include/core/SkScalar.h - platform/external/skia - Git at Google

 /*
  * Copyright (C) 2006 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #ifndef SkScalar_DEFINED
 #define SkScalar_DEFINED

 #include "SkFixed.h"

 /** \file SkScalar.h

     Types and macros for the data type SkScalar. This is the fractional numeric type
     that, depending on the compile-time flag SK_SCALAR_IS_FLOAT, may be implemented
     either as an IEEE float, or as a 16.16 SkFixed. The macros in this file are written
     to allow the calling code to manipulate SkScalar values without knowing which representation
     is in effect.
 */

 #ifdef SK_SCALAR_IS_FLOAT
     #include "SkFloatingPoint.h"

     /** SkScalar is our type for fractional values and coordinates. Depending on
         compile configurations, it is either represented as an IEEE float, or
         as a 16.16 fixed point integer.
     */
     typedef float   SkScalar;
     extern const uint32_t gIEEENotANumber;
     extern const uint32_t gIEEEInfinity;

     /** SK_Scalar1 is defined to be 1.0 represented as an SkScalar
     */
     #define SK_Scalar1              (1.0f)
     /** SK_Scalar1 is defined to be 1/2 represented as an SkScalar
     */
     #define SK_ScalarHalf           (0.5f)
     /** SK_ScalarInfinity is defined to be infinity as an SkScalar
     */
     #define SK_ScalarInfinity           (*(const float*)&gIEEEInfinity)
     /** SK_ScalarMax is defined to be the largest value representable as an SkScalar
     */
     #define SK_ScalarMax            (3.4028235e+38f)
     /** SK_ScalarMin is defined to be the smallest value representable as an SkScalar
     */
     #define SK_ScalarMin            (1.1754944e-38f)
     /** SK_ScalarNaN is defined to be 'Not a Number' as an SkScalar
     */
     #define SK_ScalarNaN      (*(const float*)(const void*)&gIEEENotANumber)
     /** SkScalarIsNaN(n) returns true if argument is not a number
     */
     static inline bool SkScalarIsNaN(float x) { return x != x; }
     /** SkIntToScalar(n) returns its integer argument as an SkScalar
     */
     #define SkIntToScalar(n)        ((float)(n))
     /** SkFixedToScalar(n) returns its SkFixed argument as an SkScalar
     */
     #define SkFixedToScalar(x)      SkFixedToFloat(x)
     /** SkScalarToFixed(n) returns its SkScalar argument as an SkFixed
     */
     #define SkScalarToFixed(x)      SkFloatToFixed(x)

     #define SkScalarToFloat(n)      (n)
     #define SkFloatToScalar(n)      (n)

     #define SkScalarToDouble(n)      (double)(n)
     #define SkDoubleToScalar(n)      (float)(n)

