/*
- * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ * Copyright (c) 2016 Samsung Electronics Co., Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <dali-toolkit/internal/text/rendering/atlas/text-atlas-renderer.h>
// EXTERNAL INCLUDES
-#include <dali/integration-api/debug.h>
-#include <dali/devel-api/rendering/renderer.h>
-#include <dali/devel-api/rendering/geometry.h>
+#include <dali/public-api/rendering/geometry.h>
+#include <dali/public-api/rendering/renderer.h>
+#include <dali/public-api/images/frame-buffer-image.h>
#include <dali/devel-api/text-abstraction/font-client.h>
+#include <dali/integration-api/debug.h>
+#include <dali/public-api/animation/constraints.h>
// INTERNAL INCLUDES
#include <dali-toolkit/devel-api/controls/control-depth-index-ranges.h>
namespace
{
#if defined(DEBUG_ENABLED)
- Debug::Filter* gLogFilter = Debug::Filter::New(Debug::Concise, true, "LOG_TEXT_RENDERING");
+ Debug::Filter* gLogFilter = Debug::Filter::New(Debug::NoLogging, true, "LOG_TEXT_RENDERING");
#endif
+#define MAKE_SHADER(A)#A
+
+const char* VERTEX_SHADER = MAKE_SHADER(
+attribute mediump vec2 aPosition;
+attribute mediump vec2 aTexCoord;
+attribute mediump vec4 aColor;
+uniform mediump vec2 uOffset;
+uniform mediump mat4 uMvpMatrix;
+varying mediump vec2 vTexCoord;
+varying mediump vec4 vColor;
+
+void main()
+{
+ mediump vec4 position = vec4( aPosition.xy + uOffset, 0.0, 1.0 );
+ gl_Position = uMvpMatrix * position;
+ vTexCoord = aTexCoord;
+ vColor = aColor;
+}
+);
+
+const char* FRAGMENT_SHADER_L8 = MAKE_SHADER(
+uniform lowp vec4 uColor;
+uniform lowp vec4 textColorAnimatable;
+uniform sampler2D sTexture;
+varying mediump vec2 vTexCoord;
+varying mediump vec4 vColor;
+
+void main()
+{
+ mediump vec4 color = texture2D( sTexture, vTexCoord );
+ gl_FragColor = vec4( vColor.rgb * uColor.rgb * textColorAnimatable.rgb, uColor.a * vColor.a * textColorAnimatable.a * color.r );
+}
+);
+
+const char* FRAGMENT_SHADER_RGBA = MAKE_SHADER(
+uniform lowp vec4 uColor;
+uniform lowp vec4 textColorAnimatable;
+uniform sampler2D sTexture;
+varying mediump vec2 vTexCoord;
+
+void main()
+{
+ gl_FragColor = texture2D( sTexture, vTexCoord ) * uColor * textColorAnimatable;
+}
+);
+
const float ZERO( 0.0f );
const float HALF( 0.5f );
const float ONE( 1.0f );
const uint32_t DEFAULT_ATLAS_WIDTH = 512u;
const uint32_t DEFAULT_ATLAS_HEIGHT = 512u;
+const int NO_OUTLINE( 0 );
}
struct AtlasRenderer::Impl
mQuadVertexFormat[ "aPosition" ] = Property::VECTOR2;
mQuadVertexFormat[ "aTexCoord" ] = Property::VECTOR2;
mQuadVertexFormat[ "aColor" ] = Property::VECTOR4;
- mQuadIndexFormat[ "indices" ] = Property::INTEGER;
}
bool IsGlyphUnderlined( GlyphIndex index,
}
void AddGlyphs( Text::ViewInterface& view,
+ Actor textControl,
+ Property::Index animatablePropertyIndex,
const Vector<Vector2>& positions,
const Vector<GlyphInfo>& glyphs,
const Vector4& defaultColor,
const Vector4* const colorsBuffer,
const ColorIndex* const colorIndicesBuffer,
- int depth )
+ int depth,
+ float minLineOffset )
{
AtlasManager::AtlasSlot slot;
std::vector< MeshRecord > meshContainer;
TextCacheEntry textCacheEntry;
mDepth = depth;
- const Vector2& actorSize( view.GetControlSize() );
const Vector2& textSize( view.GetLayoutSize() );
const Vector2 halfTextSize( textSize * 0.5f );
const Vector2& shadowOffset( view.GetShadowOffset() );
Vector< TextCacheEntry > newTextCache;
const GlyphInfo* const glyphsBuffer = glyphs.Begin();
const Vector2* const positionsBuffer = positions.Begin();
