/***************************************************************************/ | |
/* */ | |
/* ftcalc.c */ | |
/* */ | |
/* Arithmetic computations (body). */ | |
/* */ | |
/* Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2008 by */ | |
/* David Turner, Robert Wilhelm, and Werner Lemberg. */ | |
/* */ | |
/* This file is part of the FreeType project, and may only be used, */ | |
/* modified, and distributed under the terms of the FreeType project */ | |
/* license, LICENSE.TXT. By continuing to use, modify, or distribute */ | |
/* this file you indicate that you have read the license and */ | |
/* understand and accept it fully. */ | |
/* */ | |
/***************************************************************************/ | |
/*************************************************************************/ | |
/* */ | |
/* Support for 1-complement arithmetic has been totally dropped in this */ | |
/* release. You can still write your own code if you need it. */ | |
/* */ | |
/*************************************************************************/ | |
/*************************************************************************/ | |
/* */ | |
/* Implementing basic computation routines. */ | |
/* */ | |
/* FT_MulDiv(), FT_MulFix(), FT_DivFix(), FT_RoundFix(), FT_CeilFix(), */ | |
/* and FT_FloorFix() are declared in freetype.h. */ | |
/* */ | |
/*************************************************************************/ | |
#include <ft2build.h> | |
#include FT_GLYPH_H | |
#include FT_INTERNAL_CALC_H | |
#include FT_INTERNAL_DEBUG_H | |
#include FT_INTERNAL_OBJECTS_H | |
#ifdef FT_MULFIX_INLINED | |
#undef FT_MulFix | |
#endif | |
/* we need to define a 64-bits data type here */ | |
#ifdef FT_LONG64 | |
typedef FT_INT64 FT_Int64; | |
#else | |
typedef struct FT_Int64_ | |
{ | |
FT_UInt32 lo; | |
FT_UInt32 hi; | |
} FT_Int64; | |
#endif /* FT_LONG64 */ | |
/*************************************************************************/ | |
/* */ | |
/* The macro FT_COMPONENT is used in trace mode. It is an implicit */ | |
/* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ | |
/* messages during execution. */ | |
/* */ | |
#undef FT_COMPONENT | |
#define FT_COMPONENT trace_calc | |
/* The following three functions are available regardless of whether */ | |
/* FT_LONG64 is defined. */ | |
/* documentation is in freetype.h */ | |
FT_EXPORT_DEF( FT_Fixed ) | |
FT_RoundFix( FT_Fixed a ) | |
{ | |
return ( a >= 0 ) ? ( a + 0x8000L ) & ~0xFFFFL | |
: -((-a + 0x8000L ) & ~0xFFFFL ); | |
} | |
/* documentation is in freetype.h */ | |
FT_EXPORT_DEF( FT_Fixed ) | |
FT_CeilFix( FT_Fixed a ) | |
