Flutter Impeller
impeller::RoundSuperellipseGeometry Class Referencefinal

A Geometry class that generates fillable vertices (with or without texture coordinates) directly from a round superellipse object regardless of radii uniformity. More...

#include <round_superellipse_geometry.h>

Inheritance diagram for impeller::RoundSuperellipseGeometry:
impeller::Geometry

Public Member Functions

 RoundSuperellipseGeometry (const Rect &bounds, const RoundingRadii &radii)
 
 RoundSuperellipseGeometry (const Rect &bounds, float corner_radius)
 
 ~RoundSuperellipseGeometry () override
 
bool CoversArea (const Matrix &transform, const Rect &rect) const override
 Determines if this geometry, transformed by the given transform, will completely cover all surface area of the given rect. More...
 
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< GeometryMakeFillPath (const flutter::DlPath &path, std::optional< Rect > inner_rect=std::nullopt)
 
static std::unique_ptr< GeometryMakeStrokePath (const flutter::DlPath &path, const StrokeParameters &stroke={})
 
static std::unique_ptr< GeometryMakeCover ()
 
static std::unique_ptr< GeometryMakeRect (const Rect &rect)
 
static std::unique_ptr< GeometryMakeOval (const Rect &rect)
 
static std::unique_ptr< GeometryMakeLine (const Point &p0, const Point &p1, const StrokeParameters &stroke)
 
static std::unique_ptr< GeometryMakeCircle (const Point &center, Scalar radius)
 
static std::unique_ptr< GeometryMakeStrokedCircle (const Point &center, Scalar radius, Scalar stroke_width)
 
static std::unique_ptr< GeometryMakeFilledArc (const Rect &oval_bounds, Degrees start, Degrees sweep, bool include_center)
 
static std::unique_ptr< GeometryMakeStrokedArc (const Rect &oval_bounds, Degrees start, Degrees sweep, const StrokeParameters &stroke)
 
static std::unique_ptr< GeometryMakeRoundRect (const Rect &rect, const Size &radii)
 
static std::unique_ptr< GeometryMakeRoundSuperellipse (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. More...
 
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 superellipse object regardless of radii uniformity.

A rounded superellipse is a shape similar to a typical rounded rectangle (RoundSuperellipse), but with smoother transitions between the straight sides and the rounded corners. It resembles the RoundedRectangle shape in SwiftUI with the .continuous corner style. Technically, it is created by replacing the four corners of a superellipse (also known as a Lamé curve) with circular arcs.

The bounds defines the position and size of the shape. The corner_radius corresponds to SwiftUI's cornerRadius parameter, which is close to, but not exactly equals to, the radius of the corner circles.

See also
|StrokeRoundSuperellipseGeometry|

Definition at line 30 of file round_superellipse_geometry.h.

Constructor & Destructor Documentation

◆ RoundSuperellipseGeometry() [1/2]

impeller::RoundSuperellipseGeometry::RoundSuperellipseGeometry ( const Rect bounds,
const RoundingRadii radii 
)

Definition at line 366 of file round_superellipse_geometry.cc.

368  : bounds_(bounds.GetPositive()), radii_(radii.Scaled(bounds_)) {}

◆ RoundSuperellipseGeometry() [2/2]

impeller::RoundSuperellipseGeometry::RoundSuperellipseGeometry ( const Rect bounds,
float  corner_radius 
)

Definition at line 370 of file round_superellipse_geometry.cc.

372  : RoundSuperellipseGeometry(bounds,
373  RoundingRadii::MakeRadius(corner_radius)) {}
RoundSuperellipseGeometry(const Rect &bounds, const RoundingRadii &radii)
constexpr static RoundingRadii MakeRadius(Scalar radius)

◆ ~RoundSuperellipseGeometry()

impeller::RoundSuperellipseGeometry::~RoundSuperellipseGeometry ( )
override

Definition at line 375 of file round_superellipse_geometry.cc.

375 {}

Member Function Documentation

◆ CoversArea()

bool impeller::RoundSuperellipseGeometry::CoversArea ( const Matrix transform,
const Rect rect 
) const
overridevirtual

Determines if this geometry, transformed by the given transform, will completely cover all surface area of the given rect.

This is a conservative estimate useful for certain optimizations.

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

Reimplemented from impeller::Geometry.

Definition at line 443 of file round_superellipse_geometry.cc.

444  {
445  if (!transform.IsTranslationScaleOnly()) {
446  return false;
447  }
448  Scalar left_inset = std::max(radii_.top_left.width, radii_.bottom_left.width);
449  Scalar right_inset =
450  std::max(radii_.top_right.width, radii_.bottom_right.width);
451  Scalar top_inset = std::max(radii_.top_left.height, radii_.top_right.height);
452  Scalar bottom_inset =
453  std::max(radii_.bottom_left.height, radii_.bottom_right.height);
454  Rect coverage =
455  Rect::MakeLTRB(bounds_.GetLeft() + left_inset * kGapFactor,
456  bounds_.GetTop() + top_inset * kGapFactor,
457  bounds_.GetRight() - right_inset * kGapFactor,
458  bounds_.GetBottom() - bottom_inset * kGapFactor);
459  return coverage.TransformBounds(transform).Contains(rect);
460 }
float Scalar
Definition: scalar.h:19
TRect< Scalar > Rect
Definition: rect.h:792
constexpr auto GetBottom() const
Definition: rect.h:361
constexpr auto GetTop() const
Definition: rect.h:357
constexpr auto GetLeft() const
Definition: rect.h:355
constexpr auto GetRight() const
Definition: rect.h:359
constexpr static TRect MakeLTRB(Type left, Type top, Type right, Type bottom)
Definition: rect.h:129
Type height
Definition: size.h:29
Type width
Definition: size.h:28

References impeller::RoundingRadii::bottom_left, impeller::RoundingRadii::bottom_right, impeller::TRect< T >::Contains(), impeller::TRect< T >::GetBottom(), impeller::TRect< T >::GetLeft(), impeller::TRect< T >::GetRight(), impeller::TRect< T >::GetTop(), impeller::TSize< T >::height, impeller::TRect< Scalar >::MakeLTRB(), impeller::RoundingRadii::top_left, impeller::RoundingRadii::top_right, transform, impeller::TRect< T >::TransformBounds(), and impeller::TSize< T >::width.

◆ IsAxisAlignedRect()

bool impeller::RoundSuperellipseGeometry::IsAxisAlignedRect ( ) const
overridevirtual

Reimplemented from impeller::Geometry.

Definition at line 462 of file round_superellipse_geometry.cc.

462  {
463  return false;
464 }

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