Flutter Impeller
impeller::FillRoundRectGeometry Class Referencefinal

A Geometry class that produces fillable vertices from any |RoundRect| object regardless of radii uniformity. More...

#include <round_rect_geometry.h>

Inheritance diagram for impeller::FillRoundRectGeometry:
impeller::FillPathSourceGeometry impeller::Geometry

Public Member Functions

 FillRoundRectGeometry (const RoundRect &round_rect)
 
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...
 
- Public Member Functions inherited from impeller::FillPathSourceGeometry
 ~FillPathSourceGeometry () override
 
- Public Member Functions inherited from impeller::Geometry
virtual ~Geometry ()
 
virtual bool IsAxisAlignedRect () const
 
virtual bool CanApplyMaskFilter () const
 
virtual Scalar ComputeAlphaCoverage (const Matrix &transform) const
 

Protected Member Functions

const PathSourceGetSource () const override
 
- Protected Member Functions inherited from impeller::FillPathSourceGeometry
 FillPathSourceGeometry (std::optional< Rect > inner_rect)
 

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 produces fillable vertices from any |RoundRect| object regardless of radii uniformity.

This class uses the |FillPathSourceGeometry| base class to do the work by providing a |RoundRectPathSoure| iterator.

Definition at line 59 of file round_rect_geometry.h.

Constructor & Destructor Documentation

◆ FillRoundRectGeometry()

impeller::FillRoundRectGeometry::FillRoundRectGeometry ( const RoundRect round_rect)
explicit

Definition at line 66 of file round_rect_geometry.cc.

67  : FillPathSourceGeometry(std::nullopt), round_rect_source_(round_rect) {}
FillPathSourceGeometry(std::optional< Rect > inner_rect)

Member Function Documentation

◆ CoversArea()

bool impeller::FillRoundRectGeometry::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::FillPathSourceGeometry.

Definition at line 73 of file round_rect_geometry.cc.

74  {
75  // Similar procedure to |RoundRectGeometry| except that we have different
76  // radii at every corner.
77  if (!transform.IsTranslationScaleOnly()) {
78  return false;
79  }
80  const RoundRect& round_rect = round_rect_source_.GetRoundRect();
81 
82  const Rect& bounds = round_rect.GetBounds();
83  const RoundingRadii& radii = round_rect.GetRadii();
84 
85  Scalar left_margin = std::max(radii.top_left.width, radii.bottom_left.width);
86  Scalar right_margin =
87  std::max(radii.top_right.width, radii.bottom_right.width);
88  Scalar top_margin = std::max(radii.top_left.height, radii.top_right.height);
89  Scalar bottom_margin =
90  std::max(radii.bottom_left.height, radii.bottom_right.height);
91 
92  bool flat_on_tb = bounds.GetWidth() > left_margin + right_margin;
93  bool flat_on_lr = bounds.GetHeight() > top_margin + bottom_margin;
94  if (!flat_on_tb && !flat_on_lr) {
95  return false;
96  }
97  // We either transform the bounds and delta-transform the radii,
98  // or we compute the vertical and horizontal bounds and then
99  // transform each. Either way there are 2 transform operations.
100  // We could also get a weaker answer by computing just the
101  // "inner rect" and only doing a coverage analysis on that,
102  // but this process will produce more culling results.
103  if (flat_on_tb) {
104  Rect vertical_bounds = bounds.Expand(-left_margin, 0, -right_margin, 0);
105  Rect coverage = vertical_bounds.TransformBounds(transform);
106  if (coverage.Contains(rect)) {
107  return true;
108  }
109  }
110  if (flat_on_lr) {
111  Rect horizontal_bounds = bounds.Expand(0, -top_margin, 0, -bottom_margin);
112  Rect coverage = horizontal_bounds.TransformBounds(transform);
113  if (coverage.Contains(rect)) {
114  return true;
115  }
116  }
117  return false;
118 }
const RoundRect & GetRoundRect() const
Definition: round_rect.h:155
float Scalar
Definition: scalar.h:19
TRect< Scalar > Rect
Definition: rect.h:792
constexpr TRect< T > Expand(T left, T top, T right, T bottom) const
Returns a rectangle with expanded edges. Negative expansion results in shrinking.
Definition: rect.h:622
constexpr TRect TransformBounds(const Matrix &transform) const
Creates a new bounding box that contains this transformed rectangle.
Definition: rect.h:476

References impeller::RoundingRadii::bottom_left, impeller::RoundingRadii::bottom_right, impeller::TRect< T >::Contains(), impeller::TRect< T >::Expand(), impeller::RoundRect::GetBounds(), impeller::TRect< T >::GetHeight(), impeller::RoundRect::GetRadii(), impeller::RoundRectPathSource::GetRoundRect(), impeller::TRect< T >::GetWidth(), impeller::TSize< T >::height, impeller::RoundingRadii::top_left, impeller::RoundingRadii::top_right, transform, impeller::TRect< T >::TransformBounds(), and impeller::TSize< T >::width.

◆ GetSource()

const PathSource & impeller::FillRoundRectGeometry::GetSource ( ) const
overrideprotectedvirtual

The PathSource object that will be iterated to produce the filled vertices.

Implements impeller::FillPathSourceGeometry.

Definition at line 69 of file round_rect_geometry.cc.

69  {
70  return round_rect_source_;
71 }

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