fdo#52540 refix graphite layout generally

Change-Id: I13896adbc3d8b006c3b192dbf40e766d718a8bac
Reviewed-on: https://gerrit.libreoffice.org/14959Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

vcl/source/glyphs/graphite_layout.cxx

@@ -569,33 +569,36 @@ gr_segment * GraphiteLayout::CreateSegment(ImplLayoutArgs& rArgs)
         int limit = rArgs.mnEndCharPos;
         if (!(SAL_LAYOUT_COMPLEX_DISABLED & rArgs.mnFlags))
         {
-            const int nSegCharMin = maximum<int>(0, mnMinCharPos - EXTRA_CONTEXT_LENGTH);
-            const int nSegCharLimit = minimum(rArgs.mnLength, mnEndCharPos + EXTRA_CONTEXT_LENGTH);
-            if (nSegCharMin < mnSegCharOffset)
+            int nSegCharMin = maximum<int>(0, mnMinCharPos - EXTRA_CONTEXT_LENGTH);
+            int nSegCharLimit = minimum(rArgs.mnLength, mnEndCharPos + EXTRA_CONTEXT_LENGTH);
+            while (nSegCharMin < mnSegCharOffset)
             {
-                int sameDirEnd = findSameDirLimit(rArgs.mpStr + nSegCharMin,
+                int sameDirEnd = nSegCharMin + findSameDirLimit(rArgs.mpStr + nSegCharMin,
                     rArgs.mnEndCharPos - nSegCharMin, bRtl);
-                if (sameDirEnd == rArgs.mnEndCharPos)
+                if (sameDirEnd >= rArgs.mnMinCharPos)
+                {
                     mnSegCharOffset = nSegCharMin;
+                    break;
+                }
+                else
+                    nSegCharMin = sameDirEnd;
             }
             if (nSegCharLimit > limit)
             {
                 limit += findSameDirLimit(rArgs.mpStr + rArgs.mnEndCharPos,
                     nSegCharLimit - rArgs.mnEndCharPos, bRtl);
+                if (limit > rArgs.mnLength)
+                    limit = rArgs.mnLength;
             }
         }
-
-        size_t numchars = gr_count_unicode_characters(gr_utf16, rArgs.mpStr + mnSegCharOffset,
-                 rArgs.mpStr + (rArgs.mnLength > limit + 64 ? limit + 64 : rArgs.mnLength), NULL);
-        static com::sun::star::uno::Reference< com::sun::star::i18n::XCharacterClassification > xCharClass;
-        if ( !xCharClass.is() )
-            xCharClass = vcl::unohelper::CreateCharacterClassification();
-        size_t numchars2 = rArgs.mnEndCharPos - mnSegCharOffset; // fdo#52540, fdo#68313, fdo#70666 avoid bad ligature replacement, fdo#88051 layout problem
-        if (numchars > numchars2 && (rArgs.mpStr[mnSegCharOffset + numchars2] == '\t' ||
-            xCharClass->getType(rArgs.mpStr + mnSegCharOffset, numchars2 + 1) == ::com::sun::star::i18n::UnicodeType::LOWERCASE_LETTER))
+        else
         {
-            numchars = numchars2;
+            limit = minimum(rArgs.mnLength, mnEndCharPos + EXTRA_CONTEXT_LENGTH);
+            mnSegCharOffset = maximum<int>(0, mnMinCharPos - EXTRA_CONTEXT_LENGTH);
         }
+
+        size_t numchars = gr_count_unicode_characters(gr_utf16, rArgs.mpStr + mnSegCharOffset,
+                 rArgs.mpStr + limit, NULL);
         if (mpFeatures)
             pSegment = gr_make_seg(mpFont, mpFace, 0, mpFeatures->values(), gr_utf16,
                                         rArgs.mpStr + mnSegCharOffset, numchars, bRtl);