tdf#80194 autoEsc: use fontmetrics in calculation

This replaces the previous 7.0 patch in
commit 2940d1905b921d9909b08b1e32014d3c44474ef0
where the following is still true:
THIS WILL CHANGE THE POSITION OF EDITENG SUBSCRIPTS
AND SUPERSCRIPTS IN EXISTING DOCUMENTS!
That is because they were very poorly placed
before - using a formula that is very different
from how Writer does it. Everyone in the bug reports
indicates that Writer does it good, but Impress
does it really bad. (tdf#89849, tdf#63083).

Instead of using the previous patch's 80%/20%
generalization, copy Writer's use of the actual
ascent and descent of the font to determine
the best position for the subscript or superscript.

Change-Id: I0f10f6174b0709f3bc3b9acdc54b7b1fd59c5ee2
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/90489
Reviewed-by: Justin Luth <justin_luth@sil.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Justin Luth <justin_luth@sil.org>

4 files changed, 46 insertions, 13 deletions

diff --git a/editeng/source/editeng/editattr.cxx b/editeng/source/editeng/editattr.cxx
index a99e4d496f74..e48445c27c30 100644
--- a/editeng/source/editeng/editattr.cxx
+++ b/editeng/source/editeng/editattr.cxx
@@ -266,17 +266,13 @@ EditCharAttribEscapement::EditCharAttribEscapement( const SvxEscapementItem& rAt
     assert(rAttr.Which() == EE_CHAR_ESCAPEMENT);
 }
 
-void EditCharAttribEscapement::SetFont( SvxFont& rFont, OutputDevice* )
+void EditCharAttribEscapement::SetFont( SvxFont& rFont, OutputDevice* pOutDev )
 {
     sal_uInt16 const nProp = static_cast<const SvxEscapementItem*>(GetItem())->GetProportionalHeight();
     rFont.SetPropr( static_cast<sal_uInt8>(nProp) );
 
     short nEsc = static_cast<const SvxEscapementItem*>(GetItem())->GetEsc();
-    if ( nEsc == DFLT_ESC_AUTO_SUPER )
-        nEsc =  .8 * (100 - nProp);
-    else if ( nEsc == DFLT_ESC_AUTO_SUB )
-        nEsc =  .2 * -(100 - nProp);
-    rFont.SetEscapement( nEsc );
+    rFont.SetNonAutoEscapement( nEsc, pOutDev );
 }
 
 
diff --git a/editeng/source/editeng/editdoc.cxx b/editeng/source/editeng/editdoc.cxx
index 42fc1f3cc22c..9e9eb17e6177 100644
--- a/editeng/source/editeng/editdoc.cxx
+++ b/editeng/source/editeng/editdoc.cxx
@@ -2007,11 +2007,7 @@ void CreateFont( SvxFont& rFont, const SfxItemSet& rSet, bool bSearchInParent, S
         rFont.SetPropr( static_cast<sal_uInt8>(nProp) );
 
         short nEsc = rEsc.GetEsc();
-        if ( nEsc == DFLT_ESC_AUTO_SUPER )
-            nEsc = .8 * (100 - nProp);
-        else if ( nEsc == DFLT_ESC_AUTO_SUB )
-            nEsc = .2 * -(100 - nProp);
-        rFont.SetEscapement( nEsc );
+        rFont.SetNonAutoEscapement( nEsc );
     }
     if ( bSearchInParent || ( rSet.GetItemState( EE_CHAR_PAIRKERNING ) == SfxItemState::SET ) )
         rFont.SetKerning( rSet.Get( EE_CHAR_PAIRKERNING ).GetValue() ? FontKerning::FontSpecific : FontKerning::NONE );
diff --git a/editeng/source/editeng/impedit4.cxx b/editeng/source/editeng/impedit4.cxx
index 25d7ecc0aa8a..050eed8667f4 100644
--- a/editeng/source/editeng/impedit4.cxx
+++ b/editeng/source/editeng/impedit4.cxx
@@ -69,6 +69,7 @@
 #include <unotools/textsearch.hxx>
 #include <comphelper/processfactory.hxx>
 #include <vcl/help.hxx>
+#include <vcl/metric.hxx>
 #include <svtools/rtfkeywd.hxx>
 #include <editeng/edtdlg.hxx>
 
