Add SkScalarTruncToScalar and speed up SkScalarFraction.

include/core/SkScalar.h

 /*
  * 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
 
@@ skipping 20 matching lines @@
 #define SK_ScalarInfinity           SK_FloatInfinity
 #define SK_ScalarNegativeInfinity   SK_FloatNegativeInfinity
 #define SK_ScalarNaN                SK_FloatNaN
 
 #define SkFixedToScalar(x)          SkFixedToFloat(x)
 #define SkScalarToFixed(x)          SkFloatToFixed(x)
 
 #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 SkScalarFraction(x)         sk_float_mod(x, 1.0f)
 #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)
@@ skipping 14 matching lines @@
 #define SK_ScalarInfinity           SK_DoubleInfinity
 #define SK_ScalarNegativeInfinity   SK_DoubleNegativeInfinity
 #define SK_ScalarNaN                SK_DoubleNaN
 
 #define SkFixedToScalar(x)          SkFixedToDouble(x)
 #define SkScalarToFixed(x)          SkDoubleToFixed(x)
 
 #define SkScalarFloorToScalar(x)    floor(x)
 #define SkScalarCeilToScalar(x)     ceil(x)
 #define SkScalarRoundToScalar(x)    floor((x) + 0.5)
+#define SkScalarTruncToScalar(x)    trunc(x)
 
 #define SkScalarFloorToInt(x)       (int)floor(x)
 #define SkScalarCeilToInt(x)        (int)ceil(x)
 #define SkScalarRoundToInt(x)       (int)floor((x) + 0.5)
 
 #define SkScalarAbs(x)              abs(x)
 #define SkScalarCopySign(x, y)      copysign(x, y)
 #define SkScalarMod(x, y)           fmod(x,y)
-#define SkScalarFraction(x)         fmod(x, 1.0)
 #define SkScalarSqrt(x)             sqrt(x)
 #define SkScalarPow(b, e)           pow(b, e)
 
 #define SkScalarSin(radians)        sin(radians)
 #define SkScalarCos(radians)        cos(radians)
 #define SkScalarTan(radians)        tan(radians)
 #define SkScalarASin(val)           asin(val)
 #define SkScalarACos(val)           acos(val)
 #define SkScalarATan2(y, x)         atan2(y,x)
 #define SkScalarExp(x)              exp(x)
@@ skipping 58 matching lines @@
  *      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);
 }
 
@@ skipping 79 matching lines @@
     SkASSERT(n >= 0);
     for (int i = 0; i < n; ++i) {
         if (a[i] != b[i]) {
             return false;
         }
     }
     return true;
 }
 
 #endif