vcl/inc/bitmap/ScanlineTools.hxx

   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 #ifndef INCLUDED_VCL_INC_BITMAP_SCANLINETOOLS_HXX
  12 #define INCLUDED_VCL_INC_BITMAP_SCANLINETOOLS_HXX
  13
  14 #include <tools/color.hxx>
  15 #include <vcl/BitmapPalette.hxx>
  16
  17 namespace vcl::bitmap
  18 {
  19 class ScanlineTransformer
  20 {
  21 public:
  22     virtual void startLine(sal_uInt8* pLine) = 0;
  23     virtual void skipPixel(sal_uInt32 nPixel) = 0;
  24     virtual Color readPixel() = 0;
  25     virtual void writePixel(Color nColor) = 0;
  26
  27     virtual ~ScanlineTransformer() = default;
  28 };
  29
  30 class ScanlineTransformer_ARGB final : public ScanlineTransformer
  31 {
  32 private:
  33     sal_uInt8* pData;
  34
  35 public:
  36     virtual void startLine(sal_uInt8* pLine) override { pData = pLine; }
  37
  38     virtual void skipPixel(sal_uInt32 nPixel) override { pData += nPixel << 2; }
  39
  40     virtual Color readPixel() override
  41     {
  42         const Color aColor(ColorTransparency, pData[4], pData[1], pData[2], pData[3]);
  43         pData += 4;
  44         return aColor;
  45     }
  46
  47     virtual void writePixel(Color nColor) override
  48     {
  49         *pData++ = 255 - nColor.GetAlpha();
  50         *pData++ = nColor.GetRed();
  51         *pData++ = nColor.GetGreen();
  52         *pData++ = nColor.GetBlue();
  53     }
  54 };
  55
  56 class ScanlineTransformer_BGR final : public ScanlineTransformer
  57 {
  58 private:
  59     sal_uInt8* pData;
  60
  61 public:
  62     virtual void startLine(sal_uInt8* pLine) override { pData = pLine; }
  63
  64     virtual void skipPixel(sal_uInt32 nPixel) override { pData += (nPixel << 1) + nPixel; }
  65
  66     virtual Color readPixel() override
  67     {
  68         const Color aColor(pData[2], pData[1], pData[0]);
  69         pData += 3;
  70         return aColor;
  71     }
  72
  73     virtual void writePixel(Color nColor) override
  74     {
  75         *pData++ = nColor.GetBlue();
  76         *pData++ = nColor.GetGreen();
  77         *pData++ = nColor.GetRed();
  78     }
  79 };
  80
  81 class ScanlineTransformer_8BitPalette final : public ScanlineTransformer
  82 {
  83 private:
  84     sal_uInt8* pData;
  85     const BitmapPalette& mrPalette;
  86
  87 public:
  88     explicit ScanlineTransformer_8BitPalette(const BitmapPalette& rPalette)
  89         : pData(nullptr)
  90         , mrPalette(rPalette)
  91     {
  92     }
  93
  94     virtual void startLine(sal_uInt8* pLine) override { pData = pLine; }
  95
  96     virtual void skipPixel(sal_uInt32 nPixel) override { pData += nPixel; }
  97
  98     virtual Color readPixel() override
  99     {
 100         const sal_uInt8 nIndex(*pData++);
 101         if (nIndex < mrPalette.GetEntryCount())
 102             return mrPalette[nIndex];
 103         else
 104             return COL_BLACK;
 105     }
 106
 107     virtual void writePixel(Color nColor) override
 108     {
 109         *pData++ = static_cast<sal_uInt8>(mrPalette.GetBestIndex(nColor));
 110     }
 111 };
 112
 113 class ScanlineTransformer_4BitPalette final : public ScanlineTransformer
 114 {
 115 private:
 116     sal_uInt8* pData;
 117     const BitmapPalette& mrPalette;
 118     sal_uInt32 mnX;
 119     sal_uInt32 mnShift;
 120
 121 public:
 122     explicit ScanlineTransformer_4BitPalette(const BitmapPalette& rPalette)
