conncomp.h

barcode readers [ from Image]

//
// ConnComp.h
//   Pipeline stage finds the connected components in a binary (0,*) image.
//   Any non-zero value is treated as a pixel that should be labeled.
//   An efficient UNION-FIND algorithm is used.
//   Note that because the output type is byte, only 255 components can be
//   correctly identified. If there are more components than that the output
//   will be incorrect.
//
// Copyright (C) 2003, 2006 by Jon A. Webb (Contact via GMail; username is jonawebb)
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//

#ifndef CConnComp_h
#define CConnComp_h

#include "PipelineStage.h"

#include <e32cons.h>

namespace Algorithm
{

	class CConnComp :
		public Core::MPipelineStage
	{
		// Lifecycle
	public:
		IMPORT_C static CConnComp* NewL();
		~CConnComp(void);
	private:
		void InitializeL();
		CConnComp();

		// Operations
	private:
		// Returns the next unassigned label. 
		unsigned short NewLabelL();
		// Merges two labels. 
		void Merge(unsigned short, unsigned short);
		// Finds the mapping for a label.
		unsigned short Lookup(unsigned short);
		void ExtendTableL(unsigned int nNewMaxSize);

		///////////////////// Overrides ////////////////////////
		//
		// Overrides from MPipelineStage:
		//
			// Operations
		public:
			Core::CImage FrontL();
			void PushL(Core::CImage);

			// Accessors
		public:
			bool Empty() const;
		//
		//
		/////////////////// End of overrides ///////////////////

	private:
		// Attributes
		// The initial table size
		enum {TableSize = 4096};
		bool ibEmpty;
		// The image being labeled.
		Core::CImage iImage;
		// The table -- pointer and current size
		unsigned short *iTable;
		unsigned int inCurrentSize; 
		// The last assigned label.
		unsigned short iCurrentLabel;
	};

};

#endif // CConnComp_h