tdf#85761 vcl: JPEG export does not save PPI values correctly

JPEG values are currently hardcoded to 96PPI when we export JPEGs. The
Graphic class doesn't have an easy way to get the PPI, but this can
actually be calculated from the pref size and pref map mode (no idea
why it is called "Pref").

Interestingly, you need to get a multiplier to work this out, relative
to units of 100th mm. The EPS filter code had a function that does
exactly this, but it's entirely based on MapMode units so it was really
implemented in the wrong class IMO. I have thus moved it out of PSWriter
and into MapMode.

This also fixes tdf#65695, which was partially fixed, but had the JPEG
PPI hardcoded to 96dpi.

Also fixes tdf#97481.

Change-Id: Iedb674141dd4e22fcbfb7be357dc777f732aa3aa
Reviewed-on: https://gerrit.libreoffice.org/22339
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>
Reviewed-on: https://gerrit.libreoffice.org/22380
Reviewed-on: https://gerrit.libreoffice.org/22454

8 files changed, 200 insertions, 7 deletions

diff --git a/vcl/CppunitTest_vcl_mapmode.mk b/vcl/CppunitTest_vcl_mapmode.mk
new file mode 100644
index 000000000000..daee48078e31
--- /dev/null
+++ b/vcl/CppunitTest_vcl_mapmode.mk
@@ -0,0 +1,53 @@
+# -*- Mode: makefile-gmake; tab-width: 4; indent-tabs-mode: t -*-
+#
+# 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/.
+#
+
+$(eval $(call gb_CppunitTest_CppunitTest,vcl_mapmode))
+
+$(eval $(call gb_CppunitTest_set_include,vcl_mapmode,\
+    $$(INCLUDE) \
+    -I$(SRCDIR)/vcl/inc \
+))
+
+$(eval $(call gb_CppunitTest_add_exception_objects,vcl_mapmode, \
+	vcl/qa/cppunit/mapmode \
+))
+
+$(eval $(call gb_CppunitTest_use_externals,vcl_mapmode,boost_headers))
+
+$(eval $(call gb_CppunitTest_use_libraries,vcl_mapmode, \
+	comphelper \
+	cppu \
+	cppuhelper \
+	sal \
+	svt \
+	test \
+	tl \
+	tk \
+	unotest \
+	vcl \
+	$(gb_UWINAPI) \
+))
+
+$(eval $(call gb_CppunitTest_use_api,vcl_mapmode,\
+	udkapi \
+	offapi \
+))
+
+$(eval $(call gb_CppunitTest_use_ure,vcl_mapmode))
+$(eval $(call gb_CppunitTest_use_vcl,vcl_mapmode))
+
+$(eval $(call gb_CppunitTest_use_components,vcl_mapmode,\
+	configmgr/source/configmgr \
+	i18npool/util/i18npool \
+	ucb/source/core/ucb1 \
+))
+
+$(eval $(call gb_CppunitTest_use_configuration,vcl_mapmode))
+
+# vim: set noet sw=4 ts=4:
diff --git a/vcl/Module_vcl.mk b/vcl/Module_vcl.mk
index aa26183c774e..93a944605177 100644
--- a/vcl/Module_vcl.mk
+++ b/vcl/Module_vcl.mk
@@ -104,6 +104,7 @@ $(eval $(call gb_Module_add_check_targets,vcl,\
 	CppunitTest_vcl_fontcharmap \
 	CppunitTest_vcl_complextext \
 	CppunitTest_vcl_filters_test \
+	CppunitTest_vcl_mapmode \
 	CppunitTest_vcl_outdev \
 	CppunitTest_vcl_app_test \
 	CppunitTest_vcl_wmf_test \
diff --git a/vcl/qa/cppunit/mapmode.cxx b/vcl/qa/cppunit/mapmode.cxx
new file mode 100644
index 000000000000..87c20a3bd666
--- /dev/null
+++ b/vcl/qa/cppunit/mapmode.cxx
@@ -0,0 +1,65 @@
+/* -*- 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 <test/bootstrapfixture.hxx>
+#include <cppunit/TestAssert.h>
+#include <cppunit/TestFixture.h>
+
+#include <osl/file.hxx>
