gecko/modules/libpr0n/decoders/nsIconDecoder.h

101 lines
3.5 KiB
C++

/* -*- 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 mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 2001
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Scott MacGregor <mscott@netscape.com>
* Bobby Holley <bobbyholley@gmail.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either 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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* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
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* ***** END LICENSE BLOCK ***** */
#ifndef nsIconDecoder_h__
#define nsIconDecoder_h__
#include "Decoder.h"
#include "nsCOMPtr.h"
#include "imgIDecoderObserver.h"
namespace mozilla {
namespace imagelib {
class RasterImage;
//////////////////////////////////////////////////////////////////////////////////////////////
// The icon decoder is a decoder specifically tailored for loading icons
// from the OS. We've defined our own little format to represent these icons
// and this decoder takes that format and converts it into 24-bit RGB with alpha channel
// support. It was modeled a bit off the PPM decoder.
//
// Assumptions about the decoder:
// (1) We receive ALL of the data from the icon channel in one OnDataAvailable call. We don't
// support multiple ODA calls yet.
// (2) the format of the incoming data is as follows:
// The first two bytes contain the width and the height of the icon.
// The remaining bytes contain the icon data, 4 bytes per pixel, in
// ARGB order (platform endianness, A in highest bits, B in lowest
// bits), row-primary, top-to-bottom, left-to-right, with
// premultiplied alpha.
//
//
//////////////////////////////////////////////////////////////////////////////////////////////
class nsIconDecoder : public Decoder
{
public:
nsIconDecoder();
virtual ~nsIconDecoder();
virtual void WriteInternal(const char* aBuffer, PRUint32 aCount);
PRUint8 mWidth;
PRUint8 mHeight;
PRUint32 mPixBytesRead;
PRUint32 mPixBytesTotal;
PRUint8* mImageData;
PRUint32 mState;
};
enum {
iconStateStart = 0,
iconStateHaveHeight = 1,
iconStateReadPixels = 2,
iconStateFinished = 3
};
} // namespace imagelib
} // namespace mozilla
#endif // nsIconDecoder_h__