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/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkScalar_DEFINED
#define SkScalar_DEFINED
#include "../private/SkFloatingPoint.h"
#undef SK_SCALAR_IS_FLOAT
#define SK_SCALAR_IS_FLOAT 1
typedef float SkScalar;
#define SK_Scalar1 1.0f
#define SK_ScalarHalf 0.5f
#define SK_ScalarSqrt2 1.41421356f
#define SK_ScalarPI 3.14159265f
#define SK_ScalarTanPIOver8 0.414213562f
#define SK_ScalarRoot2Over2 0.707106781f
#define SK_ScalarMax 3.402823466e+38f
#define SK_ScalarInfinity SK_FloatInfinity
#define SK_ScalarNegativeInfinity SK_FloatNegativeInfinity
#define SK_ScalarNaN SK_FloatNaN
#define SkScalarFloorToScalar(x) sk_float_floor(x)
#define SkScalarCeilToScalar(x) sk_float_ceil(x)
#define SkScalarRoundToScalar(x) sk_float_floor((x) + 0.5f)
#define SkScalarTruncToScalar(x) sk_float_trunc(x)
#define SkScalarFloorToInt(x) sk_float_floor2int(x)
#define SkScalarCeilToInt(x) sk_float_ceil2int(x)
#define SkScalarRoundToInt(x) sk_float_round2int(x)
#define SkScalarAbs(x) sk_float_abs(x)
#define SkScalarCopySign(x, y) sk_float_copysign(x, y)
#define SkScalarMod(x, y) sk_float_mod(x,y)
#define SkScalarSqrt(x) sk_float_sqrt(x)
#define SkScalarPow(b, e) sk_float_pow(b, e)
#define SkScalarSin(radians) (float)sk_float_sin(radians)
#define SkScalarCos(radians) (float)sk_float_cos(radians)
#define SkScalarTan(radians) (float)sk_float_tan(radians)
#define SkScalarASin(val) (float)sk_float_asin(val)
#define SkScalarACos(val) (float)sk_float_acos(val)
#define SkScalarATan2(y, x) (float)sk_float_atan2(y,x)
#define SkScalarExp(x) (float)sk_float_exp(x)
#define SkScalarLog(x) (float)sk_float_log(x)
#define SkScalarLog2(x) (float)sk_float_log2(x)
//////////////////////////////////////////////////////////////////////////////////////////////////
#define SkIntToScalar(x) static_cast<SkScalar>(x)
#define SkIntToFloat(x) static_cast<float>(x)
#define SkScalarTruncToInt(x) static_cast<int>(x)
#define SkScalarToFloat(x) static_cast<float>(x)
#define SkFloatToScalar(x) static_cast<SkScalar>(x)
#define SkScalarToDouble(x) static_cast<double>(x)
#define SkDoubleToScalar(x) static_cast<SkScalar>(x)
#define SK_ScalarMin (-SK_ScalarMax)
static inline bool SkScalarIsNaN(SkScalar x) { return x != x; }
/** Returns true if x is not NaN and not infinite
*/
static inline bool SkScalarIsFinite(SkScalar x) {
// We rely on the following behavior of infinities and nans
// 0 * finite --> 0
// 0 * infinity --> NaN
// 0 * NaN --> NaN
SkScalar prod = x * 0;
// At this point, prod will either be NaN or 0
return !SkScalarIsNaN(prod);
}
static inline bool SkScalarsAreFinite(SkScalar a, SkScalar b) {
SkScalar prod = 0;
prod *= a;
prod *= b;
// At this point, prod will either be NaN or 0
return !SkScalarIsNaN(prod);
}
static inline bool SkScalarsAreFinite(const SkScalar array[], int count) {
SkScalar prod = 0;
for (int i = 0; i < count; ++i) {
prod *= array[i];
}
// At this point, prod will either be NaN or 0
return !SkScalarIsNaN(prod);
}
/**
* Variant of SkScalarRoundToInt, that performs the rounding step (adding 0.5) explicitly using
* double, to avoid possibly losing the low bit(s) of the answer before calling floor().
