Layout fixes
[platform/core/uifw/dali-toolkit.git] / dali-toolkit / internal / text / layouts / layout-engine.cpp
index 4e090e0..e165103 100644 (file)
@@ -19,6 +19,7 @@
 #include <dali-toolkit/internal/text/layouts/layout-engine.h>
 
 // EXTERNAL INCLUDES
+#include <limits>
 #include <dali/public-api/math/vector2.h>
 #include <dali/public-api/text-abstraction/font-client.h>
 
@@ -35,140 +36,181 @@ namespace Toolkit
 namespace Text
 {
 
+namespace
+{
+
+const float MAX_FLOAT = std::numeric_limits<float>::max();
+const bool RTL = true;
+
+} //namespace
+
 /**
  * @brief Stores temporary layout info of the line.
  */
 struct LineLayout
 {
+  LineLayout()
+  : glyphIndex( 0u ),
+    characterIndex( 0u ),
+    numberOfCharacters( 0u ),
+    numberOfGlyphs( 0u ),
+    length( 0.f ),
+    widthAdvanceDiff( 0.f ),
+    wsLengthEndOfLine( 0.f ),
+    ascender( 0.f ),
+    descender( MAX_FLOAT )
+  {}
+
+  ~LineLayout()
+  {}
+
+  void Clear()
+  {
+    glyphIndex = 0u;
+    characterIndex = 0u;
+    numberOfCharacters = 0u;
+    numberOfGlyphs = 0u;
+    length = 0.f;
+    widthAdvanceDiff = 0.f;
+    wsLengthEndOfLine = 0.f;
+    ascender = 0.f;
+    descender = MAX_FLOAT;
+  }
+
   GlyphIndex     glyphIndex;         ///< Index of the first glyph to be laid-out.
   CharacterIndex characterIndex;     ///< Index of the first character to be laid-out.
   Length         numberOfCharacters; ///< The number of characters which fit in one line.
   Length         numberOfGlyphs;     ///< The number of glyph which fit in one line.
   float          length;             ///< The length of the glyphs which fit in one line.
+  float          widthAdvanceDiff;   ///< The difference between the xBearing + width and the advance of the last glyph.
   float          wsLengthEndOfLine;  ///< The length of the white spaces at the end of the line.
-  float          height;             ///< The maximum height of all fonts in the line.
   float          ascender;           ///< The maximum ascender of all fonts in the line.
+  float          descender;          ///< The minimum descender of all fonts in the line.
 };
 
 struct LayoutEngine::Impl
 {
   Impl()
   : mLayout( LayoutEngine::SINGLE_LINE_BOX ),
-    mAlignment( LayoutEngine::ALIGN_BEGIN )
+    mHorizontalAlignment( LayoutEngine::HORIZONTAL_ALIGN_BEGIN ),
+    mVerticalAlignment( LayoutEngine::VERTICAL_ALIGN_TOP )
   {
     mFontClient = TextAbstraction::FontClient::Get();
   }
 
   /**
-   * Retrieves the line layout for a given box width.
+   * @brief Updates the line ascender and descender with the metrics of a new font.
+   *
+   * @param[in] fontId The id of the new font.
+   * @param[in,out] lineLayout The line layout.
    */
-  void GetLineLayoutForBox( const LayoutParameters& parameters,
-                            LineLayout& lineLayout )
+  void UpdateLineHeight( FontId fontId, LineLayout& lineLayout )
   {
-    // Initializes the line layout.
-    lineLayout.numberOfCharacters = 0u;
-    lineLayout.numberOfGlyphs = 0u;
-    lineLayout.length = 0.f;
-    lineLayout.wsLengthEndOfLine = 0.f;
-    lineLayout.height = 0.f;
-    lineLayout.ascender = 0.f;
-
-    // Get the last glyph index.
-    const GlyphIndex lastGlyphIndex = parameters.totalNumberOfGlyphs - 1u;
+    Text::FontMetrics fontMetrics;
+    mFontClient.GetFontMetrics( fontId, fontMetrics );
 
