[base] Fortify emboldening code against egregious distortions. * src/base/ftoutln.c (FT_Outline_EmboldenXY): Threshold emboldening strength when it leads to segment collapse.
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diff --git a/ChangeLog b/ChangeLog
index f2f7957..8fa12b5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2012-11-04 Alexei Podtelezhnikov <apodtele@gmail.com>
+
+ [base] Fortify emboldening code against egregious distortions.
+
+ * src/base/ftoutln.c (FT_Outline_EmboldenXY): Threshold emboldening
+ strength when it leads to segment collapse.
+
2012-11-03 Alexei Podtelezhnikov <apodtele@gmail.com>
[base] Clean up emboldening code and improve comments there.
diff --git a/src/base/ftoutln.c b/src/base/ftoutln.c
index 798f8c9..1208752 100644
--- a/src/base/ftoutln.c
+++ b/src/base/ftoutln.c
@@ -922,7 +922,7 @@
for ( c = 0; c < outline->n_contours; c++ )
{
FT_Vector in, out, shift;
- FT_Fixed l_in, l_out, d;
+ FT_Fixed l_in, l_out, l, q, d;
int last = outline->contours[c];
@@ -962,8 +962,22 @@
else
shift.y = -shift.y;
- shift.x = FT_MulDiv( shift.x, xstrength, d );
- shift.y = FT_MulDiv( shift.y, ystrength, d );
+ /* threshold strength to better handle collapsing segments */
+ l = FT_MIN( l_in, l_out );
+ q = out.x * in.y - out.y * in.x;
+ if ( orientation == FT_ORIENTATION_TRUETYPE )
+ q = -q;
+
+ if ( xstrength * q < d * l )
+ shift.x = FT_MulDiv( shift.x, xstrength, d );
+ else
+ shift.x = FT_MulDiv( shift.x, l, q );
+
+
+ if ( ystrength * q < d * l )
+ shift.y = FT_MulDiv( shift.y, ystrength, d );
+ else
+ shift.y = FT_MulDiv( shift.y, l, q );
}
else
shift.x = shift.y = 0;