From 78f93c2ef1acd324c289286fe3c13a429340839b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Caol=C3=A1n=20McNamara?= <caolanm@redhat.com>
Date: Tue, 4 Jun 2013 15:48:23 +0100
Subject: [PATCH] Resolves: rhbz#968892 force render full grapheme with
 fallback font

Change-Id: I5bb98c61d047e69d74666261b2c489d80f344502
---
 vcl/generic/glyphs/gcach_layout.cxx | 61 ++++++++++++++++++++++---------------
 vcl/inc/generic/glyphcache.hxx      |  5 +++
 2 files changed, 42 insertions(+), 24 deletions(-)

diff --git a/vcl/generic/glyphs/gcach_layout.cxx b/vcl/generic/glyphs/gcach_layout.cxx
index 4fd4cf4..3c3c6de 100644
--- a/vcl/generic/glyphs/gcach_layout.cxx
+++ b/vcl/generic/glyphs/gcach_layout.cxx
@@ -41,6 +41,10 @@
 #include <unicode/uscript.h>
 #include <unicode/ubidi.h>
 
+#include <com/sun/star/lang/XMultiServiceFactory.hpp>
+#include <com/sun/star/i18n/CharacterIteratorMode.hpp>
+#include <comphelper/processfactory.hxx>
+
 // =======================================================================
 // layout implementation for ServerFont
 // =======================================================================
@@ -90,23 +94,42 @@ void ServerFontLayout::AdjustLayout( ImplLayoutArgs& rArgs )
     }
 }
 
-// =======================================================================
-
-static bool lcl_CharIsJoiner(sal_Unicode cChar)
+void ServerFontLayout::setNeedFallback(ImplLayoutArgs& rArgs, sal_Int32 nCharPos,
+    bool bRightToLeft)
 {
-    return ((cChar == 0x200C) || (cChar == 0x200D));
-}
+    if (nCharPos < 0)
+        return;
 
-static bool needPreviousCode(sal_Unicode cChar)
-{
-    return lcl_CharIsJoiner(cChar) || U16_IS_LEAD(cChar);
-}
+    using namespace ::com::sun::star;
 
-static bool needNextCode(sal_Unicode cChar)
-{
-    return lcl_CharIsJoiner(cChar) || U16_IS_TRAIL(cChar);
+    if (!mxBreak.is())
+    {
+        uno::Reference< lang::XMultiServiceFactory > xFactory =
+            comphelper::getProcessServiceFactory();
+        mxBreak = uno::Reference< i18n::XBreakIterator >(xFactory->createInstance(
+            "com.sun.star.i18n.BreakIterator"), uno::UNO_QUERY);
+    }
+
+    LanguageTag aLangTag(rArgs.meLanguage);
+    lang::Locale aLocale(aLangTag.getLocale());
+
+    //if position nCharPos is missing in the font, grab the entire grapheme and
+    //mark all glyphs as missing so the whole thing is rendered with the same
+    //font
+    OUString aRun(rArgs.mpStr);
+    sal_Int32 nDone;
+    sal_Int32 nGraphemeStartPos =
+        mxBreak->previousCharacters(aRun, nCharPos, aLocale,
+            i18n::CharacterIteratorMode::SKIPCELL, 1, nDone);
+    sal_Int32 nGraphemeEndPos =
+        mxBreak->nextCharacters(aRun, nCharPos, aLocale,
+            i18n::CharacterIteratorMode::SKIPCELL, 1, nDone);
+
+    rArgs.NeedFallback(nGraphemeStartPos, nGraphemeEndPos, bRightToLeft);
 }
 
+// =======================================================================
+
 std::ostream &operator <<(std::ostream& s, ServerFont* pFont)
 {
 #ifndef SAL_LOG_INFO
@@ -401,9 +424,7 @@ bool HbLayoutEngine::layout(ServerFontLayout& rLayout, ImplLayoutArgs& rArgs)
             // if needed request glyph fallback by updating LayoutArgs
             if (!nGlyphIndex)
             {
-                if (nCharPos >= 0)
-                    rArgs.NeedFallback(nCharPos, bRightToLeft);
-
+                rLayout.setNeedFallback(rArgs, nCharPos, bRightToLeft);
                 if (SAL_LAYOUT_FOR_FALLBACK & rArgs.mnFlags)
                     continue;
             }
@@ -1006,15 +1027,7 @@ bool IcuLayoutEngine::layout(ServerFontLayout& rLayout, ImplLayoutArgs& rArgs)
             // if needed request glyph fallback by updating LayoutArgs
             if( !nGlyphIndex )
             {
-                if( nCharPos >= 0 )
-                {
-                    rArgs.NeedFallback( nCharPos, bRightToLeft );
-                    if ( (nCharPos > 0) && needPreviousCode(rArgs.mpStr[nCharPos-1]) )
-                        rArgs.NeedFallback( nCharPos-1, bRightToLeft );
-                    else if ( (nCharPos + 1 < nEndRunPos) && needNextCode(rArgs.mpStr[nCharPos+1]) )
-                        rArgs.NeedFallback( nCharPos+1, bRightToLeft );
-                }
-
+                rLayout.setNeedFallback(rArgs, nCharPos, bRightToLeft);
                 if( SAL_LAYOUT_FOR_FALLBACK & rArgs.mnFlags )
                     continue;
             }
diff --git a/vcl/inc/generic/glyphcache.hxx b/vcl/inc/generic/glyphcache.hxx
index a7363f9..d6cdee1 100644
--- a/vcl/inc/generic/glyphcache.hxx
+++ b/vcl/inc/generic/glyphcache.hxx
@@ -37,6 +37,7 @@
 #include <boost/unordered_map.hpp>
 #include <boost/unordered_set.hpp>
 #include <boost/shared_ptr.hpp>
+#include <com/sun/star/i18n/XBreakIterator.hpp>
 
 namespace basegfx { class B2DPolyPolygon; }
 
@@ -311,6 +312,7 @@
 {
 private:
     ServerFont&     mrServerFont;
+    com::sun::star::uno::Reference<com::sun::star::i18n::XBreakIterator> mxBreak;
 
     // enforce proper copy semantic
     SAL_DLLPRIVATE  ServerFontLayout( const ServerFontLayout& );
@@ -324,5 +326,7 @@
     virtual void    AdjustLayout( ImplLayoutArgs& );
     virtual void    DrawText( SalGraphics& ) const;
+    void            setNeedFallback(ImplLayoutArgs& rArgs, sal_Int32 nIndex,
+                        bool bRightToLeft);
     ServerFont&     GetServerFont() const   { return mrServerFont; }
 };