+#include <osl/process.h>
+
+#include <vcl/mapmod.hxx>
+
+class VclMapModeTest : public test::BootstrapFixture
+{
+public:
+    VclMapModeTest() : BootstrapFixture(true, false) {}
+
+    void testMultiplier();
+
+    CPPUNIT_TEST_SUITE(VclMapModeTest);
+    CPPUNIT_TEST(testMultiplier);
+    CPPUNIT_TEST_SUITE_END();
+};
+
+void VclMapModeTest::testMultiplier()
+{
+    MapMode aMapMode;
+    CPPUNIT_ASSERT_MESSAGE( "Default map mode is MAP_PIXEL, multiplier should be 1", aMapMode.GetUnitMultiplier() == 1 );
+    aMapMode.SetMapUnit( MAP_SYSFONT );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_SYSFONT, multiplier should be 1", aMapMode.GetUnitMultiplier() == 1 );
+    aMapMode.SetMapUnit( MAP_APPFONT );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_APPFONT, multiplier should be 1", aMapMode.GetUnitMultiplier() == 1 );
+    aMapMode.SetMapUnit( MAP_100TH_MM );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_100TH_MM, multiplier should be 1", aMapMode.GetUnitMultiplier() == 1 );
+    aMapMode.SetMapUnit( MAP_10TH_MM );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_10TH_MM, multiplier should be 10", aMapMode.GetUnitMultiplier() == 10 );
+    aMapMode.SetMapUnit( MAP_MM );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_MM, multiplier should be 100", aMapMode.GetUnitMultiplier() == 100 );
+    aMapMode.SetMapUnit( MAP_CM );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_CM, multiplier should be 1000", aMapMode.GetUnitMultiplier() == 1000 );
+    aMapMode.SetMapUnit( MAP_1000TH_INCH );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_1000TH_INCH, multiplier should be 2.54", aMapMode.GetUnitMultiplier() == 2.54 );
+    aMapMode.SetMapUnit( MAP_100TH_INCH );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_100TH_INCH, multiplier should be 2.54", aMapMode.GetUnitMultiplier() == 25.4 );
+    aMapMode.SetMapUnit( MAP_10TH_INCH );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_10TH_INCH, multiplier should be 254", aMapMode.GetUnitMultiplier() == 254 );
+    aMapMode.SetMapUnit( MAP_INCH );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_INCH, multiplier should be 2540", aMapMode.GetUnitMultiplier() == 2540 );
+    aMapMode.SetMapUnit( MAP_TWIP );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_TWIP, multiplier should be 1.76388889", aMapMode.GetUnitMultiplier() == 1.76388889 );
+    aMapMode.SetMapUnit( MAP_POINT );
+    CPPUNIT_ASSERT_MESSAGE( "Map mode is MAP_POINT, multiplier should be 35.27777778", aMapMode.GetUnitMultiplier() == 35.27777778 );
+}
+
+CPPUNIT_TEST_SUITE_REGISTRATION(VclMapModeTest);
+
+CPPUNIT_PLUGIN_IMPLEMENT();
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/source/filter/jpeg/JpegWriter.cxx b/vcl/source/filter/jpeg/JpegWriter.cxx
index 28143ac71148..9d8034b8af83 100644
--- a/vcl/source/filter/jpeg/JpegWriter.cxx
+++ b/vcl/source/filter/jpeg/JpegWriter.cxx
@@ -228,7 +228,11 @@ bool JPEGWriter::Write( const Graphic& rGraphic )
         if( !mbNative )
             mpBuffer = new sal_uInt8[ AlignedWidth4Bytes( mbGreys ? mpReadAccess->Width() * 8L : mpReadAccess->Width() * 24L ) ];
 
