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)

	~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...

void	SetPerFrameData (Scalar 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

Scalar	GetScale () const

TextFrame &	operator= (TextFrame &&other)=default

	TextFrame (const TextFrame &other)=default

const Matrix &	GetTransform () const

Point	GetOffset () const

Matrix	GetOffsetTransform () const

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

static Scalar	RoundScaledFontSize (Scalar 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 22 of file text_frame.h.

Constructor & Destructor Documentation

◆ TextFrame() [1/3]

impeller::TextFrame::TextFrame ( )

default

◆ TextFrame() [2/3]

impeller::TextFrame::TextFrame	(	std::vector< TextRun > &	runs,
		Rect	bounds,
		bool	has_color
	)

Definition at line 14 of file text_frame.cc.

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

◆ ~TextFrame()

impeller::TextFrame::~TextFrame ( )

default

◆ TextFrame() [3/3]

impeller::TextFrame::TextFrame ( const TextFrame & other )

default

Member Function Documentation

◆ ComputeSubpixelPosition()

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

static

Definition at line 69 of file text_frame.cc.

                              {
   Point pos = transform * glyph_position.position;
   switch (alignment) {
     case AxisAlignment::kNone:
       return Point(0, 0);
     case AxisAlignment::kX:
       return Point(ComputeFractionalPosition(pos.x), 0);
     case AxisAlignment::kY:
       return Point(0, ComputeFractionalPosition(pos.y));
     case AxisAlignment::kAll:
       return Point(ComputeFractionalPosition(pos.x),
                    ComputeFractionalPosition(pos.y));
   }
 }

References impeller::ComputeFractionalPosition(), impeller::kAll, impeller::kNone, 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 135 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 31 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 19 of file text_frame.cc.

                                 {
   return bounds_;
 }

◆ 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 130 of file text_frame.cc.

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

◆ GetOffset()

Point impeller::TextFrame::GetOffset ( ) const

Definition at line 106 of file text_frame.cc.

                                  {
   return offset_;
 }

◆ GetOffsetTransform()

Matrix impeller::TextFrame::GetOffsetTransform ( ) const

Definition at line 87 of file text_frame.cc.

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

References impeller::Matrix::MakeTranslation().

◆ GetRunCount()

size_t impeller::TextFrame::GetRunCount ( ) const

The number of runs in this text frame.

Returns: The run count.

Definition at line 23 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 27 of file text_frame.cc.

                                                    {
   return runs_;
 }

◆ GetScale()

Scalar impeller::TextFrame::GetScale ( ) const

Definition at line 102 of file text_frame.cc.

                                  {
   return scale_;
 }

◆ GetTransform()

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

inline

Definition at line 100 of file text_frame.h.

100 { 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 36 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 122 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.

◆ operator=()

TextFrame& impeller::TextFrame::operator= ( TextFrame && other )

default

◆ RoundScaledFontSize()

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

static

Definition at line 41 of file text_frame.cc.

                                                   {
   // 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.
   constexpr Scalar kMaximumTextScale = 48;
   Scalar result = std::round(scale * 200) / 200;
   return std::clamp(result, 0.0f, kMaximumTextScale);
 }

References scale.

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

◆ SetPerFrameData()

void impeller::TextFrame::SetPerFrameData	(	Scalar	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 91 of file text_frame.cc.

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

References offset, scale, and transform.

Friends And Related Function Documentation

◆ LazyGlyphAtlas

friend class LazyGlyphAtlas

friend

Definition at line 108 of file text_frame.h.

◆ TypographerContextSkia

friend class TypographerContextSkia

friend

Definition at line 107 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() [1/3]

◆ TextFrame() [2/3]

◆ ~TextFrame()

◆ TextFrame() [3/3]

Member Function Documentation

◆ ComputeSubpixelPosition()

◆ GetAtlasGenerationAndID()

◆ GetAtlasType()

◆ GetBounds()

◆ GetFrameBounds()

◆ GetOffset()

◆ GetOffsetTransform()

◆ GetRunCount()

◆ GetRuns()

◆ GetScale()

◆ GetTransform()

◆ HasColor()

◆ IsFrameComplete()

◆ operator=()

◆ RoundScaledFontSize()

◆ SetPerFrameData()

Friends And Related Function Documentation

◆ LazyGlyphAtlas

◆ TypographerContextSkia