Flutter Impeller
impeller::CubicPathComponent Struct Reference

#include <path_component.h>

Public Types

using PointProc = std::function< void(const Point &point)>
 

Public Member Functions

 CubicPathComponent ()
 
 CubicPathComponent (const QuadraticPathComponent &q)
 
 CubicPathComponent (Point ap1, Point acp1, Point acp2, Point ap2)
 
Point Solve (Scalar time) const
 
Point SolveDerivative (Scalar time) const
 
void AppendPolylinePoints (Scalar scale, std::vector< Point > &points) const
 
std::vector< PointExtrema () const
 
void ToLinearPathComponents (Scalar scale, const PointProc &proc) const
 
void ToLinearPathComponents (Scalar scale, VertexWriter &writer) const
 
CubicPathComponent Subsegment (Scalar t0, Scalar t1) const
 
bool operator== (const CubicPathComponent &other) const
 
std::optional< Vector2GetStartDirection () const
 
std::optional< Vector2GetEndDirection () const
 

Public Attributes

Point p1
 
Point cp1
 
Point cp2
 
Point p2
 

Detailed Description

Definition at line 101 of file path_component.h.

Member Typedef Documentation

◆ PointProc

using impeller::CubicPathComponent::PointProc = std::function<void(const Point& point)>

Definition at line 130 of file path_component.h.

Constructor & Destructor Documentation

◆ CubicPathComponent() [1/3]

impeller::CubicPathComponent::CubicPathComponent ( )
inline

Definition at line 111 of file path_component.h.

111 {}

Referenced by Subsegment().

◆ CubicPathComponent() [2/3]

impeller::CubicPathComponent::CubicPathComponent ( const QuadraticPathComponent q)
inlineexplicit

Definition at line 113 of file path_component.h.

114  : p1(q.p1),
115  cp1(q.p1 + (q.cp - q.p1) * (2.0 / 3.0)),
116  cp2(q.p2 + (q.cp - q.p2) * (2.0 / 3.0)),
117  p2(q.p2) {}

◆ CubicPathComponent() [3/3]

impeller::CubicPathComponent::CubicPathComponent ( Point  ap1,
Point  acp1,
Point  acp2,
Point  ap2 
)
inline

Definition at line 119 of file path_component.h.

120  : p1(ap1), cp1(acp1), cp2(acp2), p2(ap2) {}

Member Function Documentation

◆ AppendPolylinePoints()

void impeller::CubicPathComponent::AppendPolylinePoints ( Scalar  scale,
std::vector< Point > &  points 
) const

Definition at line 229 of file path_component.cc.

231  {
233  scale, [&points](const Point& point) { points.emplace_back(point); });
234 }

References scale, and ToLinearPathComponents().

◆ Extrema()

std::vector< Point > impeller::CubicPathComponent::Extrema ( ) const

Definition at line 332 of file path_component.cc.

332  {
333  /*
334  * As described in: https://pomax.github.io/bezierinfo/#extremities
335  */
336  std::vector<Scalar> values;
337 
340 
341  std::vector<Point> points = {p1, p2};
342 
343  for (const auto& value : values) {
344  points.emplace_back(Solve(value));
345  }
346 
347  return points;
348 }

References cp1, cp2, impeller::CubicPathBoundingPopulateValues(), p1, p2, Solve(), impeller::TPoint< T >::x, and impeller::TPoint< T >::y.

Referenced by impeller::QuadraticPathComponent::Extrema(), and impeller::testing::TEST().

◆ GetEndDirection()

std::optional< Vector2 > impeller::CubicPathComponent::GetEndDirection ( ) const

Definition at line 363 of file path_component.cc.

363  {
364  if (p2 != cp2) {
365  return (p2 - cp2).Normalize();
366  }
367  if (p2 != cp1) {
368  return (p2 - cp1).Normalize();
369  }
370  if (p2 != p1) {
371  return (p2 - p1).Normalize();
372  }
373  return std::nullopt;
374 }

References cp1, cp2, p1, and p2.

Referenced by impeller::PathComponentEndDirectionVisitor::operator()().

◆ GetStartDirection()

std::optional< Vector2 > impeller::CubicPathComponent::GetStartDirection ( ) const

Definition at line 350 of file path_component.cc.

350  {
351  if (p1 != cp1) {
352  return (p1 - cp1).Normalize();
353  }
354  if (p1 != cp2) {
355  return (p1 - cp2).Normalize();
356  }
357  if (p1 != p2) {
358  return (p1 - p2).Normalize();
359  }
360  return std::nullopt;
361 }

References cp1, cp2, p1, and p2.

Referenced by impeller::PathComponentStartDirectionVisitor::operator()().

◆ operator==()

bool impeller::CubicPathComponent::operator== ( const CubicPathComponent other) const
inline

Definition at line 138 of file path_component.h.

138  {
139  return p1 == other.p1 && cp1 == other.cp1 && cp2 == other.cp2 &&
140  p2 == other.p2;
141  }

References cp1, cp2, p1, and p2.