+ const Vector2 lineOffsetPosition( minLineOffset, 0.f );
for( uint32_t i = 0, glyphSize = glyphs.Size(); i < glyphSize; ++i )
{
const GlyphInfo& glyph = *( glyphsBuffer + i );
-
const bool underlineGlyph = underlineEnabled || IsGlyphUnderlined( i, underlineRuns );
thereAreUnderlinedGlyphs = thereAreUnderlinedGlyphs || underlineGlyph;
lastUnderlinedFontId = glyph.fontId;
} // underline
- if( !mGlyphManager.IsCached( glyph.fontId, glyph.index, slot ) )
+ bool glyphNotCached = !mGlyphManager.IsCached( glyph.fontId, glyph.index, slot ); // Check FontGlyphRecord vector for entry with glyph index and fontId
+
+ DALI_LOG_INFO( gLogFilter, Debug::Verbose, "AddGlyphs fontID[%u] glyphIndex[%u] [%s]\n", glyph.fontId, glyph.index, (glyphNotCached)?"not cached":"cached" );
+
+ if( glyphNotCached )
{
- // Select correct size for new atlas if needed....?
- if( lastFontId != glyph.fontId )
+ MaxBlockSize& blockSize = mBlockSizes[currentBlockSize];
+
+ if ( lastFontId != glyph.fontId )
{
uint32_t index = 0u;
+ // Looks through all stored block sizes until finds the one which mataches required glyph font it. Ensures new atlas block size will match existing for same font id.
+ // CalculateBlocksSize() above ensures a block size entry exists.
for( std::vector<MaxBlockSize>::const_iterator it = mBlockSizes.begin(),
endIt = mBlockSizes.end();
it != endIt;
++it, ++index )
{
- const MaxBlockSize& blockSize = *it;
- if( blockSize.mFontId == glyph.fontId )
+ const MaxBlockSize& blockSizeEntry = *it;
+ if( blockSizeEntry.mFontId == glyph.fontId )
{
- currentBlockSize = index;
- mGlyphManager.SetNewAtlasSize( DEFAULT_ATLAS_WIDTH,
- DEFAULT_ATLAS_HEIGHT,
- blockSize.mNeededBlockWidth,
- blockSize.mNeededBlockHeight );
+ blockSize = mBlockSizes[index];
}
}
}
// Create a new image for the glyph
- BufferImage bitmap = mFontClient.CreateBitmap( glyph.fontId, glyph.index );
+ PixelData bitmap;
+
+ // Whether the current glyph is a color one.
+ const bool isColorGlyph = mFontClient.IsColorGlyph( glyph.fontId, glyph.index );
+
+ // Retrieve the emoji's bitmap.
+ TextAbstraction::FontClient::GlyphBufferData glyphBufferData;
+ glyphBufferData.width = isColorGlyph ? glyph.width : 0; // Desired width and height.
+ glyphBufferData.height = isColorGlyph ? glyph.height : 0;
+
+ mFontClient.CreateBitmap( glyph.fontId,
+ glyph.index,
+ glyphBufferData,
+ NO_OUTLINE );
+
+ // Create the pixel data.
+ bitmap = PixelData::New( glyphBufferData.buffer,
+ glyph.width * glyph.height * GetBytesPerPixel( glyphBufferData.format ),
+ glyph.width,
+ glyph.height,
+ glyphBufferData.format,
+ PixelData::DELETE_ARRAY );
+
if( bitmap )
{
- MaxBlockSize& blockSize = mBlockSizes[currentBlockSize];
-
// Ensure that the next image will fit into the current block size
- bool setSize = false;
if( bitmap.GetWidth() > blockSize.mNeededBlockWidth )
{
- setSize = true;
blockSize.mNeededBlockWidth = bitmap.GetWidth();
}
+
if( bitmap.GetHeight() > blockSize.mNeededBlockHeight )
{
- setSize = true;
blockSize.mNeededBlockHeight = bitmap.GetHeight();
}
- if( setSize )
- {
- mGlyphManager.SetNewAtlasSize( DEFAULT_ATLAS_WIDTH,
- DEFAULT_ATLAS_HEIGHT,
- blockSize.mNeededBlockWidth,
- blockSize.mNeededBlockHeight );
- }
+ // If CheckAtlas in AtlasManager::Add can't fit the bitmap in the current atlas it will create a new atlas
+
+ // Setting the block size and size of new atlas does not mean a new one will be created. An existing atlas may still surffice.