-    FontId lastFontId = 0u;
-    for( GlyphIndex glyphIndex = lineLayout.glyphIndex;
-         glyphIndex < parameters.totalNumberOfGlyphs;
-         ++glyphIndex )
+    // Sets the maximum ascender.
+    if( fontMetrics.ascender > lineLayout.ascender )
     {
-      // Get the glyph info.
-      const GlyphInfo& glyphInfo = *( parameters.glyphsBuffer + glyphIndex );
-
-      // Check whether is a white space.
-      const Character character = *( parameters.textBuffer + lineLayout.numberOfCharacters );
-      const bool isWhiteSpace = TextAbstraction::IsWhiteSpace( character );
-
-      // Get the character indices for the current glyph. The last character index is needed
-      // because there are glyphs formed by more than one character but their break info is
-      // given only for the last character.
-      const Length charactersPerGlyph = *( parameters.charactersPerGlyphBuffer + glyphIndex );
-
-      // Increase the number of characters.
-      lineLayout.numberOfCharacters += charactersPerGlyph;
-
-      // Increase the number of glyphs.
-      lineLayout.numberOfGlyphs++;
-
-      // Increase the accumulated length.
-      const float glyphLength = ( glyphIndex == lastGlyphIndex ) ? glyphInfo.width : glyphInfo.advance;
+      lineLayout.ascender = fontMetrics.ascender;
+    }
 
-      if( isWhiteSpace )
-      {
-        // Add the length to the length of white spaces at the end of the line.
-        lineLayout.wsLengthEndOfLine += glyphLength;
-      }
-      else
-      {
-        // Add as well any previous white space length.
-        lineLayout.length += lineLayout.wsLengthEndOfLine + glyphLength;
+    // Sets the minimum descender.
+    if( fontMetrics.descender < lineLayout.descender )
+    {
+      lineLayout.descender = fontMetrics.descender;
+    }
+  }
 
-        // Clear the white space length at the end of the line.
-        lineLayout.wsLengthEndOfLine = 0.f;
-      }
+  /**
+   * @brief Merges a temporary line layout into the line layout.
+   *
+   * @param[in,out] lineLayout The line layout.
+   * @param[in] tmpLineLayout A temporary line layout.
+   */
+  void MergeLineLayout( LineLayout& lineLayout,
+                        const LineLayout& tmpLineLayout )
+  {
+    lineLayout.numberOfCharacters += tmpLineLayout.numberOfCharacters;
+    lineLayout.numberOfGlyphs += tmpLineLayout.numberOfGlyphs;
+    lineLayout.length += tmpLineLayout.length;
 
-      if( lastFontId != glyphInfo.fontId )
-      {
-        Text::FontMetrics fontMetrics;
-        mFontClient.GetFontMetrics( glyphInfo.fontId, fontMetrics );
+    if( 0.f < tmpLineLayout.length )
+    {
+      lineLayout.length += lineLayout.wsLengthEndOfLine;
 
-        // Sets the maximum height.
-        if( fontMetrics.height > lineLayout.height )
-        {
-          lineLayout.height = fontMetrics.height;
-        }
+      lineLayout.wsLengthEndOfLine = tmpLineLayout.wsLengthEndOfLine;
+      lineLayout.widthAdvanceDiff = tmpLineLayout.widthAdvanceDiff;
+    }
+    else
+    {
+      lineLayout.wsLengthEndOfLine += tmpLineLayout.wsLengthEndOfLine;
+    }
 
-        // Sets the maximum ascender.
-        if( fontMetrics.ascender > lineLayout.ascender )
-        {
-          lineLayout.ascender = fontMetrics.ascender;
-        }
+    if( tmpLineLayout.ascender > lineLayout.ascender )
+    {
+      lineLayout.ascender = tmpLineLayout.ascender;
+    }
 
-        lastFontId = glyphInfo.fontId;
-      }
+    if( tmpLineLayout.descender < lineLayout.descender )
+    {
+      lineLayout.descender = tmpLineLayout.descender;
     }
   }
 