@@ -928,14 +929,23 @@ void ImpEditEngine::WriteItemAsRTF( const SfxPoolItem& rItem, SvStream& rOutput,
             sal_uInt16 const nProp = static_cast<const SvxEscapementItem&>(rItem).GetProportionalHeight();
             sal_uInt16 nProp100 = nProp*100;    // For SWG-Token Prop in 100th percent.
             short nEsc = static_cast<const SvxEscapementItem&>(rItem).GetEsc();
+            const FontMetric& rFontMetric = GetRefDevice()->GetFontMetric();
+            double fFontHeight = rFontMetric.GetAscent() + rFontMetric.GetDescent();
+            double fAutoAscent = .8;
+            double fAutoDescent = .2;
+            if ( fFontHeight )
+            {
+                fAutoAscent = rFontMetric.GetAscent() / fFontHeight;
+                fAutoDescent = rFontMetric.GetDescent() / fFontHeight;
+            }
             if ( nEsc == DFLT_ESC_AUTO_SUPER )
             {
-                nEsc =  .8 * (100 - nProp);
+                nEsc =  fAutoAscent * (100 - nProp);
                 nProp100++; // A 1 afterwards means 'automatic'.
             }
             else if ( nEsc == DFLT_ESC_AUTO_SUB )
             {
-                nEsc =  .2 * -(100 - nProp);
+                nEsc =  fAutoDescent * -(100 - nProp);
                 nProp100++;
             }
             // SWG:
diff --git a/editeng/source/items/svxfont.cxx b/editeng/source/items/svxfont.cxx
index a8792df4c729..f6ff6cf92681 100644
--- a/editeng/source/items/svxfont.cxx
+++ b/editeng/source/items/svxfont.cxx
@@ -17,6 +17,7 @@
  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  */
 
+#include <vcl/metric.hxx>
 #include <vcl/outdev.hxx>
 #include <vcl/print.hxx>
 #include <tools/debug.hxx>
@@ -55,6 +56,36 @@ SvxFont::SvxFont( const SvxFont &rFont )
     SetLanguage(rFont.GetLanguage());
 }
 
+void SvxFont::SetNonAutoEscapement(short nNewEsc, const OutputDevice* pOutDev)
+{
+    nEsc = nNewEsc;
+    if ( abs(nEsc) == DFLT_ESC_AUTO_SUPER )
+    {
+        double fAutoAscent = .8;
+        double fAutoDescent = .2;
+        if ( pOutDev )
+        {
+            const FontMetric& rFontMetric = pOutDev->GetFontMetric();
+            double fFontHeight = rFontMetric.GetAscent() + rFontMetric.GetDescent();
+            if ( fFontHeight )
+            {
+                fAutoAscent = rFontMetric.GetAscent() / fFontHeight;
+                fAutoDescent = rFontMetric.GetDescent() / fFontHeight;
+            }
+        }
+
+        if ( nEsc == DFLT_ESC_AUTO_SUPER )
+            nEsc = fAutoAscent * (100 - nPropr);
+        else //DFLT_ESC_AUTO_SUB
+            nEsc = fAutoDescent * -(100 - nPropr);
+    }
+
+    if ( nEsc > MAX_ESC_POS )
+        nEsc = MAX_ESC_POS;
+    else if  ( nEsc < -MAX_ESC_POS )
+        nEsc = -MAX_ESC_POS;
+}
+
 void SvxFont::DrawArrow( OutputDevice &rOut, const tools::Rectangle& rRect,
     const Size& rSize, const Color& rCol, bool bLeft )
 {