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[base] Fix integer overflow. 

* src/base/ftoutln.c (FT_Outline_EmboldenXY): Normalize incoming and
outgoing vectors and use fixed point arithmetic.
This commit is contained in:
Alexei Podtelezhnikov 2013-01-23 20:11:40 -05:00
parent e1a2ac1900
commit da11e5e764
2 changed files with 24 additions and 10 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2013-01-23 Alexei Podtelezhnikov <apodtele@gmail.com>
[base] Fix integer overflow.
* src/base/ftoutln.c (FT_Outline_EmboldenXY): Normalize incoming and
outgoing vectors and use fixed point arithmetic.
2013-01-23 Alexei Podtelezhnikov <apodtele@gmail.com>
[base] Fix integer overflow.

27
src/base/ftoutln.c
View File

@ -937,10 +937,12 @@
v_prev = points[last];
v_cur = v_first;
/* compute the incoming vector and its length */
/* compute the incoming normalized vector */
in.x = v_cur.x - v_prev.x;
in.y = v_cur.y - v_prev.y;
l_in = FT_Vector_Length( &in );
in.x = FT_DivFix( in.x, l_in );
in.y = FT_DivFix( in.y, l_in );
for ( n = first; n <= last; n++ )
{
@ -949,20 +951,24 @@
else
v_next = v_first;
/* compute the outgoing vector and its length */
/* compute the outgoing normalized vector */
out.x = v_next.x - v_cur.x;
out.y = v_next.y - v_cur.y;
l_out = FT_Vector_Length( &out );
out.x = FT_DivFix( out.x, l_out );
out.y = FT_DivFix( out.y, l_out );
d = l_in * l_out + in.x * out.x + in.y * out.y;
d = FT_MulFix( in.x, out.x ) + FT_MulFix( in.y, out.y );
/* shift only if turn is less then ~160 degrees */
if ( 16 * d > l_in * l_out )
if ( d > -0xF000L )
{
d = d + 0x10000L;
/* shift components are aligned along bisector */
/* and directed according to the outline orientation. */
shift.x = l_out * in.y + l_in * out.y;
shift.y = l_out * in.x + l_in * out.x;
shift.x = in.y + out.y;
shift.y = in.x + out.x;
if ( orientation == FT_ORIENTATION_TRUETYPE )
shift.x = -shift.x;
@ -970,18 +976,19 @@
shift.y = -shift.y;
/* threshold strength to better handle collapsing segments */
l = FT_MIN( l_in, l_out );
q = out.x * in.y - out.y * in.x;
q = FT_MulFix( out.x, in.y ) - FT_MulFix( out.y, in.x );
if ( orientation == FT_ORIENTATION_TRUETYPE )
q = -q;
if ( FT_MulDiv( xstrength, q, l ) < d )
l = FT_MIN( l_in, l_out );
if ( FT_MulFix( xstrength, q ) =< FT_MulFix( d, l ) )
shift.x = FT_MulDiv( shift.x, xstrength, d );
else
shift.x = FT_MulDiv( shift.x, l, q );
if ( FT_MulDiv( ystrength, q, l ) < d )
if ( FT_MulFix( ystrength, q ) =< FT_MulFix( d, l ) )
shift.y = FT_MulDiv( shift.y, ystrength, d );
else
shift.y = FT_MulDiv( shift.y, l, q );