   /**
    * Retrieves the line layout for a given box width.
    */
-  void GetMultiLineLayoutForBox( const LayoutParameters& parameters,
-                                 LineLayout& lineLayout )
+  void GetLineLayoutForBox( const LayoutParameters& parameters,
+                            LineLayout& lineLayout )
   {
-    // Initializes the line layout.
-    lineLayout.numberOfCharacters = 0u;
-    lineLayout.numberOfGlyphs = 0u;
-    lineLayout.length = 0.f;
-    lineLayout.wsLengthEndOfLine = 0.f;
-    lineLayout.height = 0.f;
-    lineLayout.ascender = 0.f;
-
     // Stores temporary line layout which has not been added to the final line layout.
     LineLayout tmpLineLayout;
-    tmpLineLayout.numberOfCharacters = 0u;
-    tmpLineLayout.numberOfGlyphs = 0u;
-    tmpLineLayout.length = 0.f;
-    tmpLineLayout.wsLengthEndOfLine = 0.f;
-    tmpLineLayout.height = 0.f;
-    tmpLineLayout.ascender = 0.f;
-
-    // Get the last glyph index.
+
+    const bool isMultiline = mLayout == MULTI_LINE_BOX;
     const GlyphIndex lastGlyphIndex = parameters.totalNumberOfGlyphs - 1u;
 
-    FontId lastFontId = 0u;
+    // If the first glyph has a negative bearing its absolute value needs to be added to the line length.
+    // In the case the line starts with a right to left character the bearing needs to be substracted to the line length.
+    const GlyphInfo& glyphInfo = *( parameters.glyphsBuffer + lineLayout.glyphIndex );
+    float initialHorizontalBearing = glyphInfo.xBearing;
+
+    lineLayout.characterIndex = *( parameters.glyphsToCharactersBuffer + lineLayout.glyphIndex );
+    const CharacterDirection firstCharacterDirection = ( NULL == parameters.characterDirectionBuffer ) ? false : *( parameters.characterDirectionBuffer + lineLayout.characterIndex );
+
+    if( RTL == firstCharacterDirection )
+    {
+      initialHorizontalBearing = -initialHorizontalBearing;
+
+      if( 0.f < glyphInfo.xBearing )
+      {
+        tmpLineLayout.length = glyphInfo.xBearing;
+        initialHorizontalBearing = 0.f;
+      }
+    }
+    else
+    {
+      if( 0.f > glyphInfo.xBearing )
+      {
+        tmpLineLayout.length = -glyphInfo.xBearing;
+        initialHorizontalBearing = 0.f;
+      }
+    }
+
+    // Calculate the line height if there is no characters.
+    FontId lastFontId = glyphInfo.fontId;
+    UpdateLineHeight( lastFontId, tmpLineLayout );
+
+    const float boundingBoxWidth = parameters.boundingBox.width - initialHorizontalBearing;
+
+    bool oneWordLaidOut = false;
+
     for( GlyphIndex glyphIndex = lineLayout.glyphIndex;
          glyphIndex < parameters.totalNumberOfGlyphs;
          ++glyphIndex )
     {
+      const bool isLastGlyph = glyphIndex == lastGlyphIndex;
+
       // Get the glyph info.
       const GlyphInfo& glyphInfo = *( parameters.glyphsBuffer + glyphIndex );
 
@@ -199,114 +241,62 @@ struct LayoutEngine::Impl
       if( isWhiteSpace )
       {
         // Add the length to the length of white spaces at the end of the line.
-        tmpLineLayout.wsLengthEndOfLine += glyphInfo.advance; // I use the advance as the width is always zero for the white spaces.
+        tmpLineLayout.wsLengthEndOfLine += glyphInfo.advance; // The advance is used as the width is always zero for the white spaces.
       }
       else
       {
         // Add as well any previous white space length.
-        tmpLineLayout.length += tmpLineLayout.wsLengthEndOfLine + ( glyphIndex == lastGlyphIndex ) ? glyphInfo.width : glyphInfo.advance;
+        tmpLineLayout.length += tmpLineLayout.wsLengthEndOfLine + glyphInfo.advance;
+        if( RTL == firstCharacterDirection )
+        {
+          tmpLineLayout.widthAdvanceDiff = -glyphInfo.xBearing;
+        }
+        else
+        {
+          tmpLineLayout.widthAdvanceDiff = glyphInfo.xBearing + glyphInfo.width - glyphInfo.advance;
+        }
 
