0,0 → 1,974 |
/***************************************************************************/ |
/* */ |
/* ftcalc.c */ |
/* */ |
/* Arithmetic computations (body). */ |
/* */ |
/* Copyright 1996-2006, 2008, 2012-2013 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_TRIGONOMETRY_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 emulate a 64-bit data type if a real one isn't available */ |
|
#ifndef FT_LONG64 |
|
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 ); |
} |
|
|
FT_BASE_DEF ( FT_Int ) |
FT_MSB( FT_UInt32 z ) |
{ |
FT_Int shift = 0; |
|
/* determine msb bit index in `shift' */ |
if ( z >= ( 1L << 16 ) ) |
{ |
z >>= 16; |
shift += 16; |
} |
if ( z >= ( 1L << 8 ) ) |
{ |
z >>= 8; |
shift += 8; |
} |
if ( z >= ( 1L << 4 ) ) |
{ |
z >>= 4; |
shift += 4; |
} |
if ( z >= ( 1L << 2 ) ) |
{ |
z >>= 2; |
shift += 2; |
} |
if ( z >= ( 1L << 1 ) ) |
{ |
z >>= 1; |
shift += 1; |
} |
|
return shift; |
} |
|
|
/* documentation is in ftcalc.h */ |
|
FT_BASE_DEF( FT_Fixed ) |
FT_Hypot( FT_Fixed x, |
FT_Fixed y ) |
{ |
FT_Vector v; |
|
|
v.x = x; |
v.y = y; |
|
return FT_Vector_Length( &v ); |
} |
|
|
#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; |
} |
|
|
/* 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; |
} |
|
|
/* 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_UInt64)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 >= 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; |
} |
|
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/* 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; |
|
|
/* XXX: this function does not allow 64-bit arguments */ |
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 ( (FT_Int32)c > 0 ) |
{ |
FT_Int64 temp, temp2; |
|
|
ft_multo64( (FT_Int32)a, (FT_Int32)b, &temp ); |
|
temp2.hi = 0; |
temp2.lo = (FT_UInt32)(c >> 1); |
FT_Add64( &temp, &temp2, &temp ); |
a = ft_div64by32( temp.hi, temp.lo, (FT_Int32)c ); |
} |
else |
a = 0x7FFFFFFFL; |
|
return ( s < 0 ? -a : a ); |
} |
|
|
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 ( (FT_Int32)c > 0 ) |
{ |
FT_Int64 temp; |
|
|
ft_multo64( (FT_Int32)a, (FT_Int32)b, &temp ); |
a = ft_div64by32( temp.hi, temp.lo, (FT_Int32)c ); |
} |
else |
a = 0x7FFFFFFFL; |
|
return ( s < 0 ? -a : a ); |
} |
|
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/* 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; |
|
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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 */ |
|
} |
|
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/* documentation is in freetype.h */ |
|
FT_EXPORT_DEF( FT_Long ) |
FT_DivFix( FT_Long a, |
FT_Long b ) |
{ |
FT_Int32 s; |
FT_UInt32 q; |
|
|
/* XXX: this function does not allow 64-bit arguments */ |
s = (FT_Int32)a; a = FT_ABS( a ); |
s ^= (FT_Int32)b; b = FT_ABS( b ); |
|
if ( (FT_UInt32)b == 0 ) |
{ |
/* check for division by 0 */ |
q = (FT_UInt32)0x7FFFFFFFL; |
} |
else if ( ( a >> 16 ) == 0 ) |
{ |
/* compute result directly */ |
q = (FT_UInt32)( ( (FT_ULong)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, (FT_Int32)b ); |
} |
|
return ( s < 0 ? -(FT_Int32)q : (FT_Int32)q ); |
} |
|
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#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_THROW( Invalid_Argument ); |
|
/* compute discriminant */ |
delta = FT_MulFix( matrix->xx, matrix->yy ) - |
FT_MulFix( matrix->xy, matrix->yx ); |
|
if ( !delta ) |
return FT_THROW( 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_Long result; /* avoid overflow on 16-bit system */ |
|
|
/* 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; |
|
|
/* XXX: this function does not allow 64-bit arguments */ |
ft_multo64( (FT_Int32)in_x, (FT_Int32)out_y, &z1 ); |
ft_multo64( (FT_Int32)in_y, (FT_Int32)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 |
} |
|
/* XXX: only the sign of return value, +1/0/-1 must be used */ |
return (FT_Int)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 */ |