     /** SkScalarFraction(x) returns the signed fractional part of the argument
     */
     #define SkScalarFraction(x)     sk_float_mod(x, 1.0f)
     /** Rounds the SkScalar to the nearest integer value
     */
     #define SkScalarRound(x)        sk_float_round2int(x)
     /** Returns the smallest integer that is >= the specified SkScalar
     */
     #define SkScalarCeil(x)         sk_float_ceil2int(x)
     /** Returns the largest integer that is <= the specified SkScalar
     */
     #define SkScalarFloor(x)        sk_float_floor2int(x)
     /** Returns the absolute value of the specified SkScalar
     */
     #define SkScalarAbs(x)          sk_float_abs(x)
     /** Returns the value pinned between 0 and max inclusive
     */
     inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) {
         return x < 0 ? 0 : x > max ? max : x;
     }
     /** Returns the value pinned between min and max inclusive
     */
     inline SkScalar SkScalarPin(SkScalar x, SkScalar min, SkScalar max) {
         return x < min ? min : x > max ? max : x;
     }
     /** Returns the specified SkScalar squared (x*x)
     */
     inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
     /** Returns the product of two SkScalars
     */
     #define SkScalarMul(a, b)       ((float)(a) * (b))
     /** Returns the product of two SkScalars plus a third SkScalar
     */
     #define SkScalarMulAdd(a, b, c) ((float)(a) * (b) + (c))
     /** Returns the product of a SkScalar and an int rounded to the nearest integer value
     */
     #define SkScalarMulRound(a, b) SkScalarRound((float)(a) * (b))
     /** Returns the product of a SkScalar and an int promoted to the next larger int
     */
     #define SkScalarMulCeil(a, b) SkScalarCeil((float)(a) * (b))
     /** Returns the product of a SkScalar and an int truncated to the next smaller int
     */
     #define SkScalarMulFloor(a, b) SkScalarFloor((float)(a) * (b))
     /** Returns the quotient of two SkScalars (a/b)
     */
     #define SkScalarDiv(a, b)       ((float)(a) / (b))
     /** Returns the mod of two SkScalars (a mod b)
     */
     #define SkScalarMod(x,y)        sk_float_mod(x,y)
     /** Returns the product of the first two arguments, divided by the third argument
     */
     #define SkScalarMulDiv(a, b, c) ((float)(a) * (b) / (c))
     /** Returns the multiplicative inverse of the SkScalar (1/x)
     */
     #define SkScalarInvert(x)       (SK_Scalar1 / (x))
     #define SkScalarFastInvert(x)   (SK_Scalar1 / (x))
     /** Returns the square root of the SkScalar
     */
     #define SkScalarSqrt(x)         sk_float_sqrt(x)
     /** Returns the average of two SkScalars (a+b)/2
     */
     #define SkScalarAve(a, b)       (((a) + (b)) * 0.5f)
     /** Returns the geometric mean of two SkScalars
     */
     #define SkScalarMean(a, b)      sk_float_sqrt((float)(a) * (b))
     /** Returns one half of the specified SkScalar
     */
     #define SkScalarHalf(a)         ((a) * 0.5f)

     #define SK_ScalarSqrt2          1.41421356f
     #define SK_ScalarPI             3.14159265f
     #define SK_ScalarTanPIOver8     0.414213562f
     #define SK_ScalarRoot2Over2     0.707106781f

     #define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180))
     float SkScalarSinCos(SkScalar radians, SkScalar* cosValue);
     #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)

     inline SkScalar SkMaxScalar(SkScalar a, SkScalar b) { return a > b ? a : b; }
     inline SkScalar SkMinScalar(SkScalar a, SkScalar b) { return a < b ? a : b; }

 #else
     typedef SkFixed SkScalar;

     #define SK_Scalar1              SK_Fixed1
     #define SK_ScalarHalf           SK_FixedHalf
     #define SK_ScalarInfinity   SK_FixedMax
     #define SK_ScalarMax            SK_FixedMax
     #define SK_ScalarMin            SK_FixedMin
     #define SK_ScalarNaN            SK_FixedNaN
     #define SkScalarIsNaN(x)        ((x) == SK_FixedNaN)
     #define SkIntToScalar(n)        SkIntToFixed(n)
     #define SkFixedToScalar(x)      (x)
     #define SkScalarToFixed(x)      (x)
     #ifdef SK_CAN_USE_FLOAT
         #define SkScalarToFloat(n)  SkFixedToFloat(n)
         #define SkFloatToScalar(n)  SkFloatToFixed(n)

         #define SkScalarToDouble(n) SkFixedToDouble(n)
         #define SkDoubleToScalar(n) SkDoubleToFixed(n)
     #endif
     #define SkScalarFraction(x)     SkFixedFraction(x)
     #define SkScalarRound(x)        SkFixedRound(x)
     #define SkScalarCeil(x)         SkFixedCeil(x)
     #define SkScalarFloor(x)        SkFixedFloor(x)
     #define SkScalarAbs(x)          SkFixedAbs(x)
     #define SkScalarClampMax(x, max) SkClampMax(x, max)
     #define SkScalarPin(x, min, max) SkPin32(x, min, max)
     #define SkScalarSquare(x)       SkFixedSquare(x)
     #define SkScalarMul(a, b)       SkFixedMul(a, b)
     #define SkScalarMulAdd(a, b, c) SkFixedMulAdd(a, b, c)
     #define SkScalarMulRound(a, b)  SkFixedMulCommon(a, b, SK_FixedHalf)
     #define SkScalarMulCeil(a, b)   SkFixedMulCommon(a, b, SK_Fixed1 - 1)
     #define SkScalarMulFloor(a, b)  SkFixedMulCommon(a, b, 0)
     #define SkScalarDiv(a, b)       SkFixedDiv(a, b)
     #define SkScalarMod(a, b)       SkFixedMod(a, b)
     #define SkScalarMulDiv(a, b, c) SkMulDiv(a, b, c)
     #define SkScalarInvert(x)       SkFixedInvert(x)
     #define SkScalarFastInvert(x)   SkFixedFastInvert(x)
     #define SkScalarSqrt(x)         SkFixedSqrt(x)
     #define SkScalarAve(a, b)       SkFixedAve(a, b)
     #define SkScalarMean(a, b)      SkFixedMean(a, b)
     #define SkScalarHalf(a)         ((a) >> 1)

