1/*
2 * Copyright 2018 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkCubicMap_DEFINED
9#define SkCubicMap_DEFINED
10
11#include "include/core/SkPoint.h"
12
13/**
14 * Fast evaluation of a cubic ease-in / ease-out curve. This is defined as a parametric cubic
15 * curve inside the unit square.
16 *
17 * pt[0] is implicitly { 0, 0 }
18 * pt[3] is implicitly { 1, 1 }
19 * pts[1,2].X are inside the unit [0..1]
20 */
21class SK_API SkCubicMap {
22public:
23 SkCubicMap(SkPoint p1, SkPoint p2);
24
25 static bool IsLinear(SkPoint p1, SkPoint p2) {
26 return SkScalarNearlyEqual(p1.fX, p1.fY) && SkScalarNearlyEqual(p2.fX, p2.fY);
27 }
28
29 float computeYFromX(float x) const;
30
31 SkPoint computeFromT(float t) const;
32
33private:
34 enum Type {
35 kLine_Type, // x == y
36 kCubeRoot_Type, // At^3 == x
37 kSolver_Type, // general monotonic cubic solver
38 };
39
40 SkPoint fCoeff[3];
41 Type fType;
42};
43
44#endif
45
46