vcl/source/bitmap/BitmapSobelGreyFilter.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  */
  10
  11 #include <sal/config.h>
  12
  13 #include <algorithm>
  14
  15 #include <vcl/bitmap.hxx>
  16 #include <vcl/bitmapex.hxx>
  17 #include <vcl/bitmapaccess.hxx>
  18 #include <vcl/BitmapSobelGreyFilter.hxx>
  19
  20 #include <bitmapwriteaccess.hxx>
  21
  22 BitmapEx BitmapSobelGreyFilter::execute(BitmapEx const& rBitmapEx) const
  23 {
  24     Bitmap aBitmap(rBitmapEx.GetBitmap());
  25
  26     bool bRet = aBitmap.ImplMakeGreyscales(256);
  27
  28     if (bRet)
  29     {
  30         bRet = false;
  31
  32         Bitmap::ScopedReadAccess pReadAcc(aBitmap);
  33
  34         if (pReadAcc)
  35         {
  36             Bitmap aNewBmp(aBitmap.GetSizePixel(), 8, &pReadAcc->GetPalette());
  37             BitmapScopedWriteAccess pWriteAcc(aNewBmp);
  38
  39             if (pWriteAcc)
  40             {
  41                 BitmapColor aGrey(sal_uInt8(0));
  42                 const tools::Long nWidth = pWriteAcc->Width();
  43                 const tools::Long nHeight = pWriteAcc->Height();
  44                 const tools::Long nMask111 = -1, nMask121 = 0, nMask131 = 1;
  45                 const tools::Long nMask211 = -2, nMask221 = 0, nMask231 = 2;
  46                 const tools::Long nMask311 = -1, nMask321 = 0, nMask331 = 1;
  47                 const tools::Long nMask112 = 1, nMask122 = 2, nMask132 = 1;
  48                 const tools::Long nMask212 = 0, nMask222 = 0, nMask232 = 0;
  49                 const tools::Long nMask312 = -1, nMask322 = -2, nMask332 = -1;
  50                 tools::Long nGrey11, nGrey12, nGrey13;
  51                 tools::Long nGrey21, nGrey22, nGrey23;
  52                 tools::Long nGrey31, nGrey32, nGrey33;
  53                 std::unique_ptr<long[]> pHMap(new long[nWidth + 2]);
  54                 std::unique_ptr<long[]> pVMap(new long[nHeight + 2]);
  55                 tools::Long nX, nY, nSum1, nSum2;
  56
  57                 // fill mapping tables
  58                 pHMap[0] = 0;
  59
  60                 for (nX = 1; nX <= nWidth; nX++)
  61                 {
  62                     pHMap[nX] = nX - 1;
  63                 }
  64
  65                 pHMap[nWidth + 1] = nWidth - 1;
  66
  67                 pVMap[0] = 0;
  68
  69                 for (nY = 1; nY <= nHeight; nY++)
  70                 {
  71                     pVMap[nY] = nY - 1;
  72                 }
  73
  74                 pVMap[nHeight + 1] = nHeight - 1;
  75
  76                 for (nY = 0; nY < nHeight; nY++)
  77                 {
  78                     nGrey11 = pReadAcc->GetPixel(pVMap[nY], pHMap[0]).GetIndex();
  79                     nGrey12 = pReadAcc->GetPixel(pVMap[nY], pHMap[1]).GetIndex();
  80                     nGrey13 = pReadAcc->GetPixel(pVMap[nY], pHMap[2]).GetIndex();
  81                     nGrey21 = pReadAcc->GetPixel(pVMap[nY + 1], pHMap[0]).GetIndex();
  82                     nGrey22 = pReadAcc->GetPixel(pVMap[nY + 1], pHMap[1]).GetIndex();
  83                     nGrey23 = pReadAcc->GetPixel(pVMap[nY + 1], pHMap[2]).GetIndex();
  84                     nGrey31 = pReadAcc->GetPixel(pVMap[nY + 2], pHMap[0]).GetIndex();
  85                     nGrey32 = pReadAcc->GetPixel(pVMap[nY + 2], pHMap[1]).GetIndex();
  86                     nGrey33 = pReadAcc->GetPixel(pVMap[nY + 2], pHMap[2]).GetIndex();
  87
  88                     Scanline pScanline = pWriteAcc->GetScanline(nY);
  89                     for (nX = 0; nX < nWidth; nX++)
  90                     {
  91                         nSum1 = nSum2 = 0;
  92
  93                         nSum1 += nMask111 * nGrey11;
  94                         nSum2 += nMask112 * nGrey11;
  95
  96                         nSum1 += nMask121 * nGrey12;
  97                         nSum2 += nMask122 * nGrey12;
  98
  99                         nSum1 += nMask131 * nGrey13;
 100                         nSum2 += nMask132 * nGrey13;
 101
 102                         nSum1 += nMask211 * nGrey21;
 103                         nSum2 += nMask212 * nGrey21;
 104
 105                         nSum1 += nMask221 * nGrey22;
 106                         nSum2 += nMask222 * nGrey22;
 107
 108                         nSum1 += nMask231 * nGrey23;
 109                         nSum2 += nMask232 * nGrey23;
 110
 111                         nSum1 += nMask311 * nGrey31;
 112                         nSum2 += nMask312 * nGrey31;
 113
 114                         nSum1 += nMask321 * nGrey32;
 115                         nSum2 += nMask322 * nGrey32;
 116
 117                         nSum1 += nMask331 * nGrey33;
 118                         nSum2 += nMask332 * nGrey33;
 119
 120                         nSum1 = static_cast<tools::Long>(
 121                             sqrt(static_cast<double>(nSum1 * nSum1 + nSum2 * nSum2)));
 122
 123                         aGrey.SetIndex(~static_cast<sal_uInt8>(
 124                             std::clamp(nSum1, tools::Long(0), tools::Long(255))));
 125                         pWriteAcc->SetPixelOnData(pScanline, nX, aGrey);
 126
 127                         if (nX < (nWidth - 1))
 128                         {
 129                             const tools::Long nNextX = pHMap[nX + 3];
 130
 131                             nGrey11 = nGrey12;
 132                             nGrey12 = nGrey13;
 133                             nGrey13 = pReadAcc->GetPixel(pVMap[nY], nNextX).GetIndex();
 134                             nGrey21 = nGrey22;
 135                             nGrey22 = nGrey23;
 136                             nGrey23 = pReadAcc->GetPixel(pVMap[nY + 1], nNextX).GetIndex();
 137                             nGrey31 = nGrey32;
 138                             nGrey32 = nGrey33;
 139                             nGrey33 = pReadAcc->GetPixel(pVMap[nY + 2], nNextX).GetIndex();
 140                         }
 141                     }
 142                 }
 143
 144                 pHMap.reset();
 145                 pVMap.reset();
 146                 pWriteAcc.reset();
 147                 bRet = true;
 148             }
 149
 150             pReadAcc.reset();
 151
 152             if (bRet)
 153             {
 154                 const MapMode aMap(aBitmap.GetPrefMapMode());
 155                 const Size aPrefSize(aBitmap.GetPrefSize());
 156
 157                 aBitmap = aNewBmp;
 158
 159                 aBitmap.SetPrefMapMode(aMap);
 160                 aBitmap.SetPrefSize(aPrefSize);
 161             }
 162         }
 163     }
 164
 165     if (bRet)
 166         return BitmapEx(aBitmap);
 167
 168     return BitmapEx();
 169 }
 170
 171 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */