Use more conversion functions from <tools/UnitConversion.hxx>

This unifies conversion functions to provide both floating-point
and integral overloads, with correct rounding for the latter.
Also sanitizing code it templatized to allow reuse if needed.

Change-Id: Ibe1c9fe4d5baa226c600445779dbaf7dc41a02cb
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/110487
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

14 files changed, 83 insertions, 77 deletions

diff --git a/chart2/source/view/charttypes/VSeriesPlotter.cxx b/chart2/source/view/charttypes/VSeriesPlotter.cxx
index f405396e113c..92cb3786d594 100644
--- a/chart2/source/view/charttypes/VSeriesPlotter.cxx
+++ b/chart2/source/view/charttypes/VSeriesPlotter.cxx
@@ -61,6 +61,7 @@
 #include <com/sun/star/container/XChild.hpp>
 #include <com/sun/star/chart2/RelativePosition.hpp>
 #include <tools/color.hxx>
+#include <tools/UnitConversion.hxx>
 #include <rtl/ustrbuf.hxx>
 #include <rtl/math.hxx>
 #include <basegfx/vector/b2dvector.hxx>
@@ -451,8 +452,7 @@ uno::Reference< drawing::XShape > VSeriesPlotter::createDataLabel( const uno::Re
             uno::Reference< beans::XPropertySet > xProps( rDataSeries.getPropertiesOfPoint( nPointIndex ) );
             if( xProps.is() )
                 xProps->getPropertyValue( "CharHeight") >>= fViewFontSize;
-            // pt -> 1/100th mm
-            fViewFontSize *= (2540.0f / 72.0f);
+            fViewFontSize = convertPointToMm100(fViewFontSize);
         }
 
         // the font height is used for computing the size of an optional legend
diff --git a/chart2/source/view/main/ShapeFactory.cxx b/chart2/source/view/main/ShapeFactory.cxx
index 22b9f8d07820..5b7c4859beb8 100644
--- a/chart2/source/view/main/ShapeFactory.cxx
+++ b/chart2/source/view/main/ShapeFactory.cxx
@@ -56,6 +56,7 @@
 #include <basegfx/matrix/b3dhommatrix.hxx>
 #include <tools/diagnose_ex.h>
 #include <tools/helpers.hxx>
+#include <tools/UnitConversion.hxx>
 #include <sal/log.hxx>
 
 #include <algorithm>
@@ -2391,7 +2392,7 @@ uno::Reference< drawing::XShape >
         float fFontHeight = 0.0;
         if ( xShapeProp.is() && ( xShapeProp->getPropertyValue( "CharHeight" ) >>= fFontHeight ) )
         {
-            fFontHeight *= ( 2540.0f / 72.0f );  // pt -> 1/100 mm
+            fFontHeight = convertPointToMm100(fFontHeight);
             sal_Int32 nXDistance = static_cast< sal_Int32 >( ::rtl::math::round( fFontHeight * 0.18f ) );
             sal_Int32 nYDistance = static_cast< sal_Int32 >( ::rtl::math::round( fFontHeight * 0.30f ) );
             xShapeProp->setPropertyValue( "TextLeftDistance", uno::Any( nXDistance ) );
diff --git a/chart2/source/view/main/VLegend.cxx b/chart2/source/view/main/VLegend.cxx
index 77e6b5800dc5..e05aa94db702 100644
--- a/chart2/source/view/main/VLegend.cxx
+++ b/chart2/source/view/main/VLegend.cxx
@@ -42,6 +42,7 @@
 #include <rtl/math.hxx>
 #include <svl/languageoptions.hxx>
 #include <tools/diagnose_ex.h>
+#include <tools/UnitConversion.hxx>
 
 #include <vector>
 #include <algorithm>
@@ -85,8 +86,7 @@ double lcl_CalcViewFontSize(
         }
     }
 
