/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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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
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
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 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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/* the caret is the text cursor used, e.g., when editing */

#ifndef nsICaret_h__
#define nsICaret_h__

#include "nsISupports.h"
#include "nsCOMPtr.h"
#include "nsCoord.h"
#include "nsIFrameSelection.h"

struct nsRect;
struct nsPoint;

class nsIRenderingContext;
class nsIFrame;
class nsIView;
class nsIPresShell;
class nsISelection;
class nsIDOMNode;

// IID for the nsICaret interface
// dcb01833-509d-4fcb-8f7f-6beb006261b9
#define NS_ICARET_IID \
{ 0xdcb01833, 0x509d, 0x4fcb, \
  { 0x8f, 0x7f, 0x6b, 0xeb, 0x00, 0x62, 0x61, 0xb9 } }

class nsICaret: public nsISupports
{
public:
  NS_DECLARE_STATIC_IID_ACCESSOR(NS_ICARET_IID)

  enum EViewCoordinates {
      eTopLevelWindowCoordinates,
      eRenderingViewCoordinates,
      eClosestViewCoordinates,
      eIMECoordinates
    };

  NS_IMETHOD Init(nsIPresShell *inPresShell) = 0;
  NS_IMETHOD Terminate() = 0;
  
  NS_IMETHOD GetCaretDOMSelection(nsISelection **aDOMSel) = 0;
  NS_IMETHOD SetCaretDOMSelection(nsISelection *aDOMSel) = 0;

  /** SetCaretVisible will set the visibility of the caret
   *  @param inMakeVisible PR_TRUE to show the caret, PR_FALSE to hide it
   */
  NS_IMETHOD SetCaretVisible(PRBool inMakeVisible) = 0;

  /** GetCaretVisible will get the visibility of the caret
   *  @param inMakeVisible PR_TRUE it is shown, PR_FALSE it is hidden
   */
  NS_IMETHOD GetCaretVisible(PRBool *outMakeVisible) = 0;

  /** SetCaretReadOnly set the appearance of the caret
   *  @param inMakeReadonly PR_TRUE to show the caret in a 'read only' state,
   *  PR_FALSE to show the caret in normal, editing state
   */
  NS_IMETHOD SetCaretReadOnly(PRBool inMakeReadonly) = 0;

  /** GetCaretCoordinates
   *  Get the position of the caret in coordinates relative to the typed specified (aRelativeToType).
   *  If the selection is collapsed, this returns the caret location
   *    and true in outIsCollapsed.
   *  If the selection is not collapsed, this returns the location of the focus pos,
   *    and false in outIsCollapsed.
   */
  NS_IMETHOD GetCaretCoordinates(EViewCoordinates aRelativeToType, nsISelection *aDOMSel, nsRect *outCoordinates, PRBool *outIsCollapsed, nsIView **outView) = 0;

  /** Erase Caret
   *  this will erase the caret if its drawn and reset drawn status
   */
  NS_IMETHOD EraseCaret() = 0;

  NS_IMETHOD SetVisibilityDuringSelection(PRBool aVisibilityDuringSelection) = 0;
  
  /** DrawAtPosition
   *  
   *  Draw the caret explicitly, at the specified node and offset.
   *  To avoid drawing glitches, you should call EraseCaret()
   *  after each call to DrawAtPosition().
   *
   **/
  NS_IMETHOD DrawAtPosition(nsIDOMNode* aNode, PRInt32 aOffset) = 0;

  /** GetCaretFrameForNodeOffset
    *  Get the frame and content offset at which the caret is drawn,
    *  invoking the bidi caret positioning algorithm if necessary
    **/
  NS_IMETHOD GetCaretFrameForNodeOffset (nsIContent* aContentNode, PRInt32 aOffset, nsIFrameSelection::HINT aFrameHint, PRUint8 aBidiLevel,
                                         nsIFrame** aReturnFrame, PRInt32* aReturnOffset) = 0;
    
};

NS_DEFINE_STATIC_IID_ACCESSOR(nsICaret, NS_ICARET_IID)

nsresult
NS_NewCaret(nsICaret** aInstancePtrResult);


// handy stack-based class for temporarily disabling the caret

class StCaretHider
{
public:
               StCaretHider(nsICaret* aSelCon)
               : mWasVisible(PR_FALSE), mCaret(aSelCon)
               {
                 if (mCaret)
                 {
                   mCaret->GetCaretVisible(&mWasVisible);
                   if (mWasVisible)
                     mCaret->SetCaretVisible(PR_FALSE);
                 }
               }
               
               ~StCaretHider()
               {
                 if (mCaret && mWasVisible)
                   mCaret->SetCaretVisible(PR_TRUE);
                 // nsCOMPtr releases mPresShell
               }

protected:

    PRBool                  mWasVisible;
    nsCOMPtr<nsICaret>  mCaret;
};


#endif  // nsICaret_h__