Represents a collection of shaped text runs. More...

#include <text_frame.h>

Public Member Functions
	TextFrame ()

	TextFrame (std::vector< TextRun > &runs, Rect bounds, bool has_color, const PathCreator &path_creator={})

	~TextFrame ()

Rect	GetBounds () const
	The conservative bounding box for this text frame. More...

size_t	GetRunCount () const
	The number of runs in this text frame. More...

const std::vector< TextRun > &	GetRuns () const
	Returns a reference to all the text runs in this frame. More...

bool	HasColor () const
	Returns the paint color this text frame was recorded with. More...

GlyphAtlas::Type	GetAtlasType () const
	The type of atlas this run should be place in. More...

bool	IsFrameComplete () const
	Verifies that all glyphs in this text frame have computed bounds information. More...

const FrameBounds &	GetFrameBounds (size_t index) const
	Retrieve the frame bounds for the glyph at [index]. More...

std::optional< Glyph >	AsSingleGlyph () const
	If this text frame contains a single glyph (such as for an Icon), then return it, otherwise std::nullopt. More...

const Font &	GetFont () const
	Return the font of the first glyph run. More...

void	SetPerFrameData (Rational scale, Point offset, const Matrix &transform, std::optional< GlyphProperties > properties)
	Store text frame scale, offset, and properties for hashing in th glyph atlas. More...

std::pair< size_t, intptr_t >	GetAtlasGenerationAndID () const

Rational	GetScale () const

const Matrix &	GetTransform () const

fml::StatusOr< flutter::DlPath >	GetPath () const

Point	GetOffset () const

Matrix	GetOffsetTransform () const

Static Public Member Functions
static SubpixelPosition	ComputeSubpixelPosition (const TextRun::GlyphPosition &glyph_position, AxisAlignment alignment, const Matrix &transform)

static Rational	RoundScaledFontSize (Scalar scale)

static Rational	RoundScaledFontSize (Rational scale)

Friends
class	TypographerContextSkia

class	LazyGlyphAtlas

Detailed Description

Represents a collection of shaped text runs.

        This object is typically the entrypoint in the Impeller type
        rendering subsystem.

A text frame should not be reused in multiple places within a single frame, as internally it is used as a cache for various glyph properties.

Definition at line 29 of file text_frame.h.

Constructor & Destructor Documentation

◆ TextFrame() [1/2]

impeller::TextFrame::TextFrame ( )

default

◆ TextFrame() [2/2]

impeller::TextFrame::TextFrame	(	std::vector< TextRun > &	runs,
		Rect	bounds,
		bool	has_color,
		const PathCreator &	path_creator = `{}`
	)

Definition at line 16 of file text_frame.cc.

     : runs_(std::move(runs)),
       bounds_(bounds),
       has_color_(has_color),
       path_creator_(path_creator) {}

◆ ~TextFrame()

impeller::TextFrame::~TextFrame ( )

default

Member Function Documentation

◆ AsSingleGlyph()

std::optional< Glyph > impeller::TextFrame::AsSingleGlyph ( ) const

If this text frame contains a single glyph (such as for an Icon), then return it, otherwise std::nullopt.

Definition at line 168 of file text_frame.cc.

                                                   {
   if (runs_.size() == 1 && runs_[0].GetGlyphCount() == 1) {
     return runs_[0].GetGlyphPositions()[0].glyph;
   }
   return std::nullopt;
 }

◆ ComputeSubpixelPosition()

SubpixelPosition impeller::TextFrame::ComputeSubpixelPosition	(	const TextRun::GlyphPosition &	glyph_position,
		AxisAlignment	alignment,
		const Matrix &	transform
	)

static

Definition at line 94 of file text_frame.cc.