-    // pt -> 1/100th mm
-    return (fResult * (2540.0 / 72.0));
+    return convertPointToMm100(fResult);
 }
 
 void lcl_getProperties(
diff --git a/filter/source/msfilter/svdfppt.cxx b/filter/source/msfilter/svdfppt.cxx
index 1d7a36032d4c..8cfbf6ed3922 100644
--- a/filter/source/msfilter/svdfppt.cxx
+++ b/filter/source/msfilter/svdfppt.cxx
@@ -3800,8 +3800,8 @@ void PPTNumberFormatCreator::ImplGetNumberFormat( SdrPowerPointImport const & rM
     rNumberFormat.SetBulletChar( nBuChar );
     rNumberFormat.SetBulletRelSize( static_cast<sal_uInt16>(nBulletHeight) );
     rNumberFormat.SetBulletColor( aCol );
-    sal_uInt32 nAbsLSpace = ( nTextOfs * 2540 ) / 576;
-    sal_uInt32 nFirstLineOffset = nAbsLSpace - ( nBulletOfs * 2540 ) / 576;
+    sal_uInt32 nAbsLSpace = convertMasterUnitToMm100(nTextOfs);
+    sal_uInt32 nFirstLineOffset = nAbsLSpace - convertMasterUnitToMm100(nBulletOfs);
     rNumberFormat.SetAbsLSpace( nAbsLSpace );
     rNumberFormat.SetFirstLineOffset( -static_cast<sal_Int32>(nFirstLineOffset) );
 }
@@ -6211,8 +6211,8 @@ void PPTParagraphObj::ApplyTo( SfxItemSet& rSet,  std::optional< sal_Int16 >& rS
     if ( !nIsBullet2 )
     {
         SvxLRSpaceItem aLRSpaceItem( EE_PARA_LRSPACE );
-        sal_uInt16 nAbsLSpace = static_cast<sal_uInt16>( ( _nTextOfs * 2540 ) / 576 );
-        auto const nFirstLineOffset = nAbsLSpace - static_cast<sal_uInt16>( ( _nBulletOfs * 2540 ) / 576 );
+        auto const nAbsLSpace = convertMasterUnitToMm100(_nTextOfs);
+        auto const nFirstLineOffset = nAbsLSpace - convertMasterUnitToMm100(_nBulletOfs);
         aLRSpaceItem.SetLeft( nAbsLSpace );
         aLRSpaceItem.SetTextFirstLineOffsetValue( -nFirstLineOffset );
         rSet.Put( aLRSpaceItem );
@@ -6290,7 +6290,7 @@ void PPTParagraphObj::ApplyTo( SfxItemSet& rSet,  std::optional< sal_Int16 >& rS
         SvxULSpaceItem aULSpaceItem( EE_PARA_ULSPACE );
         nVal2 = static_cast<sal_Int16>(nUpperDist);
         if ( nVal2 <= 0 )
-            aULSpaceItem.SetUpper( static_cast<sal_uInt16>((static_cast<sal_uInt32>(- nVal2) * 2540 ) / ( 72 * 8 ) ) );
+            aULSpaceItem.SetUpper(static_cast<sal_uInt16>(convertMasterUnitToMm100(-nVal2)));
         else
         {
             aULSpaceItem.SetUpperValue( 0 );
@@ -6298,7 +6298,7 @@ void PPTParagraphObj::ApplyTo( SfxItemSet& rSet,  std::optional< sal_Int16 >& rS
         }
         nVal2 = static_cast<sal_Int16>(nLowerDist);
         if ( nVal2 <= 0 )
-            aULSpaceItem.SetLower( static_cast<sal_uInt16>((static_cast<sal_uInt32>(- nVal2) * 2540 ) / ( 72 * 8 ) ) );
+            aULSpaceItem.SetLower(static_cast<sal_uInt16>(convertMasterUnitToMm100(-nVal2)));
         else
         {
             aULSpaceItem.SetLowerValue( 0 );
diff --git a/include/tools/UnitConversion.hxx b/include/tools/UnitConversion.hxx
index 57f8e39119f0..7aac3f36ebd0 100644
--- a/include/tools/UnitConversion.hxx
+++ b/include/tools/UnitConversion.hxx
@@ -12,46 +12,60 @@
 
 #include <sal/types.h>
 #include <cassert>
-#include <limits>
+#include <type_traits>
 
-constexpr sal_Int64 convertTwipToMm100(sal_Int64 n)
+template <typename I> constexpr bool isBetween(I n, sal_Int64 min, sal_Int64 max)
 {
-    assert(n < std::numeric_limits<sal_Int64>::max() / 127
-           && n > std::numeric_limits<sal_Int64>::min() / 127);
-    return (n >= 0) ? (n * 127 + 36) / 72 : (n * 127 - 36) / 72;
+    assert(max > 0 && min < 0);
+    if constexpr (std::is_signed_v<I>)
+        return n >= min && n <= max;
+    else
+        return n <= sal_uInt64(max);
 }
 
-constexpr sal_Int64 convertMm100ToTwip(sal_Int64 n)
+constexpr int actualMul(int m, int d) { return (m % d == 0) ? m / d : (d % m == 0) ? 1 : m; }
+constexpr int actualDiv(int m, int d) { return (m % d == 0) ? 1 : (d % m == 0) ? d / m : d; }
+
+// Ensure correct rounding for both positive and negative integers
+template <int mul, int div, typename I, std::enable_if_t<std::is_integral_v<I>, int> = 0>
+constexpr sal_Int64 MulDiv(I n)
 {
-    assert(n < std::numeric_limits<sal_Int64>::max() / 72
-           && n > std::numeric_limits<sal_Int64>::min() / 72);
-    return (n >= 0) ? (n * 72 + 63) / 127 : (n * 72 - 63) / 127;
+    static_assert(mul > 0 && div > 0);
+    constexpr int m = actualMul(mul, div), d = actualDiv(mul, div);
+    assert(isBetween(n, (SAL_MIN_INT64 + d / 2) / m, (SAL_MAX_INT64 - d / 2) / m));
+    return (n >= 0 ? (sal_Int64(n) * m + d / 2) : (sal_Int64(n) * m - d / 2)) / d;
 }
-
-constexpr sal_Int64 sanitiseMm100ToTwip(sal_Int64 n)
+template <int mul, int div, typename F, std::enable_if_t<std::is_floating_point_v<F>, int> = 0>
+constexpr double MulDiv(F f)
 {
-    if (n >= std::numeric_limits<sal_Int64>::max() / 72
-        || n <= std::numeric_limits<sal_Int64>::min() / 72)
-        return n / 127 * 72; // do without correction; can not overflow here
-    else
-        return convertMm100ToTwip(n);
+    static_assert(mul > 0 && div > 0);
+    return f * (double(mul) / div);
 }
 
-constexpr sal_Int64 convertPointToTwip(sal_Int64 nNumber) { return nNumber * 20; }
-
-constexpr sal_Int64 convertPointToMm100(sal_Int64 nNumber)
+template <int mul, int div, typename I, std::enable_if_t<std::is_integral_v<I>, int> = 0>
+constexpr sal_Int64 sanitizeMulDiv(I n)
 {
-    return convertTwipToMm100(convertPointToTwip(nNumber));
+    constexpr int m = actualMul(mul, div), d = actualDiv(mul, div);
+    if constexpr (m > d)
+        if (!isBetween(n, SAL_MIN_INT64 / m * d + d / 2, SAL_MAX_INT64 / m * d - d / 2))
+            return n > 0 ? SAL_MAX_INT64 : SAL_MIN_INT64; // saturate
+    if (!isBetween(n, (SAL_MIN_INT64 + d / 2) / m, (SAL_MAX_INT64 - d / 2) / m))
+        return (n >= 0 ? n + d / 2 : n - d / 2) / d * m; // divide before multiplication
+    return MulDiv<mul, div>(n);
 }
 
-constexpr double convertPointToTwip(double fNumber) { return fNumber * 20.0; }
+template <typename N> constexpr auto convertTwipToMm100(N n) { return MulDiv<127, 72>(n); }
+template <typename N> constexpr auto convertMm100ToTwip(N n) { return MulDiv<72, 127>(n); }
+
+constexpr sal_Int64 sanitiseMm100ToTwip(sal_Int64 n) { return sanitizeMulDiv<72, 127>(n); }
 
-constexpr double convertPointToMm100(double fNumber) { return fNumber * (2540.0 / 72.0); }
+template <typename N> constexpr auto convertPointToTwip(N n) { return MulDiv<20, 1>(n); }
 
-// Convert PPT's "master unit" (1/576 inch) to mm/100
-constexpr sal_Int64 convertMasterUnitToMm100(sal_Int64 n) { return n * (2540.0 / 576.0); }
+template <typename N> constexpr auto convertPointToMm100(N n) { return MulDiv<2540, 72>(n); }
+template <typename N> constexpr auto convertMm100ToPoint(N n) { return MulDiv<72, 2540>(n); }
 
-// Convert mm/100 to PPT's "master unit"
-constexpr sal_Int64 convertMm100ToMasterUnit(sal_Int64 n) { return n / (2540.0 / 576.0); }
+// PPT's "master unit" (1/576 inch) <=> mm/100
+template <typename N> constexpr auto convertMasterUnitToMm100(N n) { return MulDiv<2540, 576>(n); }
+template <typename N> constexpr auto convertMm100ToMasterUnit(N n) { return MulDiv<576, 2540>(n); }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/oox/source/drawingml/chart/typegroupconverter.cxx b/oox/source/drawingml/chart/typegroupconverter.cxx
index f6cea5df9b38..6cc4d81eba25 100644
--- a/oox/source/drawingml/chart/typegroupconverter.cxx
+++ b/oox/source/drawingml/chart/typegroupconverter.cxx
@@ -43,6 +43,7 @@
 #include <oox/token/namespaces.hxx>
 #include <oox/token/properties.hxx>
 #include <oox/token/tokens.hxx>
+#include <tools/UnitConversion.hxx>
 
 namespace oox::drawingml::chart {
 
@@ -489,7 +490,7 @@ void TypeGroupConverter::convertMarker( PropertySet& rPropSet, sal_Int32 nOoxSym
     }
 
     // symbol size (points in OOXML, 1/100 mm in Chart2)
-    sal_Int32 nSize = static_cast< sal_Int32 >( nOoxSize * (2540.0 / 72.0) + 0.5 );
+    sal_Int32 nSize = convertPointToMm100(nOoxSize);
     aSymbol.Size.Width = aSymbol.Size.Height = nSize;
 
     if(xShapeProps.is())
diff --git a/oox/source/ole/vbacontrol.cxx b/oox/source/ole/vbacontrol.cxx
index 1b85c27dd6f6..07c91483c773 100644
--- a/oox/source/ole/vbacontrol.cxx
+++ b/oox/source/ole/vbacontrol.cxx
@@ -30,6 +30,7 @@
 #include <osl/diagnose.h>
 #include <rtl/ustrbuf.hxx>
 #include <sal/log.hxx>
+#include <tools/UnitConversion.hxx>
 #include <xmlscript/xmldlg_imexp.hxx>
 #include <oox/helper/attributelist.hxx>
 #include <oox/helper/binaryinputstream.hxx>
@@ -706,8 +707,7 @@ void VbaFormControl::moveEmbeddedToAbsoluteParent()
     const AxFontDataModel* pFontModel = dynamic_cast< const AxFontDataModel* >( mxCtrlModel.get() );
     if( pFontModel && (pFontModel->getControlType() == API_CONTROL_GROUPBOX) )
     {
-        // convert points to 1/100 mm (1 pt = 1/72 inch = 2.54/72 cm = 2540/72 1/100 mm)
-        sal_Int32 nFontHeight = static_cast< sal_Int32 >( pFontModel->getFontHeight() * 2540 / 72 );
+        sal_Int32 nFontHeight = convertPointToMm100(pFontModel->getFontHeight());
         aDistance.second += nFontHeight / 2;
     }
 
diff --git a/sd/source/core/drawdoc4.cxx b/sd/source/core/drawdoc4.cxx
index 48ad50b89ced..a71b9ea8b6bc 100644
--- a/sd/source/core/drawdoc4.cxx
+++ b/sd/source/core/drawdoc4.cxx
@@ -30,6 +30,7 @@
 #include <DrawDocShell.hxx>
 #include <editeng/eeitem.hxx>
 #include <tools/diagnose_ex.h>
+#include <tools/UnitConversion.hxx>
 
 #include <vcl/idle.hxx>
 #include <vcl/settings.hxx>
@@ -1342,8 +1343,7 @@ sal_uInt32 SdDrawDocument::convertFontHeightToCTL( sal_uInt32 nWesternFontHeight
         double fTemp = double(nWesternFontHeight) * 1.333;
         nWesternFontHeight = static_cast<sal_uInt32>(fTemp);
         // make some nice values for UI that displays PT instead of 1/100th mm
-        nWesternFontHeight = ((nWesternFontHeight * 72) + 1270) / 2540L;
-        nWesternFontHeight = ((nWesternFontHeight * 2540L) + 36) / 72;
+        nWesternFontHeight = convertPointToMm100(convertMm100ToPoint(nWesternFontHeight));
     }
     return nWesternFontHeight;
 }
diff --git a/sd/source/core/stlpool.cxx b/sd/source/core/stlpool.cxx
index f1ff79ac566d..8345ba75ed60 100644
--- a/sd/source/core/stlpool.cxx
+++ b/sd/source/core/stlpool.cxx
@@ -47,6 +47,7 @@
 #include <svx/sdr/table/tabledesign.hxx>
 #include <editeng/autokernitem.hxx>
 #include <tools/diagnose_ex.h>
+#include <tools/UnitConversion.hxx>
 
 #include <editeng/lrspitem.hxx>
 #include <editeng/adjustitem.hxx>
@@ -284,7 +285,7 @@ void SdStyleSheetPool::CreateLayoutStyleSheets(std::u16string_view rLayoutName,
             }
 
             // FontSize
-            nFontSize = static_cast<sal_uInt16>((nFontSize * 2540L) / 72);  // Pt --> 1/100 mm
+            nFontSize = static_cast<sal_uInt16>(convertPointToMm100(nFontSize));
             SfxItemSet& rOutlineSet = pSheet->GetItemSet();
             rOutlineSet.Put( SvxFontHeightItem( nFontSize, 100, EE_CHAR_FONTHEIGHT ) );
             rOutlineSet.Put( SvxFontHeightItem( nFontSize, 100, EE_CHAR_FONTHEIGHT_CJK ) );
diff --git a/sd/source/filter/eppt/epptso.cxx b/sd/source/filter/eppt/epptso.cxx
index c42848ae4aff..77095a8e497e 100644
--- a/sd/source/filter/eppt/epptso.cxx
+++ b/sd/source/filter/eppt/epptso.cxx
@@ -1011,8 +1011,7 @@ void PPTWriter::ImplAdjustFirstLineLineSpacing( TextObj& rTextObj, EscherPropert
 
     if ( ( nLineSpacing > 0 ) && ( nLineSpacing < 100 ) )
     {
-        double fCharHeight = rPortion.mnCharHeight;
-        fCharHeight *= 2540 / 72.0;
+        double fCharHeight = convertPointToMm100<double>(rPortion.mnCharHeight);
         fCharHeight *= 100 - nLineSpacing;
         fCharHeight /= 100;
 
diff --git a/sd/source/filter/eppt/pptx-epptooxml.cxx b/sd/source/filter/eppt/pptx-epptooxml.cxx
index ce4e103edc91..4028523698ac 100644
--- a/sd/source/filter/eppt/pptx-epptooxml.cxx
+++ b/sd/source/filter/eppt/pptx-epptooxml.cxx
@@ -31,6 +31,7 @@
 #include <sax/fshelper.hxx>
 #include <rtl/ustrbuf.hxx>
 #include <sal/log.hxx>
+#include <tools/UnitConversion.hxx>
 #include <com/sun/star/animations/TransitionType.hpp>
 #include <com/sun/star/animations/TransitionSubType.hpp>
 #include <com/sun/star/beans/XPropertySetInfo.hpp>
@@ -1025,8 +1026,8 @@ bool PowerPointExport::WriteComments(sal_uInt32 nPageNum)
                                     XML_idx, OString::number(nLastIndex));
 
                 pFS->singleElementNS(XML_p, XML_pos,
-                                     XML_x, OString::number(static_cast<sal_Int64>((57600*aRealPoint2D.X + 1270)/2540.0)),
-                                     XML_y, OString::number(static_cast<sal_Int64>((57600*aRealPoint2D.Y + 1270)/2540.0)));
+                                     XML_x, OString::number(std::round(convertMm100ToMasterUnit(aRealPoint2D.X * 100))),
+                                     XML_y, OString::number(std::round(convertMm100ToMasterUnit(aRealPoint2D.Y * 100))));
 
                 pFS->startElementNS(XML_p, XML_text);
                 pFS->write(xText->getString());
diff --git a/sd/source/filter/eppt/pptx-text.cxx b/sd/source/filter/eppt/pptx-text.cxx
index f18c7c449ff1..fa030624a798 100644
--- a/sd/source/filter/eppt/pptx-text.cxx
+++ b/sd/source/filter/eppt/pptx-text.cxx
@@ -49,6 +49,7 @@
 #include <svl/languageoptions.hxx>
 #include <osl/diagnose.h>
 #include <i18nlangtag/languagetag.hxx>
+#include <tools/UnitConversion.hxx>
 