+ mGlyphManager.SetNewAtlasSize( DEFAULT_ATLAS_WIDTH,
+ DEFAULT_ATLAS_HEIGHT,
+ blockSize.mNeededBlockWidth,
+ blockSize.mNeededBlockHeight );
// Locate a new slot for our glyph
- mGlyphManager.Add( glyph, bitmap, slot );
+ mGlyphManager.Add( glyph, bitmap, slot ); // slot will be 0 is glyph not added
}
}
else
}
// Move the origin (0,0) of the mesh to the center of the actor
- const Vector2 position = *( positionsBuffer + i ) - halfTextSize;
+ const Vector2 position = *( positionsBuffer + i ) - halfTextSize - lineOffsetPosition;
- // Generate mesh data for this quad, plugging in our supplied position
- AtlasManager::Mesh2D newMesh;
- mGlyphManager.GenerateMeshData( slot.mImageId, position, newMesh );
- textCacheEntry.mFontId = glyph.fontId;
- textCacheEntry.mImageId = slot.mImageId;
- textCacheEntry.mIndex = glyph.index;
- newTextCache.PushBack( textCacheEntry );
+ if ( 0u != slot.mImageId ) // invalid slot id, glyph has failed to be added to atlas
+ {
+ // Generate mesh data for this quad, plugging in our supplied position
+ AtlasManager::Mesh2D newMesh;
+ mGlyphManager.GenerateMeshData( slot.mImageId, position, newMesh );
+ textCacheEntry.mFontId = glyph.fontId;
+ textCacheEntry.mImageId = slot.mImageId;
+ textCacheEntry.mIndex = glyph.index;
+ newTextCache.PushBack( textCacheEntry );
- AtlasManager::Vertex2D* verticesBuffer = newMesh.mVertices.Begin();
+ AtlasManager::Vertex2D* verticesBuffer = newMesh.mVertices.Begin();
+
+ // Get the color of the character.
+ const ColorIndex colorIndex = useDefaultColor ? 0u : *( colorIndicesBuffer + i );
+ const Vector4& color = ( useDefaultColor || ( 0u == colorIndex ) ) ? defaultColor : *( colorsBuffer + colorIndex - 1u );
- // Adjust the vertices if the fixed-size font should be down-scaled
- if( glyph.scaleFactor > 0 )
- {
for( unsigned int index = 0u, size = newMesh.mVertices.Count();
index < size;
++index )
{
AtlasManager::Vertex2D& vertex = *( verticesBuffer + index );
- // Set the position of the vertex.
- vertex.mPosition.x = position.x + ( ( vertex.mPosition.x - position.x ) * glyph.scaleFactor );
- vertex.mPosition.y = position.y + ( ( vertex.mPosition.y - position.y ) * glyph.scaleFactor );
+ // Set the color of the vertex.
+ vertex.mColor = color;
}
- }
- // Get the color of the character.
- const ColorIndex colorIndex = useDefaultColor ? 0u : *( colorIndicesBuffer + i );
- const Vector4& color = ( useDefaultColor || ( 0u == colorIndex ) ) ? defaultColor : *( colorsBuffer + colorIndex - 1u );
-
- for( unsigned int index = 0u, size = newMesh.mVertices.Count();
- index < size;
- ++index )
- {
- AtlasManager::Vertex2D& vertex = *( verticesBuffer + index );
-
- // Set the color of the vertex.
- vertex.mColor = color;
+ // Find an existing mesh data object to attach to ( or create a new one, if we can't find one using the same atlas)
+ StitchTextMesh( meshContainer,
+ newMesh,
+ extents,
+ position.y + glyph.yBearing,
+ underlineGlyph,
+ currentUnderlinePosition,
+ currentUnderlineThickness,
+ slot );
+
+ lastFontId = glyph.fontId; // Prevents searching for existing blocksizes when string of the same fontId.
