skia2/tests/SkFixed15Test.cpp

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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "Test.h"
#include "SkFixed15.h"
DEF_TEST(SkFixed15, r) {
// For all v, v*0 == 0, v*1 == v.
for (uint16_t bits = 0; bits <= 32768; bits++) {
auto v = SkFixed15::Load(bits);
REPORTER_ASSERT(r, v * 0.0f == 0.0f);
REPORTER_ASSERT(r, v * 1.0f == v);
}
// Division and multiplication by powers of 2 is exact.
SkFixed15 v = 1.0f;
REPORTER_ASSERT(r, (v>>1) == 0.50f);
REPORTER_ASSERT(r, (v>>2) == 0.25f);
REPORTER_ASSERT(r, (v>>2<<1) == 0.50f);
// FromU8() should be just as good as going through float.
for (int x = 0; x < 256; x++) {
REPORTER_ASSERT(r, SkFixed15::FromU8(x) == SkFixed15(x * (1/255.0f)));
}
// to_u8() and FromU8() should roundtrip all bytes.
for (int x = 0; x < 256; x++) {
REPORTER_ASSERT(r, x == SkFixed15::FromU8(x).to_u8());
}
}