         // Clear the white space length at the end of the line.
         tmpLineLayout.wsLengthEndOfLine = 0.f;
       }
 
       // Check if the accumulated length fits in the width of the box.
-      if( lineLayout.length + tmpLineLayout.length + ( ( 0.f < tmpLineLayout.length ) ? lineLayout.wsLengthEndOfLine : 0.f ) > parameters.boundingBox.width )
+      if( isMultiline && oneWordLaidOut && !isWhiteSpace &&
+          ( lineLayout.length + lineLayout.wsLengthEndOfLine + tmpLineLayout.length + tmpLineLayout.widthAdvanceDiff > boundingBoxWidth ) )
       {
         // Current word does not fit in the box's width.
         return;
       }
 
-      if( TextAbstraction::LINE_MUST_BREAK == lineBreakInfo )
+      if( ( isMultiline || isLastGlyph ) &&
+          ( TextAbstraction::LINE_MUST_BREAK == lineBreakInfo ) )
       {
         // Must break the line. Update the line layout and return.
-        lineLayout.numberOfCharacters += tmpLineLayout.numberOfCharacters;
-        lineLayout.numberOfGlyphs += tmpLineLayout.numberOfGlyphs;
-        lineLayout.length += tmpLineLayout.length;
-
-        if( 0.f < tmpLineLayout.length )
-        {
-          lineLayout.length += lineLayout.wsLengthEndOfLine;
-
-          lineLayout.wsLengthEndOfLine = tmpLineLayout.wsLengthEndOfLine;
-        }
-        else
-        {
-          lineLayout.wsLengthEndOfLine += tmpLineLayout.wsLengthEndOfLine;
-        }
-
-        if( tmpLineLayout.height > lineLayout.height )
-        {
-          lineLayout.height = tmpLineLayout.height;
-        }
+        MergeLineLayout( lineLayout, tmpLineLayout );
 
-        if( tmpLineLayout.ascender > lineLayout.ascender )
-        {
-          lineLayout.ascender = tmpLineLayout.ascender;
-        }
-
-        tmpLineLayout.numberOfCharacters = 0u;
-        tmpLineLayout.numberOfGlyphs = 0u;
-        tmpLineLayout.length = 0u;
-        tmpLineLayout.wsLengthEndOfLine = 0u;
-        tmpLineLayout.height = 0.f;
-        tmpLineLayout.ascender = 0.f;
         return;
       }
 
-      if( TextAbstraction::WORD_BREAK == wordBreakInfo )
+      if( isMultiline &&
+          ( TextAbstraction::WORD_BREAK == wordBreakInfo ) )
       {
-        // Current glyph is the last one of the current word.
-        // Add the temporal layout to the current one.
-        lineLayout.numberOfCharacters += tmpLineLayout.numberOfCharacters;
-        lineLayout.numberOfGlyphs += tmpLineLayout.numberOfGlyphs;
-        lineLayout.length += tmpLineLayout.length;
-        if( 0.f < tmpLineLayout.length )
-        {
-          lineLayout.length += lineLayout.wsLengthEndOfLine;
-
-          lineLayout.wsLengthEndOfLine = tmpLineLayout.wsLengthEndOfLine;
-        }
-        else
+        if( !oneWordLaidOut && !isWhiteSpace )
         {
-          lineLayout.wsLengthEndOfLine += tmpLineLayout.wsLengthEndOfLine;
+          oneWordLaidOut = true;
         }
 
