summaryrefslogtreecommitdiffstats
path: root/src/helper/geom-pathstroke.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'src/helper/geom-pathstroke.cpp')
-rw-r--r--src/helper/geom-pathstroke.cpp200
1 files changed, 144 insertions, 56 deletions
diff --git a/src/helper/geom-pathstroke.cpp b/src/helper/geom-pathstroke.cpp
index 1908f2db7..eb0c432c6 100644
--- a/src/helper/geom-pathstroke.cpp
+++ b/src/helper/geom-pathstroke.cpp
@@ -159,6 +159,7 @@ void miter_join_internal(Geom::Path& res, Geom::Curve const& outgoing, double mi
Geom::Point p = Geom::intersection_point(incoming.finalPoint(), tang1, outgoing.initialPoint(), tang2);
bool satisfied = false;
+ bool inc_ls = res.back_open().degreesOfFreedom() <= 4;
if (p.isFinite()) {
// check size of miter
@@ -166,32 +167,20 @@ void miter_join_internal(Geom::Path& res, Geom::Curve const& outgoing, double mi
satisfied = Geom::distance(p, point_on_path) <= miter * 2.0 * width;
if (satisfied) {
// miter OK, check to see if we can do a relocation
- bool ls = res.back_open().degreesOfFreedom() <= 4;
- if (ls) {
+ if (inc_ls) {
res.setFinal(p);
} else {
res.appendNew<Geom::LineSegment>(p);
}
} else if (clip) {
// miter needs clipping, find two points
- Geom::Line bisector(point_on_path, p);
- Geom::Point point_limit = point_on_path + miter * 2.0 * width * bisector.versor();
+ Geom::Point bisector_versor = Geom::Line(point_on_path, p).versor();
+ Geom::Point point_limit = point_on_path + miter * 2.0 * width * bisector_versor;
- Geom::Line line_limit =
- Geom::Line::from_origin_and_versor( point_limit, bisector.versor().cw() );
+ Geom::Point p1 = Geom::intersection_point(incoming.finalPoint(), tang1, point_limit, bisector_versor.cw());
+ Geom::Point p2 = Geom::intersection_point(outgoing.initialPoint(), tang2, point_limit, bisector_versor.cw());
- Geom::Line incoming_line( incoming.finalPoint(), p );
- Geom::Line outgoing_line( p, outgoing.initialPoint() );
-
- Geom::OptCrossing i1 = intersection( line_limit, incoming_line );
- Geom::OptCrossing i2 = intersection( line_limit, outgoing_line );
-
- // It would be nice to have a simple point returned by intersection!
- Geom::Point p1 = line_limit.pointAt( (*i1).ta );
- Geom::Point p2 = line_limit.pointAt( (*i2).ta );
-
- bool ls = res.back_open().degreesOfFreedom() <= 4;
- if (ls) {
+ if (inc_ls) {
res.setFinal(p1);
} else {
res.appendNew<Geom::LineSegment>(p1);
@@ -203,9 +192,9 @@ void miter_join_internal(Geom::Path& res, Geom::Curve const& outgoing, double mi
res.appendNew<Geom::LineSegment>(outgoing.initialPoint());
// check if we can do another relocation
- bool ls = outgoing.degreesOfFreedom() <= 4;
+ bool out_ls = outgoing.degreesOfFreedom() <= 4;
- if ( (satisfied || clip) && ls) {
+ if ( (satisfied || clip) && out_ls) {
res.setFinal(outgoing.finalPoint());
} else {
res.append(outgoing);
@@ -236,12 +225,15 @@ Geom::Point pick_solution(Geom::Point points[2], Geom::Point tang2, Geom::Point
return sol;
}
-void extrapolate_join(Geom::Path& path_builder, Geom::Curve const& outgoing, double miter_limit, double line_width)
+void extrapolate_join(Geom::Path& res, Geom::Curve const& outgoing, double miter, double width)
{
using namespace Geom;
- Geom::Curve const& incoming = path_builder.back();
+
+ Geom::Curve const& incoming = res.back();
+ Geom::Point startPt = incoming.finalPoint();
Geom::Point endPt = outgoing.initialPoint();
- Geom::Point tang2 = Geom::unitTangentAt(outgoing.toSBasis(), 0);
+ Geom::Point tang1 = Geom::unitTangentAt(reverse(incoming.toSBasis()), 0.);
+ Geom::Point tang2 = outgoing.unitTangentAt(0);
Geom::Circle circle1 = Geom::touching_circle(Geom::reverse(incoming.toSBasis()), 0.);
Geom::Circle circle2 = Geom::touching_circle(outgoing.toSBasis(), 0);
@@ -252,52 +244,146 @@ void extrapolate_join(Geom::Path& path_builder, Geom::Curve const& outgoing, dou
Geom::Point points[2];
int solutions = 0;
- Geom::EllipticalArc *arc0 = NULL;
Geom::EllipticalArc *arc1 = NULL;