     #define SK_ScalarSqrt2          SK_FixedSqrt2
     #define SK_ScalarPI             SK_FixedPI
     #define SK_ScalarTanPIOver8     SK_FixedTanPIOver8
     #define SK_ScalarRoot2Over2     SK_FixedRoot2Over2

     #define SkDegreesToRadians(degrees)     SkFractMul(degrees, SK_FractPIOver180)
     #define SkScalarSinCos(radians, cosPtr) SkFixedSinCos(radians, cosPtr)
     #define SkScalarSin(radians)    SkFixedSin(radians)
     #define SkScalarCos(radians)    SkFixedCos(radians)
     #define SkScalarTan(val)        SkFixedTan(val)
     #define SkScalarASin(val)       SkFixedASin(val)
     #define SkScalarACos(val)       SkFixedACos(val)
     #define SkScalarATan2(y, x)     SkFixedATan2(y,x)
     #define SkScalarExp(x)          SkFixedExp(x)
     #define SkScalarLog(x)          SkFixedLog(x)

     #define SkMaxScalar(a, b)       SkMax32(a, b)
     #define SkMinScalar(a, b)       SkMin32(a, b)
 #endif

 #define SK_ScalarNearlyZero         (SK_Scalar1 / (1 << 12))

 /*  <= is slower than < for floats, so we use < for our tolerance test
 */

 inline bool SkScalarNearlyZero(SkScalar x, SkScalar tolerance = SK_ScalarNearlyZero)
 {
     SkASSERT(tolerance > 0);
     return SkScalarAbs(x) < 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]
 */
 inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t)
 {
     SkASSERT(t >= 0 && t <= SK_Scalar1);
     return A + SkScalarMul(B - A, t);
 }

 #endif
	/*
	* Copyright (C) 2006 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#ifndef SkScalar_DEFINED
	#define SkScalar_DEFINED

	#include "SkFixed.h"

	/** \file SkScalar.h

	Types and macros for the data type SkScalar. This is the fractional numeric type
	that, depending on the compile-time flag SK_SCALAR_IS_FLOAT, may be implemented
	either as an IEEE float, or as a 16.16 SkFixed. The macros in this file are written
	to allow the calling code to manipulate SkScalar values without knowing which representation
	is in effect.
	*/

	#ifdef SK_SCALAR_IS_FLOAT
	#include "SkFloatingPoint.h"

	/** SkScalar is our type for fractional values and coordinates. Depending on
	compile configurations, it is either represented as an IEEE float, or
	as a 16.16 fixed point integer.
	*/
	typedef float SkScalar;
	extern const uint32_t gIEEENotANumber;
	extern const uint32_t gIEEEInfinity;

	/** SK_Scalar1 is defined to be 1.0 represented as an SkScalar
	*/
	#define SK_Scalar1 (1.0f)
	/** SK_Scalar1 is defined to be 1/2 represented as an SkScalar
	*/
	#define SK_ScalarHalf (0.5f)
	/** SK_ScalarInfinity is defined to be infinity as an SkScalar
	*/
	#define SK_ScalarInfinity ((const float)&gIEEEInfinity)
	/** SK_ScalarMax is defined to be the largest value representable as an SkScalar
	*/
	#define SK_ScalarMax (3.4028235e+38f)
	/** SK_ScalarMin is defined to be the smallest value representable as an SkScalar
	*/
	#define SK_ScalarMin (1.1754944e-38f)
	/** SK_ScalarNaN is defined to be 'Not a Number' as an SkScalar
	*/
	#define SK_ScalarNaN ((const float)(const void*)&gIEEENotANumber)
	/** SkScalarIsNaN(n) returns true if argument is not a number
	*/
	static inline bool SkScalarIsNaN(float x) { return x != x; }
	/** SkIntToScalar(n) returns its integer argument as an SkScalar
	*/
	#define SkIntToScalar(n) ((float)(n))
	/** SkFixedToScalar(n) returns its SkFixed argument as an SkScalar
	*/
	#define SkFixedToScalar(x) SkFixedToFloat(x)
	/** SkScalarToFixed(n) returns its SkScalar argument as an SkFixed
	*/
	#define SkScalarToFixed(x) SkFloatToFixed(x)

