nsSVGCoordCtx.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * 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 the Mozilla SVG project.
 *
 * The Initial Developer of the Original Code is
 * Crocodile Clips Ltd..
 * Portions created by the Initial Developer are Copyright (C) 2002
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Alex Fritze <alex@croczilla.com> (original author)
 *
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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"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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#ifndef __NS_NSSVGCOORDCTX_H__
#define __NS_NSSVGCOORDCTX_H__

#include "nsCOMPtr.h"
#include "nsIDOMSVGNumber.h"
#include "nsSVGNumber.h"

////////////////////////////////////////////////////////////////////////
// nsSVGCoordCtx: ref-counted class used as a context for
// percentage/unit-based calculation on svg lengths

class nsSVGCoordCtx
{
public:
  float GetMillimeterPerPixel() { return mmPerPx; }
  
  already_AddRefed<nsIDOMSVGNumber> GetLength() {
    nsIDOMSVGNumber *rv = mLength.get();
    NS_IF_ADDREF(rv);
    return rv;
  }

  
  nsrefcnt AddRef() { return ++mRefCnt; }
  nsrefcnt Release() {
    --mRefCnt;
    if (mRefCnt == 0) {
      mRefCnt = 1; // stabilize
      delete this;
      return 0;
    }
    return mRefCnt;
  }  
  
protected:
  friend class nsSVGCoordCtxHolder;
  
  nsSVGCoordCtx() : mRefCnt(1) { // addrefs
    NS_NewSVGNumber(getter_AddRefs(mLength));
  }
  
  PRUint32 mRefCnt;
  float mmPerPx;
  nsCOMPtr<nsIDOMSVGNumber> mLength;
};

#endif // __NS_NSSVGCOORDCTX_H__