skia2/include/core/SkFixed.h
bungeman 79738cc7bf Glyph positions maintain 32 bit integer part.
A glyph position when mapped from canvas space to device space may land
outside the bounds of the current 16 bit integer part of device space.
Device space is already limited to 32 bits for the integer part,
but for a short space in drawText and drawPosText it is currently
limited to 16 bits (SkFixed). Raise this limit by moving to 48.16.
This matches the current similar fix for measureText.

BUG=chromium:375322

Review URL: https://codereview.chromium.org/977623002
2015-03-11 14:05:29 -07:00

169 lines
5.2 KiB
C

/*
* 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 SkFixed_DEFINED
#define SkFixed_DEFINED
#include "SkTypes.h"
/** \file SkFixed.h
Types and macros for 16.16 fixed point
*/
/** 32 bit signed integer used to represent fractions values with 16 bits to the right of the decimal point
*/
typedef int32_t SkFixed;
#define SK_Fixed1 (1 << 16)
#define SK_FixedHalf (1 << 15)
#define SK_FixedMax (0x7FFFFFFF)
#define SK_FixedMin (-SK_FixedMax)
#define SK_FixedNaN ((int) 0x80000000)
#define SK_FixedPI (0x3243F)
#define SK_FixedSqrt2 (92682)
#define SK_FixedTanPIOver8 (0x6A0A)
#define SK_FixedRoot2Over2 (0xB505)
#define SkFixedToFloat(x) ((x) * 1.5258789e-5f)
#if 1
#define SkFloatToFixed(x) ((SkFixed)((x) * SK_Fixed1))
#else
// pins over/under flows to max/min int32 (slower than just a cast)
static inline SkFixed SkFloatToFixed(float x) {
int64_t n = x * SK_Fixed1;
return (SkFixed)n;
}
#endif
#ifdef SK_DEBUG
static inline SkFixed SkFloatToFixed_Check(float x) {
int64_t n64 = (int64_t)(x * SK_Fixed1);
SkFixed n32 = (SkFixed)n64;
SkASSERT(n64 == n32);
return n32;
}
#else
#define SkFloatToFixed_Check(x) SkFloatToFixed(x)
#endif
#define SkFixedToDouble(x) ((x) * 1.5258789e-5)
#define SkDoubleToFixed(x) ((SkFixed)((x) * SK_Fixed1))
/** Converts an integer to a SkFixed, asserting that the result does not overflow
a 32 bit signed integer
*/
#ifdef SK_DEBUG
inline SkFixed SkIntToFixed(int n)
{
SkASSERT(n >= -32768 && n <= 32767);
return n << 16;
}
#else
// force the cast to SkFixed to ensure that the answer is signed (like the debug version)
#define SkIntToFixed(n) (SkFixed)((n) << 16)
#endif
#define SkFixedRoundToInt(x) (((x) + SK_FixedHalf) >> 16)
#define SkFixedCeilToInt(x) (((x) + SK_Fixed1 - 1) >> 16)
#define SkFixedFloorToInt(x) ((x) >> 16)
#define SkFixedRoundToFixed(x) (((x) + SK_FixedHalf) & 0xFFFF0000)
#define SkFixedCeilToFixed(x) (((x) + SK_Fixed1 - 1) & 0xFFFF0000)
#define SkFixedFloorToFixed(x) ((x) & 0xFFFF0000)
#define SkFixedAbs(x) SkAbs32(x)
#define SkFixedAve(a, b) (((a) + (b)) >> 1)
SkFixed SkFixedMul_portable(SkFixed, SkFixed);
#define SkFixedDiv(numer, denom) SkDivBits(numer, denom, 16)
//////////////////////////////////////////////////////////////////////////////////////////////////////
// Now look for ASM overrides for our portable versions (should consider putting this in its own file)
#ifdef SkLONGLONG
inline SkFixed SkFixedMul_longlong(SkFixed a, SkFixed b)
{
return (SkFixed)((int64_t)a * b >> 16);
}
#define SkFixedMul(a,b) SkFixedMul_longlong(a,b)
#endif
#if defined(SK_CPU_ARM32)
/* This guy does not handle NaN or other obscurities, but is faster than
than (int)(x*65536). When built on Android with -Os, needs forcing
to inline or we lose the speed benefit.
*/
SK_ALWAYS_INLINE SkFixed SkFloatToFixed_arm(float x)
{
int32_t y, z;
asm("movs %1, %3, lsl #1 \n"
"mov %2, #0x8E \n"
"sub %1, %2, %1, lsr #24 \n"
"mov %2, %3, lsl #8 \n"
"orr %2, %2, #0x80000000 \n"
"mov %1, %2, lsr %1 \n"
"it cs \n"
"rsbcs %1, %1, #0 \n"
: "=r"(x), "=&r"(y), "=&r"(z)
: "r"(x)
: "cc"
);
return y;
}
inline SkFixed SkFixedMul_arm(SkFixed x, SkFixed y)
{
int32_t t;
asm("smull %0, %2, %1, %3 \n"
"mov %0, %0, lsr #16 \n"
"orr %0, %0, %2, lsl #16 \n"
: "=r"(x), "=&r"(y), "=r"(t)
: "r"(x), "1"(y)
:
);
return x;
}
#undef SkFixedMul
#define SkFixedMul(x, y) SkFixedMul_arm(x, y)
#undef SkFloatToFixed
#define SkFloatToFixed(x) SkFloatToFixed_arm(x)
#endif
#ifndef SkFixedMul
#define SkFixedMul(x, y) SkFixedMul_portable(x, y)
#endif
///////////////////////////////////////////////////////////////////////////////
typedef int64_t SkFixed3232; // 32.32
#define SkIntToFixed3232(x) ((SkFixed3232)(x) << 32)
#define SkFixed3232ToInt(x) ((int)((x) >> 32))
#define SkFixedToFixed3232(x) ((SkFixed3232)(x) << 16)
#define SkFixed3232ToFixed(x) ((SkFixed)((x) >> 16))
#define SkFloatToFixed3232(x) ((SkFixed3232)((x) * (65536.0f * 65536.0f)))
#define SkScalarToFixed3232(x) SkFloatToFixed3232(x)
///////////////////////////////////////////////////////////////////////////////
// 64bits wide, with a 16bit bias. Useful when accumulating lots of 16.16 so
// we don't overflow along the way
typedef int64_t Sk48Dot16;
#define Sk48Dot16FloorToInt(x) static_cast<int>((x) >> 16)
static inline float Sk48Dot16ToScalar(Sk48Dot16 x) {
return static_cast<float>(x * 1.5258789e-5); // x * (1.0f / (1 << 16))
}
#define SkFloatTo48Dot16(x) (static_cast<Sk48Dot16>((x) * (1 << 16)))
#define SkScalarTo48Dot16(x) SkFloatTo48Dot16(x)
#endif