{ | |
return ( a >= 0 ) ? ( a + 0xFFFFL ) & ~0xFFFFL | |
: -((-a + 0xFFFFL ) & ~0xFFFFL ); | |
} | |
/* documentation is in freetype.h */ | |
FT_EXPORT_DEF( FT_Fixed ) | |
FT_FloorFix( FT_Fixed a ) | |
{ | |
return ( a >= 0 ) ? a & ~0xFFFFL | |
: -((-a) & ~0xFFFFL ); | |
} | |
#ifdef FT_CONFIG_OPTION_OLD_INTERNALS | |
/* documentation is in ftcalc.h */ | |
FT_EXPORT_DEF( FT_Int32 ) | |
FT_Sqrt32( FT_Int32 x ) | |
{ | |
FT_ULong val, root, newroot, mask; | |
root = 0; | |
mask = 0x40000000L; | |
val = (FT_ULong)x; | |
do | |
{ | |
newroot = root + mask; | |
if ( newroot <= val ) | |
{ | |
val -= newroot; | |
root = newroot + mask; | |
} | |
root >>= 1; | |
mask >>= 2; | |
} while ( mask != 0 ); | |
return root; | |
} | |
#endif /* FT_CONFIG_OPTION_OLD_INTERNALS */ | |
#ifdef FT_LONG64 | |
/* documentation is in freetype.h */ | |
FT_EXPORT_DEF( FT_Long ) | |
FT_MulDiv( FT_Long a, | |
FT_Long b, | |
FT_Long c ) | |
{ | |
FT_Int s; | |
FT_Long d; | |
s = 1; | |
if ( a < 0 ) { a = -a; s = -1; } | |
if ( b < 0 ) { b = -b; s = -s; } | |
if ( c < 0 ) { c = -c; s = -s; } | |
d = (FT_Long)( c > 0 ? ( (FT_Int64)a * b + ( c >> 1 ) ) / c | |
: 0x7FFFFFFFL ); | |
return ( s > 0 ) ? d : -d; | |
} | |
#ifdef TT_USE_BYTECODE_INTERPRETER | |
/* documentation is in ftcalc.h */ | |
FT_BASE_DEF( FT_Long ) | |
FT_MulDiv_No_Round( FT_Long a, | |
FT_Long b, | |
FT_Long c ) | |
{ | |
FT_Int s; | |
FT_Long d; | |
s = 1; | |
if ( a < 0 ) { a = -a; s = -1; } | |
if ( b < 0 ) { b = -b; s = -s; } | |
if ( c < 0 ) { c = -c; s = -s; } | |
d = (FT_Long)( c > 0 ? (FT_Int64)a * b / c | |
: 0x7FFFFFFFL ); | |
return ( s > 0 ) ? d : -d; | |
} | |
#endif /* TT_USE_BYTECODE_INTERPRETER */ | |
/* documentation is in freetype.h */ | |
FT_EXPORT_DEF( FT_Long ) | |
FT_MulFix( FT_Long a, | |
FT_Long b ) | |
{ | |
#ifdef FT_MULFIX_ASSEMBLER | |
return FT_MULFIX_ASSEMBLER( a, b ); | |
#else | |
FT_Int s = 1; | |
FT_Long c; | |
if ( a < 0 ) | |
{ | |
a = -a; | |
s = -1; | |
} | |
if ( b < 0 ) | |
{ | |
b = -b; | |
s = -s; | |
} | |
c = (FT_Long)( ( (FT_Int64)a * b + 0x8000L ) >> 16 ); | |
return ( s > 0 ) ? c : -c; | |
#endif /* FT_MULFIX_ASSEMBLER */ | |
} | |
/* documentation is in freetype.h */ | |
FT_EXPORT_DEF( FT_Long ) | |
FT_DivFix( FT_Long a, | |
FT_Long b ) | |
{ | |
FT_Int32 s; | |
FT_UInt32 q; | |
s = 1; | |
if ( a < 0 ) { a = -a; s = -1; } | |
if ( b < 0 ) { b = -b; s = -s; } | |
if ( b == 0 ) | |
/* check for division by 0 */ | |
q = 0x7FFFFFFFL; | |
else | |
/* compute result directly */ | |
q = (FT_UInt32)( ( ( (FT_Int64)a << 16 ) + ( b >> 1 ) ) / b ); | |
return ( s < 0 ? -(FT_Long)q : (FT_Long)q ); | |