	#define SkScalarToFloat(n) (n)
	#define SkFloatToScalar(n) (n)

	#define SkScalarToDouble(n) (double)(n)
	#define SkDoubleToScalar(n) (float)(n)

	/** SkScalarFraction(x) returns the signed fractional part of the argument
	*/
	#define SkScalarFraction(x) sk_float_mod(x, 1.0f)
	/** Rounds the SkScalar to the nearest integer value
	*/
	#define SkScalarRound(x) sk_float_round2int(x)
	/** Returns the smallest integer that is >= the specified SkScalar
	*/
	#define SkScalarCeil(x) sk_float_ceil2int(x)
	/** Returns the largest integer that is <= the specified SkScalar
	*/
	#define SkScalarFloor(x) sk_float_floor2int(x)
	/** Returns the absolute value of the specified SkScalar
	*/
	#define SkScalarAbs(x) sk_float_abs(x)
	/** Returns the value pinned between 0 and max inclusive
	*/
	inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) {
	return x < 0 ? 0 : x > max ? max : x;
	}
	/** Returns the value pinned between min and max inclusive
	*/
	inline SkScalar SkScalarPin(SkScalar x, SkScalar min, SkScalar max) {
	return x < min ? min : x > max ? max : x;
	}
	/** Returns the specified SkScalar squared (x*x)
	*/
	inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
	/** Returns the product of two SkScalars
	*/
	#define SkScalarMul(a, b) ((float)(a) * (b))
	/** Returns the product of two SkScalars plus a third SkScalar
	*/
	#define SkScalarMulAdd(a, b, c) ((float)(a) * (b) + (c))
	/** Returns the product of a SkScalar and an int rounded to the nearest integer value
	*/
	#define SkScalarMulRound(a, b) SkScalarRound((float)(a) * (b))
	/** Returns the product of a SkScalar and an int promoted to the next larger int
	*/
	#define SkScalarMulCeil(a, b) SkScalarCeil((float)(a) * (b))
	/** Returns the product of a SkScalar and an int truncated to the next smaller int
	*/
	#define SkScalarMulFloor(a, b) SkScalarFloor((float)(a) * (b))
	/** Returns the quotient of two SkScalars (a/b)
	*/
	#define SkScalarDiv(a, b) ((float)(a) / (b))
	/** Returns the mod of two SkScalars (a mod b)
	*/
	#define SkScalarMod(x,y) sk_float_mod(x,y)
	/** Returns the product of the first two arguments, divided by the third argument
	*/
	#define SkScalarMulDiv(a, b, c) ((float)(a) * (b) / (c))
	/** Returns the multiplicative inverse of the SkScalar (1/x)
	*/
	#define SkScalarInvert(x) (SK_Scalar1 / (x))
	#define SkScalarFastInvert(x) (SK_Scalar1 / (x))
	/** Returns the square root of the SkScalar
	*/
	#define SkScalarSqrt(x) sk_float_sqrt(x)
	/** Returns the average of two SkScalars (a+b)/2
	*/
	#define SkScalarAve(a, b) (((a) + (b)) * 0.5f)
	/** Returns the geometric mean of two SkScalars
	*/
	#define SkScalarMean(a, b) sk_float_sqrt((float)(a) * (b))
	/** Returns one half of the specified SkScalar
	*/
	#define SkScalarHalf(a) ((a) * 0.5f)

	#define SK_ScalarSqrt2 1.41421356f
	#define SK_ScalarPI 3.14159265f
	#define SK_ScalarTanPIOver8 0.414213562f
	#define SK_ScalarRoot2Over2 0.707106781f

	#define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180))
	float SkScalarSinCos(SkScalar radians, SkScalar* cosValue);
	#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)

	inline SkScalar SkMaxScalar(SkScalar a, SkScalar b) { return a > b ? a : b; }
	inline SkScalar SkMinScalar(SkScalar a, SkScalar b) { return a < b ? a : b; }

