/*

 * Copyright 2018 Google Inc.

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#ifndef SkCubicMap_DEFINED

#define SkCubicMap_DEFINED

#include "include/core/SkPoint.h"

#include "include/core/SkScalar.h"

#include "include/core/SkTypes.h"

/**

 *  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]

 */

class SK_API SkCubicMap {

public:

    SkCubicMap(SkPoint p1, SkPoint p2);

    static bool IsLinear(SkPoint p1, SkPoint p2) {

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

    }

    float computeYFromX(float x) const;

    SkPoint computeFromT(float t) const;

private:

    enum Type {

        kLine_Type,     // x == y

        kCubeRoot_Type, // At^3 == x

        kSolver_Type,   // general monotonic cubic solver

    };

    SkPoint fCoeff[3];

    Type    fType;

};

#endif