} | |
#else /* !FT_LONG64 */ | |
static void | |
ft_multo64( FT_UInt32 x, | |
FT_UInt32 y, | |
FT_Int64 *z ) | |
{ | |
FT_UInt32 lo1, hi1, lo2, hi2, lo, hi, i1, i2; | |
lo1 = x & 0x0000FFFFU; hi1 = x >> 16; | |
lo2 = y & 0x0000FFFFU; hi2 = y >> 16; | |
lo = lo1 * lo2; | |
i1 = lo1 * hi2; | |
i2 = lo2 * hi1; | |
hi = hi1 * hi2; | |
/* Check carry overflow of i1 + i2 */ | |
i1 += i2; | |
hi += (FT_UInt32)( i1 < i2 ) << 16; | |
hi += i1 >> 16; | |
i1 = i1 << 16; | |
/* Check carry overflow of i1 + lo */ | |
lo += i1; | |
hi += ( lo < i1 ); | |
z->lo = lo; | |
z->hi = hi; | |
} | |
static FT_UInt32 | |
ft_div64by32( FT_UInt32 hi, | |
FT_UInt32 lo, | |
FT_UInt32 y ) | |
{ | |
FT_UInt32 r, q; | |
FT_Int i; | |
q = 0; | |
r = hi; | |
if ( r >= y ) | |
return (FT_UInt32)0x7FFFFFFFL; | |
i = 32; | |
do | |
{ | |
r <<= 1; | |
q <<= 1; | |
r |= lo >> 31; | |
if ( r >= (FT_UInt32)y ) | |
{ | |
r -= y; | |
q |= 1; | |
} | |
lo <<= 1; | |
} while ( --i ); | |
return q; | |
} | |
static void | |
FT_Add64( FT_Int64* x, | |
FT_Int64* y, | |
FT_Int64 *z ) | |
{ | |
register FT_UInt32 lo, hi; | |
lo = x->lo + y->lo; | |
hi = x->hi + y->hi + ( lo < x->lo ); | |
z->lo = lo; | |
z->hi = hi; | |
} | |
/* documentation is in freetype.h */ | |
/* The FT_MulDiv function has been optimized thanks to ideas from */ | |
/* Graham Asher. The trick is to optimize computation when everything */ | |
/* fits within 32-bits (a rather common case). */ | |
/* */ | |
/* we compute 'a*b+c/2', then divide it by 'c'. (positive values) */ | |
/* */ | |
/* 46340 is FLOOR(SQRT(2^31-1)). */ | |
/* */ | |
/* if ( a <= 46340 && b <= 46340 ) then ( a*b <= 0x7FFEA810 ) */ | |
/* */ | |
/* 0x7FFFFFFF - 0x7FFEA810 = 0x157F0 */ | |
/* */ | |
/* if ( c < 0x157F0*2 ) then ( a*b+c/2 <= 0x7FFFFFFF ) */ | |
/* */ | |
/* and 2*0x157F0 = 176096 */ | |
/* */ | |
FT_EXPORT_DEF( FT_Long ) | |
FT_MulDiv( FT_Long a, | |
FT_Long b, | |
FT_Long c ) | |
{ | |
long s; | |
if ( a == 0 || b == c ) | |
return a; | |
s = a; a = FT_ABS( a ); | |
s ^= b; b = FT_ABS( b ); | |
s ^= c; c = FT_ABS( c ); | |
if ( a <= 46340L && b <= 46340L && c <= 176095L && c > 0 ) | |
a = ( a * b + ( c >> 1 ) ) / c; | |
else if ( c > 0 ) | |
{ | |
FT_Int64 temp, temp2; | |
ft_multo64( a, b, &temp ); | |
temp2.hi = 0; | |
temp2.lo = (FT_UInt32)(c >> 1); | |
FT_Add64( &temp, &temp2, &temp ); | |
a = ft_div64by32( temp.hi, temp.lo, c ); | |
} | |
else | |
a = 0x7FFFFFFFL; | |
return ( s < 0 ? -a : a ); | |
} | |
#ifdef TT_USE_BYTECODE_INTERPRETER | |
FT_BASE_DEF( FT_Long ) | |
FT_MulDiv_No_Round( FT_Long a, | |
FT_Long b, | |
FT_Long c ) | |
{ | |
