A Geometry class that generates fillable vertices (with or without texture coordinates) directly from a round rect object with uniform radii at every corner. More...

#include <round_rect_geometry.h>

Inheritance diagram for impeller::RoundRectGeometry:

Public Member Functions
	RoundRectGeometry (const Rect &bounds, const Size &radii)

	~RoundRectGeometry () 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

Public Member Functions inherited from impeller::Geometry
virtual	~Geometry ()

virtual GeometryResult::Mode	GetResultMode () const

virtual bool	CanApplyMaskFilter () const

virtual Scalar	ComputeAlphaCoverage (const Matrix &transform) 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 class that generates fillable vertices (with or without texture coordinates) directly from a round rect object with uniform radii at every corner.

Generating vertices for a stroked ellipse would require a lot more work since the line width must be applied perpendicular to the distorted ellipse shape.

See also: |FillRoundRectGeometry|; |StrokeRoundRectGeometry|

Definition at line 25 of file round_rect_geometry.h.

Constructor & Destructor Documentation

◆ RoundRectGeometry()

impeller::RoundRectGeometry::RoundRectGeometry	(	const Rect &	bounds,
		const Size &	radii
	)

explicit

Definition at line 9 of file round_rect_geometry.cc.

10 : bounds_(bounds), radii_(radii) {}

◆ ~RoundRectGeometry()

impeller::RoundRectGeometry::~RoundRectGeometry ( )

overridedefault

Member Function Documentation

◆ CoversArea()

bool impeller::RoundRectGeometry::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 29 of file round_rect_geometry.cc.

                                                            {
  if (!transform.IsTranslationScaleOnly()) {
    return false;
  }
  bool flat_on_tb = bounds_.GetWidth() > radii_.width * 2;
  bool flat_on_lr = bounds_.GetHeight() > radii_.height * 2;
  if (!flat_on_tb && !flat_on_lr) {
    return false;
  }
  // We either transform the bounds and delta-transform the radii,
  // or we compute the vertical and horizontal bounds and then
  // transform each. Either way there are 2 transform operations.
  // We could also get a weaker answer by computing just the
  // "inner rect" and only doing a coverage analysis on that,
  // but this process will produce more culling results.
  if (flat_on_tb) {
    Rect vertical_bounds = bounds_.Expand(Size{-radii_.width, 0});
    Rect coverage = vertical_bounds.TransformBounds(transform);
    if (coverage.Contains(rect)) {
      return true;
    }
  }
  if (flat_on_lr) {
    Rect horizontal_bounds = bounds_.Expand(Size{0, -radii_.height});
    Rect coverage = horizontal_bounds.TransformBounds(transform);
    if (coverage.Contains(rect)) {
      return true;
    }
  }
  return false;
}

References impeller::TRect< T >::Contains(), impeller::TRect< T >::Expand(), impeller::TRect< T >::GetHeight(), impeller::TRect< T >::GetWidth(), impeller::TSize< T >::height, transform, impeller::TRect< T >::TransformBounds(), and impeller::TSize< T >::width.

◆ IsAxisAlignedRect()

bool impeller::RoundRectGeometry::IsAxisAlignedRect ( ) const

overridevirtual

Reimplemented from impeller::Geometry.

Definition at line 62 of file round_rect_geometry.cc.

                                                {
  return false;
}

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

impeller/entity/geometry/round_rect_geometry.h
impeller/entity/geometry/round_rect_geometry.cc

Public Member Functions