impeller::CircleGeometry Class Reference

#include <circle_geometry.h>

Inheritance diagram for impeller::CircleGeometry:

Public Member Functions
	CircleGeometry (const Point &center, Scalar radius)
	CircleGeometry (const Point &center, Scalar radius, Scalar stroke_width)
	~CircleGeometry () override
bool	CoversArea (const Matrix &transform, const IRect &rect) const override
	Determines if this geometry, transformed by the given transform, will completely cover all of the pixels within the given integer rect.
bool	IsAxisAlignedRect () const override
Scalar	ComputeAlphaCoverage (const Matrix &transform) const override
Scalar	GetRadius () const
Scalar	GetStrokeWidth () const
Point	GetCenter () const
std::optional< Rect >	GetCoverage (const Matrix &transform) const override
	The coverage rectangle of this geometry, transformed by the transform argument.
GeometryResult	GetPositionBuffer (const ContentContext &renderer, const Entity &entity, RenderPass &pass) const override
void	SetAntialiasPadding (Scalar extra_pixels)
Scalar	GetAntialiasPadding () const
Public Member Functions inherited from impeller::Geometry
virtual	~Geometry ()
virtual GeometryResult::Mode	GetResultMode () const
virtual bool	CanApplyMaskFilter () 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

Definition at line 14 of file circle_geometry.h.

Constructor & Destructor Documentation

CircleGeometry() [1/2]

impeller::CircleGeometry::CircleGeometry ( const Point &  center, Scalar  radius  )

explicit

Definition at line 16 of file circle_geometry.cc.

    : center_(center),
      radius_(radius),
      stroke_width_(-1.0f),
      padding_pixels_(0.0f) {
  FML_DCHECK(radius >= 0);
}

References FML_DCHECK.

CircleGeometry() [2/2]

impeller::CircleGeometry::CircleGeometry ( const Point &  center, Scalar  radius, Scalar  stroke_width  )

explicit

Definition at line 26 of file circle_geometry.cc.

    : center_(center),
      radius_(radius),
      stroke_width_(std::max(stroke_width, 0.0f)),
      padding_pixels_(0.0) {
  FML_DCHECK(radius >= 0);
  FML_DCHECK(stroke_width >= 0);
}

References FML_DCHECK.

~CircleGeometry()

impeller::CircleGeometry::~CircleGeometry ( )

overridedefault

Member Function Documentation

ComputeAlphaCoverage()

Scalar impeller::CircleGeometry::ComputeAlphaCoverage ( const Matrix &  transform ) const

overridevirtual

Reimplemented from impeller::Geometry.

Definition at line 38 of file circle_geometry.cc.

                                                                         {
  if (stroke_width_ < 0) {
    return 1;
  }
  return Geometry::ComputeStrokeAlphaCoverage(transform, stroke_width_);
}

References impeller::Geometry::ComputeStrokeAlphaCoverage(), and transform.

CoversArea()

bool impeller::CircleGeometry::CoversArea ( const Matrix &  transform, const IRect &  rect  ) const

overridevirtual

Determines if this geometry, transformed by the given transform, will completely cover all of the pixels within the given integer rect.

The integer rect, by definition, will contain all of the area covered by any pixel within its boundary.

The return value can be a conservative estimate which will still be useful for certain optimizations. It may return false for obscure cases that might actually contain all of the pixels if it is too computationally costly to prove containment, but it should never return 'true' unless the implementation can prove that all pixels are fully covered (rendered) by the geometry.

Returns

true if the transformed geometry is guaranteed to cover the given rect. May return false in some cases where the transformed geometry does in fact cover the rect.

Reimplemented from impeller::Geometry.

Definition at line 98 of file circle_geometry.cc.

                                                         {
  return false;
}

GetAntialiasPadding()

Scalar impeller::CircleGeometry::GetAntialiasPadding

(

)

const

Definition at line 61 of file circle_geometry.cc.

                                                 {
  return padding_pixels_;
}

GetCenter()

Point impeller::CircleGeometry::GetCenter

(

)

const

Definition at line 45 of file circle_geometry.cc.

                                      {
  return center_;
}

GetCoverage()

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

overridevirtual

The coverage rectangle of this geometry, transformed by the transform argument.

Implements impeller::Geometry.

Definition at line 88 of file circle_geometry.cc.

                                                                           {
  Scalar max_basis = transform.GetMaxBasisLengthXY();
  Scalar expansion = max_basis == 0 ? 0.0 : padding_pixels_ / max_basis;
 
  Scalar half_width = stroke_width_ < 0 ? 0.0 : stroke_width_ * 0.5f;
  Scalar outer_radius = radius_ + half_width + expansion;
  return Rect::MakeCircleBounds(center_, outer_radius)
      .TransformAndClipBounds(transform);
}

References impeller::TRect< Scalar >::MakeCircleBounds(), transform, and impeller::TRect< T >::TransformAndClipBounds().

GetPositionBuffer()

GeometryResult impeller::CircleGeometry::GetPositionBuffer ( const ContentContext &  renderer, const Entity &  entity, RenderPass &  pass  ) const

overridevirtual

Implements impeller::Geometry.

Definition at line 65 of file circle_geometry.cc.

                                                                         {
  auto& transform = entity.GetTransform();
 
  Scalar max_basis = transform.GetMaxBasisLengthXY();
  Scalar expansion = max_basis == 0 ? 0.0 : padding_pixels_ / max_basis;
 
  if (stroke_width_ < 0) {
    auto generator = renderer.GetTessellator().FilledCircle(
        transform, center_, radius_ + expansion);
    return ComputePositionGeometry(renderer, generator, entity, pass);
  }
 
  Scalar half_width =
      LineGeometry::ComputePixelHalfWidth(transform, stroke_width_);
 
  auto generator = renderer.GetTessellator().StrokedCircle(
      transform, center_, radius_, half_width + expansion);
 
  return ComputePositionGeometry(renderer, generator, entity, pass);
}

References impeller::LineGeometry::ComputePixelHalfWidth(), impeller::Geometry::ComputePositionGeometry(), impeller::Tessellator::FilledCircle(), impeller::Matrix::GetMaxBasisLengthXY(), impeller::ContentContext::GetTessellator(), impeller::Entity::GetTransform(), impeller::Tessellator::StrokedCircle(), and transform.

GetRadius()

Scalar impeller::CircleGeometry::GetRadius

(

)

const

Definition at line 49 of file circle_geometry.cc.

                                       {
  return radius_;
}

GetStrokeWidth()

Scalar impeller::CircleGeometry::GetStrokeWidth

(

)

const

Definition at line 53 of file circle_geometry.cc.

                                            {
  return stroke_width_;
}

IsAxisAlignedRect()

bool impeller::CircleGeometry::IsAxisAlignedRect ( ) const

overridevirtual

Reimplemented from impeller::Geometry.

Definition at line 103 of file circle_geometry.cc.

                                             {
  return false;
}

SetAntialiasPadding()

void impeller::CircleGeometry::SetAntialiasPadding

(

Scalar

extra_pixels

)

Definition at line 57 of file circle_geometry.cc.

                                                             {
  padding_pixels_ = extra_padding;
}

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

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