long s; | |
if ( a == 0 || b == c ) | |
return a; | |
s = a; a = FT_ABS( a ); | |
s ^= b; b = FT_ABS( b ); | |
s ^= c; c = FT_ABS( c ); | |
if ( a <= 46340L && b <= 46340L && c > 0 ) | |
a = a * b / c; | |
else if ( c > 0 ) | |
{ | |
FT_Int64 temp; | |
ft_multo64( a, b, &temp ); | |
a = ft_div64by32( temp.hi, temp.lo, c ); | |
} | |
else | |
a = 0x7FFFFFFFL; | |
return ( s < 0 ? -a : a ); | |
} | |
#endif /* TT_USE_BYTECODE_INTERPRETER */ | |
/* documentation is in freetype.h */ | |
FT_EXPORT_DEF( FT_Long ) | |
FT_MulFix( FT_Long a, | |
FT_Long b ) | |
{ | |
#ifdef FT_MULFIX_ASSEMBLER | |
return FT_MULFIX_ASSEMBLER( a, b ); | |
#elif 0 | |
/* | |
* This code is nonportable. See comment below. | |
* | |
* However, on a platform where right-shift of a signed quantity fills | |
* the leftmost bits by copying the sign bit, it might be faster. | |
*/ | |
FT_Long sa, sb; | |
FT_ULong ua, ub; | |
if ( a == 0 || b == 0x10000L ) | |
return a; | |
/* | |
* This is a clever way of converting a signed number `a' into its | |
* absolute value (stored back into `a') and its sign. The sign is | |
* stored in `sa'; 0 means `a' was positive or zero, and -1 means `a' | |
* was negative. (Similarly for `b' and `sb'). | |
* | |
* Unfortunately, it doesn't work (at least not portably). | |
* | |
* It makes the assumption that right-shift on a negative signed value | |
* fills the leftmost bits by copying the sign bit. This is wrong. | |
* According to K&R 2nd ed, section `A7.8 Shift Operators' on page 206, | |
* the result of right-shift of a negative signed value is | |
* implementation-defined. At least one implementation fills the | |
* leftmost bits with 0s (i.e., it is exactly the same as an unsigned | |
* right shift). This means that when `a' is negative, `sa' ends up | |
* with the value 1 rather than -1. After that, everything else goes | |
* wrong. | |
*/ | |
sa = ( a >> ( sizeof ( a ) * 8 - 1 ) ); | |
a = ( a ^ sa ) - sa; | |
sb = ( b >> ( sizeof ( b ) * 8 - 1 ) ); | |
b = ( b ^ sb ) - sb; | |
ua = (FT_ULong)a; | |
ub = (FT_ULong)b; | |
if ( ua <= 2048 && ub <= 1048576L ) | |
ua = ( ua * ub + 0x8000U ) >> 16; | |
else | |
{ | |
FT_ULong al = ua & 0xFFFFU; | |
ua = ( ua >> 16 ) * ub + al * ( ub >> 16 ) + | |
( ( al * ( ub & 0xFFFFU ) + 0x8000U ) >> 16 ); | |
} | |
sa ^= sb, | |
ua = (FT_ULong)(( ua ^ sa ) - sa); | |
return (FT_Long)ua; | |
#else /* 0 */ | |
FT_Long s; | |
FT_ULong ua, ub; | |
if ( a == 0 || b == 0x10000L ) | |
return a; | |
s = a; a = FT_ABS( a ); | |
s ^= b; b = FT_ABS( b ); | |
ua = (FT_ULong)a; | |
ub = (FT_ULong)b; | |
if ( ua <= 2048 && ub <= 1048576L ) | |
