Fix justification broken due to line width mis-computation

nieznanysprawiciel · Nov 13, 2024 · f875d25 · f875d25
1 parent b7166e3
commit f875d25
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Showing 4 changed files with 72 additions and 33 deletions.
diff --git a/swGUI/Prototypes/TextShowcase/Application.cpp b/swGUI/Prototypes/TextShowcase/Application.cpp
@@ -100,7 +100,7 @@ void		AddControls						( HostWindow* host )
         auto pen = std::make_shared< ImageBrush >();
         pen->SetTexture( "$(Application-Dir)/pool-water-texture.jpg" );
 
-        auto background = std::make_shared< SolidColorBrush >( Colors::WhiteSmoke );
+        auto background = std::make_shared< SolidColorBrush >( Colors::Transparent );
         auto textBlock = AddText( host, background, pen, 300, 300, Position( 400, 450 ), sLoremIpsum );
         textBlock->SetTextAlignment( sw::TextAlignment::Justify );
     }

diff --git a/swGraphicAPI/Assets/TextAsset/Text.cpp b/swGraphicAPI/Assets/TextAsset/Text.cpp
@@ -150,11 +150,12 @@ void                TextArranger::ApplyAlignement( const FontLayout& layout, std
     case TextAlignment::Justify:
     {
         // Find all spaces which will be extended.
-        auto numSpaces = std::count_if( text.begin(), text.begin() + lastCharIdx, [](wchar_t c) { return IsWhitespace(c);  });
+        auto numSpaces = std::count_if( text.begin(), text.begin() + lastCharIdx, [](wchar_t c) { return IsWhitespace(c); });
+        auto trailingSpaces = CountTrailingWhitespaces( std::wstring_view( text.data(), lastCharIdx ) );
 
         // Distribute remaining space equally between all spaces.
         // (Besides last one: we have one place less between than number of chars)
-        float offsetPerSpace = remainingSpace / ( numSpaces - 1 );
+        float offsetPerSpace = remainingSpace / ( numSpaces - trailingSpaces );
         float curOffset = 0.0f;
 
         for( Size i = 0; i < letters.size(); i++ )
@@ -175,28 +176,18 @@ void                TextArranger::ApplyAlignement( const FontLayout& layout, std
 
 float               TextArranger::TextWidth( const std::vector< Position2d >& letters, const std::wstring& text, const FontLayout& layout ) const
 {
-    Size charIdx = letters.size() - 1;
-    Position2d last = letters[ charIdx ];
-    float adjustLast = 0.0;
+    Size lastCharIdx = letters.size() - 1;
+    Size trailingSpaces = CountTrailingWhitespaces( std::wstring_view( text.c_str(), letters.size() ) );
+    i64 lastNonSpace = (i64)lastCharIdx - (i64)trailingSpaces;
 
-    if( IsSpace( text[ charIdx ] ) )
-    {
-        // If last character was space, we want to adjust to last character before.
-        adjustLast = -( this->SpaceSize + this->Interspace );
-    }
-    else if( IsNewline( text[ charIdx ] ) )
-    {
-        // Ignore newline, since last character is already in correct position.
-        float adjustLast = 0.0;
-    }
-    else
-    {
-        // Normal character. We need to move forward to right edge.
-        auto& glyph = layout.Glyphs.at( text[ charIdx ] );
-        adjustLast = (float)glyph.Width - (float)glyph.BearingX;
-    }
+    if( lastNonSpace < 0 )
+        return 0.0f;  // No characters in text (only spaces or newlines)
 
-    return letters.back().x - letters.front().x + adjustLast;
+    // We need to find right edge of the last non whitespace character in line.
+    auto lastRightEdge = TopRightVertex( layout.Glyphs.at( text[ lastNonSpace ] ), letters[ lastNonSpace ] ).x;
+    auto firstLeftEdge = TopLeftVertex( layout.Glyphs.at( text[ 0 ] ), letters[ 0 ] ).x;
+
+    return lastRightEdge - firstLeftEdge;
 }
 
 // ================================ //
@@ -256,6 +247,54 @@ Rect2d              TextArranger::ComputeTextBounds( const std::vector< Position
 
