BitmapConvolutionMatrixFilter.cxx

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 */
 
#include <tools/helpers.hxx>
 
#include <vcl/bitmap.hxx>
#include <vcl/bitmapex.hxx>
#include <vcl/BitmapConvolutionMatrixFilter.hxx>
#include <vcl/BitmapSharpenFilter.hxx>
 
#include <bitmap/BitmapWriteAccess.hxx>
 
#include <array>
 
BitmapEx BitmapConvolutionMatrixFilter::execute(BitmapEx const& rBitmapEx) const
{
    Bitmap aBitmap(rBitmapEx.GetBitmap());
 
    const sal_Int32 nDivisor = 8;
    Bitmap::ScopedReadAccess pReadAcc(aBitmap);
    if (!pReadAcc)
        return BitmapEx();
 
    Bitmap aNewBmp(aBitmap.GetSizePixel(), vcl::PixelFormat::N24_BPP);
    BitmapScopedWriteAccess pWriteAcc(aNewBmp);
    if (!pWriteAcc)
        return BitmapEx();
 
    const sal_Int32 nWidth = pWriteAcc->Width(), nWidth2 = nWidth + 2;
    const sal_Int32 nHeight = pWriteAcc->Height(), nHeight2 = nHeight + 2;
    std::unique_ptr<sal_Int32[]> pColm(new sal_Int32[nWidth2]);
    std::unique_ptr<sal_Int32[]> pRows(new sal_Int32[nHeight2]);
    std::unique_ptr<BitmapColor[]> pColRow1(new BitmapColor[nWidth2]);
    std::unique_ptr<BitmapColor[]> pColRow2(new BitmapColor[nWidth2]);
    std::unique_ptr<BitmapColor[]> pColRow3(new BitmapColor[nWidth2]);
    BitmapColor* pRowTmp1 = pColRow1.get();
    BitmapColor* pRowTmp2 = pColRow2.get();
    BitmapColor* pRowTmp3 = pColRow3.get();
    BitmapColor* pColor;
    sal_Int32 nY, nX, i, nSumR, nSumG, nSumB, nMatrixVal, nTmp;
    std::array<std::array<sal_Int32, 256>, 9> aKoeff;
    sal_Int32* pTmp;
 
    // create LUT of products of matrix value and possible color component values
    for (nY = 0; nY < 9; nY++)
    {
        for (nX = nTmp = 0, nMatrixVal = mrMatrix[nY]; nX < 256; nX++, nTmp += nMatrixVal)
        {
            aKoeff[nY][nX] = nTmp;
        }
    }
 
    // create column LUT
    for (i = 0; i < nWidth2; i++)
    {
        pColm[i] = (i > 0) ? (i - 1) : 0;
    }
 
    pColm[nWidth + 1] = pColm[nWidth];
 
    // create row LUT
    for (i = 0; i < nHeight2; i++)
    {
        pRows[i] = (i > 0) ? (i - 1) : 0;
    }
 
    pRows[nHeight + 1] = pRows[nHeight];
 
    // read first three rows of bitmap color
    for (i = 0; i < nWidth2; i++)
    {
        pColRow1[i] = pReadAcc->GetColor(pRows[0], pColm[i]);
        pColRow2[i] = pReadAcc->GetColor(pRows[1], pColm[i]);
        pColRow3[i] = pReadAcc->GetColor(pRows[2], pColm[i]);
    }
 
    // do convolution
    for (nY = 0; nY < nHeight;)
    {
        Scanline pScanline = pWriteAcc->GetScanline(nY);
        for (nX = 0; nX < nWidth; nX++)
        {
            // first row
            pTmp = aKoeff[0].data();
            pColor = pRowTmp1 + nX;
            nSumR = pTmp[pColor->GetRed()];
            nSumG = pTmp[pColor->GetGreen()];
            nSumB = pTmp[pColor->GetBlue()];
 
            pTmp = aKoeff[1].data();
            nSumR += pTmp[(++pColor)->GetRed()];
            nSumG += pTmp[pColor->GetGreen()];
            nSumB += pTmp[pColor->GetBlue()];
 
            pTmp = aKoeff[2].data();
            nSumR += pTmp[(++pColor)->GetRed()];
            nSumG += pTmp[pColor->GetGreen()];
            nSumB += pTmp[pColor->GetBlue()];
 
