1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
7 #ifndef DOM_SMIL_SMILKEYSPLINE_H_
8 #define DOM_SMIL_SMILKEYSPLINE_H_
10 #include "mozilla/ArrayUtils.h"
11 #include "mozilla/PodOperations.h"
16 * Utility class to provide scaling defined in a keySplines element.
20 constexpr SMILKeySpline() : mX1(0), mY1(0), mX2(0), mY2(0) {
21 /* caller must call Init later */\
25 * Creates a new key spline control point description.
27 * aX1, etc. are the x1, y1, x2, y2 cubic Bezier control points as defined
28 * by SMILANIM 3.2.3. They must each be in the range 0.0 <= x <= 1.0
30 SMILKeySpline(double aX1
, double aY1
, double aX2
, double aY2
)
31 : mX1(0), mY1(0), mX2(0), mY2(0) {
32 Init(aX1
, aY1
, aX2
, aY2
);
35 double X1() const { return mX1
; }
36 double Y1() const { return mY1
; }
37 double X2() const { return mX2
; }
38 double Y2() const { return mY2
; }
40 void Init(double aX1
, double aY1
, double aX2
, double aY2
);
43 * Gets the output (y) value for an input (x).
45 * @param aX The input x value. A floating-point number between 0 and
48 double GetSplineValue(double aX
) const;
50 void GetSplineDerivativeValues(double aX
, double& aDX
, double& aDY
) const;
52 bool operator==(const SMILKeySpline
& aOther
) const {
53 return mX1
== aOther
.mX1
&& mY1
== aOther
.mY1
&& mX2
== aOther
.mX2
&&
56 bool operator!=(const SMILKeySpline
& aOther
) const {
57 return !(*this == aOther
);
59 int32_t Compare(const SMILKeySpline
& aRhs
) const {
60 if (mX1
!= aRhs
.mX1
) return mX1
< aRhs
.mX1
? -1 : 1;
61 if (mY1
!= aRhs
.mY1
) return mY1
< aRhs
.mY1
? -1 : 1;
62 if (mX2
!= aRhs
.mX2
) return mX2
< aRhs
.mX2
? -1 : 1;
63 if (mY2
!= aRhs
.mY2
) return mY2
< aRhs
.mY2
? -1 : 1;
68 void CalcSampleValues();
71 * Returns x(t) given t, x1, and x2, or y(t) given t, y1, and y2.
73 static double CalcBezier(double aT
, double aA1
, double aA2
);
76 * Returns dx/dt given t, x1, and x2, or dy/dt given t, y1, and y2.
78 static double GetSlope(double aT
, double aA1
, double aA2
);
80 double GetTForX(double aX
) const;
82 double NewtonRaphsonIterate(double aX
, double aGuessT
) const;
84 double BinarySubdivide(double aX
, double aA
, double aB
) const;
86 static double A(double aA1
, double aA2
) {
87 return 1.0 - 3.0 * aA2
+ 3.0 * aA1
;
90 static double B(double aA1
, double aA2
) { return 3.0 * aA2
- 6.0 * aA1
; }
92 static double C(double aA1
) { return 3.0 * aA1
; }
99 enum { kSplineTableSize
= 11 };
100 double mSampleValues
[kSplineTableSize
] = {};
102 static const double kSampleStepSize
;
105 } // namespace mozilla
107 #endif // DOM_SMIL_SMILKEYSPLINE_H_