impeller::FillRoundRectGeometry Class Reference

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:

Public Member Functions
	FillRoundRectGeometry (const RoundRect &round_rect)
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.
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 PathSource &	GetSource () 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< 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 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.

    : FillPathSourceGeometry(std::nullopt), round_rect_source_(round_rect) {}

Member Function Documentation

CoversArea()

bool impeller::FillRoundRectGeometry::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::FillPathSourceGeometry.

Definition at line 73 of file round_rect_geometry.cc.

                                                                {
  // Similar procedure to |RoundRectGeometry| except that we have different
  // radii at every corner.
  if (!transform.IsTranslationScaleOnly()) {
    return false;
  }
  const RoundRect& round_rect = round_rect_source_.GetRoundRect();
 
  const Rect& bounds = round_rect.GetBounds();
  const RoundingRadii& radii = round_rect.GetRadii();
 
  Scalar left_margin = std::max(radii.top_left.width, radii.bottom_left.width);
  Scalar right_margin =
      std::max(radii.top_right.width, radii.bottom_right.width);
  Scalar top_margin = std::max(radii.top_left.height, radii.top_right.height);
  Scalar bottom_margin =
      std::max(radii.bottom_left.height, radii.bottom_right.height);
 
  bool flat_on_tb = bounds.GetWidth() > left_margin + right_margin;
  bool flat_on_lr = bounds.GetHeight() > top_margin + bottom_margin;
  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(-left_margin, 0, -right_margin, 0);
    Rect coverage = vertical_bounds.TransformBounds(transform);
    if (coverage.Contains(rect)) {
      return true;
    }
  }
  if (flat_on_lr) {
    Rect horizontal_bounds = bounds.Expand(0, -top_margin, 0, -bottom_margin);
    Rect coverage = horizontal_bounds.TransformBounds(transform);
    if (coverage.Contains(rect)) {
      return true;
    }
  }
  return false;
}

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.

                                                         {
  return round_rect_source_;
}

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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