[Libreoffice-commits] core.git: Branch 'libreoffice-4-3' - vcl/quartz

[Herbert Dürr]

 vcl/quartz/ctlayout.cxx |   35 +++++++++++++++++++++++++++--------
 1 file changed, 27 insertions(+), 8 deletions(-)

New commits:
commit 4adebd56d21cf104dca28a62c7015466a7a0c357
Author: Herbert Dürr <hdu at apache.org>
Date:   Tue May 20 12:00:50 2014 +0000

    Resolves: #i124935# fix expanded/condensed text breaking...
    
    in the CoreText engine
    
    the concept of an extra-width per code-unit was obsolete at least since apps
    supported unicode with its different normalization forms, diacritical marks,
    surrogate-pairs, non-printing characters such as ZWJ/ZWNJ/RLM, etc.  so of
    course modern engines like CoreText don't aid this typographical crime.
    
    The fix here extends the CTLayout::GetTextBreak() method to handle the obsolete
    semantic of per code-unit extra-widths by successively approximating the number
    of involved code-units.
    (cherry picked from commit a9b9ceff86f35be1eeff5f251d24e338db760a1e)
    
    Conflicts:
    	vcl/aqua/source/gdi/ctlayout.cxx
    
    Change-Id: I52a7f7488a9e8a303ed7271df2a24a3c85098ce3
    (cherry picked from commit 687f0c9300d499b78deea2890b4c2019adb2d67d)
    Reviewed-on: https://gerrit.libreoffice.org/9627
    Reviewed-by: Christian Lohmaier <lohmaier+LibreOffice at googlemail.com>
    Tested-by: Christian Lohmaier <lohmaier+LibreOffice at googlemail.com>

diff --git a/vcl/quartz/ctlayout.cxx b/vcl/quartz/ctlayout.cxx
index 1d96f90..f0cdc8a 100644
--- a/vcl/quartz/ctlayout.cxx
+++ b/vcl/quartz/ctlayout.cxx
@@ -569,20 +569,39 @@ long CTLayout::FillDXArray( sal_Int32* pDXArray ) const
     return nPixWidth;
 }
 
-sal_Int32 CTLayout::GetTextBreak( long nMaxWidth, long /*nCharExtra*/, int nFactor ) const
+sal_Int32 CTLayout::GetTextBreak( long nMaxWidth, long nCharExtra, int nFactor ) const
 {
     if( !mpCTLine )
         return -1;
 
     CTTypesetterRef aCTTypeSetter = CTTypesetterCreateWithAttributedString( mpAttrString );
-    const double fCTMaxWidth = (double)nMaxWidth / nFactor;
-    CFIndex nIndex = CTTypesetterSuggestClusterBreak( aCTTypeSetter, 0, fCTMaxWidth );
-    CFRelease( aCTTypeSetter );
-
-    if( nIndex >= mnCharCount )
-        return -1;
+    CFIndex nBestGuess = (nCharExtra >= 0) ? 0 : mnCharCount;
+    for( int i = 1; i <= mnCharCount; i *= 2 )
+    {
+        // guess the target width considering char-extra expansion/condensation
+        const double nTargetWidth = nMaxWidth - nBestGuess * nCharExtra;
+        const double fCTMaxWidth = nTargetWidth / nFactor;
+        // calculate the breaking index for the guessed target width
+        const CFIndex nNewIndex = CTTypesetterSuggestClusterBreak( aCTTypeSetter, 0, fCTMaxWidth );
+        if( nNewIndex >= mnCharCount ) {
+            CFRelease( aCTTypeSetter );
+            return -1;
+        }
+        // check if the original extra-width guess was good
+        if( !nCharExtra )
+            nBestGuess = nNewIndex;
+        if( nBestGuess == nNewIndex )
+            break;
+        // prepare another round for a different number of characters
+        CFIndex nNewGuess = (nNewIndex + nBestGuess + 1) / 2;
+        if( nNewGuess == nBestGuess )
+            nNewGuess += (nNewIndex > nBestGuess) ? +1 : -1;
+        nBestGuess = nNewGuess;
+    }
 
-    nIndex += mnMinCharPos;
+    // suggest the best fitting cluster break as breaking position
+    CFRelease( aCTTypeSetter );
+    const int nIndex = nBestGuess + mnMinCharPos;
     return nIndex;
 }