tdf#130573 labels exchanged in export to BMP

In the commit below, I removed the 1-bit dithered output,
so restore it.

regression from
commit b5699cd01b6a52906880c107bac6f3802ea7353d
Date:   Wed Feb 8 16:18:32 2017 +0200
convert BmpConversion to scoped enum

Note that this bug has been around since LO5.4
which means that anyone who has adjusted their
setting in
officecfg/registry/schema/org/openoffice/Office/Common.xcs
with key BMP
runs the risk of having that setting now revert to its
prior (documented) meaning.

Change-Id: Ibbda8aefbac261ff37ffab7223714f5d0343c692
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/88528
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

5 files changed, 181 insertions, 0 deletions

diff --git a/include/vcl/BitmapMonochromeMatrixFilter.hxx b/include/vcl/BitmapMonochromeMatrixFilter.hxx
new file mode 100644
index 000000000000..58d1d917f65d
--- /dev/null
+++ b/include/vcl/BitmapMonochromeMatrixFilter.hxx
@@ -0,0 +1,28 @@
+/* -*- 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/.
+ *
+ */
+
+#ifndef INCLUDED_INCLUDE_VCL_BITMAPMONOCHROMEMATRIXFILTER_HXX
+#define INCLUDED_INCLUDE_VCL_BITMAPMONOCHROMEMATRIXFILTER_HXX
+
+#include <vcl/BitmapFilter.hxx>
+
+class VCL_DLLPUBLIC BitmapMonochromeMatrixFilter final : public BitmapFilter
+{
+public:
+    /** Convert to monochrome (1-bit) bitmap using dithering
+     */
+    BitmapMonochromeMatrixFilter() {}
+
+    virtual BitmapEx execute(BitmapEx const& rBitmapEx) const override;
+};
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/include/vcl/bitmap.hxx b/include/vcl/bitmap.hxx
index 2b97bded06d1..77fef84ccaa3 100644
--- a/include/vcl/bitmap.hxx
+++ b/include/vcl/bitmap.hxx
@@ -66,6 +66,7 @@ enum class BmpConversion
 {
     NNONE,
     N1BitThreshold,
+    N1BitMatrix, // aka Dithered, used in export to bitmap
     N4BitGreys,
     N4BitColors,
     N8BitGreys,
diff --git a/vcl/Library_vcl.mk b/vcl/Library_vcl.mk
index ca818e271c22..a38c84874ff9 100644
--- a/vcl/Library_vcl.mk
+++ b/vcl/Library_vcl.mk
@@ -333,6 +333,7 @@ $(eval $(call gb_Library_add_exception_objects,vcl,\
     vcl/source/bitmap/bitmapfilter \
     vcl/source/bitmap/BitmapAlphaClampFilter \
     vcl/source/bitmap/BitmapMonochromeFilter \
+    vcl/source/bitmap/BitmapMonochromeMatrixFilter \
     vcl/source/bitmap/BitmapSmoothenFilter \
     vcl/source/bitmap/BitmapLightenFilter \
     vcl/source/bitmap/BitmapDisabledImageFilter \
diff --git a/vcl/source/bitmap/BitmapMonochromeMatrixFilter.cxx b/vcl/source/bitmap/BitmapMonochromeMatrixFilter.cxx
new file mode 100644
index 000000000000..12e72ad1c710
--- /dev/null
+++ b/vcl/source/bitmap/BitmapMonochromeMatrixFilter.cxx
@@ -0,0 +1,142 @@
+/* -*- 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 <vcl/bitmap.hxx>
+#include <vcl/bitmapex.hxx>
+#include <vcl/BitmapMonochromeMatrixFilter.hxx>
+#include <vcl/bitmapaccess.hxx>
+
+#include <bitmapwriteaccess.hxx>
+
+static void ImplCreateDitherMatrix(sal_uInt8 (*pDitherMatrix)[16][16])
+{
+    const double fVal = 3.125;
+    const double fVal16 = fVal / 16.;
+    const double fValScale = 254.;
+    sal_uInt16 pMtx[16][16];
+    sal_uInt16 nMax = 0;
+    static const sal_uInt8 pMagic[4][4] = { {
+                                                0,
+                                                14,
+                                                3,
+                                                13,
+                                            },
+                                            {
+                                                11,
+                                                5,
+                                                8,
+                                                6,
+                                            },
+                                            {
+                                                12,
+                                                2,
+                                                15,
+                                                1,
+                                            },
+                                            { 7, 9, 4, 10 } };
+