-        if( tmpLineLayout.height > lineLayout.height )
-        {
-          lineLayout.height = tmpLineLayout.height;
-        }
-
-        if( tmpLineLayout.ascender > lineLayout.ascender )
-        {
-          lineLayout.ascender = tmpLineLayout.ascender;
-        }
+        // Current glyph is the last one of the current word.
+        // Add the temporal layout to the current one.
+        MergeLineLayout( lineLayout, tmpLineLayout );
 
-        tmpLineLayout.numberOfCharacters = 0u;
-        tmpLineLayout.numberOfGlyphs = 0u;
-        tmpLineLayout.length = 0u;
-        tmpLineLayout.wsLengthEndOfLine = 0u;
-        tmpLineLayout.height = 0.f;
-        tmpLineLayout.ascender = 0.f;
+        tmpLineLayout.Clear();
       }
 
+      // Check if the font of the current glyph is the same of the previous one.
+      // If it's different the ascender and descender need to be updated.
       if( lastFontId != glyphInfo.fontId )
       {
-        Text::FontMetrics fontMetrics;
-        mFontClient.GetFontMetrics( glyphInfo.fontId, fontMetrics );
-
-        // Sets the maximum height.
-        if( fontMetrics.height > tmpLineLayout.height )
-        {
-          tmpLineLayout.height = fontMetrics.height;
-        }
-
-        // Sets the maximum ascender.
-        if( fontMetrics.ascender > tmpLineLayout.ascender )
-        {
-          tmpLineLayout.ascender = fontMetrics.ascender;
-        }
-
+        UpdateLineHeight( glyphInfo.fontId, tmpLineLayout );
         lastFontId = glyphInfo.fontId;
       }
     }
@@ -317,45 +307,97 @@ struct LayoutEngine::Impl
                    Vector<LineRun>& lines,
                    Size& actualSize )
   {
-    // TODO Switch between different layouts
-    bool update = false;
+    Vector2* glyphPositionsBuffer = glyphPositions.Begin();
 
-    switch( mLayout )
+    float penY = 0.f;
+    for( GlyphIndex index = 0u; index < layoutParameters.totalNumberOfGlyphs; )
     {
-      case LayoutEngine::SINGLE_LINE_BOX:
+      // Get the layout for the line.
+      LineLayout layout;
+      layout.glyphIndex = index;
+      GetLineLayoutForBox( layoutParameters,
+                           layout );
+
+      if( 0u == layout.numberOfGlyphs )
       {
-        update = SingleLineLayout( layoutParameters,
-                                   glyphPositions,
-                                   lines,
-                                   actualSize );
-        break;
+        // The width is too small and no characters are laid-out.
+        return false;
+      }
+
+      LineRun lineRun;
+      lineRun.glyphIndex = index;
+      lineRun.numberOfGlyphs = layout.numberOfGlyphs;
+      lineRun.characterRun.characterIndex = layout.characterIndex;
+      lineRun.characterRun.numberOfCharacters = layout.numberOfCharacters;
+      lineRun.width = layout.length + layout.widthAdvanceDiff;
+      lineRun.ascender = layout.ascender;
+      lineRun.descender = layout.descender;
+      lineRun.extraLength = layout.wsLengthEndOfLine > 0.f ? layout.wsLengthEndOfLine - layout.widthAdvanceDiff : 0.f;
+      lineRun.direction = false;
+
+      lines.PushBack( lineRun );
+
+      // Update the actual size.
+      if( lineRun.width > actualSize.width )
+      {
+        actualSize.width = lineRun.width;
       }
-      case LayoutEngine::MULTI_LINE_BOX:
+
+      actualSize.height += ( lineRun.ascender + -lineRun.descender );
+
+      // Traverse the glyphs and set the positions.
+
+      penY += layout.ascender;
+
+      // Check if the x bearing of the first character is negative.
+      // If it has a negative x bearing, it will exceed the boundaries of the actor,
+      // so the penX position needs to be moved to the right.
+      float penX = 0.f;
+
+      const GlyphInfo& glyph = *( layoutParameters.glyphsBuffer + index );
+      if( 0.f > glyph.xBearing )
       {
-        update = MultiLineLayout( layoutParameters,
-                                  glyphPositions,
-                                  lines,
-                                  actualSize );
-        break;
+        penX = -glyph.xBearing;
       }
-      default:
-        break;
+
+      for( GlyphIndex i = index; i < index + layout.numberOfGlyphs; ++i )
+      {
+        const GlyphInfo& glyph = *( layoutParameters.glyphsBuffer + i );
+        Vector2& position = *( glyphPositionsBuffer + i );
+
+        position.x = penX + glyph.xBearing;
+        position.y = penY - glyph.yBearing;
+
+        penX += glyph.advance;
+      }
+
+      penY += -layout.descender;
+
+      // Increase the glyph index.
+      index += layout.numberOfGlyphs;
     }
 
