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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 SkFDot6_DEFINED
- #define SkFDot6_DEFINED
- #include "include/core/SkMath.h"
- #include "include/core/SkScalar.h"
- #include "include/private/SkFixed.h"
- #include "include/private/SkTo.h"
- typedef int32_t SkFDot6;
- /* This uses the magic number approach suggested here:
- * http://stereopsis.com/sree/fpu2006.html and used in
- * _cairo_fixed_from_double. It does banker's rounding
- * (i.e. round to nearest even)
- */
- inline SkFDot6 SkScalarRoundToFDot6(SkScalar x, int shift = 0)
- {
- union {
- double fDouble;
- int32_t fBits[2];
- } tmp;
- int fractionalBits = 6 + shift;
- double magic = (1LL << (52 - (fractionalBits))) * 1.5;
- tmp.fDouble = SkScalarToDouble(x) + magic;
- #ifdef SK_CPU_BENDIAN
- return tmp.fBits[1];
- #else
- return tmp.fBits[0];
- #endif
- }
- #define SK_FDot6One (64)
- #define SK_FDot6Half (32)
- #ifdef SK_DEBUG
- inline SkFDot6 SkIntToFDot6(int x) {
- SkASSERT(SkToS16(x) == x);
- return x << 6;
- }
- #else
- #define SkIntToFDot6(x) ((x) << 6)
- #endif
- #define SkFDot6Floor(x) ((x) >> 6)
- #define SkFDot6Ceil(x) (((x) + 63) >> 6)
- #define SkFDot6Round(x) (((x) + 32) >> 6)
- #define SkFixedToFDot6(x) ((x) >> 10)
- inline SkFixed SkFDot6ToFixed(SkFDot6 x) {
- SkASSERT((SkLeftShift(x, 10) >> 10) == x);
- return SkLeftShift(x, 10);
- }
- #define SkScalarToFDot6(x) (SkFDot6)((x) * 64)
- #define SkFDot6ToScalar(x) ((SkScalar)(x) * 0.015625f)
- #define SkFDot6ToFloat SkFDot6ToScalar
- inline SkFixed SkFDot6Div(SkFDot6 a, SkFDot6 b) {
- SkASSERT(b != 0);
- if (SkTFitsIn<int16_t>(a)) {
- return SkLeftShift(a, 16) / b;
- } else {
- return SkFixedDiv(a, b);
- }
- }
- #endif
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