Commit dccd536a7ad9da29374775aaf3fbb3836118a479
2008-05-08T17:06:24
* During contour creation, compute whether the contour is clockwise or anti-clockwise. This will be needed later to correct fonts that do not abide to the even-odd and non-zero winding number conventions, thus breaking our nice outset glyphs.
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diff --git a/src/FTContour.cpp b/src/FTContour.cpp
index 177986c..3f6653f 100644
--- a/src/FTContour.cpp
+++ b/src/FTContour.cpp
@@ -119,6 +119,7 @@ FTPoint FTContour::ComputeOutsetPoint(FTPoint A, FTPoint B, FTPoint C)
tmp.X() * -ba.Y() + tmp.Y() * -ba.X());
}
+
void FTContour::outsetContour()
{
size_t size = PointCount();
@@ -137,11 +138,26 @@ void FTContour::outsetContour()
FTContour::FTContour(FT_Vector* contour, char* tags, unsigned int n)
{
+ FTPoint prev, cur(contour[(n - 1) % n]), next(contour[0]);
+ FTPoint a, b = next - cur;
+ double olddir, dir = atan2((next - cur).Y(), (next - cur).X());
+ double angle = 0.0;
+
// See http://freetype.sourceforge.net/freetype2/docs/glyphs/glyphs-6.html
// for a full description of FreeType tags.
for(unsigned int i = 0; i < n; i++)
{
- FTPoint cur(contour[i]);
+ prev = cur;
+ cur = next;
+ next = FTPoint(contour[(i + 1) % n]);
+ olddir = dir;
+ dir = atan2((next - cur).Y(), (next - cur).Y());
+
+ // Compute our path's new direction.
+ double t = dir - olddir;
+ if(t < -M_PI) t += 2 * M_PI;
+ if(t > M_PI) t -= 2 * M_PI;
+ angle += t;
// Only process point tags we know.
if(n < 2 || FT_CURVE_TAG(tags[i]) == FT_Curve_Tag_On)
@@ -150,36 +166,38 @@ FTContour::FTContour(FT_Vector* contour, char* tags, unsigned int n)
}
else if(FT_CURVE_TAG(tags[i]) == FT_Curve_Tag_Conic)
{
+ FTPoint prev2 = prev, next2 = next;
+
// Previous point is either the real previous point (an "on"
// point), or the midpoint between the current one and the
// previous "conic off" point.
- FTPoint prev(contour[(i - 1 + n) % n]);
if(FT_CURVE_TAG(tags[(i - 1 + n) % n]) == FT_Curve_Tag_Conic)
{
- prev = (cur + prev) * 0.5;
- AddPoint(prev);
+ prev2 = (cur + prev) * 0.5;
+ AddPoint(prev2);
}
// Next point is either the real next point or the midpoint.
- FTPoint next(contour[(i + 1) % n]);
if(FT_CURVE_TAG(tags[(i + 1) % n]) == FT_Curve_Tag_Conic)
{
- next = (cur + next) * 0.5;
+ next2 = (cur + next) * 0.5;
}
- evaluateQuadraticCurve(prev, cur, next);
+ evaluateQuadraticCurve(prev2, cur, next2);
}
else if(FT_CURVE_TAG(tags[i]) == FT_Curve_Tag_Cubic
&& FT_CURVE_TAG(tags[(i + 1) % n]) == FT_Curve_Tag_Cubic)
{
- evaluateCubicCurve(FTPoint(contour[(i - 1 + n) % n]),
- cur,
- FTPoint(contour[(i + 1) % n]),
+ evaluateCubicCurve(prev, cur, next,
FTPoint(contour[(i + 2) % n]));
}
}
- /* Create (or not) front outset and/or back outset */
+ // If final angle is positive (+2PI), it's an anti-clockwise contour,
+ // otherwise (-2PI) it's clockwise.
+ clockwise = (angle < 0.0);
+
+ // Create (or not) front outset and/or back outset.
outsetContour();
}
@@ -191,7 +209,7 @@ void FTContour::buildFrontOutset(float outset)
FTPoint point = FTPoint(Point(i).X() + Outset(i).X() * outset,
Point(i).Y() + Outset(i).Y() * outset,
0);
- AddFrontPoint(point);
+ AddFrontPoint(point);
}
}
void FTContour::buildBackOutset(float outset)
@@ -201,7 +219,7 @@ void FTContour::buildBackOutset(float outset)
FTPoint point = FTPoint(Point(i).X() + Outset(i).X() * outset,
Point(i).Y() + Outset(i).Y() * outset,
0);
- AddBackPoint(point);
+ AddBackPoint(point);
}
}
diff --git a/src/FTContour.h b/src/FTContour.h
index 17e121a..36b16df 100644
--- a/src/FTContour.h
+++ b/src/FTContour.h
@@ -207,6 +207,12 @@ class FTContour
PointVector outsetPointList;
PointVector frontPointList;
PointVector backPointList;
+
+ /**
+ * Is this contour clockwise or anti-clockwise?
+ */
+ bool clockwise;
};
#endif // __FTContour__
+