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 *
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 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
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 * Contributor(s):
 *
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 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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#ifndef nsIViewObserver_h___
#define nsIViewObserver_h___

#include "nsISupports.h"
#include "nsEvent.h"
#include "nsColor.h"
#include "nsRect.h"

class nsIRenderingContext;
class nsGUIEvent;

// cb03e6e3-9d14-4018-85f8-7d46af878c98
#define NS_IVIEWOBSERVER_IID   \
{ 0xcb03e6e3, 0x9d14, 0x4018, \
  { 0x85, 0xf8, 0x7d, 0x46, 0xaf, 0x87, 0x8c, 0x98 } }

class nsIViewObserver : public nsISupports
{
public:
  
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_IVIEWOBSERVER_IID)

  /* called when the observer needs to paint. This paints the entire
   * frame subtree rooted at the view, including frame subtrees from
   * subdocuments.
   * @param aRenderingContext rendering context to paint to; the origin
   * of the view is painted at (0,0) in the rendering context's current
   * transform. For best results this should transform to pixel-aligned
   * coordinates.
   * @param aDirtyRegion the region to be painted, in the coordinates of aRootView
   * @return error status
   */
  NS_IMETHOD Paint(nsIView*             aRootView,
                   nsIRenderingContext* aRenderingContext,
                   const nsRegion&      aDirtyRegion) = 0;

  /**
   * @see nsLayoutUtils::ComputeRepaintRegionForCopy
   */
  NS_IMETHOD ComputeRepaintRegionForCopy(nsIView*      aRootView,
                                         nsIView*      aMovingView,
                                         nsPoint       aDelta,
                                         const nsRect& aCopyRect,
                                         nsRegion*     aRepaintRegion) = 0;

  /* called when the observer needs to handle an event
   * @param aView  - where to start processing the event; the root view,
   * or the view that's currently capturing this sort of event; must be a view
   * for this presshell
   * @param aEvent - event notification
   * @param aEventStatus - out parameter for event handling
   *                       status
   * @param aHandled - whether the correct frame was found to
   *                   handle the event
   * @return error status
   */
  NS_IMETHOD HandleEvent(nsIView*       aView,
                         nsGUIEvent*    aEvent,
                         nsEventStatus* aEventStatus) = 0;

  /* called when the view has been resized and the
   * content within the view needs to be reflowed.
   * @param aWidth - new width of view
   * @param aHeight - new height of view
   * @return error status
   */
  NS_IMETHOD ResizeReflow(nsIView * aView, nscoord aWidth, nscoord aHeight) = 0;

  /**
   * Hack to find out if the view observer is itself visible, in lieu
   * of having the view trees linked.
   */
  NS_IMETHOD_(PRBool) IsVisible() = 0;

  /**
   * Notify the observer that we're about to start painting.  This
   * gives the observer a chance to make some last-minute invalidates
   * and geometry changes if it wants to.
   */
  NS_IMETHOD_(void) WillPaint() = 0;

  /**
   * Notify the observer that it should invalidate the frame bounds for
   * the frame associated with this view.
   */
  NS_IMETHOD_(void) InvalidateFrameForView(nsIView *aView) = 0;

  /**
   * Dispatch the given synthesized mouse move event, and if
   * aFlushOnHoverChange is true, flush layout if :hover changes cause
   * any restyles.
   */
  NS_IMETHOD_(void) DispatchSynthMouseMove(nsGUIEvent *aEvent,
                                           PRBool aFlushOnHoverChange) = 0;
};

NS_DEFINE_STATIC_IID_ACCESSOR(nsIViewObserver, NS_IVIEWOBSERVER_IID)

#endif