}
-
- // Find an existing mesh data object to attach to ( or create a new one, if we can't find one using the same atlas)
- StitchTextMesh( meshContainer,
- newMesh,
- extents,
- position.y + glyph.yBearing,
- underlineGlyph,
- currentUnderlinePosition,
- currentUnderlineThickness,
- slot );
- lastFontId = glyph.fontId;
}
} // glyphs
// For each MeshData object, create a mesh actor and add to the renderable actor
if( !meshContainer.empty() )
{
+ if( !mActor )
+ {
+ // Create a container actor to act as a common parent for text and shadow, to avoid color inheritence issues.
+ mActor = Actor::New();
+ mActor.SetParentOrigin( ParentOrigin::TOP_LEFT );
+ mActor.SetAnchorPoint( AnchorPoint::TOP_LEFT );
+ mActor.SetSize( textSize );
+ mActor.SetColorMode( USE_OWN_MULTIPLY_PARENT_COLOR );
+ }
+
for( std::vector< MeshRecord >::iterator it = meshContainer.begin(),
endIt = meshContainer.end();
it != endIt; ++it )
{
MeshRecord& meshRecord = *it;
- Actor actor = CreateMeshActor( meshRecord, textSize );
+ Actor actor = CreateMeshActor( textControl, animatablePropertyIndex, defaultColor, meshRecord, textSize, STYLE_NORMAL );
+
+ // Whether the actor has renderers.
+ const bool hasRenderer = actor.GetRendererCount() > 0u;
// Create an effect if necessary
- if( style == STYLE_DROP_SHADOW )
+ if( hasRenderer &&
+ ( style == STYLE_DROP_SHADOW ) )
{
// Change the color of the vertices.
for( Vector<AtlasManager::Vertex2D>::Iterator vIt = meshRecord.mMesh.mVertices.Begin(),
vertex.mColor = shadowColor;
}
- // Create a container actor to act as a common parent for text and shadow, to avoid color inheritence issues.
- Actor containerActor = Actor::New();
- containerActor.SetParentOrigin( ParentOrigin::CENTER );
- containerActor.SetSize( actorSize );
-
- Actor shadowActor = CreateMeshActor( meshRecord, textSize );
+ Actor shadowActor = CreateMeshActor(textControl, animatablePropertyIndex, defaultColor, meshRecord, textSize, STYLE_DROP_SHADOW );
#if defined(DEBUG_ENABLED)
shadowActor.SetName( "Text Shadow renderable actor" );
#endif
// Offset shadow in x and y
shadowActor.RegisterProperty("uOffset", shadowOffset );
- if( actor.GetRendererCount() )
- {
- Dali::Renderer renderer( shadowActor.GetRendererAt( 0 ) );
- int depthIndex = renderer.GetProperty<int>(Dali::Renderer::Property::DEPTH_INDEX);
- renderer.SetProperty( Dali::Renderer::Property::DEPTH_INDEX, depthIndex - 1 );
- containerActor.Add( shadowActor );
- containerActor.Add( actor );
- actor = containerActor;
- }
+ Dali::Renderer renderer( shadowActor.GetRendererAt( 0 ) );
+ int depthIndex = renderer.GetProperty<int>(Dali::Renderer::Property::DEPTH_INDEX);
+ renderer.SetProperty( Dali::Renderer::Property::DEPTH_INDEX, depthIndex - 1 );
+ mActor.Add( shadowActor );
}
- if( mActor )
+ if( hasRenderer )
{
mActor.Add( actor );
}
- else
- {
- mActor = actor;
- }
}
}
#if defined(DEBUG_ENABLED)
mTextCache.Resize( 0 );
}
- Actor CreateMeshActor( const MeshRecord& meshRecord, const Vector2& actorSize )
+ Actor CreateMeshActor( Actor textControl, Property::Index animatablePropertyIndex, const Vector4& defaultColor, const MeshRecord& meshRecord,
+ const Vector2& actorSize, Style style )
{
PropertyBuffer quadVertices = PropertyBuffer::New( mQuadVertexFormat );
- PropertyBuffer quadIndices = PropertyBuffer::New( mQuadIndexFormat );
quadVertices.SetData( const_cast< AtlasManager::Vertex2D* >( &meshRecord.mMesh.mVertices[ 0 ] ), meshRecord.mMesh.mVertices.Size() );
- quadIndices.SetData( const_cast< unsigned int* >( &meshRecord.mMesh.mIndices[ 0 ] ), meshRecord.mMesh.mIndices.Size() );
Geometry quadGeometry = Geometry::New();
quadGeometry.AddVertexBuffer( quadVertices );
- quadGeometry.SetIndexBuffer( quadIndices );
+ quadGeometry.SetIndexBuffer( &meshRecord.mMesh.mIndices[0], meshRecord.mMesh.mIndices.Size() );
TextureSet textureSet( mGlyphManager.GetTextures( meshRecord.mAtlasId ) );
- Shader shader( mGlyphManager.GetShader( meshRecord.mAtlasId ) );
+
+ // Choose the shader to use.