	#else
	typedef SkFixed SkScalar;

	#define SK_Scalar1 SK_Fixed1
	#define SK_ScalarHalf SK_FixedHalf
	#define SK_ScalarInfinity SK_FixedMax
	#define SK_ScalarMax SK_FixedMax
	#define SK_ScalarMin SK_FixedMin
	#define SK_ScalarNaN SK_FixedNaN
	#define SkScalarIsNaN(x) ((x) == SK_FixedNaN)
	#define SkIntToScalar(n) SkIntToFixed(n)
	#define SkFixedToScalar(x) (x)
	#define SkScalarToFixed(x) (x)
	#ifdef SK_CAN_USE_FLOAT
	#define SkScalarToFloat(n) SkFixedToFloat(n)
	#define SkFloatToScalar(n) SkFloatToFixed(n)

	#define SkScalarToDouble(n) SkFixedToDouble(n)
	#define SkDoubleToScalar(n) SkDoubleToFixed(n)
	#endif
	#define SkScalarFraction(x) SkFixedFraction(x)
	#define SkScalarRound(x) SkFixedRound(x)
	#define SkScalarCeil(x) SkFixedCeil(x)
	#define SkScalarFloor(x) SkFixedFloor(x)
	#define SkScalarAbs(x) SkFixedAbs(x)
	#define SkScalarClampMax(x, max) SkClampMax(x, max)
	#define SkScalarPin(x, min, max) SkPin32(x, min, max)
	#define SkScalarSquare(x) SkFixedSquare(x)
	#define SkScalarMul(a, b) SkFixedMul(a, b)
	#define SkScalarMulAdd(a, b, c) SkFixedMulAdd(a, b, c)
	#define SkScalarMulRound(a, b) SkFixedMulCommon(a, b, SK_FixedHalf)
	#define SkScalarMulCeil(a, b) SkFixedMulCommon(a, b, SK_Fixed1 - 1)
	#define SkScalarMulFloor(a, b) SkFixedMulCommon(a, b, 0)
	#define SkScalarDiv(a, b) SkFixedDiv(a, b)
	#define SkScalarMod(a, b) SkFixedMod(a, b)
	#define SkScalarMulDiv(a, b, c) SkMulDiv(a, b, c)
	#define SkScalarInvert(x) SkFixedInvert(x)
	#define SkScalarFastInvert(x) SkFixedFastInvert(x)
	#define SkScalarSqrt(x) SkFixedSqrt(x)
	#define SkScalarAve(a, b) SkFixedAve(a, b)
	#define SkScalarMean(a, b) SkFixedMean(a, b)
	#define SkScalarHalf(a) ((a) >> 1)

	#define SK_ScalarSqrt2 SK_FixedSqrt2
	#define SK_ScalarPI SK_FixedPI
	#define SK_ScalarTanPIOver8 SK_FixedTanPIOver8
	#define SK_ScalarRoot2Over2 SK_FixedRoot2Over2

	#define SkDegreesToRadians(degrees) SkFractMul(degrees, SK_FractPIOver180)
	#define SkScalarSinCos(radians, cosPtr) SkFixedSinCos(radians, cosPtr)
	#define SkScalarSin(radians) SkFixedSin(radians)
	#define SkScalarCos(radians) SkFixedCos(radians)
	#define SkScalarTan(val) SkFixedTan(val)
	#define SkScalarASin(val) SkFixedASin(val)
	#define SkScalarACos(val) SkFixedACos(val)
	#define SkScalarATan2(y, x) SkFixedATan2(y,x)
	#define SkScalarExp(x) SkFixedExp(x)
	#define SkScalarLog(x) SkFixedLog(x)

	#define SkMaxScalar(a, b) SkMax32(a, b)
	#define SkMinScalar(a, b) SkMin32(a, b)
	#endif

	#define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12))

	/* <= is slower than < for floats, so we use < for our tolerance test
	*/

	inline bool SkScalarNearlyZero(SkScalar x, SkScalar tolerance = SK_ScalarNearlyZero)
	{
	SkASSERT(tolerance > 0);
	return SkScalarAbs(x) < 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]
	*/
	inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t)
	{
	SkASSERT(t >= 0 && t <= SK_Scalar1);
	return A + SkScalarMul(B - A, t);
	}

	#endif