ua = ( ua * ub + 0x8000UL ) >> 16; | |
else | |
{ | |
FT_ULong al = ua & 0xFFFFUL; | |
ua = ( ua >> 16 ) * ub + al * ( ub >> 16 ) + | |
( ( al * ( ub & 0xFFFFUL ) + 0x8000UL ) >> 16 ); | |
} | |
return ( s < 0 ? -(FT_Long)ua : (FT_Long)ua ); | |
#endif /* 0 */ | |
} | |
/* documentation is in freetype.h */ | |
FT_EXPORT_DEF( FT_Long ) | |
FT_DivFix( FT_Long a, | |
FT_Long b ) | |
{ | |
FT_Int32 s; | |
FT_UInt32 q; | |
s = a; a = FT_ABS( a ); | |
s ^= b; b = FT_ABS( b ); | |
if ( b == 0 ) | |
{ | |
/* check for division by 0 */ | |
q = 0x7FFFFFFFL; | |
} | |
else if ( ( a >> 16 ) == 0 ) | |
{ | |
/* compute result directly */ | |
q = (FT_UInt32)( (a << 16) + (b >> 1) ) / (FT_UInt32)b; | |
} | |
else | |
{ | |
/* we need more bits; we have to do it by hand */ | |
FT_Int64 temp, temp2; | |
temp.hi = (FT_Int32) (a >> 16); | |
temp.lo = (FT_UInt32)(a << 16); | |
temp2.hi = 0; | |
temp2.lo = (FT_UInt32)( b >> 1 ); | |
FT_Add64( &temp, &temp2, &temp ); | |
q = ft_div64by32( temp.hi, temp.lo, b ); | |
} | |
return ( s < 0 ? -(FT_Int32)q : (FT_Int32)q ); | |
} | |
#if 0 | |
/* documentation is in ftcalc.h */ | |
FT_EXPORT_DEF( void ) | |
FT_MulTo64( FT_Int32 x, | |
FT_Int32 y, | |
FT_Int64 *z ) | |
{ | |
FT_Int32 s; | |
s = x; x = FT_ABS( x ); | |
s ^= y; y = FT_ABS( y ); | |
ft_multo64( x, y, z ); | |
if ( s < 0 ) | |
{ | |
z->lo = (FT_UInt32)-(FT_Int32)z->lo; | |
z->hi = ~z->hi + !( z->lo ); | |
} | |
} | |
/* apparently, the second version of this code is not compiled correctly */ | |
/* on Mac machines with the MPW C compiler.. tsk, tsk, tsk... */ | |
#if 1 | |
FT_EXPORT_DEF( FT_Int32 ) | |
FT_Div64by32( FT_Int64* x, | |
FT_Int32 y ) | |
{ | |
FT_Int32 s; | |
FT_UInt32 q, r, i, lo; | |
s = x->hi; | |
if ( s < 0 ) | |
{ | |
x->lo = (FT_UInt32)-(FT_Int32)x->lo; | |
x->hi = ~x->hi + !x->lo; | |
} | |
s ^= y; y = FT_ABS( y ); | |
/* Shortcut */ | |
if ( x->hi == 0 ) | |
{ | |
if ( y > 0 ) | |
q = x->lo / y; | |
else | |
q = 0x7FFFFFFFL; | |
return ( s < 0 ? -(FT_Int32)q : (FT_Int32)q ); | |
} | |
r = x->hi; | |
lo = x->lo; | |
if ( r >= (FT_UInt32)y ) /* we know y is to be treated as unsigned here */ | |
return ( s < 0 ? 0x80000001UL : 0x7FFFFFFFUL ); | |
/* Return Max/Min Int32 if division overflow. */ | |
/* This includes division by zero! */ | |
q = 0; | |
for ( i = 0; i < 32; i++ ) | |
{ | |
r <<= 1; | |
q <<= 1; | |
r |= lo >> 31; | |
if ( r >= (FT_UInt32)y ) | |
{ | |
r -= y; | |
q |= 1; | |
} | |
lo <<= 1; | |
} | |
return ( s < 0 ? -(FT_Int32)q : (FT_Int32)q ); | |
} | |
#else /* 0 */ | |
FT_EXPORT_DEF( FT_Int32 ) | |
FT_Div64by32( FT_Int64* x, | |
FT_Int32 y ) | |