+    // Build MagicSquare
+    for (long i = 0; i < 4; i++)
+        for (long j = 0; j < 4; j++)
+            for (long k = 0; k < 4; k++)
+                for (long l = 0; l < 4; l++)
+                {
+                    pMtx[(k << 2) + i][(l << 2) + j] = static_cast<sal_uInt16>(
+                        0.5 + pMagic[i][j] * fVal + pMagic[k][l] * fVal16);
+                    nMax = std::max(pMtx[(k << 2) + i][(l << 2) + j], nMax);
+                }
+
+    // Scale to interval [0;254]
+    double tmp = fValScale / nMax;
+    for (long i = 0; i < 16; i++)
+        for (long j = 0; j < 16; j++)
+            (*pDitherMatrix)[i][j] = static_cast<sal_uInt8>(tmp * pMtx[i][j]);
+}
+
+BitmapEx BitmapMonochromeMatrixFilter::execute(BitmapEx const& aBitmapEx) const
+{
+    Bitmap aBitmap = aBitmapEx.GetBitmap();
+    Bitmap::ScopedReadAccess pReadAcc(aBitmap);
+    bool bRet = false;
+
+    if (pReadAcc)
+    {
+        Bitmap aNewBmp(aBitmap.GetSizePixel(), 1);
+        BitmapScopedWriteAccess pWriteAcc(aNewBmp);
+
+        if (pWriteAcc)
+        {
+            const BitmapColor aBlack(pWriteAcc->GetBestMatchingColor(COL_BLACK));
+            const BitmapColor aWhite(pWriteAcc->GetBestMatchingColor(COL_WHITE));
+            const long nWidth = pWriteAcc->Width();
+            const long nHeight = pWriteAcc->Height();
+            sal_uInt8 pDitherMatrix[16][16];
+
+            ImplCreateDitherMatrix(&pDitherMatrix);
+
+            if (pReadAcc->HasPalette())
+            {
+                for (long nY = 0; nY < nHeight; nY++)
+                {
+                    for (long nX = 0, nModY = nY % 16; nX < nWidth; nX++)
+                    {
+                        const sal_uInt8 cIndex = pReadAcc->GetPixelIndex(nY, nX);
+                        if (pReadAcc->GetPaletteColor(cIndex).GetLuminance()
+                            > pDitherMatrix[nModY][nX % 16])
+                        {
+                            pWriteAcc->SetPixel(nY, nX, aWhite);
+                        }
+                        else
+                            pWriteAcc->SetPixel(nY, nX, aBlack);
+                    }
+                }
+            }
+            else
+            {
+                for (long nY = 0; nY < nHeight; nY++)
+                {
+                    for (long nX = 0, nModY = nY % 16; nX < nWidth; nX++)
+                    {
+                        if (pReadAcc->GetPixel(nY, nX).GetLuminance()
+                            > pDitherMatrix[nModY][nX % 16])
+                        {
+                            pWriteAcc->SetPixel(nY, nX, aWhite);
+                        }
+                        else
+                            pWriteAcc->SetPixel(nY, nX, aBlack);
+                    }
+                }
+            }
+
+            pWriteAcc.reset();
+            bRet = true;
+        }
+
+        pReadAcc.reset();
+
+        if (bRet)
+        {
+            const MapMode aMap(aBitmap.GetPrefMapMode());
+            const Size aSize(aBitmap.GetPrefSize());
+
+            aBitmap = aNewBmp;
+
+            aBitmap.SetPrefMapMode(aMap);
+            aBitmap.SetPrefSize(aSize);
+        }
+    }
+
+    if (bRet)
+        return BitmapEx(aBitmap);
+
+    return BitmapEx();
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/source/gdi/bitmap3.cxx b/vcl/source/gdi/bitmap3.cxx
index a22f77431257..508d1af46f57 100644
--- a/vcl/source/gdi/bitmap3.cxx
+++ b/vcl/source/gdi/bitmap3.cxx
@@ -30,6 +30,7 @@
 #include <vcl/opengl/OpenGLHelper.hxx>
 #endif
 #include <vcl/BitmapMonochromeFilter.hxx>
+#include <vcl/BitmapMonochromeMatrixFilter.hxx>
 
 #include <BitmapScaleSuperFilter.hxx>
 #include <BitmapScaleConvolutionFilter.hxx>
@@ -255,6 +256,14 @@ bool Bitmap::Convert( BmpConversion eConversion )
         }
         break;
 
+        case BmpConversion::N1BitMatrix:
+        {
+            BitmapEx aBmpEx(*this);
+            bRet = BitmapFilter::Filter(aBmpEx, BitmapMonochromeMatrixFilter());
+            *this = aBmpEx.GetBitmap();
+        }
+        break;
+
         case BmpConversion::N4BitGreys:
             bRet = ImplMakeGreyscales( 16 );
         break;