SkScalar.h

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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 "include/private/base/SkAssert.h"
#include "include/private/base/SkFloatingPoint.h"
 
typedef float SkScalar;
 
#define SK_Scalar1                  1.0f
#define SK_ScalarHalf               0.5f
#define SK_ScalarSqrt2              SK_FloatSqrt2
#define SK_ScalarPI                 SK_FloatPI
#define SK_ScalarTanPIOver8         0.414213562f
#define SK_ScalarRoot2Over2         0.707106781f
#define SK_ScalarMax                3.402823466e+38f
#define SK_ScalarMin                (-SK_ScalarMax)
#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_round(x)
#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)   sk_float_saturate2int(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)     sk_double_to_float(x)
 
static inline bool SkScalarIsNaN(SkScalar x) { return x != x; }
 
static inline bool SkScalarIsFinite(SkScalar x) { return sk_float_isfinite(x); }
 
static inline bool SkScalarsAreFinite(SkScalar a, SkScalar b) {
    return sk_floats_are_finite(a, b);
}
 
static inline bool SkScalarsAreFinite(const SkScalar array[], int count) {
    return sk_floats_are_finite(array, count);
}
 
static inline SkScalar SkScalarFraction(SkScalar x) {
    return x - SkScalarTruncToScalar(x);
}
 
static inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
 
#define SkScalarInvert(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 bool SkScalarIsInt(SkScalar x) {
    return x == SkScalarFloorToScalar(x);
}
 
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;
}
 
#define SK_ScalarSinCosNearlyZero   (SK_Scalar1 / (1 << 16))
 
static inline float SkScalarSinSnapToZero(SkScalar radians) {
    float v = SkScalarSin(radians);
    return SkScalarNearlyZero(v, SK_ScalarSinCosNearlyZero) ? 0.0f : v;
}
 
static inline float SkScalarCosSnapToZero(SkScalar radians) {
    float v = SkScalarCos(radians);
    return SkScalarNearlyZero(v, SK_ScalarSinCosNearlyZero) ? 0.0f : v;
}
 
static inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) {
    SkASSERT(t >= 0 && t <= SK_Scalar1);
    return A + (B - A) * t;
}
 
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