{ | |
FT_Int32 s; | |
FT_UInt32 q; | |
s = x->hi; | |
if ( s < 0 ) | |
{ | |
x->lo = (FT_UInt32)-(FT_Int32)x->lo; | |
x->hi = ~x->hi + !x->lo; | |
} | |
s ^= y; y = FT_ABS( y ); | |
/* Shortcut */ | |
if ( x->hi == 0 ) | |
{ | |
if ( y > 0 ) | |
q = ( x->lo + ( y >> 1 ) ) / y; | |
else | |
q = 0x7FFFFFFFL; | |
return ( s < 0 ? -(FT_Int32)q : (FT_Int32)q ); | |
} | |
q = ft_div64by32( x->hi, x->lo, y ); | |
return ( s < 0 ? -(FT_Int32)q : (FT_Int32)q ); | |
} | |
#endif /* 0 */ | |
#endif /* 0 */ | |
#endif /* FT_LONG64 */ | |
/* documentation is in ftglyph.h */ | |
FT_EXPORT_DEF( void ) | |
FT_Matrix_Multiply( const FT_Matrix* a, | |
FT_Matrix *b ) | |
{ | |
FT_Fixed xx, xy, yx, yy; | |
if ( !a || !b ) | |
return; | |
xx = FT_MulFix( a->xx, b->xx ) + FT_MulFix( a->xy, b->yx ); | |
xy = FT_MulFix( a->xx, b->xy ) + FT_MulFix( a->xy, b->yy ); | |
yx = FT_MulFix( a->yx, b->xx ) + FT_MulFix( a->yy, b->yx ); | |
yy = FT_MulFix( a->yx, b->xy ) + FT_MulFix( a->yy, b->yy ); | |
b->xx = xx; b->xy = xy; | |
b->yx = yx; b->yy = yy; | |
} | |
/* documentation is in ftglyph.h */ | |
FT_EXPORT_DEF( FT_Error ) | |
FT_Matrix_Invert( FT_Matrix* matrix ) | |
{ | |
FT_Pos delta, xx, yy; | |
if ( !matrix ) | |
return FT_Err_Invalid_Argument; | |
/* compute discriminant */ | |
delta = FT_MulFix( matrix->xx, matrix->yy ) - | |
FT_MulFix( matrix->xy, matrix->yx ); | |
if ( !delta ) | |
return FT_Err_Invalid_Argument; /* matrix can't be inverted */ | |
matrix->xy = - FT_DivFix( matrix->xy, delta ); | |
matrix->yx = - FT_DivFix( matrix->yx, delta ); | |
xx = matrix->xx; | |
yy = matrix->yy; | |
matrix->xx = FT_DivFix( yy, delta ); | |
matrix->yy = FT_DivFix( xx, delta ); | |
return FT_Err_Ok; | |
} | |
/* documentation is in ftcalc.h */ | |
FT_BASE_DEF( void ) | |
FT_Matrix_Multiply_Scaled( const FT_Matrix* a, | |
FT_Matrix *b, | |
FT_Long scaling ) | |
{ | |
FT_Fixed xx, xy, yx, yy; | |
FT_Long val = 0x10000L * scaling; | |
if ( !a || !b ) | |
return; | |
xx = FT_MulDiv( a->xx, b->xx, val ) + FT_MulDiv( a->xy, b->yx, val ); | |
xy = FT_MulDiv( a->xx, b->xy, val ) + FT_MulDiv( a->xy, b->yy, val ); | |
yx = FT_MulDiv( a->yx, b->xx, val ) + FT_MulDiv( a->yy, b->yx, val ); | |
yy = FT_MulDiv( a->yx, b->xy, val ) + FT_MulDiv( a->yy, b->yy, val ); | |
b->xx = xx; b->xy = xy; | |
b->yx = yx; b->yy = yy; | |
} | |
/* documentation is in ftcalc.h */ | |
FT_BASE_DEF( void ) | |
FT_Vector_Transform_Scaled( FT_Vector* vector, | |
const FT_Matrix* matrix, | |
FT_Long scaling ) | |
{ | |
FT_Pos xz, yz; | |
FT_Long val = 0x10000L * scaling; | |
if ( !vector || !matrix ) | |
return; | |