*
* This routine will likely be slower than SkScalarRoundToInt(), and should only be used when the
* extra precision is known to be valuable.
*
* In particular, this catches the following case:
* SkScalar x = 0.49999997;
* int ix = SkScalarRoundToInt(x);
* SkASSERT(0 == ix); // <--- fails
* ix = SkDScalarRoundToInt(x);
* SkASSERT(0 == ix); // <--- succeeds
*/
static inline int SkDScalarRoundToInt(SkScalar x) {
double xx = x;
xx += 0.5;
return (int)floor(xx);
}
/** Returns the fractional part of the scalar. */
static inline SkScalar SkScalarFraction(SkScalar x) {
return x - SkScalarTruncToScalar(x);
}
static inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) {
x = SkTMin(x, max);
x = SkTMax<SkScalar>(x, 0);
return x;
}
static inline SkScalar SkScalarPin(SkScalar x, SkScalar min, SkScalar max) {
return SkTPin(x, min, max);
}
SkScalar SkScalarSinCos(SkScalar radians, SkScalar* cosValue);
static inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
#define SkScalarInvert(x) (SK_Scalar1 / (x))
#define SkScalarFastInvert(x) (SK_Scalar1 / (x))
#define SkScalarAve(a, b) (((a) + (b)) * SK_ScalarHalf)
#define SkScalarHalf(a) ((a) * SK_ScalarHalf)
#define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180))
#define SkRadiansToDegrees(radians) ((radians) * (180 / SK_ScalarPI))
static inline SkScalar SkMaxScalar(SkScalar a, SkScalar b) { return a > b ? a : b; }
static inline SkScalar SkMinScalar(SkScalar a, SkScalar b) { return a < b ? a : b; }
static inline bool SkScalarIsInt(SkScalar x) {
return x == SkScalarFloorToScalar(x);
}
/**
* Returns -1 || 0 || 1 depending on the sign of value:
* -1 if x < 0
* 0 if x == 0
* 1 if x > 0
*/
static inline int SkScalarSignAsInt(SkScalar x) {
return x < 0 ? -1 : (x > 0);
}
// Scalar result version of above
static inline SkScalar SkScalarSignAsScalar(SkScalar x) {
return x < 0 ? -SK_Scalar1 : ((x > 0) ? SK_Scalar1 : 0);
}
#define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12))
static inline bool SkScalarNearlyZero(SkScalar x,
SkScalar tolerance = SK_ScalarNearlyZero) {
SkASSERT(tolerance >= 0);
return SkScalarAbs(x) <= tolerance;
}
static inline bool SkScalarNearlyEqual(SkScalar x, SkScalar y,
SkScalar tolerance = SK_ScalarNearlyZero) {
SkASSERT(tolerance >= 0);
return SkScalarAbs(x-y) <= tolerance;
}
/** Linearly interpolate between A and B, based on t.
If t is 0, return A
If t is 1, return B
else interpolate.
t must be [0..SK_Scalar1]
*/
static inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) {
SkASSERT(t >= 0 && t <= SK_Scalar1);
return A + (B - A) * t;
}
/** Interpolate along the function described by (keys[length], values[length])
for the passed searchKey. SearchKeys outside the range keys[0]-keys[Length]
clamp to the min or max value. This function was inspired by a desire
to change the multiplier for thickness in fakeBold; therefore it assumes
the number of pairs (length) will be small, and a linear search is used.
Repeated keys are allowed for discontinuous functions (so long as keys is
monotonically increasing), and if key is the value of a repeated scalar in
keys, the first one will be used. However, that may change if a binary
search is used.
*/
SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[],
const SkScalar values[], int length);
/*
* Helper to compare an array of scalars.
*/
static inline bool SkScalarsEqual(const SkScalar a[], const SkScalar b[], int n) {
SkASSERT(n >= 0);
for (int i = 0; i < n; ++i) {
if (a[i] != b[i]) {
return false;
}
}
return true;
}
#endif
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