                              {
   Point pos = transform * glyph_position.position;
   switch (alignment) {
     case AxisAlignment::kNone:
       return SubpixelPosition::kSubpixel00;
     case AxisAlignment::kX:
       return ComputeFractionalPosition(pos.x);
     case AxisAlignment::kY:
       return static_cast<SubpixelPosition>(ComputeFractionalPosition(pos.y)
                                            << 2);
     case AxisAlignment::kAll:
       return static_cast<SubpixelPosition>(
           ComputeFractionalPosition(pos.x) |
           (ComputeFractionalPosition(pos.y) << 2));
   }
 }

References impeller::ComputeFractionalPosition(), impeller::kAll, impeller::kNone, impeller::kSubpixel00, impeller::kX, impeller::kY, impeller::TextRun::GlyphPosition::position, transform, impeller::TPoint< T >::x, and impeller::TPoint< T >::y.

Referenced by impeller::TextContents::ComputeVertexData().

◆ GetAtlasGenerationAndID()

std::pair< size_t, intptr_t > impeller::TextFrame::GetAtlasGenerationAndID ( ) const

Definition at line 180 of file text_frame.cc.

                                                                    {
   return std::make_pair(generation_, atlas_id_);
 }

◆ GetAtlasType()

GlyphAtlas::Type impeller::TextFrame::GetAtlasType ( ) const

The type of atlas this run should be place in.

Definition at line 39 of file text_frame.cc.

                                              {
   return has_color_ ? GlyphAtlas::Type::kColorBitmap
                     : GlyphAtlas::Type::kAlphaBitmap;
 }

References impeller::GlyphAtlas::kAlphaBitmap, and impeller::GlyphAtlas::kColorBitmap.

◆ GetBounds()

Rect impeller::TextFrame::GetBounds ( ) const

The conservative bounding box for this text frame.

Returns: The bounds rectangle. If there are no glyphs in this text frame and empty Rectangle is returned instead.

Definition at line 27 of file text_frame.cc.

                                 {
   return bounds_;
 }

◆ GetFont()

const Font & impeller::TextFrame::GetFont ( ) const

Return the font of the first glyph run.

Definition at line 164 of file text_frame.cc.

                                      {
   return runs_[0].GetFont();
 }

◆ GetFrameBounds()

const FrameBounds & impeller::TextFrame::GetFrameBounds ( size_t index ) const

Retrieve the frame bounds for the glyph at [index].

This method is only valid if [IsFrameComplete] returns true.

Definition at line 175 of file text_frame.cc.

                                                                {
   FML_DCHECK(index < bound_values_.size());
   return bound_values_[index];
 }

◆ GetOffset()

Point impeller::TextFrame::GetOffset ( ) const

Definition at line 133 of file text_frame.cc.

                                  {
   return offset_;
 }

◆ GetOffsetTransform()

Matrix impeller::TextFrame::GetOffsetTransform ( ) const

Definition at line 114 of file text_frame.cc.

                                            {
   return transform_ * Matrix::MakeTranslation(offset_);
 }

References impeller::Matrix::MakeTranslation().

◆ GetPath()

fml::StatusOr< flutter::DlPath > impeller::TextFrame::GetPath ( ) const

Definition at line 149 of file text_frame.cc.

                                                     {
   if (path_creator_) {
     return path_creator_();
   }
   return fml::Status(fml::StatusCode::kCancelled, "no path creator specified.");
 }

◆ GetRunCount()

size_t impeller::TextFrame::GetRunCount ( ) const

The number of runs in this text frame.

Returns: The run count.

Definition at line 31 of file text_frame.cc.

                                     {
   return runs_.size();
 }

◆ GetRuns()

const std::vector< TextRun > & impeller::TextFrame::GetRuns ( ) const

Returns a reference to all the text runs in this frame.

Returns: The runs in this frame.

Definition at line 35 of file text_frame.cc.

                                                    {
   return runs_;
 }

◆ GetScale()

Rational impeller::TextFrame::GetScale ( ) const

Definition at line 129 of file text_frame.cc.

                                    {
   return scale_;
 }

◆ GetTransform()

const Matrix& impeller::TextFrame::GetTransform ( ) const

inline

Definition at line 114 of file text_frame.h.

