tdf#66819: Disable ligatures with character spacing

When character spacing is not zero, optional ligatures should be
disabled (e.g. this what CSS requires and what browsers implement:
https://drafts.csswg.org/css-text/#letter-spacing-property).

This disables both “liga” and “clig” OpenType features because they are
optional features and are enabled by default, it does not disable “rlig”
because it is for orthographically-required ligatures, nor “dlig” or
“hlig” because they are disabled by default.

The character spacing values (confusingly called kerning in the source
code) are moved from SvxFont to vcl::Font so it can’t be accessed in
OutputDevice and pass the relevant flag to SalLayout.

Change-Id: Ieacc875df3896ad7a63ae8d116f4c6ff7265b9a5
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/138711
Tested-by: Jenkins
Reviewed-by: خالد حسني <khaled@aliftype.com>

3 files changed, 5 insertions, 7 deletions

diff --git a/include/editeng/svxfont.hxx b/include/editeng/svxfont.hxx
index ac4ec390128a..f4810ba25640 100644
--- a/include/editeng/svxfont.hxx
+++ b/include/editeng/svxfont.hxx
@@ -41,7 +41,6 @@ class EDITENG_DLLPUBLIC SvxFont : public vcl::Font
     SvxCaseMap   eCaseMap;      // Text Markup
     short nEsc;                 // Degree of Superscript/Subscript
     sal_uInt8  nPropr;          // Degree of reduction of the font height
-    short nKern;                // Kerning in Pt
 
 public:
     SvxFont();
@@ -59,17 +58,12 @@ public:
     void SetProprRel( const sal_uInt8 nNewPropr )
         { SetPropr( static_cast<sal_uInt8>( static_cast<tools::Long>(nNewPropr) * static_cast<tools::Long>(nPropr) / 100 ) ); }
 
-    // Kerning
-    short GetFixKerning() const { return nKern; }
-    void  SetFixKerning( const short nNewKern ) { nKern = nNewKern; }
-
     SvxCaseMap GetCaseMap() const { return eCaseMap; }
     void    SetCaseMap( const SvxCaseMap eNew ) { eCaseMap = eNew; }
 
     // Is-Methods:
     bool IsCaseMap() const { return SvxCaseMap::NotMapped != eCaseMap; }
     bool IsCapital() const { return SvxCaseMap::SmallCaps == eCaseMap; }
-    bool IsKern() const { return 0 != nKern; }
     bool IsEsc() const { return 0 != nEsc; }
 
     // Consider Upper case, Lower case letters etc.
diff --git a/include/vcl/font.hxx b/include/vcl/font.hxx
index b371990ba11c..222f7d962774 100644
--- a/include/vcl/font.hxx
+++ b/include/vcl/font.hxx
@@ -133,6 +133,9 @@ public:
     void                SetKerning( FontKerning nKerning );
     FontKerning         GetKerning() const;
     bool                IsKerning() const;
+    void                SetFixKerning(const short nSpacing);
+    short               GetFixKerning() const;
+    bool                IsFixKerning() const;
 
     void                SetOutline( bool bOutline );
     bool                IsOutline() const;
diff --git a/include/vcl/rendercontext/SalLayoutFlags.hxx b/include/vcl/rendercontext/SalLayoutFlags.hxx
index e8c5901d8528..576a4abd8fbd 100644
--- a/include/vcl/rendercontext/SalLayoutFlags.hxx
+++ b/include/vcl/rendercontext/SalLayoutFlags.hxx
@@ -30,12 +30,13 @@ enum class SalLayoutFlags
     DisableKerning = 0x0010,
     KerningAsian = 0x0020,
     Vertical = 0x0040,
+    DisableLigatures = 0x0200,
     ForFallback = 0x2000,
     GlyphItemsOnly = 0x4000,
 };
 namespace o3tl
 {
-template <> struct typed_flags<SalLayoutFlags> : is_typed_flags<SalLayoutFlags, 0x6077>
+template <> struct typed_flags<SalLayoutFlags> : is_typed_flags<SalLayoutFlags, 0x6277>
 {
 };
 }