◆ Solve()

Point impeller::CubicPathComponent::Solve ( Scalar  time) const

Definition at line 215 of file path_component.cc.

215  {
216  return {
217  CubicSolve(time, p1.x, cp1.x, cp2.x, p2.x), // x
218  CubicSolve(time, p1.y, cp1.y, cp2.y, p2.y), // y
219  };
220 }

References cp1, cp2, impeller::CubicSolve(), p1, p2, impeller::TPoint< T >::x, and impeller::TPoint< T >::y.

Referenced by Extrema(), Subsegment(), and ToLinearPathComponents().

◆ SolveDerivative()

Point impeller::CubicPathComponent::SolveDerivative ( Scalar  time) const

Definition at line 222 of file path_component.cc.

222  {
223  return {
224  CubicSolveDerivative(time, p1.x, cp1.x, cp2.x, p2.x), // x
225  CubicSolveDerivative(time, p1.y, cp1.y, cp2.y, p2.y), // y
226  };
227 }

References cp1, cp2, impeller::CubicSolveDerivative(), p1, p2, impeller::TPoint< T >::x, and impeller::TPoint< T >::y.

◆ Subsegment()

CubicPathComponent impeller::CubicPathComponent::Subsegment ( Scalar  t0,
Scalar  t1 
) const

Definition at line 250 of file path_component.cc.

250  {
251  auto p0 = Solve(t0);
252  auto p3 = Solve(t1);
253  auto d = Lower();
254  auto scale = (t1 - t0) * (1.0 / 3.0);
255  auto p1 = p0 + scale * d.Solve(t0);
256  auto p2 = p3 - scale * d.Solve(t1);
257  return CubicPathComponent(p0, p1, p2, p3);
258 }

References CubicPathComponent(), p1, p2, scale, and Solve().

◆ ToLinearPathComponents() [1/2]

void impeller::CubicPathComponent::ToLinearPathComponents ( Scalar  scale,
const PointProc proc 
) const

Definition at line 260 of file path_component.cc.

261  {
262  Scalar line_count = std::ceilf(ComputeCubicSubdivisions(scale, *this));
263  for (size_t i = 1; i < line_count; i++) {
264  proc(Solve(i / line_count));
265  }
266  proc(p2);
267 }

References impeller::ComputeCubicSubdivisions(), p2, scale, and Solve().

Referenced by AppendPolylinePoints(), and impeller::Path::WritePolyline().

◆ ToLinearPathComponents() [2/2]

void impeller::CubicPathComponent::ToLinearPathComponents ( Scalar  scale,
VertexWriter writer 
) const

Definition at line 236 of file path_component.cc.

237  {
238  Scalar line_count = std::ceilf(ComputeCubicSubdivisions(scale, *this));
239  for (size_t i = 1; i < line_count; i++) {
240  writer.Write(Solve(i / line_count));
241  }
242  writer.Write(p2);
243 }

References impeller::ComputeCubicSubdivisions(), p2, scale, Solve(), and impeller::VertexWriter::Write().

Member Data Documentation

◆ cp1

◆ cp2

◆ p1

◆ p2


The documentation for this struct was generated from the following files:
impeller::TPoint::y
Type y
Definition: point.h:31
impeller::Scalar
float Scalar
Definition: scalar.h:18
impeller::CubicPathComponent::p1
Point p1
Definition: path_component.h:103
impeller::CubicPathComponent::cp2
Point cp2
Definition: path_component.h:107
impeller::CubicPathComponent::Solve
Point Solve(Scalar time) const
Definition: path_component.cc:215
impeller::CubicPathBoundingPopulateValues
static void CubicPathBoundingPopulateValues(std::vector< Scalar > &values, Scalar p1, Scalar p2, Scalar p3, Scalar p4)
Definition: path_component.cc:277
impeller::CubicSolveDerivative
static Scalar CubicSolveDerivative(Scalar t, Scalar p0, Scalar p1, Scalar p2, Scalar p3)
Definition: path_component.cc:104
impeller::CubicPathComponent::cp1
Point cp1
Definition: path_component.h:105
impeller::Point
TPoint< Scalar > Point
Definition: point.h:322
impeller::CubicSolve
static Scalar CubicSolve(Scalar t, Scalar p0, Scalar p1, Scalar p2, Scalar p3)
Definition: path_component.cc:93
impeller::TPoint::x
Type x
Definition: point.h:30
impeller::CubicPathComponent::CubicPathComponent
CubicPathComponent()
Definition: path_component.h:111
impeller::CubicPathComponent::ToLinearPathComponents
void ToLinearPathComponents(Scalar scale, const PointProc &proc) const
Definition: path_component.cc:260
impeller::ComputeCubicSubdivisions
Scalar ComputeCubicSubdivisions(Scalar scale_factor, Point p0, Point p1, Point p2, Point p3)
Definition: wangs_formula.cc:23
scale
const Scalar scale
Definition: stroke_path_geometry.cc:308
impeller::CubicPathComponent::p2
Point p2
Definition: path_component.h:109