impeller::ArcStrokeGeometry Class Reference

A Geometry that produces fillable vertices representing the stroked outline of an |Arc| object using the base class |StrokeSegmentsGeometry| and utilizing the special |RecordArc| extension method provided by the |PathAndArcSegmentReceiver|. More...

#include <stroke_path_geometry.h>

Inheritance diagram for impeller::ArcStrokeGeometry:

Public Member Functions
	ArcStrokeGeometry (const Arc &arc, const StrokeParameters &parameters)
Public Member Functions inherited from impeller::StrokeSegmentsGeometry
	~StrokeSegmentsGeometry () override
Scalar	GetStrokeWidth () const
Scalar	GetMiterLimit () const
Cap	GetStrokeCap () const
Join	GetStrokeJoin () const
Scalar	ComputeAlphaCoverage (const Matrix &transform) const override
Public Member Functions inherited from impeller::Geometry
virtual	~Geometry ()
virtual bool	CoversArea (const Matrix &transform, const Rect &rect) const
	Determines if this geometry, transformed by the given transform, will completely cover all surface area of the given rect.
virtual bool	IsAxisAlignedRect () const
virtual bool	CanApplyMaskFilter () const

Protected Member Functions
std::optional< Rect >	GetCoverage (const Matrix &transform) const override
void	Dispatch (PathAndArcSegmentReceiver &receiver, Tessellator &tessellator, Scalar scale) const override
Protected Member Functions inherited from impeller::StrokeSegmentsGeometry
	StrokeSegmentsGeometry (const StrokeParameters &parameters)
std::optional< Rect >	GetStrokeCoverage (const Matrix &transform, const Rect &segment_bounds) const

Additional Inherited Members
Static Public Member Functions inherited from impeller::Geometry
static std::unique_ptr< Geometry >	MakeFillPath (const flutter::DlPath &path, std::optional< Rect > inner_rect=std::nullopt)
static std::unique_ptr< Geometry >	MakeStrokePath (const flutter::DlPath &path, const StrokeParameters &stroke={})
static std::unique_ptr< Geometry >	MakeCover ()
static std::unique_ptr< Geometry >	MakeRect (const Rect &rect)
static std::unique_ptr< Geometry >	MakeOval (const Rect &rect)
static std::unique_ptr< Geometry >	MakeLine (const Point &p0, const Point &p1, const StrokeParameters &stroke)
static std::unique_ptr< Geometry >	MakeCircle (const Point &center, Scalar radius)
static std::unique_ptr< Geometry >	MakeStrokedCircle (const Point &center, Scalar radius, Scalar stroke_width)
static std::unique_ptr< Geometry >	MakeFilledArc (const Rect &oval_bounds, Degrees start, Degrees sweep, bool include_center)
static std::unique_ptr< Geometry >	MakeStrokedArc (const Rect &oval_bounds, Degrees start, Degrees sweep, const StrokeParameters &stroke)
static std::unique_ptr< Geometry >	MakeRoundRect (const Rect &rect, const Size &radii)
static std::unique_ptr< Geometry >	MakeRoundSuperellipse (const Rect &rect, Scalar corner_radius)
static Scalar	ComputeStrokeAlphaCoverage (const Matrix &entity, Scalar stroke_width)
	Compute an alpha value to simulate lower coverage of fractional pixel strokes.
static GeometryResult	ComputePositionGeometry (const ContentContext &renderer, const Tessellator::VertexGenerator &generator, const Entity &entity, RenderPass &pass)

Detailed Description

A Geometry that produces fillable vertices representing the stroked outline of an |Arc| object using the base class |StrokeSegmentsGeometry| and utilizing the special |RecordArc| extension method provided by the |PathAndArcSegmentReceiver|.

Definition at line 132 of file stroke_path_geometry.h.

Constructor & Destructor Documentation

ArcStrokeGeometry()

impeller::ArcStrokeGeometry::ArcStrokeGeometry	(	const Arc &	arc,
		const StrokeParameters &	parameters
	)

Definition at line 862 of file stroke_path_geometry.cc.

    : StrokeSegmentsGeometry(parameters), arc_(arc) {}

Member Function Documentation

Dispatch()

void impeller::ArcStrokeGeometry::Dispatch ( PathAndArcSegmentReceiver &  receiver, Tessellator &  tessellator, Scalar  scale  ) const

overrideprotectedvirtual

Dispatch the path segments to the StrokePathSegmentReceiver for the provided transform scale.

Implements impeller::StrokeSegmentsGeometry.

Definition at line 871 of file stroke_path_geometry.cc.

                                                     {
  Point center = arc_.GetOvalCenter();
  Size radii = arc_.GetOvalSize() * 0.5f;
 
  auto trigs =
      tessellator.GetTrigsForDeviceRadius(scale * radii.MaxDimension());
  Arc::Iteration iterator =
      arc_.ComputeIterations(trigs.GetSteps(), /*simplify_360=*/false);
  Point start = center + iterator.start * radii;
  bool include_center = arc_.IncludeCenter();
 
  receiver.BeginContour(start, include_center);
  receiver.RecordArc(arc_, center, radii);
  if (include_center) {
    Point end = center + iterator.end * radii;
    receiver.RecordLine(end, center);
    receiver.RecordLine(center, start);
  }
  receiver.EndContour(start, include_center);
}

References impeller::PathTessellator::SegmentReceiver::BeginContour(), impeller::Arc::ComputeIterations(), impeller::Arc::Iteration::end, end, impeller::PathTessellator::SegmentReceiver::EndContour(), impeller::Arc::GetOvalCenter(), impeller::Arc::GetOvalSize(), impeller::Tessellator::GetTrigsForDeviceRadius(), impeller::Arc::IncludeCenter(), impeller::TSize< T >::MaxDimension(), impeller::PathAndArcSegmentReceiver::RecordArc(), impeller::PathTessellator::SegmentReceiver::RecordLine(), impeller::Arc::Iteration::start, and start.

GetCoverage()

std::optional< Rect > impeller::ArcStrokeGeometry::GetCoverage ( const Matrix &  transform ) const

overrideprotectedvirtual

Implements impeller::Geometry.

Definition at line 866 of file stroke_path_geometry.cc.

                                   {
  return GetStrokeCoverage(transform, arc_.GetTightArcBounds());
}

References impeller::StrokeSegmentsGeometry::GetStrokeCoverage(), impeller::Arc::GetTightArcBounds(), and transform.

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

• impeller/entity/geometry/stroke_path_geometry.h
• impeller/entity/geometry/stroke_path_geometry.cc