 #include <vcl/settings.hxx>
 #include <vcl/metric.hxx>
@@ -775,12 +776,12 @@ void ParagraphObj::ImplGetNumberingLevel( PPTExBulletProvider* pBuProv, sal_Int1
     {
         sal_Int32 nVal(0);
         if ( aAny >>= nVal )
-            nTextOfs = static_cast< sal_Int16 >( nVal / ( 2540.0 / 576 ) + 0.5 ) ;
+            nTextOfs = convertMm100ToMasterUnit(nVal);
     }
     if ( GetPropertyValue( aAny, mXPropSet, "ParaFirstLineIndent" ) )
     {
         if ( aAny >>= nBulletOfs )
-            nBulletOfs = static_cast< sal_Int32 >( nBulletOfs / ( 2540.0 / 576 ) + 0.5 );
+            nBulletOfs = convertMm100ToMasterUnit(nBulletOfs);
     }
     if ( GetPropertyValue( aAny, mXPropSet, "NumberingIsNumber" ) )
         aAny >>= bNumberingIsNumber;
@@ -843,9 +844,9 @@ void ParagraphObj::ImplGetNumberingLevel( PPTExBulletProvider* pBuProv, sal_Int1
                     else if ( aPropName == "StartWith" )
                         nStartWith = *o3tl::doAccess<sal_Int16>(rPropValue.Value);
                     else if ( aPropName == "LeftMargin" )
-                        nTextOfs = nTextOfs + static_cast< sal_Int16 >( *o3tl::doAccess<sal_Int32>(rPropValue.Value) / ( 2540.0 / 576 ) );
+                        nTextOfs += convertMm100ToMasterUnit(*o3tl::doAccess<sal_Int32>(rPropValue.Value));
                     else if ( aPropName == "FirstLineOffset" )
-                        nBulletOfs += static_cast<sal_Int16>( *o3tl::doAccess<sal_Int32>(rPropValue.Value) / ( 2540.0 / 576 ) );
+                        nBulletOfs += convertMm100ToMasterUnit(*o3tl::doAccess<sal_Int32>(rPropValue.Value));
                     else if ( aPropName == "BulletColor" )
                     {
                         sal_uInt32 nSOColor = *o3tl::doAccess<sal_uInt32>(rPropValue.Value);
@@ -1143,15 +1144,15 @@ void ParagraphObj::ImplGetParagraphValues( PPTExBulletProvider* pBuProv, bool bG
 
     if ( ImplGetPropertyValue( "ParaBottomMargin", bGetPropStateValue ) )
     {
-        double fSpacing = *o3tl::doAccess<sal_uInt32>(mAny) + ( 2540.0 / 576.0 ) - 1;
-        mnLineSpacingBottom = static_cast<sal_Int16>(-( fSpacing * 576.0 / 2540.0 ) );
+        double fSpacing = *o3tl::doAccess<sal_uInt32>(mAny) + convertMasterUnitToMm100(1.0) - 1;
+        mnLineSpacingBottom = std::round(-convertMm100ToMasterUnit(fSpacing));
     }
     meLineSpacingBottom = ePropState;
 
     if ( ImplGetPropertyValue( "ParaTopMargin", bGetPropStateValue ) )
     {
-        double fSpacing = *o3tl::doAccess<sal_uInt32>(mAny) + ( 2540.0 / 576.0 ) - 1;
-        mnLineSpacingTop = static_cast<sal_Int16>(-( fSpacing * 576.0 / 2540.0 ) );
+        double fSpacing = *o3tl::doAccess<sal_uInt32>(mAny) + convertMasterUnitToMm100(1.0) - 1;
+        mnLineSpacingTop = std::round(-convertMm100ToMasterUnit(fSpacing));
     }
     meLineSpacingTop = ePropState;
 
diff --git a/vbahelper/source/vbahelper/vbahelper.cxx b/vbahelper/source/vbahelper/vbahelper.cxx
index 7859c84018c2..17fc5ce651f0 100644
--- a/vbahelper/source/vbahelper/vbahelper.cxx
+++ b/vbahelper/source/vbahelper/vbahelper.cxx
@@ -69,6 +69,7 @@
 #include <vcl/window.hxx>
 #include <vcl/syswin.hxx>
 #include <tools/diagnose_ex.h>
+#include <tools/UnitConversion.hxx>
 #include <vbahelper/vbahelper.hxx>
 
 using namespace ::com::sun::star;
@@ -78,8 +79,6 @@ using namespace ::ooo::vba;
 namespace ooo::vba
 {
 