+ Geom::EllipticalArc *arc2 = NULL;
+ Geom::Point sol;
+ Geom::Point p1;
+ Geom::Point p2;
if (!inc_ls && !out_ls) {
+ // Two circles
solutions = Geom::circle_circle_intersection(circle1.center(), circle1.ray(),
circle2.center(), circle2.ray(),
points[0], points[1]);
if (solutions == 2) {
- Geom::Point sol = pick_solution(points, tang2, endPt);
-
- arc0 = circle1.arc(incoming.finalPoint(), 0.5*(incoming.finalPoint()+sol), sol, true);
- arc1 = circle2.arc(sol, 0.5*(sol+endPt), endPt, true);
+ sol = pick_solution(points, tang2, endPt);
+ arc1 = circle1.arc(startPt, 0.5*(startPt+sol), sol, true);
+ arc2 = circle2.arc(sol, 0.5*(sol+endPt), endPt, true);
}
} else if (inc_ls && !out_ls) {
+ // Line and circle
solutions = Geom::circle_line_intersection(circle2, incoming.initialPoint(), incoming.finalPoint(), points[0], points[1]);
if (solutions == 2) {
- Geom::Point sol = pick_solution(points, tang2, endPt);
- path_builder.setFinal(sol);
- arc1 = circle2.arc(sol, 0.5*(sol+endPt), endPt, true);
+ sol = pick_solution(points, tang2, endPt);
+ arc2 = circle2.arc(sol, 0.5*(sol+endPt), endPt, true);
}
} else if (!inc_ls && out_ls) {
+ // Circle and line
solutions = Geom::circle_line_intersection(circle1, outgoing.initialPoint(), outgoing.finalPoint(), points[0], points[1]);
if (solutions == 2) {
- Geom::Point sol = pick_solution(points, tang2, endPt);
- arc0 = circle1.arc(incoming.finalPoint(), 0.5*(sol+incoming.finalPoint()), sol, true);
+ sol = pick_solution(points, tang2, endPt);
+ arc1 = circle1.arc(startPt, 0.5*(sol+startPt), sol, true);
}
}
if (solutions != 2)
// no solutions available, fall back to miter
- return miter_join(path_builder, outgoing, miter_limit, line_width);
+ return miter_clip_join(res, outgoing, miter, width);
- if (arc0)
- path_builder.append(*arc0);
- if (arc1)
- path_builder.append(*arc1);
+ // We have a solution, thus sol is defined.
+ p1 = sol;
+
+ // See if we need to clip. Miter length is measured along a circular arc that is tangent to the
+ // bisector of the incoming and out going angles and passes through the end point (sol) of the
+ // line join.
+
+ // Center of circle is intersection of a line orthogonal to bisector and a line bisecting
+ // a chord connecting the path end point (point_on_path) and the join end point (sol).
+ Geom::Point point_on_path = startPt + Geom::rot90(tang1)*width;
+ Geom::Line bisector = make_angle_bisector_line(startPt, point_on_path, endPt);
+ Geom::Line ortho = make_orthogonal_line(point_on_path, bisector);
+
+ Geom::LineSegment chord(point_on_path, sol);
+ Geom::Line bisector_chord = make_bisector_line(chord);
+
+ Geom::Line limit_line;
+ double miter_limit = 2.0 * width * miter;
+ bool clipped = false;
+
+ if (are_parallel(bisector_chord, ortho)) {
+ // No intersection (can happen if curvatures are equal but opposite)
+ if (Geom::distance(point_on_path, sol) > miter_limit) {
+ clipped = true;
+ Geom::Point limit_point = point_on_path + miter_limit * bisector.versor();
+ limit_line = make_parallel_line( limit_point, ortho );
+ }
+ } else {
+ Geom::Point center =
+ Geom::intersection_point( bisector_chord.pointAt(0), bisector_chord.versor(),
+ ortho.pointAt(0), ortho.versor() );
+ Geom::Coord radius = distance(center, point_on_path);
+ Geom::Circle circle_center(center, radius);
- delete arc0;
- delete arc1;
+ double limit_angle = miter_limit / radius;
+
+ Geom::Ray start_ray(center, point_on_path);
+ Geom::Ray end_ray(center, sol);
+ Geom::Line limit_line(center, 0); // Angle set below
+
+ if (Geom::cross(start_ray.versor(), end_ray.versor()) > 0) {
+ limit_line.setAngle(start_ray.angle() - limit_angle);
+ } else {
+ limit_line.setAngle(start_ray.angle() + limit_angle);
+ }
+
+ Geom::EllipticalArc *arc_center = circle_center.arc(point_on_path, 0.5*(point_on_path + sol), sol, true);
+ if (arc_center && arc_center->sweepAngle() > limit_angle) {
+ // We need to clip
+ clipped = true;
+
+ if (!inc_ls) {
+ // Incoming circular
+ solutions = Geom::circle_line_intersection(circle1, limit_line.pointAt(0), limit_line.pointAt(1), points[0], points[1]);
+
+ if (solutions == 2) {
+ p1 = pick_solution(points, tang2, endPt);
+ delete arc1;
+ arc1 = circle1.arc(startPt, 0.5*(p1+startPt), p1, true);
+ }
+ } else {
+ p1 = Geom::intersection_point(startPt, tang1, limit_line.pointAt(0), limit_line.versor());
+ }
+
+ if (!out_ls) {
+ // Outgoing circular
+ solutions = Geom::circle_line_intersection(circle2, limit_line.pointAt(0), limit_line.pointAt(1), points[0], points[1]);
+
+ if (solutions == 2) {
+ p2 = pick_solution(points, tang1, endPt);
+ delete arc2;
+ arc2 = circle2.arc(p2, 0.5*(p2+endPt), endPt, true);
+ }
+ } else {
+ p2 = Geom::intersection_point(endPt, tang2, limit_line.pointAt(0), limit_line.versor());
+ }
+ }
+ }
+
+ // Add initial
+ if (arc1) {
+ res.append(*arc1);
+ } else {
+ // Straight line segment: move last point
+ res.setFinal(p1);
+ }
+
+ if (clipped) {
+ res.appendNew<Geom::LineSegment>(p2);
+ }
- if (!inc_ls && out_ls)
- path_builder.appendNew<Geom::LineSegment>(outgoing.finalPoint());
- else
- path_builder.append(outgoing);
+ // Add outgoing
+ if (arc2) {
+ res.append(*arc2);
+ res.append(outgoing);
+ } else {
+ // Straight line segment:
+ res.appendNew<Geom::LineSegment>(outgoing.finalPoint());
+ }
+
+ delete arc1;
+ delete arc2;
}
void join_inside(Geom::Path& res, Geom::Curve const& outgoing)
@@ -322,7 +408,14 @@ void join_inside(Geom::Path& res, Geom::Curve const& outgoing)
}
}
-void outline_helper(Geom::Path& res, Geom::Path const& to_add, double width, double miter, Inkscape::LineJoinType join)
+bool decide(Geom::Curve const& incoming, Geom::Curve const& outgoing)
+{
+ Geom::Point tang1 = Geom::unitTangentAt(reverse(incoming.toSBasis()), 0.);
+ Geom::Point tang2 = outgoing.unitTangentAt(0.);
+ return (Geom::cross(tang1, tang2) < 0);
+}
+
+void outline_helper(Geom::Path& res, Geom::Path const& to_add, double width, bool on_outside, double miter, Inkscape::LineJoinType join)
{
if (res.size() == 0 || to_add.size() == 0)
return;
@@ -335,14 +428,6 @@ void outline_helper(Geom::Path& res, Geom::Path const& to_add, double width, dou
return;
}
- Geom::Point tang1 = Geom::unitTangentAt(reverse(res.back().toSBasis()), 0.);
- Geom::Point tang2 = Geom::unitTangentAt(to_add.front().toSBasis(), 0.);
- // Geom::Point discontinuity_vec = to_add.initialPoint() - res.finalPoint();
- bool on_outside = (Geom::cross(tang1, tang2) < 0);
- // std::cout << std::fixed << std::setprecision(3)
- // << " in: " << tang1 << " out: " << tang2
- // << " side: " << (on_outside?"inside":"outside") << std::endl;
-
if (on_outside) {
join_func *jf;
switch (join) {
@@ -635,7 +720,8 @@ Geom::Path half_outline(Geom::Path const& input, double width, double miter, Lin
if (u == 0) {
res.append(temp);
} else {
- outline_helper(res, temp, width, miter, join);
+ bool on_outside = decide(input[u-1], input[u]);
+ outline_helper(res, temp, width, on_outside, miter, join);
if (temp.size() > 0)
res.insert(res.end(), ++temp.begin(), temp.end());
}
@@ -644,7 +730,8 @@ Geom::Path half_outline(Geom::Path const& input, double width, double miter, Lin
if (u < k - 1) {
temp = Geom::Path();
offset_curve(temp, &input[u+1], width);
- outline_helper(res, temp, width, miter, join);
+ bool on_outside = decide(input[u], input[u+1]);
+ outline_helper(res, temp, width, on_outside, miter, join);
if (temp.size() > 0)
res.insert(res.end(), ++temp.begin(), temp.end());
}
@@ -657,7 +744,8 @@ Geom::Path half_outline(Geom::Path const& input, double width, double miter, Lin
temp.append(c1);
Geom::Path temp2;
temp2.append(c2);
- outline_helper(temp, temp2, width, miter, join);
+ bool on_outside = decide(input.back(), input.front());
+ outline_helper(temp, temp2, width, on_outside, miter, join);
res.erase(res.begin());
res.erase_last();
//
generated by cgit v1.2.3 (git 2.25.1) at 2026-05-31 17:13:13 +0000