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 whether any glyph in any run in this TextFrame is colored and so would be cached with color already baked in to the colored glyph. More...

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

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

Detailed Description

Represents a collection of shaped text runs.

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

Definition at line 26 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 125 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().

◆ GetAtlasType()

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

The type of atlas this run should be place in.

        This return value depends primarily on the HasColor
        property.

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 an 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 121 of file text_frame.cc.

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

◆ GetPath()

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

Definition at line 114 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_;
 }

◆ HasColor()

bool impeller::TextFrame::HasColor ( ) const

Returns whether any glyph in any run in this TextFrame is colored and so would be cached with color already baked in to the colored glyph.

Non-bitmap/COLR fonts only store an alpha bitmap, but COLR fonts can potentially use the paint color in the glyph atlas, so the color the text is being rendered with must be considered as part of the cache key.

Definition at line 44 of file text_frame.cc.

                                {
   return has_color_;
 }

◆ 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::TextContents::ComputeVertexData(), and impeller::testing::TEST_P().

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

Detailed Description

Constructor & Destructor Documentation

◆ TextFrame() [1/2]

◆ TextFrame() [2/2]

◆ ~TextFrame()

Member Function Documentation

◆ AsSingleGlyph()

◆ ComputeSubpixelPosition()

◆ GetAtlasType()

◆ GetBounds()

◆ GetFont()

◆ GetPath()

◆ GetRunCount()

◆ GetRuns()

◆ HasColor()

◆ RoundScaledFontSize() [1/2]

◆ RoundScaledFontSize() [2/2]