t mDragAction;
 163   uint32_t mDragActionFromChildProcess;
 164
 165   nsSize mTargetSize;
 166   nsCOMPtr<nsIDOMNode> mSourceNode;
 167   nsCString mTriggeringPrincipalURISpec;
 168   nsCOMPtr<nsIDOMDocument> mSourceDocument;       // the document at the drag source. will be null
 169                                                   //  if it came from outside the app.
 170   nsContentPolicyType mContentPolicyType;         // the contentpolicy type passed to the channel
 171                                                   // when initiating the drag session
 172   RefPtr<mozilla::dom::DataTransfer> mDataTransfer;
 173
 174   // used to determine the image to appear on the cursor while dragging
 175   nsCOMPtr<nsIDOMNode> mImage;
 176   // offset of cursor within the image
 177   mozilla::CSSIntPoint mImageOffset;
 178
 179   // set if a selection is being dragged
 180   RefPtr<mozilla::dom::Selection> mSelection;
 181
 182   // set if the image in mImage is a popup. If this case, the popup will be opened
 183   // and moved instead of using a drag image.
 184   nsCOMPtr<nsIContent> mDragPopup;
 185
 186   // the screen position where drag gesture occurred, used for positioning the
 187   // drag image.
 188   mozilla::CSSIntPoint mScreenPosition;
 189
 190   // the screen position where the drag ended
 191   mozilla::LayoutDeviceIntPoint mEndDragPoint;
 192
 193   uint32_t mSuppressLevel;
 194
 195   // The input source of the drag event. Possible values are from MouseEvent.
 196   uint16_t mInputSource;
 197
 198   nsTArray<RefPtr<mozilla::dom::ContentParent>> mChildProcesses;
 199 };
 200
 201 #endif // nsBaseDragService_h__