            // second row
            pTmp = aKoeff[3].data();
            pColor = pRowTmp2 + nX;
            nSumR += pTmp[pColor->GetRed()];
            nSumG += pTmp[pColor->GetGreen()];
            nSumB += pTmp[pColor->GetBlue()];
 
            pTmp = aKoeff[4].data();
            nSumR += pTmp[(++pColor)->GetRed()];
            nSumG += pTmp[pColor->GetGreen()];
            nSumB += pTmp[pColor->GetBlue()];
 
            pTmp = aKoeff[5].data();
            nSumR += pTmp[(++pColor)->GetRed()];
            nSumG += pTmp[pColor->GetGreen()];
            nSumB += pTmp[pColor->GetBlue()];
 
            // third row
            pTmp = aKoeff[6].data();
            pColor = pRowTmp3 + nX;
            nSumR += pTmp[pColor->GetRed()];
            nSumG += pTmp[pColor->GetGreen()];
            nSumB += pTmp[pColor->GetBlue()];
 
            pTmp = aKoeff[7].data();
            nSumR += pTmp[(++pColor)->GetRed()];
            nSumG += pTmp[pColor->GetGreen()];
            nSumB += pTmp[pColor->GetBlue()];
 
            pTmp = aKoeff[8].data();
            nSumR += pTmp[(++pColor)->GetRed()];
            nSumG += pTmp[pColor->GetGreen()];
            nSumB += pTmp[pColor->GetBlue()];
 
            // calculate destination color
            pWriteAcc->SetPixelOnData(
                pScanline, nX,
                BitmapColor(static_cast<sal_uInt8>(MinMax(nSumR / nDivisor, 0, 255)),
                            static_cast<sal_uInt8>(MinMax(nSumG / nDivisor, 0, 255)),
                            static_cast<sal_uInt8>(MinMax(nSumB / nDivisor, 0, 255))));
        }
 
        if (++nY < nHeight)
        {
            if (pRowTmp1 == pColRow1.get())
            {
                pRowTmp1 = pColRow2.get();
                pRowTmp2 = pColRow3.get();
                pRowTmp3 = pColRow1.get();
            }
            else if (pRowTmp1 == pColRow2.get())
            {
                pRowTmp1 = pColRow3.get();
                pRowTmp2 = pColRow1.get();
                pRowTmp3 = pColRow2.get();
            }
            else
            {
                pRowTmp1 = pColRow1.get();
                pRowTmp2 = pColRow2.get();
                pRowTmp3 = pColRow3.get();
            }
 
            for (i = 0; i < nWidth2; i++)
            {
                pRowTmp3[i] = pReadAcc->GetColor(pRows[nY + 2], pColm[i]);
            }
        }
    }
 
    pWriteAcc.reset();
    pReadAcc.reset();
 
    const MapMode aMap(aBitmap.GetPrefMapMode());
    const Size aPrefSize(aBitmap.GetPrefSize());
 
    aBitmap = aNewBmp;
 
    aBitmap.SetPrefMapMode(aMap);
    aBitmap.SetPrefSize(aPrefSize);
 
    return BitmapEx(aBitmap);
}
 
const sal_Int32 g_SharpenMatrix[] = { -1, -1, -1, -1, 16, -1, -1, -1, -1 };
 
BitmapSharpenFilter::BitmapSharpenFilter()
    : BitmapConvolutionMatrixFilter(g_SharpenMatrix)
{
}
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