 // ================================ //
 
+Size                TextArranger::CountTrailingWhitespaces( const std::wstring_view& text )
+{
+    for( auto iter = text.rbegin(); iter != text.rend(); iter++ )
+    {
+        if( !IsWhitespace( *iter ) )
+            return std::distance( text.rbegin(), iter );
+    }
+
+    return 0;
+}
+
+// ================================ //
+
+Position2d          TextArranger::TopLeftVertex( const Glyph& glyph, Position2d position )
+{
+    Position2d bearing = Position2d( (float)glyph.BearingX, (float)glyph.BearingY );
+    return position + bearing;
+}
+
+// ================================ //
+
+Position2d          TextArranger::TopRightVertex( const Glyph& glyph, Position2d position )
+{
+    Position2d bearing = Position2d( (float)glyph.BearingX, (float)glyph.BearingY );
+    Position2d quadTopRight = Position2d( (float)glyph.Width, 0.f );
+    return quadTopRight + position + bearing;
+}
+
+// ================================ //
+
+Position2d          TextArranger::BottomLeftVertex( const Glyph& glyph, Position2d position )
+{
+    Position2d bearing = Position2d( (float)glyph.BearingX, (float)glyph.BearingY );
+    Position2d quadBottomLeft = Position2d( 0.f, -(float)glyph.Height );
+    return quadBottomLeft + position + bearing;
+}
+
+// ================================ //
+
+Position2d          TextArranger::BottomRightVertex( const Glyph& glyph, Position2d position )
+{
+    Position2d bearing = Position2d( (float)glyph.BearingX, (float)glyph.BearingY );
+    Position2d quadBottomRight = Position2d( (float)glyph.Width, -(float)glyph.Height );
+    return quadBottomRight + position + bearing;
+}
+
+// ================================ //
+
 Nullable< geom::IndexedGeometryBuffer< geom::VertexShape2D, Index32 > >
 TextArranger::GenerateGeometry( const std::wstring& text, const FontAssetPtr font, bool genBackground ) const
 {

diff --git a/swGraphicAPI/Assets/TextAsset/Text.h b/swGraphicAPI/Assets/TextAsset/Text.h
@@ -75,6 +75,12 @@ class TextArranger
     static bool                 IsSpace( wchar_t character );
     static Size                 EstimateLineLength( std::wstring_view text );
     static Rect2d               ComputeTextBounds( const std::vector< Position2d >& letters );
+    static Size                 CountTrailingWhitespaces( const std::wstring_view& text );
+
+    static Position2d           TopLeftVertex( const Glyph& glyph, Position2d pos );
+    static Position2d           TopRightVertex( const Glyph& glyph, Position2d pos );
+    static Position2d           BottomLeftVertex( const Glyph& glyph, Position2d pos );
+    static Position2d           BottomRightVertex( const Glyph& glyph, Position2d pos );
 
 public:
     Nullable< geom::IndexedGeometryBuffer< geom::VertexShape2D, Index32 > >   GenerateGeometry( const std::wstring& text, const FontAssetPtr font, bool genBackground ) const;

diff --git a/swGraphicAPI/Assets/TextAsset/Text.inl b/swGraphicAPI/Assets/TextAsset/Text.inl
@@ -147,25 +147,19 @@ inline void
 TextGeometryGenerator< VertexType, IndexType, TextAcc >::PutLetterVertex( VertexType& vertex, const Glyph& glyph,
                                                                           Position2d position, Size vertexIdx ) const
 {
-    Position2d bearing = Position2d( (float)glyph.BearingX, (float)glyph.BearingY );
-
     switch ( vertexIdx % 4 )
     {
         case 0:
-            Position2d quadTopLeft = Position2d( 0.f, 0.f );
-            TextAcc::GetPos( vertex ) = quadTopLeft + position + bearing;
+            TextAcc::GetPos( vertex ) = TextArranger::TopLeftVertex( glyph, position );
             break;
         case 1:
-            Position2d quadTopRight = Position2d( (float)glyph.Width, 0.f );
-            TextAcc::GetPos( vertex ) = quadTopRight + position + bearing;
+            TextAcc::GetPos( vertex ) = TextArranger::TopRightVertex( glyph, position );
             break;
         case 2:
-            Position2d quadBottomLeft = Position2d( 0.f, -(float)glyph.Height );
-            TextAcc::GetPos( vertex ) = quadBottomLeft + position + bearing;
+            TextAcc::GetPos( vertex ) = TextArranger::BottomLeftVertex( glyph, position );
             break;
         case 3:
-            Position2d quadBottomRight = Position2d( (float)glyph.Width, -(float)glyph.Height );
-            TextAcc::GetPos( vertex ) = quadBottomRight + position + bearing;
+            TextAcc::GetPos( vertex ) = TextArranger::BottomRightVertex( glyph, position );
             break;
     }
 }