Flutter Impeller
impeller::RoundRectGeometry Class Referencefinal

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:
impeller::Geometry

Public Member Functions

 RoundRectGeometry (const Rect &bounds, const Size &radii)
 
 ~RoundRectGeometry () 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 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 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 29 of file round_rect_geometry.cc.

30  {
31  if (!transform.IsTranslationScaleOnly()) {
32  return false;
33  }
34  bool flat_on_tb = bounds_.GetWidth() > radii_.width * 2;
35  bool flat_on_lr = bounds_.GetHeight() > radii_.height * 2;
36  if (!flat_on_tb && !flat_on_lr) {
37  return false;
38  }
39  // We either transform the bounds and delta-transform the radii,
40  // or we compute the vertical and horizontal bounds and then
41  // transform each. Either way there are 2 transform operations.
42  // We could also get a weaker answer by computing just the
43  // "inner rect" and only doing a coverage analysis on that,
44  // but this process will produce more culling results.
45  if (flat_on_tb) {
46  Rect vertical_bounds = bounds_.Expand(Size{-radii_.width, 0});
47  Rect coverage = vertical_bounds.TransformBounds(transform);
48  if (coverage.Contains(rect)) {
49  return true;
50  }
51  }
52  if (flat_on_lr) {
53  Rect horizontal_bounds = bounds_.Expand(Size{0, -radii_.height});
54  Rect coverage = horizontal_bounds.TransformBounds(transform);
55  if (coverage.Contains(rect)) {
56  return true;
57  }
58  }
59  return false;
60 }
TRect< Scalar > Rect
Definition: rect.h:792
TSize< Scalar > Size
Definition: size.h:159
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
constexpr Type GetHeight() const
Returns the height of the rectangle, equivalent to |GetSize().height|.
Definition: rect.h:351
constexpr Type GetWidth() const
Returns the width of the rectangle, equivalent to |GetSize().width|.
Definition: rect.h:345
Type height
Definition: size.h:29
Type width
Definition: size.h:28

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.

62  {
63  return false;
64 }

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