-        bRet = WriteJPEG( this, &mrStream, mpReadAccess->Width(), mpReadAccess->Height(), mbGreys, mnQuality, maChromaSubsampling, mxStatusIndicator );
+        SAL_INFO("vcl", "\nJPEG Export - DPI X: " << rGraphic.GetPPI().getX() << "\nJPEG Export - DPI Y: " << rGraphic.GetPPI().getY());
+
+        bRet = WriteJPEG( this, &mrStream, mpReadAccess->Width(),
+                          mpReadAccess->Height(), rGraphic.GetPPI(), mbGreys,
+                          mnQuality, maChromaSubsampling, mxStatusIndicator );
 
         delete[] mpBuffer;
         mpBuffer = NULL;
diff --git a/vcl/source/filter/jpeg/jpeg.h b/vcl/source/filter/jpeg/jpeg.h
index 1f8c21f62aac..63c4b2ac3d28 100644
--- a/vcl/source/filter/jpeg/jpeg.h
+++ b/vcl/source/filter/jpeg/jpeg.h
@@ -24,6 +24,7 @@
 
 #include <com/sun/star/uno/Reference.hxx>
 #include <sal/types.h>
+#include <basegfx/vector/b2dsize.hxx>
 
 #include <jpeglib.h>
 
@@ -38,7 +39,8 @@ void jpeg_svstream_src (j_decompress_ptr cinfo, void* infile);
 
 void jpeg_svstream_dest (j_compress_ptr cinfo, void* outfile);
 
-bool    WriteJPEG( JPEGWriter* pJPEGWriter, void* pOutputStream, long nWidth, long nHeight, bool bGreyScale,
+bool    WriteJPEG( JPEGWriter* pJPEGWriter, void* pOutputStream,
+                   long nWidth, long nHeight, basegfx::B2DSize aPPI, bool bGreyScale,
                    long nQualityPercent, long aChromaSubsampling,
                    css::uno::Reference<css::task::XStatusIndicator> const & status);
 
diff --git a/vcl/source/filter/jpeg/jpegc.cxx b/vcl/source/filter/jpeg/jpegc.cxx
index a9ddddc3124b..df6951049ebb 100644
--- a/vcl/source/filter/jpeg/jpegc.cxx
+++ b/vcl/source/filter/jpeg/jpegc.cxx
@@ -231,7 +231,7 @@ void ReadJPEG( JPEGReader* pJPEGReader, void* pInputStream, long* pLines,
 }
 
 bool WriteJPEG( JPEGWriter* pJPEGWriter, void* pOutputStream,
-                long nWidth, long nHeight, bool bGreys,
+                long nWidth, long nHeight, basegfx::B2DSize aPPI, bool bGreys,
                 long nQualityPercent, long aChromaSubsampling,
                 css::uno::Reference<css::task::XStatusIndicator> const & status )
 {
@@ -270,8 +270,8 @@ bool WriteJPEG( JPEGWriter* pJPEGWriter, void* pOutputStream,
     jpeg_set_quality( &cinfo, (int) nQualityPercent, FALSE );
 
     cinfo.density_unit = 1;
-    cinfo.X_density = 96;
-    cinfo.Y_density = 96;
+    cinfo.X_density = aPPI.getX();
+    cinfo.Y_density = aPPI.getY();
 
