Require Sk4f::toBytes() clamps

src/core/SkNx.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkNx_DEFINED
 #define SkNx_DEFINED
 
@@ skipping 90 matching lines @@
 
     SkNf(T a, T b)                               : fLo(a),       fHi(b)       { REQUIRE(N==2); }
     SkNf(T a, T b, T c, T d)                     : fLo(a,b),     fHi(c,d)     { REQUIRE(N==4); }
     SkNf(T a, T b, T c, T d, T e, T f, T g, T h) : fLo(a,b,c,d), fHi(e,f,g,h) { REQUIRE(N==8); }
 
     void store(T vals[N]) const {
         fLo.store(vals);
         fHi.store(vals+N/2);
     }
     // Please see note on FromBytes().
-    // Truncates [0.0,256.0) floats to [0,255] bytes.  Other inputs are unspecified.
+    // Clamps to [0.0,255.0] floats and truncates to [0,255] bytes.
     void toBytes(uint8_t bytes[N]) const {
         fLo.toBytes(bytes);
         fHi.toBytes(bytes+N/2);
     }
 
     SkNi<N,I> castTrunc() const { return SkNi<N,I>(fLo.castTrunc(), fHi.castTrunc()); }
 
     SkNf operator + (const SkNf& o) const { return SkNf(fLo + o.fLo, fHi + o.fHi); }
     SkNf operator - (const SkNf& o) const { return SkNf(fLo - o.fLo, fHi - o.fHi); }
     SkNf operator * (const SkNf& o) const { return SkNf(fLo * o.fLo, fHi * o.fHi); }
@@ skipping 87 matching lines @@
     static int32_t MyNi(float);
     static int64_t MyNi(double);
     typedef decltype(MyNi(T())) I;
 public:
     SkNf() {}
     explicit SkNf(T val) : fVal(val) {}
     static SkNf Load(const T vals[1]) { return SkNf(vals[0]); }
     static SkNf FromBytes(const uint8_t bytes[1]) { return SkNf((T)bytes[0]); }
 
     void store(T vals[1]) const { vals[0] = fVal; }
-    void toBytes(uint8_t bytes[1]) const { bytes[0] = (uint8_t)(fVal); }
+    void toBytes(uint8_t bytes[1]) const { bytes[0] = (uint8_t)(SkTMin(fVal, (T)255.0)); }
 
     SkNi<1,I> castTrunc() const { return SkNi<1,I>(fVal); }
 
     SkNf operator + (const SkNf& o) const { return SkNf(fVal + o.fVal); }
     SkNf operator - (const SkNf& o) const { return SkNf(fVal - o.fVal); }
     SkNf operator * (const SkNf& o) const { return SkNf(fVal * o.fVal); }
     SkNf operator / (const SkNf& o) const { return SkNf(fVal / o.fVal); }
 
     SkNf operator == (const SkNf& o) const { return SkNf(fVal == o.fVal); }
     SkNf operator != (const SkNf& o) const { return SkNf(fVal != o.fVal); }
@@ skipping 60 matching lines @@
 typedef SkNi<4,  uint16_t> Sk4h;
 typedef SkNi<8,  uint16_t> Sk8h;
 typedef SkNi<16, uint16_t> Sk16h;
 
 typedef SkNi<16, uint8_t> Sk16b;
 
 typedef SkNi<4,  int32_t> Sk4i;
 typedef SkNi<4, uint32_t> Sk4u;
 
 #endif//SkNx_DEFINED