+ const bool isColorShader = ( STYLE_DROP_SHADOW != style ) && ( Pixel::BGRA8888 == mGlyphManager.GetPixelFormat( meshRecord.mAtlasId ) );
+ Shader shader;
+ if( isColorShader )
+ {
+ // The glyph is an emoji and is not a shadow.
+ if( !mShaderRgba )
+ {
+ mShaderRgba = Shader::New( VERTEX_SHADER, FRAGMENT_SHADER_RGBA );
+ }
+ shader = mShaderRgba;
+ }
+ else
+ {
+ // The glyph is text or a shadow.
+ if( !mShaderL8 )
+ {
+ mShaderL8 = Shader::New( VERTEX_SHADER, FRAGMENT_SHADER_L8 );
+ }
+ shader = mShaderL8;
+ }
+
+ DALI_LOG_INFO( gLogFilter, Debug::Verbose, "defaultColor[%f, %f, %f, %f ]\n", defaultColor.r, defaultColor.g, defaultColor.b, defaultColor.a );
+
+ Dali::Property::Index shaderTextColorIndex = shader.RegisterProperty( "textColorAnimatable", defaultColor );
+
+ if ( animatablePropertyIndex != Property::INVALID_INDEX )
+ {
+ // create constraint for the animatable text's color Property with textColorAnimatable in the shader.
+ if( shaderTextColorIndex )
+ {
+ Constraint constraint = Constraint::New<Vector4>( shader, shaderTextColorIndex, EqualToConstraint() );
+ constraint.AddSource( Source( textControl, animatablePropertyIndex ) );
+ constraint.Apply();
+ }
+ }
+ else
+ {
+ // If not animating the text colour then set to 1's so shader uses the current vertex color
+ shader.RegisterProperty( "textColorAnimatable", Vector4(1.0, 1.0, 1.0, 1.0 ) );
+ }
+
Dali::Renderer renderer = Dali::Renderer::New( quadGeometry, shader );
renderer.SetTextures( textureSet );
- renderer.SetProperty( Dali::Renderer::Property::BLENDING_MODE, BlendingMode::ON );
+ renderer.SetProperty( Dali::Renderer::Property::BLEND_MODE, BlendMode::ON );
renderer.SetProperty( Dali::Renderer::Property::DEPTH_INDEX, DepthIndex::CONTENT + mDepth );
+
Actor actor = Actor::New();
#if defined(DEBUG_ENABLED)
actor.SetName( "Text renderable actor" );
#endif
actor.AddRenderer( renderer );
-
// Keep all of the origins aligned
actor.SetParentOrigin( ParentOrigin::TOP_LEFT );
actor.SetAnchorPoint( AnchorPoint::TOP_LEFT );
-
actor.SetSize( actorSize );
actor.RegisterProperty("uOffset", Vector2::ZERO );
+ actor.SetColorMode( USE_OWN_MULTIPLY_PARENT_COLOR );
return actor;
}
blockIt != blockEndIt;
++blockIt )
{
- if( (*blockIt).mFontId == fontId )
+ if( (*blockIt).mFontId == fontId ) // Different size fonts will have a different fontId
{
+ DALI_LOG_INFO( gLogFilter, Debug::Verbose, "Text::AtlasRenderer::CalculateBlocksSize match found fontID(%u) glyphIndex(%u)\n", fontId, (*glyphIt).index );
foundFont = true;
break;
}
maxBlockSize.mNeededBlockWidth = static_cast< uint32_t >( fontMetrics.height );
maxBlockSize.mNeededBlockHeight = maxBlockSize.mNeededBlockWidth;
maxBlockSize.mFontId = fontId;
-
+ DALI_LOG_INFO( gLogFilter, Debug::Verbose, "Text::AtlasRenderer::CalculateBlocksSize New font with no matched blocksize, setting blocksize[%u]\n", maxBlockSize.mNeededBlockWidth );
mBlockSizes.push_back( maxBlockSize );
}
}
vert.mPosition.y = baseLine;
vert.mTexCoords.x = ZERO;
vert.mTexCoords.y = ZERO;
+ vert.mColor = underlineColor;
newMesh.mVertices.PushBack( vert );
