widget/src/xpwidgets/nsBaseDragService.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Netscape Communications Corporation.
  19  * Portions created by the Initial Developer are Copyright (C) 1998
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *
  24  * Alternatively, the contents of this file may be used under the terms of
  25  * either the GNU General Public License Version 2 or later (the "GPL"), or
  26  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  27  * in which case the provisions of the GPL or the LGPL are applicable instead
  28  * of those above. If you wish to allow use of your version of this file only
  29  * under the terms of either the GPL or the LGPL, and not to allow others to
  30  * use your version of this file under the terms of the MPL, indicate your
  31  * decision by deleting the provisions above and replace them with the notice
  32  * and other provisions required by the GPL or the LGPL. If you do not delete
  33  * the provisions above, a recipient may use your version of this file under
  34  * the terms of any one of the MPL, the GPL or the LGPL.
  35  *
  36  * ***** END LICENSE BLOCK ***** */
  37
  38 #ifndef nsBaseDragService_h__
  39 #define nsBaseDragService_h__
  40
  41 #include "nsIDragService.h"
  42 #include "nsIDragSession.h"
  43 #include "nsITransferable.h"
  44 #include "nsISupportsArray.h"
  45 #include "nsIDOMDocument.h"
  46 #include "nsCOMPtr.h"
  47 #include "nsIRenderingContext.h"
  48 #include "nsIDOMDataTransfer.h"
  49
  50 #include "gfxImageSurface.h"
  51
  52 // translucency level for drag images
  53 #define DRAG_TRANSLUCENCY 0.65
  54
  55 class nsIDOMNode;
  56 class nsIFrame;
  57 class nsPresContext;
  58 class nsIImageLoadingContent;
  59 class nsICanvasElementExternal;
  60
  61 /**
  62  * XP DragService wrapper base class
  63  */
  64
  65 class nsBaseDragService : public nsIDragService,
  66                           public nsIDragSession
  67 {
  68
  69 public:
  70   nsBaseDragService();
  71   virtual ~nsBaseDragService();
  72
  73   //nsISupports
  74   NS_DECL_ISUPPORTS
  75
  76   //nsIDragSession and nsIDragService
  77   NS_DECL_NSIDRAGSERVICE
  78   NS_DECL_NSIDRAGSESSION
  79
  80   void SetDragEndPoint(nsIntPoint aEndDragPoint) { mEndDragPoint = aEndDragPoint; }
  81
  82   PRUint16 GetInputSource() { return mInputSource; }
  83
  84 protected:
  85
  86   /**
  87    * Draw the drag image, if any, to a surface and return it. The drag image
  88    * is constructed from mImage if specified, or aDOMNode if mImage is null.
  89    *
  90    * aRegion may be used to draw only a subset of the element. This region
  91    * should be supplied using x and y coordinates measured in css pixels
  92    * that are relative to the upper-left corner of the window.
  93    *
  94    * aScreenX and aScreenY should be the screen coordinates of the mouse click
  95    * for the drag.
  96    *
  97    * On return, aScreenDragRect will contain the screen coordinates of the
  98    * area being dragged. This is used by the platform-specific part of the
  99    * drag service to determine the drag feedback.
 100    *
 101    * If there is no drag image, the returned surface will be null, but
 102    * aScreenDragRect will still be set to the drag area.
 103    *
 104    * aPresContext will be set to the nsPresContext used determined from
 105    * whichever of mImage or aDOMNode is used.
 106    */
 107   nsresult DrawDrag(nsIDOMNode* aDOMNode,
 108                     nsIScriptableRegion* aRegion,
 109                     PRInt32 aScreenX, PRInt32 aScreenY,
 110                     nsIntRect* aScreenDragRect,
 111                     gfxASurface** aSurface,
 112                     nsPresContext **aPresContext);
 113
 114   /**
 115    * Draw a drag image for an image node specified by aImageLoader or aCanvas.
 116    * This is called by DrawDrag.
 117    */
 118   nsresult DrawDragForImage(nsPresContext* aPresContext,
 119                             nsIImageLoadingContent* aImageLoader,
 120                             nsICanvasElementExternal* aCanvas,
 121                             PRInt32 aScreenX, PRInt32 aScreenY,
 122                             nsIntRect* aScreenDragRect,
 123                             gfxASurface** aSurface);
 124
 125   /**
 126    * Convert aScreenX and aScreenY from CSS pixels into unscaled device pixels.
 127    */
 128   void
 129   ConvertToUnscaledDevPixels(nsPresContext* aPresContext,
 130                              PRInt32* aScreenX, PRInt32* aScreenY);
 131
 132   PRPackedBool mCanDrop;
 133   PRPackedBool mOnlyChromeDrop;
 134   PRPackedBool mDoingDrag;
 135   // true if mImage should be used to set a drag image
 136   PRPackedBool mHasImage;
 137   // true if the user cancelled the drag operation
 138   PRPackedBool mUserCancelled;
 139
 140   PRUint32 mDragAction;
 141   nsSize mTargetSize;
 142   nsCOMPtr<nsIDOMNode> mSourceNode;
 143   nsCOMPtr<nsIDOMDocument> mSourceDocument;       // the document at the drag source. will be null
 144                                                   //  if it came from outside the app.
 145   nsCOMPtr<nsIDOMDataTransfer> mDataTransfer;
 146
 147   // used to determine the image to appear on the cursor while dragging
 148   nsCOMPtr<nsIDOMNode> mImage;
 149   // offset of cursor within the image
 150   PRInt32 mImageX;
 151   PRInt32 mImageY;
 152
 153   // set if a selection is being dragged
 154   nsCOMPtr<nsISelection> mSelection;
 155
 156   // the screen position where drag gesture occurred, used for positioning the
 157   // drag image when no image is specified. If a value is -1, no event was
 158   // supplied so the screen position is not known
 159   PRInt32 mScreenX;
 160   PRInt32 mScreenY;
 161
 162   // the screen position where the drag ended
 163   nsIntPoint mEndDragPoint;
 164
 165   PRUint32 mSuppressLevel;
 166
 167   // The input source of the drag event. Possible values are from nsIDOMNSMouseEvent.
 168   PRUint16 mInputSource;
 169 };
 170
 171 #endif // nsBaseDragService_h__