michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  *
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsIconDecoder_h__
michael@0: #define nsIconDecoder_h__
michael@0: 
michael@0: #include "Decoder.h"
michael@0: 
michael@0: #include "nsCOMPtr.h"
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace image {
michael@0: class RasterImage;
michael@0: 
michael@0: //////////////////////////////////////////////////////////////////////////////////////////////
michael@0: // The icon decoder is a decoder specifically tailored for loading icons 
michael@0: // from the OS. We've defined our own little format to represent these icons
michael@0: // and this decoder takes that format and converts it into 24-bit RGB with alpha channel
michael@0: // support. It was modeled a bit off the PPM decoder.
michael@0: //
michael@0: // Assumptions about the decoder:
michael@0: // (1) We receive ALL of the data from the icon channel in one OnDataAvailable call. We don't
michael@0: //     support multiple ODA calls yet.
michael@0: // (2) the format of the incoming data is as follows:
michael@0: //     The first two bytes contain the width and the height of the icon. 
michael@0: //     The remaining bytes contain the icon data, 4 bytes per pixel, in
michael@0: //       ARGB order (platform endianness, A in highest bits, B in lowest
michael@0: //       bits), row-primary, top-to-bottom, left-to-right, with
michael@0: //       premultiplied alpha.
michael@0: //
michael@0: //
michael@0: //////////////////////////////////////////////////////////////////////////////////////////////
michael@0: 
michael@0: class nsIconDecoder : public Decoder
michael@0: {
michael@0: public:
michael@0: 
michael@0:   nsIconDecoder(RasterImage &aImage);
michael@0:   virtual ~nsIconDecoder();
michael@0: 
michael@0:   virtual void WriteInternal(const char* aBuffer, uint32_t aCount, DecodeStrategy aStrategy);
michael@0: 
michael@0:   uint8_t mWidth;
michael@0:   uint8_t mHeight;
michael@0:   uint32_t mPixBytesRead;
michael@0:   uint32_t mState;
michael@0: };
michael@0: 
michael@0: enum {
michael@0:   iconStateStart      = 0,
michael@0:   iconStateHaveHeight = 1,
michael@0:   iconStateReadPixels = 2,
michael@0:   iconStateFinished   = 3
michael@0: };
michael@0: 
michael@0: } // namespace image
michael@0: } // namespace mozilla
michael@0: 
michael@0: #endif // nsIconDecoder_h__