-namespace { const double factor =  2540.0 / 72.0; }
-
 // helper method to determine if the view ( calc ) is in print-preview mode
 static bool isInPrintPreview( SfxViewFrame* pView )
 {
@@ -624,23 +623,17 @@ double getPixelTo100thMillimeterConversionFactor( const css::uno::Reference< css
 double PointsToPixels( const css::uno::Reference< css::awt::XDevice >& xDevice, double fPoints, bool bVertical)
 {
     double fConvertFactor = getPixelTo100thMillimeterConversionFactor( xDevice, bVertical );
-    return PointsToHmm( fPoints ) * fConvertFactor;
+    return convertPointToMm100(fPoints) * fConvertFactor;
 }
 double PixelsToPoints( const css::uno::Reference< css::awt::XDevice >& xDevice, double fPixels, bool bVertical)
 {
     double fConvertFactor = getPixelTo100thMillimeterConversionFactor( xDevice, bVertical );
-    return HmmToPoints(static_cast<sal_Int32>(fPixels/fConvertFactor));
+    return convertMm100ToPoint(fPixels / fConvertFactor);
 }
 
-sal_Int32 PointsToHmm( double fPoints )
-{
-    return static_cast<sal_Int32>( fPoints * factor + 0.5 );
-}
+sal_Int32 PointsToHmm(double fPoints) { return std::round(convertPointToMm100(fPoints)); }
 
-double HmmToPoints( sal_Int32 nHmm )
-{
-    return nHmm / factor;
-}
+double HmmToPoints(sal_Int32 nHmm) { return convertMm100ToPoint<double>(nHmm); }
 
 ConcreteXShapeGeometryAttributes::ConcreteXShapeGeometryAttributes( const css::uno::Reference< css::drawing::XShape >& xShape )
 {
@@ -1047,7 +1040,7 @@ Millimeter::Millimeter(double mm):m_nMillimeter(mm) {}
 
 void Millimeter::setInPoints(double points)
 {
-    m_nMillimeter = points * factor / 100.0;
+    m_nMillimeter = convertPointToMm100(points) / 100.0;
 }
 
 double Millimeter::getInHundredthsOfOneMillimeter() const
@@ -1057,13 +1050,13 @@ double Millimeter::getInHundredthsOfOneMillimeter() const
 
 sal_Int32 Millimeter::getInHundredthsOfOneMillimeter(double points)
 {
-    sal_Int32 mm = static_cast<sal_Int32>(points * factor);
+    sal_Int32 mm = std::round(convertPointToMm100(points));
     return mm;
 }
 
 double Millimeter::getInPoints(int _hmm)
 {
-    double points = double( static_cast<double>(_hmm) / factor);
+    double points = convertMm100ToPoint<double>(_hmm);
     return points;
 }
 
diff --git a/vcl/unx/gtk3/a11y/gtk3atktextattributes.cxx b/vcl/unx/gtk3/a11y/gtk3atktextattributes.cxx
index 914466315ce2..31c5ebd3585b 100644
--- a/vcl/unx/gtk3/a11y/gtk3atktextattributes.cxx
+++ b/vcl/unx/gtk3/a11y/gtk3atktextattributes.cxx
@@ -37,6 +37,7 @@
 #include <com/sun/star/accessibility/XAccessibleComponent.hpp>
 
 #include <i18nlangtag/languagetag.hxx>
+#include <tools/UnitConversion.hxx>
 
 #include <stdio.h>
 #include <string.h>
@@ -173,12 +174,6 @@ get_value( const uno::Sequence< beans::PropertyValue >& rAttributeList,
 #define get_weight_value( list, index ) get_value( list, index, Weight2String )
 #define get_language_string( list, index ) get_value( list, index, Locale2String )
 
-static double toPoint(sal_Int16 n)
-{
-    // 100th mm -> pt
-    return static_cast<double>(n * 72) / 2540;
-}
-
 /*****************************************************************************/
 
 static bool
@@ -908,7 +903,7 @@ LineSpacing2LineHeight( const uno::Any& rAny )
         if( ls.Mode == style::LineSpacingMode::PROP )
             ret = g_strdup_printf( "%d%%", ls.Height );
         else if( ls.Mode == style::LineSpacingMode::FIX )
-            ret = g_strdup_printf( "%.3gpt", toPoint(ls.Height) );
+            ret = g_strdup_printf("%.3gpt", convertMm100ToPoint<double>(ls.Height));
     }
 
     return ret;