SkCubicMap Class Reference

#include <SkCubicMap.h>

Public Member Functions
	SkCubicMap (SkPoint p1, SkPoint p2)
float	computeYFromX (float x) const
SkPoint	computeFromT (float t) const

Static Public Member Functions
static bool	IsLinear (SkPoint p1, SkPoint p2)

Detailed Description

Fast evaluation of a cubic ease-in / ease-out curve. This is defined as a parametric cubic curve inside the unit square.

pt[0] is implicitly { 0, 0 } pt[3] is implicitly { 1, 1 } pts[1,2].X are inside the unit [0..1]

Definition at line 23 of file SkCubicMap.h.

Constructor & Destructor Documentation

SkCubicMap()

SkCubicMap::SkCubicMap	(	SkPoint	p1,
		SkPoint	p2
	)

Definition at line 88 of file SkCubicMap.cpp.

                                             {
    // Clamp X values only (we allow Ys outside [0..1]).
    p1.fX = std::min(std::max(p1.fX, 0.0f), 1.0f);
    p2.fX = std::min(std::max(p2.fX, 0.0f), 1.0f);
 
    auto s1 = skvx::float2::Load(&p1) * 3;
    auto s2 = skvx::float2::Load(&p2) * 3;
 
    (1 + s1 - s2).store(&fCoeff[0]);
    (s2 - s1 - s1).store(&fCoeff[1]);
    s1.store(&fCoeff[2]);
 
    fType = kSolver_Type;
    if (SkScalarNearlyEqual(p1.fX, p1.fY) && SkScalarNearlyEqual(p2.fX, p2.fY)) {
        fType = kLine_Type;
    } else if (coeff_nearly_zero(fCoeff[1].fX) && coeff_nearly_zero(fCoeff[2].fX)) {
        fType = kCubeRoot_Type;
    }
}

Member Function Documentation

computeFromT()

SkPoint SkCubicMap::computeFromT

(

float

t

)

const

Definition at line 108 of file SkCubicMap.cpp.

                                              {
    auto a = skvx::float2::Load(&fCoeff[0]);
    auto b = skvx::float2::Load(&fCoeff[1]);
    auto c = skvx::float2::Load(&fCoeff[2]);
 
    SkPoint result;
    (((a * t + b) * t + c) * t).store(&result);
    return result;
}

computeYFromX()

float SkCubicMap::computeYFromX

(

float

x

)

const

Definition at line 61 of file SkCubicMap.cpp.

                                             {
    x = SkTPin(x, 0.0f, 1.0f);
 
    if (nearly_zero(x) || nearly_zero(1 - x)) {
        return x;
    }
    if (fType == kLine_Type) {
        return x;
    }
    float t;
    if (fType == kCubeRoot_Type) {
        t = std::pow(x / fCoeff[0].fX, 1.0f / 3);
    } else {
        t = compute_t_from_x(fCoeff[0].fX, fCoeff[1].fX, fCoeff[2].fX, x);
    }
    float a = fCoeff[0].fY;
    float b = fCoeff[1].fY;
    float c = fCoeff[2].fY;
    float y = ((a * t + b) * t + c) * t;
 
    return y;
}

IsLinear()

static bool SkCubicMap::IsLinear ( SkPoint  p1, SkPoint  p2  )

inlinestatic

Definition at line 27 of file SkCubicMap.h.

                                                 {
        return SkScalarNearlyEqual(p1.fX, p1.fY) && SkScalarNearlyEqual(p2.fX, p2.fY);
    }

---

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

• third_party/skia/include/core/SkCubicMap.h
• third_party/skia/src/core/SkCubicMap.cpp