-    return update;
+    return true;
   }
 
   void ReLayoutRightToLeftLines( const LayoutParameters& layoutParameters,
                                  Vector<Vector2>& glyphPositions )
   {
+    // Traverses the paragraphs with right to left characters.
     for( LineIndex lineIndex = 0u; lineIndex < layoutParameters.numberOfBidirectionalInfoRuns; ++lineIndex )
     {
-      const BidirectionalLineInfoRun& bidiLine = *( layoutParameters.lineBidirectionalInfoRunsBuffer +lineIndex  );
+      const BidirectionalLineInfoRun& bidiLine = *( layoutParameters.lineBidirectionalInfoRunsBuffer + lineIndex );
 
       float penX = 0.f;
 
+      const CharacterIndex characterVisualIndex = bidiLine.characterRun.characterIndex + *bidiLine.visualToLogicalMap;
+      const GlyphInfo& glyph = *( layoutParameters.glyphsBuffer + *( layoutParameters.charactersToGlyphsBuffer + characterVisualIndex ) );
+
+      penX = -glyph.xBearing;
+
       Vector2* glyphPositionsBuffer = glyphPositions.Begin();
 
+      // Traverses the characters of the right to left paragraph.
       for( CharacterIndex characterLogicalIndex = 0u;
            characterLogicalIndex < bidiLine.characterRun.numberOfCharacters;
            ++characterLogicalIndex )
@@ -369,7 +411,9 @@ struct LayoutEngine::Impl
         for( GlyphIndex index = 0u; index < numberOfGlyphs; ++index )
         {
           // Convert the character in the visual order into the glyph in the visual order.
-          GlyphIndex glyphIndex = 1u + *( layoutParameters.charactersToGlyphsBuffer + characterVisualIndex + index ) - numberOfGlyphs;
+          const GlyphIndex glyphIndex = *( layoutParameters.charactersToGlyphsBuffer + characterVisualIndex ) + index;
+
+          DALI_ASSERT_DEBUG( 0u <= glyphIndex && glyphIndex < layoutParameters.totalNumberOfGlyphs );
 
           const GlyphInfo& glyph = *( layoutParameters.glyphsBuffer + glyphIndex );
           Vector2& position = *( glyphPositionsBuffer + glyphIndex );
@@ -382,6 +426,7 @@ struct LayoutEngine::Impl
   }
 
   void Align( const LayoutParameters& layoutParameters,
+              const Size& layoutSize,
               const Vector<LineRun>& lines,
               Vector<Vector2>& glyphPositions )
   {
@@ -423,10 +468,10 @@ struct LayoutEngine::Impl
 
       // 2) Calculate the alignment offset accordingly with the align option,
       //    the box width, line length, and the paragraphs direction.
-      float alignOffset = CalculateAlignment( layoutParameters.boundingBox.width,
-                                              line.lineSize.width,
-                                              line.extraLength,
-                                              paragraphDirection );
+      float alignOffset = CalculateHorizontalAlignment( layoutSize.width,
+                                                        line.width,
+                                                        line.extraLength,
+                                                        paragraphDirection );
 
       // 3) Traverse all glyphs and update the 'x' position.
       for( GlyphIndex index = line.glyphIndex,
@@ -441,155 +486,42 @@ struct LayoutEngine::Impl
     }
   }
 
