LibreOffice Module vcl (master) 1
BitmapSobelGreyFilter.cxx
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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 <vcl/bitmap.hxx>
14#include <vcl/bitmapex.hxx>
16
18
19#include <algorithm>
20
22{
23 Bitmap aBitmap(rBitmapEx.GetBitmap());
24
25 bool bRet = aBitmap.ImplMakeGreyscales();
26
27 if (bRet)
28 {
29 bRet = false;
30
31 Bitmap::ScopedReadAccess pReadAcc(aBitmap);
32
33 if (pReadAcc)
34 {
36 &pReadAcc->GetPalette());
37 BitmapScopedWriteAccess pWriteAcc(aNewBmp);
38
39 if (pWriteAcc)
40 {
41 BitmapColor aGrey(sal_uInt8(0));
42 const sal_Int32 nWidth = pWriteAcc->Width();
43 const sal_Int32 nHeight = pWriteAcc->Height();
44 const sal_Int32 nMask111 = -1, nMask121 = 0, nMask131 = 1;
45 const sal_Int32 nMask211 = -2, nMask221 = 0, nMask231 = 2;
46 const sal_Int32 nMask311 = -1, nMask321 = 0, nMask331 = 1;
47 const sal_Int32 nMask112 = 1, nMask122 = 2, nMask132 = 1;
48 const sal_Int32 nMask212 = 0, nMask222 = 0, nMask232 = 0;
49 const sal_Int32 nMask312 = -1, nMask322 = -2, nMask332 = -1;
50 sal_Int32 nGrey11, nGrey12, nGrey13;
51 sal_Int32 nGrey21, nGrey22, nGrey23;
52 sal_Int32 nGrey31, nGrey32, nGrey33;
53 std::unique_ptr<long[]> pHMap(new long[nWidth + 2]);
54 std::unique_ptr<long[]> pVMap(new long[nHeight + 2]);
55 sal_Int32 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<sal_Int32>(
121 sqrt(static_cast<double>(nSum1 * nSum1 + nSum2 * nSum2)));
122
123 aGrey.SetIndex(~static_cast<sal_uInt8>(
124 std::clamp(nSum1, sal_Int32(0), sal_Int32(255))));
125 pWriteAcc->SetPixelOnData(pScanline, nX, aGrey);
126
127 if (nX < (nWidth - 1))
128 {
129 const sal_Int32 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: */
sal_uInt8 * Scanline
Definition: Scanline.hxx:26
sal_uInt8 GetIndex() const
Definition: BitmapColor.hxx:70
void SetIndex(sal_uInt8 cIndex)
Definition: BitmapColor.hxx:75
Bitmap GetBitmap(Color aTransparentReplaceColor) const
Definition: BitmapEx.cxx:203
const BitmapPalette & GetPalette() const
BitmapColor GetPixel(tools::Long nY, tools::Long nX) const
virtual BitmapEx execute(BitmapEx const &rBitmapEx) const override
void SetPrefMapMode(const MapMode &rMapMode)
const MapMode & GetPrefMapMode() const
Size GetSizePixel() const
void SetPrefSize(const Size &rSize)
SAL_DLLPRIVATE bool ImplMakeGreyscales()
const Size & GetPrefSize() const
HashMap_OWString_Interface aMap
unsigned char sal_uInt8