     if ( ( nWidth > 128 ) || ( nHeight > 128 ) )
         jpeg_simple_progression( &cinfo );
diff --git a/vcl/source/gdi/graph.cxx b/vcl/source/gdi/graph.cxx
index dc4de009768f..7185b22febfe 100644
--- a/vcl/source/gdi/graph.cxx
+++ b/vcl/source/gdi/graph.cxx
@@ -37,8 +37,8 @@ static void ImplDrawDefault( OutputDevice* pOutDev, const OUString* pText,
                              vcl::Font* pFont, const Bitmap* pBitmap, const BitmapEx* pBitmapEx,
                              const Point& rDestPt, const Size& rDestSize )
 {
-    sal_uInt16      nPixel = (sal_uInt16) pOutDev->PixelToLogic( Size( 1, 1 ) ).Width();
-    sal_uInt16      nPixelWidth = nPixel;
+    sal_uInt16  nPixel = (sal_uInt16) pOutDev->PixelToLogic( Size( 1, 1 ) ).Width();
+    sal_uInt16  nPixelWidth = nPixel;
     Point       aPoint( rDestPt.X() + nPixelWidth, rDestPt.Y() + nPixelWidth );
     Size        aSize( rDestSize.Width() - ( nPixelWidth << 1 ), rDestSize.Height() - ( nPixelWidth << 1 ) );
     bool        bFilled = ( pBitmap != NULL || pBitmapEx != NULL || pFont != NULL );
@@ -424,6 +424,28 @@ void Graphic::SetPrefMapMode( const MapMode& rPrefMapMode )
     mpImpGraphic->ImplSetPrefMapMode( rPrefMapMode );
 }
 
+basegfx::B2DSize Graphic::GetPPI() const
+{
+    MapMode aMapMode = GetPrefMapMode();
+
+    double fWidthInches = ( GetPrefSize().Width() * aMapMode.GetUnitMultiplier() ) / 2540;
+    double fHeightInches = ( GetPrefSize().Height() * aMapMode.GetUnitMultiplier() ) / 2540;
+    double fPpiX = 0;
+    double fPpiY = 0;
+
+    if ( fWidthInches > 0 || fHeightInches > 0 ) // we don't want a divide by 0 situation
+    {
+        fPpiX = GetSizePixel().Width() / fWidthInches;
+        fPpiY = GetSizePixel().Height() / fHeightInches;
+    }
+    else
+    {
+        SAL_WARN("vcl", "PPI X is " << fPpiX << " and PPI Y is " << fPpiY << ": thus we are making this 0 DPI. This is unlikely.");
+    }
+
+    return basegfx::B2DSize( fPpiX, fPpiY );
+}
+
 Size Graphic::GetSizePixel( const OutputDevice* pRefDevice ) const
 {
     Size aRet;
diff --git a/vcl/source/gdi/mapmod.cxx b/vcl/source/gdi/mapmod.cxx
index 860742648ea7..c8892010ac0f 100644
--- a/vcl/source/gdi/mapmod.cxx
+++ b/vcl/source/gdi/mapmod.cxx
@@ -210,6 +210,52 @@ void MapMode::SetScaleY( const Fraction& rScaleY )
     mpImplMapMode->maScaleY.ReduceInaccurate(32);
 }
 
+double MapMode::GetUnitMultiplier() const
+{
+    double  nMul;
+    switch ( GetMapUnit() )
+    {
+        case MAP_PIXEL :
+        case MAP_SYSFONT :
+        case MAP_APPFONT :
+
+        case MAP_100TH_MM :
+            nMul = 1;
+            break;
+        case MAP_10TH_MM :
+            nMul = 10;
+            break;
+        case MAP_MM :
+            nMul = 100;
+            break;
+        case MAP_CM :
+            nMul = 1000;
+            break;
+        case MAP_1000TH_INCH :
+            nMul = 2.54;
+            break;
+        case MAP_100TH_INCH :
+            nMul = 25.4;
+            break;
+        case MAP_10TH_INCH :
+            nMul = 254;
+            break;
+        case MAP_INCH :
+            nMul = 2540;
+            break;
+        case MAP_TWIP :
+            nMul = 1.76388889;
+            break;
+        case MAP_POINT :
+            nMul = 35.27777778;
+            break;
+        default:
+            nMul = 1.0;
+            break;
+    }
+    return nMul;
+}
+
 MapMode& MapMode::operator=( const MapMode& rMapMode )
 {
     DBG_ASSERT( rMapMode.mpImplMapMode->mnRefCount < 0xFFFFFFFE, "MapMode: RefCount overflow" );