-  bool SingleLineLayout( const LayoutParameters& layoutParameters,
-                         Vector<Vector2>& glyphPositions,
-                         Vector<LineRun>& lines,
-                         Size& actualSize )
-  {
-    LineLayout layout;
-    layout.glyphIndex = 0u;
-    GetLineLayoutForBox( layoutParameters,
-                         layout );
-
-    // Create a line run and add it to the lines.
-    const GlyphIndex lastGlyphIndex = layoutParameters.totalNumberOfGlyphs - 1u;
-
-    LineRun lineRun;
-    lineRun.glyphIndex = 0u;
-    lineRun.numberOfGlyphs = layoutParameters.totalNumberOfGlyphs;
-    lineRun.characterRun.characterIndex = 0u;
-    lineRun.characterRun.numberOfCharacters = *( layoutParameters.glyphsToCharactersBuffer + lastGlyphIndex ) + *( layoutParameters.charactersPerGlyphBuffer + lastGlyphIndex );
-    lineRun.lineSize.width = layout.length;
-    lineRun.lineSize.height = layout.height;
-    lineRun.extraLength = layout.wsLengthEndOfLine;
-
-    lines.PushBack( lineRun );
-
-    // Update the actual size.
-    actualSize.width = layout.length;
-    actualSize.height = layout.height;
-
-    float penX = 0.f;
-    float penY = layout.height;
-
-    Vector2* glyphPositionsBuffer = glyphPositions.Begin();
-    for( GlyphIndex glyphIndex = 0u; glyphIndex < layout.numberOfGlyphs; ++glyphIndex )
-    {
-      const GlyphInfo& glyph = *( layoutParameters.glyphsBuffer + glyphIndex );
-      Vector2& position = *( glyphPositionsBuffer + glyphIndex );
-
-      position.x = penX + glyph.xBearing;
-      position.y = penY - glyph.yBearing;
-
-      penX += glyph.advance;
-    }
-
-    return true;
-  }
-
-  bool MultiLineLayout( const LayoutParameters& layoutParameters,
-                        Vector<Vector2>& glyphPositions,
-                        Vector<LineRun>& lines,
-                        Size& actualSize )
-  {
-    float penY = 0.f;
-    for( GlyphIndex index = 0u; index < layoutParameters.totalNumberOfGlyphs; )
-    {
-      float penX = 0.f;
-
-      // Get the layout for the line.
-      LineLayout layout;
-      layout.glyphIndex = index;
-      GetMultiLineLayoutForBox( layoutParameters,
-                                layout );
-
-      if( 0u == layout.numberOfGlyphs )
-      {
-        // The width is too small and no characters are laid-out.
-        return false;
-      }
-
-      // Create a line run and add it to the lines.
-      const GlyphIndex lastGlyphIndex = index + layout.numberOfGlyphs - 1u;
-
-      LineRun lineRun;
-      lineRun.glyphIndex = index;
-      lineRun.numberOfGlyphs = layout.numberOfGlyphs;
-      lineRun.characterRun.characterIndex = *( layoutParameters.glyphsToCharactersBuffer + index );
-      lineRun.characterRun.numberOfCharacters = ( *( layoutParameters.glyphsToCharactersBuffer + lastGlyphIndex ) + *( layoutParameters.charactersPerGlyphBuffer + lastGlyphIndex ) ) - lineRun.characterRun.characterIndex;
-      lineRun.lineSize.width = layout.length;
-      lineRun.lineSize.height = layout.height;
-      lineRun.extraLength = layout.wsLengthEndOfLine;
-
-      lines.PushBack( lineRun );
-
-      // Update the actual size.
-      if( layout.length > actualSize.width )
-      {
-        actualSize.width = layout.length;
-      }
-
-      actualSize.height += layout.height;
-
-      // Traverse the glyphs and set the positions.
-
-      penY += layout.height;
-
-      Vector2* glyphPositionsBuffer = glyphPositions.Begin();
-      for( GlyphIndex i = index; i < index + layout.numberOfGlyphs; ++i )
-      {
-        const GlyphInfo& glyph = *( layoutParameters.glyphsBuffer + i );
-        Vector2& position = *( glyphPositionsBuffer + i );
-
-        position.x = penX + glyph.xBearing;
-        position.y = penY - glyph.yBearing;
-
-        penX += glyph.advance;
-      }
-
-      // Increase the glyph index.
-      index += layout.numberOfGlyphs;
-    }
-
-    return true;
-  }
-
-  float CalculateAlignment( float boxWidth,
-                            float lineLength,
-                            float extraLength,
-                            bool paragraphDirection )
+  float CalculateHorizontalAlignment( float boxWidth,
+                                      float lineLength,
+                                      float extraLength,
+                                      bool paragraphDirection )
   {
     float offset = 0.f;
 
