sobel.cpp

来自「barcode readers [ from Image]」· C++ 代码 · 共 100 行

//
// Sobel
//   Averages the 9 pixels surrounding a central pixel.
//
// 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
//

#include "Sobel.h"

#include "Debug.h"
#include "Image.h"
#include "GrayImageIter.h"
#include "GrayIndex.h"
#include "ImageSize.h"
#include "Replicate.h"

#include <e32std.h>
#include <fbs.h>

using namespace Core;

namespace Algorithm
{

	EXPORT_C CSobel* CSobel::NewL()
	{	
		return new (ELeave) CSobel();	
	}

	CSobel::~CSobel()
	{
	}

	CSobel::CSobel() :
		ibEmpty(true)
	{
	}

	CImage CSobel::FrontL() 
	{
		if (ibEmpty) {
			User::Leave(KErrGeneral);
			return CImage();
		}
		ibEmpty = true;
		return iImage;
	}

	void CSobel::PushL(CImage image)
	{
		IReplicate rRepl(image);
		rRepl.CastL(iImage);

		image.LockLC();
		IGrayImageIter rIter(iImage);
		IGrayIndex rGray(image);
		IImageSize rSize(image);

		int i = 1;
		rIter.NextRow();
		for (; i<rSize.Height()-1; i++) {
			int j = 1;
			rIter++;
			for (; j<rSize.Width()-1; j++) {
				int nSumHoriz = int(rGray[i+1][j-1]) + int(2*rGray[i+1][j]) + int(rGray[i+1][j+1]) -
					           (int(rGray[i-1][j-1]) + int(2*rGray[i-1][j]) + int(rGray[i-1][j+1]));
				int nSumVert = int(rGray[i-1][j+1]) + int(2*rGray[i][j+1]) + int(rGray[i+1][j+1]) -
					           (int(rGray[i-1][j-1]) + int(2*rGray[i][j-1]) + int(rGray[i+1][j-1]));
				nSumHoriz = Abs(nSumHoriz);
				nSumVert = Abs(nSumVert);
				rIter++() = (unsigned char) Min(255, (nSumHoriz + nSumVert));
			}
			rIter.NextRow();
		}
		CleanupStack::PopAndDestroy(); // unlock bitmaps
		CDebug::ShowImage(iImage);
		ibEmpty = false;
	}

	bool CSobel::Empty() const
	{
		return ibEmpty;
	}

};