114 { return transform_; }

◆ HasColor()

bool impeller::TextFrame::HasColor ( ) const

Returns the paint color this text frame was recorded with.

        Non-bitmap/COLR fonts always use a black text color here, but
        COLR fonts can potentially use the paint color in the glyph
        atlas, so this color must be considered as part of the cache
        key.

Definition at line 44 of file text_frame.cc.

                                {
   return has_color_;
 }

◆ IsFrameComplete()

bool impeller::TextFrame::IsFrameComplete ( ) const

Verifies that all glyphs in this text frame have computed bounds information.

Definition at line 156 of file text_frame.cc.

                                       {
   size_t run_size = 0;
   for (const auto& x : runs_) {
     run_size += x.GetGlyphCount();
   }
   return bound_values_.size() == run_size;
 }

References x.

◆ RoundScaledFontSize() [1/2]

Rational impeller::TextFrame::RoundScaledFontSize ( Rational scale )

static

Definition at line 66 of file text_frame.cc.

                                                       {
   Rational result = Rational(
       std::round((scale.GetNumerator() * static_cast<Scalar>(kDenominator))) /
           scale.GetDenominator(),
       kDenominator);
   return std::clamp(result, Rational(0, kDenominator),
                     Rational(kMaximumTextScale * kDenominator, kDenominator));
 }

References impeller::Rational::GetDenominator(), and impeller::Rational::GetNumerator().

◆ RoundScaledFontSize() [2/2]

Rational impeller::TextFrame::RoundScaledFontSize ( Scalar scale )

static

Definition at line 55 of file text_frame.cc.

                                                     {
   if (scale > kMaximumTextScale) {
     return Rational(kMaximumTextScale * kDenominator, kDenominator);
   }
   // An arbitrarily chosen maximum text scale to ensure that regardless of the
   // CTM, a glyph will fit in the atlas. If we clamp significantly, this may
   // reduce fidelity but is preferable to the alternative of failing to render.
   Rational result = Rational(std::round(scale * kDenominator), kDenominator);
   return result < kZero ? kZero : result;
 }

References impeller::kZero.

Referenced by impeller::FirstPassDispatcher::drawTextFrame(), and impeller::testing::TEST_P().

◆ SetPerFrameData()

void impeller::TextFrame::SetPerFrameData	(	Rational	scale,
		Point	offset,
		const Matrix &	transform,
		std::optional< GlyphProperties >	properties
	)

Store text frame scale, offset, and properties for hashing in th glyph atlas.

Definition at line 118 of file text_frame.cc.

                                                                          {
   bound_values_.clear();
   scale_ = scale;
   offset_ = offset;
   properties_ = properties;
   transform_ = transform;
 }

References transform.

Friends And Related Function Documentation

◆ LazyGlyphAtlas

friend class LazyGlyphAtlas

friend

Definition at line 124 of file text_frame.h.

◆ TypographerContextSkia

friend class TypographerContextSkia

friend

Definition at line 123 of file text_frame.h.

The documentation for this class was generated from the following files:

impeller/typographer/text_frame.h
impeller/typographer/text_frame.cc

Public Member Functions

Static Public Member Functions

Friends

Detailed Description

Constructor & Destructor Documentation

◆ TextFrame() [1/2]

◆ TextFrame() [2/2]

◆ ~TextFrame()

Member Function Documentation

◆ AsSingleGlyph()

◆ ComputeSubpixelPosition()

◆ GetAtlasGenerationAndID()

◆ GetAtlasType()

◆ GetBounds()

◆ GetFont()

◆ GetFrameBounds()

◆ GetOffset()

◆ GetOffsetTransform()

◆ GetPath()

◆ GetRunCount()

◆ GetRuns()

◆ GetScale()

◆ GetTransform()

◆ HasColor()

◆ IsFrameComplete()

◆ RoundScaledFontSize() [1/2]

◆ RoundScaledFontSize() [2/2]

◆ SetPerFrameData()

Friends And Related Function Documentation

◆ LazyGlyphAtlas

◆ TypographerContextSkia