| /* |
| * 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 |