From 8d92a2cdf4665c1831b524af0a316208947e27c1 Mon Sep 17 00:00:00 2001
From: Victor Cebollada <v.cebollada@samsung.com>
Date: Thu, 14 Jul 2016 09:29:28 +0100
Subject: [PATCH] Fix for the cursor position with the arabic script.
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* This is a workaround to fix an issue with complex characters in the arabic
  script like i.e. رّ or الأَبْجَدِيَّة العَرَبِيَّة.

  A proper fix needs to be done in order to be able to place the cursor
  correctly in all characters.

Change-Id: I22ba797b6487c3ca11bdb15fdd0168d16810ba15
Signed-off-by: Victor Cebollada <v.cebollada@samsung.com>
---
 .../internal/text/cursor-helper-functions.cpp      | 45 ++++++++++++++++++----
 1 file changed, 37 insertions(+), 8 deletions(-)

diff --git a/dali-toolkit/internal/text/cursor-helper-functions.cpp b/dali-toolkit/internal/text/cursor-helper-functions.cpp
index 2b5e328..b3b7250 100644
--- a/dali-toolkit/internal/text/cursor-helper-functions.cpp
+++ b/dali-toolkit/internal/text/cursor-helper-functions.cpp
@@ -107,10 +107,10 @@ CharacterIndex GetClosestCursorIndex( VisualModelPtr visualModel,
 
   CharacterIndex logicalIndex = 0u;
 
-  const Length numberOfGlyphs = visualModel->mGlyphs.Count();
-  const Length numberOfLines  = visualModel->mLines.Count();
-  if( ( 0 == numberOfGlyphs ) ||
-      ( 0 == numberOfLines ) )
+  const Length totalNumberOfGlyphs = visualModel->mGlyphs.Count();
+  const Length totalNumberOfLines  = visualModel->mLines.Count();
+  if( ( 0 == totalNumberOfGlyphs ) ||
+      ( 0 == totalNumberOfLines ) )
   {
     return logicalIndex;
   }
@@ -184,14 +184,43 @@ CharacterIndex GetClosestCursorIndex( VisualModelPtr visualModel,
       // Get the position of the first glyph.
       const Vector2& position = *( positionsBuffer + firstLogicalGlyphIndex );
 
-      // Whether the glyph can be split, like Latin ligatures fi, ff or Arabic ï»».
-      const Length numberOfCharacters = *( charactersPerGlyphBuffer + firstLogicalGlyphIndex );
+      // Whether the glyph can be split, like Latin ligatures fi, ff or Arabic (ل + ا).
+      Length numberOfCharacters = *( charactersPerGlyphBuffer + firstLogicalGlyphIndex );
       if( direction != LTR )
       {
         // As characters are being traversed in visual order,
         // for right to left ligatures, the character which contains the
         // number of glyphs in the table is found first.
         // Jump the number of characters to the next glyph is needed.
+
+        if( 0u == numberOfCharacters )
+        {
+          // TODO: This is a workaround to fix an issue with complex characters in the arabic
+          // script like i.e. رّ or الأَبْجَدِيَّة العَرَبِيَّة
+          // There are characters that are not shaped in one glyph but in combination with
+          // the next one generates two of them.
+          // The visual to logical conversion table have characters in different order than
+          // expected even if all of them are arabic.
+
+          // The workaround doesn't fix the issue completely but it prevents the application
+          // to hang in an infinite loop.
+
+          // Find the number of characters.
+          for( GlyphIndex index = firstLogicalGlyphIndex + 1u;
+               ( 0u == numberOfCharacters ) && ( index < totalNumberOfGlyphs ) ;
+               ++index )
+          {
+            numberOfCharacters = *( charactersPerGlyphBuffer + index );
+          }
+
+          if( 2u > numberOfCharacters )
+          {
+            continue;
+          }
+
+          --numberOfCharacters;
+        }
+
         visualIndex += numberOfCharacters - 1u;
       }
 
@@ -264,7 +293,7 @@ CharacterIndex GetClosestCursorIndex( VisualModelPtr visualModel,
     {
       // The paragraph direction is right to left.
 
-      if( ( lineIndex != numberOfLines - 1u ) && // is not the last line.
+      if( ( lineIndex != totalNumberOfLines - 1u ) && // is not the last line.
           ( visualIndex == startCharacter ) )
       {
         // It places the cursor just after the first character in visual order.
@@ -285,7 +314,7 @@ CharacterIndex GetClosestCursorIndex( VisualModelPtr visualModel,
     // This branch checks if the closest line is the one with the last '\n'. If it is, it decrements the visual index to place
     // the cursor just before the last '\n'.
 
-    if( ( lineIndex != numberOfLines - 1u ) &&
+    if( ( lineIndex != totalNumberOfLines - 1u ) &&
         TextAbstraction::IsNewParagraph( *( logicalModel->mText.Begin() + visualIndex - 1u ) ) )
     {
       --visualIndex;
-- 
2.7.4