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Code Issues 9 Releases Wiki Activity

* src/base/ftcalc.c (FT_Vector_NormLen): Explicate type conversions.

This commit is contained in:
Alexei Podtelezhnikov 2015-07-27 23:22:34 -04:00
parent c1c0720cc3
commit e8b186eedb
2 changed files with 26 additions and 13 deletions
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4
ChangeLog
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@ -1,3 +1,7 @@
2015-07-27 Alexei Podtelezhnikov <apodtele@gmail.com>
* src/base/ftcalc.c (FT_Vector_NormLen): Explicate type conversions.
2015-07-26 Matthias Clasen <matthias.clasen@gmail.com>
[cff] Don't use `hmtx' table for LSB (#45520).

35
src/base/ftcalc.c
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@ -790,15 +790,18 @@
FT_BASE_DEF( FT_UInt32 )
FT_Vector_NormLen( FT_Vector* vector )
{
FT_Int32 x = vector->x;
FT_Int32 y = vector->y;
FT_Int32 x_ = vector->x;
FT_Int32 y_ = vector->y;
FT_Int32 b, z;
FT_UInt32 u, v, l;
FT_UInt32 x, y, u, v, l;
FT_Int sx = 1, sy = 1, shift;
FT_MOVE_SIGN( x, sx );
FT_MOVE_SIGN( y, sy );
FT_MOVE_SIGN( x_, sx );
FT_MOVE_SIGN( y_, sy );
x = (FT_UInt32)x_;
y = (FT_UInt32)y_;
/* trivial cases */
if ( x == 0 )
@ -814,12 +817,15 @@
return x;
}
/* estimate length and prenormalize */
l = x > y ? (FT_UInt32)x + ( y >> 1 )
: (FT_UInt32)y + ( x >> 1 );
/* estimate length and prenormalize by shifting so that */
/* the new approximate length is between 2/3 and 4/3. */
/* The magic contsnt 0xAAAAAAAAUL (2/3 of 2^32) helps */
/* to achive this in 16.16 fixed-point representation. */
l = x > y ? x + ( y >> 1 )
: y + ( x >> 1 );
shift = 31 - FT_MSB( l );
shift -= 15 + ( l >= 0xAAAAAAAAUL >> shift );
shift -= 15 + ( l >= ( 0xAAAAAAAAUL >> shift ) );
if ( shift > 0 )
{
@ -827,8 +833,8 @@
y <<= shift;
/* reestimate length for tiny vectors */
l = x > y ? (FT_UInt32)x + ( y >> 1 )
: (FT_UInt32)y + ( x >> 1 );
l = x > y ? x + ( y >> 1 )
: y + ( x >> 1 );
}
else
{
@ -840,11 +846,14 @@
/* lower linear approximation for reciprocal length minus one */
b = 0x10000 - (FT_Int32)l;
x_ = (FT_Int32)x;
y_ = (FT_Int32)y;
/* Newton's iterations */
do
{
u = (FT_UInt32)( x + ( x * b >> 16 ) );
v = (FT_UInt32)( y + ( y * b >> 16 ) );
u = (FT_UInt32)( x_ + ( x_ * b >> 16 ) );
v = (FT_UInt32)( y_ + ( y_ * b >> 16 ) );
/* converting to signed gives difference with 2^32 */
z = -(FT_Int32)( u * u + v * v ) / 0x200;