xz = FT_MulDiv( vector->x, matrix->xx, val ) + | |
FT_MulDiv( vector->y, matrix->xy, val ); | |
yz = FT_MulDiv( vector->x, matrix->yx, val ) + | |
FT_MulDiv( vector->y, matrix->yy, val ); | |
vector->x = xz; | |
vector->y = yz; | |
} | |
/* documentation is in ftcalc.h */ | |
FT_BASE_DEF( FT_Int32 ) | |
FT_SqrtFixed( FT_Int32 x ) | |
{ | |
FT_UInt32 root, rem_hi, rem_lo, test_div; | |
FT_Int count; | |
root = 0; | |
if ( x > 0 ) | |
{ | |
rem_hi = 0; | |
rem_lo = x; | |
count = 24; | |
do | |
{ | |
rem_hi = ( rem_hi << 2 ) | ( rem_lo >> 30 ); | |
rem_lo <<= 2; | |
root <<= 1; | |
test_div = ( root << 1 ) + 1; | |
if ( rem_hi >= test_div ) | |
{ | |
rem_hi -= test_div; | |
root += 1; | |
} | |
} while ( --count ); | |
} | |
return (FT_Int32)root; | |
} | |
/* documentation is in ftcalc.h */ | |
FT_BASE_DEF( FT_Int ) | |
ft_corner_orientation( FT_Pos in_x, | |
FT_Pos in_y, | |
FT_Pos out_x, | |
FT_Pos out_y ) | |
{ | |
FT_Int result; | |
/* deal with the trivial cases quickly */ | |
if ( in_y == 0 ) | |
{ | |
if ( in_x >= 0 ) | |
result = out_y; | |
else | |
result = -out_y; | |
} | |
else if ( in_x == 0 ) | |
{ | |
if ( in_y >= 0 ) | |
result = -out_x; | |
else | |
result = out_x; | |
} | |
else if ( out_y == 0 ) | |
{ | |
if ( out_x >= 0 ) | |
result = in_y; | |
else | |
result = -in_y; | |
} | |
else if ( out_x == 0 ) | |
{ | |
if ( out_y >= 0 ) | |
result = -in_x; | |
else | |
result = in_x; | |
} | |
else /* general case */ | |
{ | |
#ifdef FT_LONG64 | |
FT_Int64 delta = (FT_Int64)in_x * out_y - (FT_Int64)in_y * out_x; | |
if ( delta == 0 ) | |
result = 0; | |
else | |
result = 1 - 2 * ( delta < 0 ); | |
#else | |
FT_Int64 z1, z2; | |
ft_multo64( in_x, out_y, &z1 ); | |
ft_multo64( in_y, out_x, &z2 ); | |
if ( z1.hi > z2.hi ) | |
result = +1; | |
else if ( z1.hi < z2.hi ) | |
result = -1; | |
else if ( z1.lo > z2.lo ) | |
result = +1; | |
else if ( z1.lo < z2.lo ) | |
result = -1; | |
else | |
result = 0; | |
#endif | |
} | |
return result; | |
} | |
/* documentation is in ftcalc.h */ | |
FT_BASE_DEF( FT_Int ) | |
ft_corner_is_flat( FT_Pos in_x, | |
FT_Pos in_y, | |
FT_Pos out_x, | |
FT_Pos out_y ) | |
{ | |
FT_Pos ax = in_x; | |
FT_Pos ay = in_y; | |
FT_Pos d_in, d_out, d_corner; | |
if ( ax < 0 ) | |
ax = -ax; | |
if ( ay < 0 ) | |
ay = -ay; | |
d_in = ax + ay; | |
ax = out_x; | |
if ( ax < 0 ) | |
ax = -ax; | |
ay = out_y; | |
if ( ay < 0 ) | |
ay = -ay; | |
d_out = ax + ay; | |
ax = out_x + in_x; | |
if ( ax < 0 ) | |
ax = -ax; | |
ay = out_y + in_y; | |
if ( ay < 0 ) | |
ay = -ay; | |
d_corner = ax + ay; | |
return ( d_in + d_out - d_corner ) < ( d_corner >> 4 ); | |
} | |
/* END */ |