-    Alignment alignment = mAlignment;
+    HorizontalAlignment alignment = mHorizontalAlignment;
     if( paragraphDirection &&
-        ( ALIGN_CENTER != alignment ) )
+        ( HORIZONTAL_ALIGN_CENTER != alignment ) )
     {
-      if( ALIGN_BEGIN == alignment )
+      if( HORIZONTAL_ALIGN_BEGIN == alignment )
       {
-        alignment = ALIGN_END;
+        alignment = HORIZONTAL_ALIGN_END;
       }
       else
       {
-        alignment = ALIGN_BEGIN;
+        alignment = HORIZONTAL_ALIGN_BEGIN;
       }
     }
 
     switch( alignment )
     {
-      case ALIGN_BEGIN:
+      case HORIZONTAL_ALIGN_BEGIN:
       {
         offset = 0.f;
         break;
       }
-      case ALIGN_CENTER:
+      case HORIZONTAL_ALIGN_CENTER:
       {
         offset = 0.5f * ( boxWidth - lineLength );
         const int intOffset = static_cast<int>( offset ); // try to avoid pixel alignment.
         offset = static_cast<float>( intOffset );
         break;
       }
-      case ALIGN_END:
+      case HORIZONTAL_ALIGN_END:
       {
         offset = boxWidth - lineLength;
         break;
@@ -605,7 +537,8 @@ struct LayoutEngine::Impl
   }
 
   LayoutEngine::Layout mLayout;
-  LayoutEngine::Alignment mAlignment;
+  LayoutEngine::HorizontalAlignment mHorizontalAlignment;
+  LayoutEngine::VerticalAlignment mVerticalAlignment;
 
   TextAbstraction::FontClient mFontClient;
 };
@@ -631,14 +564,24 @@ unsigned int LayoutEngine::GetLayout() const
   return mImpl->mLayout;
 }
 
-void LayoutEngine::SetAlignment( Alignment alignment )
+void LayoutEngine::SetHorizontalAlignment( HorizontalAlignment alignment )
+{
+  mImpl->mHorizontalAlignment = alignment;
+}
+
+LayoutEngine::HorizontalAlignment LayoutEngine::GetHorizontalAlignment() const
+{
+  return mImpl->mHorizontalAlignment;
+}
+
+void LayoutEngine::SetVerticalAlignment( VerticalAlignment alignment )
 {
-  mImpl->mAlignment = alignment;
+  mImpl->mVerticalAlignment = alignment;
 }
 
-LayoutEngine::Alignment LayoutEngine::GetAlignment() const
+LayoutEngine::VerticalAlignment LayoutEngine::GetVerticalAlignment() const
 {
-  return mImpl->mAlignment;
+  return mImpl->mVerticalAlignment;
 }
 
 bool LayoutEngine::LayoutText( const LayoutParameters& layoutParameters,
@@ -660,10 +603,12 @@ void LayoutEngine::ReLayoutRightToLeftLines( const LayoutParameters& layoutParam
 }
 
 void LayoutEngine::Align( const LayoutParameters& layoutParameters,
+                          const Size& layoutSize,
                           const Vector<LineRun>& lines,
                           Vector<Vector2>& glyphPositions )
 {
   mImpl->Align( layoutParameters,
+                layoutSize,
                 lines,
                 glyphPositions );
 }