vert.mPosition.x = brx;
vert.mPosition.y = baseLine;
vert.mTexCoords.x = u;
+ vert.mColor = underlineColor;
newMesh.mVertices.PushBack( vert );
vert.mPosition.x = tlx;
vert.mPosition.y = baseLine + thickness;
vert.mTexCoords.x = ZERO;
vert.mTexCoords.y = v;
+ vert.mColor = underlineColor;
newMesh.mVertices.PushBack( vert );
vert.mPosition.x = brx;
vert.mPosition.y = baseLine + thickness;
vert.mTexCoords.x = u;
+ vert.mColor = underlineColor;
newMesh.mVertices.PushBack( vert );
// Six indices in counter clockwise winding
newMesh.mIndices.PushBack( faceIndex + 1u );
faceIndex += 4;
- vert.mColor = underlineColor;
-
Toolkit::Internal::AtlasMeshFactory::AppendMesh( meshRecords[ index ].mMesh, newMesh );
}
}
Actor mActor; ///< The actor parent which renders the text
AtlasGlyphManager mGlyphManager; ///< Glyph Manager to handle upload and caching
- TextAbstraction::FontClient mFontClient; ///> The font client used to supply glyph information
- std::vector< MaxBlockSize > mBlockSizes; ///> Maximum size needed to contain a glyph in a block within a new atlas
- Vector< TextCacheEntry > mTextCache; ///> Caches data from previous render
- Property::Map mQuadVertexFormat; ///> Describes the vertex format for text
- Property::Map mQuadIndexFormat; ///> Describes the index format for text
- int mDepth; ///> DepthIndex passed by control when connect to stage
+ TextAbstraction::FontClient mFontClient; ///< The font client used to supply glyph information
+ Shader mShaderL8; ///< The shader for glyphs and emoji's shadows.
+ Shader mShaderRgba; ///< The shader for emojis.
+ std::vector< MaxBlockSize > mBlockSizes; ///< Maximum size needed to contain a glyph in a block within a new atlas
+ Vector< TextCacheEntry > mTextCache; ///< Caches data from previous render
+ Property::Map mQuadVertexFormat; ///< Describes the vertex format for text
+ int mDepth; ///< DepthIndex passed by control when connect to stage
};
Text::RendererPtr AtlasRenderer::New()
return Text::RendererPtr( new AtlasRenderer() );
}
-Actor AtlasRenderer::Render( Text::ViewInterface& view, int depth )
+Actor AtlasRenderer::Render( Text::ViewInterface& view,
+ Actor textControl,
+ Property::Index animatablePropertyIndex,
+ float& alignmentOffset,
+ int depth )
{
+ DALI_LOG_INFO( gLogFilter, Debug::General, "Text::AtlasRenderer::Render()\n" );
+
UnparentAndReset( mImpl->mActor );
Length numberOfGlyphs = view.GetNumberOfGlyphs();
numberOfGlyphs = view.GetGlyphs( glyphs.Begin(),
positions.Begin(),
+ alignmentOffset,
0u,
numberOfGlyphs );
const Vector4& defaultColor = view.GetTextColor();
mImpl->AddGlyphs( view,
+ textControl,
+ animatablePropertyIndex,
positions,
glyphs,
defaultColor,
colorsBuffer,
colorIndicesBuffer,
- depth );
+ depth,
+ alignmentOffset );
/* In the case where AddGlyphs does not create a renderable Actor for example when glyphs are all whitespace create a new Actor. */
/* This renderable actor is used to position the text, other "decorations" can rely on there always being an Actor regardless of it is whitespace or regular text. */