 123         : pData(nullptr)
 124         , mrPalette(rPalette)
 125         , mnX(0)
 126         , mnShift(0)
 127     {
 128     }
 129
 130     virtual void skipPixel(sal_uInt32 nPixel) override
 131     {
 132         mnX += nPixel;
 133         if (nPixel & 1) // is nPixel an odd number
 134             mnShift ^= 4;
 135     }
 136
 137     virtual void startLine(sal_uInt8* pLine) override
 138     {
 139         pData = pLine;
 140         mnX = 0;
 141         mnShift = 4;
 142     }
 143
 144     virtual Color readPixel() override
 145     {
 146         const sal_uInt32 nDataIndex = mnX / 2;
 147         const sal_uInt8 nIndex((pData[nDataIndex] >> mnShift) & 0x0f);
 148         mnX++;
 149         mnShift ^= 4;
 150
 151         if (nIndex < mrPalette.GetEntryCount())
 152             return mrPalette[nIndex];
 153         else
 154             return COL_BLACK;
 155     }
 156
 157     virtual void writePixel(Color nColor) override
 158     {
 159         const sal_uInt32 nDataIndex = mnX / 2;
 160         const sal_uInt8 nColorIndex = mrPalette.GetBestIndex(nColor);
 161         pData[nDataIndex] |= (nColorIndex & 0x0f) << mnShift;
 162         mnX++;
 163         mnShift ^= 4;
 164     }
 165 };
 166
 167 class ScanlineTransformer_1BitPalette final : public ScanlineTransformer
 168 {
 169 private:
 170     sal_uInt8* pData;
 171     const BitmapPalette& mrPalette;
 172     sal_uInt32 mnX;
 173
 174 public:
 175     explicit ScanlineTransformer_1BitPalette(const BitmapPalette& rPalette)
 176         : pData(nullptr)
 177         , mrPalette(rPalette)
 178         , mnX(0)
 179     {
 180     }
 181
 182     virtual void skipPixel(sal_uInt32 nPixel) override { mnX += nPixel; }
 183
 184     virtual void startLine(sal_uInt8* pLine) override
 185     {
 186         pData = pLine;
 187         mnX = 0;
 188     }
 189
 190     virtual Color readPixel() override
 191     {
 192         const sal_uInt8 nIndex((pData[mnX >> 3] >> (7 - (mnX & 7))) & 1);
 193         mnX++;
 194
 195         if (nIndex < mrPalette.GetEntryCount())
 196             return mrPalette[nIndex];
 197         else
 198             return COL_BLACK;
 199     }
 200
 201     virtual void writePixel(Color nColor) override
 202     {
 203         if (mrPalette.GetBestIndex(nColor) & 1)
 204             pData[mnX >> 3] |= 1 << (7 - (mnX & 7));
 205         else
 206             pData[mnX >> 3] &= ~(1 << (7 - (mnX & 7)));
 207         mnX++;
 208     }
 209 };
 210
 211 std::unique_ptr<ScanlineTransformer> getScanlineTransformer(sal_uInt16 nBits,
 212                                                             const BitmapPalette& rPalette)
 213 {
 214     switch (nBits)
 215     {
 216         case 1:
 217             return std::make_unique<ScanlineTransformer_1BitPalette>(rPalette);
 218         case 4:
 219             return std::make_unique<ScanlineTransformer_4BitPalette>(rPalette);
 220         case 8:
 221             return std::make_unique<ScanlineTransformer_8BitPalette>(rPalette);
 222         case 24:
 223             return std::make_unique<ScanlineTransformer_BGR>();
 224         case 32:
 225             return std::make_unique<ScanlineTransformer_ARGB>();
 226         default:
 227             assert(false);
 228             break;
 229     }
 230     return nullptr;
 231 }
 232 }
 233
 234 #endif
 235
 236 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */