multi-screen-projector/engine/thirdparty/clipper2/src/clipper.offset.cpp
2025-03-13 08:40:48 +00:00

646 lines
19 KiB
C++

/*******************************************************************************
* Author : Angus Johnson *
* Date : 17 April 2024 *
* Website : http://www.angusj.com *
* Copyright : Angus Johnson 2010-2024 *
* Purpose : Path Offset (Inflate/Shrink) *
* License : http://www.boost.org/LICENSE_1_0.txt *
*******************************************************************************/
#include <cmath>
#include "clipper2/clipper.h"
#include "clipper2/clipper.offset.h"
namespace Clipper2Lib {
const double default_arc_tolerance = 0.25;
const double floating_point_tolerance = 1e-12;
//------------------------------------------------------------------------------
// Miscellaneous methods
//------------------------------------------------------------------------------
std::optional<size_t> GetLowestClosedPathIdx(const Paths64& paths)
{
std::optional<size_t> result;
Point64 botPt = Point64(INT64_MAX, INT64_MIN);
for (size_t i = 0; i < paths.size(); ++i)
{
for (const Point64& pt : paths[i])
{
if ((pt.y < botPt.y) ||
((pt.y == botPt.y) && (pt.x >= botPt.x))) continue;
result = i;
botPt.x = pt.x;
botPt.y = pt.y;
}
}
return result;
}
PointD GetUnitNormal(const Point64& pt1, const Point64& pt2)
{
double dx, dy, inverse_hypot;
if (pt1 == pt2) return PointD(0.0, 0.0);
dx = static_cast<double>(pt2.x - pt1.x);
dy = static_cast<double>(pt2.y - pt1.y);
inverse_hypot = 1.0 / hypot(dx, dy);
dx *= inverse_hypot;
dy *= inverse_hypot;
return PointD(dy, -dx);
}
inline bool AlmostZero(double value, double epsilon = 0.001)
{
return std::fabs(value) < epsilon;
}
inline double Hypot(double x, double y)
{
//see https://stackoverflow.com/a/32436148/359538
return std::sqrt(x * x + y * y);
}
inline PointD NormalizeVector(const PointD& vec)
{
double h = Hypot(vec.x, vec.y);
if (AlmostZero(h)) return PointD(0,0);
double inverseHypot = 1 / h;
return PointD(vec.x * inverseHypot, vec.y * inverseHypot);
}
inline PointD GetAvgUnitVector(const PointD& vec1, const PointD& vec2)
{
return NormalizeVector(PointD(vec1.x + vec2.x, vec1.y + vec2.y));
}
inline bool IsClosedPath(EndType et)
{
return et == EndType::Polygon || et == EndType::Joined;
}
inline Point64 GetPerpendic(const Point64& pt, const PointD& norm, double delta)
{
#ifdef USINGZ
return Point64(pt.x + norm.x * delta, pt.y + norm.y * delta, pt.z);
#else
return Point64(pt.x + norm.x * delta, pt.y + norm.y * delta);
#endif
}
inline PointD GetPerpendicD(const Point64& pt, const PointD& norm, double delta)
{
#ifdef USINGZ
return PointD(pt.x + norm.x * delta, pt.y + norm.y * delta, pt.z);
#else
return PointD(pt.x + norm.x * delta, pt.y + norm.y * delta);
#endif
}
inline void NegatePath(PathD& path)
{
for (PointD& pt : path)
{
pt.x = -pt.x;
pt.y = -pt.y;
#ifdef USINGZ
pt.z = pt.z;
#endif
}
}
//------------------------------------------------------------------------------
// ClipperOffset::Group methods
//------------------------------------------------------------------------------
ClipperOffset::Group::Group(const Paths64& _paths, JoinType _join_type, EndType _end_type):
paths_in(_paths), join_type(_join_type), end_type(_end_type)
{
bool is_joined =
(end_type == EndType::Polygon) ||
(end_type == EndType::Joined);
for (Path64& p: paths_in)
StripDuplicates(p, is_joined);
if (end_type == EndType::Polygon)
{
lowest_path_idx = GetLowestClosedPathIdx(paths_in);
// the lowermost path must be an outer path, so if its orientation is negative,
// then flag the whole group is 'reversed' (will negate delta etc.)
// as this is much more efficient than reversing every path.
is_reversed = (lowest_path_idx.has_value()) && Area(paths_in[lowest_path_idx.value()]) < 0;
}
else
{
lowest_path_idx = std::nullopt;
is_reversed = false;
}
}
//------------------------------------------------------------------------------
// ClipperOffset methods
//------------------------------------------------------------------------------
void ClipperOffset::AddPath(const Path64& path, JoinType jt_, EndType et_)
{
Paths64 paths;
paths.push_back(path);
AddPaths(paths, jt_, et_);
}
void ClipperOffset::AddPaths(const Paths64 &paths, JoinType jt_, EndType et_)
{
if (paths.size() == 0) return;
groups_.push_back(Group(paths, jt_, et_));
}
void ClipperOffset::BuildNormals(const Path64& path)
{
norms.clear();
norms.reserve(path.size());
if (path.size() == 0) return;
Path64::const_iterator path_iter, path_stop_iter = --path.cend();
for (path_iter = path.cbegin(); path_iter != path_stop_iter; ++path_iter)
norms.push_back(GetUnitNormal(*path_iter,*(path_iter +1)));
norms.push_back(GetUnitNormal(*path_stop_iter, *(path.cbegin())));
}
void ClipperOffset::DoBevel(const Path64& path, size_t j, size_t k)
{
PointD pt1, pt2;
if (j == k)
{
double abs_delta = std::abs(group_delta_);
#ifdef USINGZ
pt1 = PointD(path[j].x - abs_delta * norms[j].x, path[j].y - abs_delta * norms[j].y, path[j].z);
pt2 = PointD(path[j].x + abs_delta * norms[j].x, path[j].y + abs_delta * norms[j].y, path[j].z);
#else
pt1 = PointD(path[j].x - abs_delta * norms[j].x, path[j].y - abs_delta * norms[j].y);
pt2 = PointD(path[j].x + abs_delta * norms[j].x, path[j].y + abs_delta * norms[j].y);
#endif
}
else
{
#ifdef USINGZ
pt1 = PointD(path[j].x + group_delta_ * norms[k].x, path[j].y + group_delta_ * norms[k].y, path[j].z);
pt2 = PointD(path[j].x + group_delta_ * norms[j].x, path[j].y + group_delta_ * norms[j].y, path[j].z);
#else
pt1 = PointD(path[j].x + group_delta_ * norms[k].x, path[j].y + group_delta_ * norms[k].y);
pt2 = PointD(path[j].x + group_delta_ * norms[j].x, path[j].y + group_delta_ * norms[j].y);
#endif
}
path_out.push_back(Point64(pt1));
path_out.push_back(Point64(pt2));
}
void ClipperOffset::DoSquare(const Path64& path, size_t j, size_t k)
{
PointD vec;
if (j == k)
vec = PointD(norms[j].y, -norms[j].x);
else
vec = GetAvgUnitVector(
PointD(-norms[k].y, norms[k].x),
PointD(norms[j].y, -norms[j].x));
double abs_delta = std::abs(group_delta_);
// now offset the original vertex delta units along unit vector
PointD ptQ = PointD(path[j]);
ptQ = TranslatePoint(ptQ, abs_delta * vec.x, abs_delta * vec.y);
// get perpendicular vertices
PointD pt1 = TranslatePoint(ptQ, group_delta_ * vec.y, group_delta_ * -vec.x);
PointD pt2 = TranslatePoint(ptQ, group_delta_ * -vec.y, group_delta_ * vec.x);
// get 2 vertices along one edge offset
PointD pt3 = GetPerpendicD(path[k], norms[k], group_delta_);
if (j == k)
{
PointD pt4 = PointD(pt3.x + vec.x * group_delta_, pt3.y + vec.y * group_delta_);
PointD pt = ptQ;
GetSegmentIntersectPt(pt1, pt2, pt3, pt4, pt);
//get the second intersect point through reflecion
path_out.push_back(Point64(ReflectPoint(pt, ptQ)));
path_out.push_back(Point64(pt));
}
else
{
PointD pt4 = GetPerpendicD(path[j], norms[k], group_delta_);
PointD pt = ptQ;
GetSegmentIntersectPt(pt1, pt2, pt3, pt4, pt);
path_out.push_back(Point64(pt));
//get the second intersect point through reflecion
path_out.push_back(Point64(ReflectPoint(pt, ptQ)));
}
}
void ClipperOffset::DoMiter(const Path64& path, size_t j, size_t k, double cos_a)
{
double q = group_delta_ / (cos_a + 1);
#ifdef USINGZ
path_out.push_back(Point64(
path[j].x + (norms[k].x + norms[j].x) * q,
path[j].y + (norms[k].y + norms[j].y) * q,
path[j].z));
#else
path_out.push_back(Point64(
path[j].x + (norms[k].x + norms[j].x) * q,
path[j].y + (norms[k].y + norms[j].y) * q));
#endif
}
void ClipperOffset::DoRound(const Path64& path, size_t j, size_t k, double angle)
{
if (deltaCallback64_) {
// when deltaCallback64_ is assigned, group_delta_ won't be constant,
// so we'll need to do the following calculations for *every* vertex.
double abs_delta = std::fabs(group_delta_);
double arcTol = (arc_tolerance_ > floating_point_tolerance ?
std::min(abs_delta, arc_tolerance_) :
std::log10(2 + abs_delta) * default_arc_tolerance);
double steps_per_360 = std::min(PI / std::acos(1 - arcTol / abs_delta), abs_delta * PI);
step_sin_ = std::sin(2 * PI / steps_per_360);
step_cos_ = std::cos(2 * PI / steps_per_360);
if (group_delta_ < 0.0) step_sin_ = -step_sin_;
steps_per_rad_ = steps_per_360 / (2 * PI);
}
Point64 pt = path[j];
PointD offsetVec = PointD(norms[k].x * group_delta_, norms[k].y * group_delta_);
if (j == k) offsetVec.Negate();
#ifdef USINGZ
path_out.push_back(Point64(pt.x + offsetVec.x, pt.y + offsetVec.y, pt.z));
#else
path_out.push_back(Point64(pt.x + offsetVec.x, pt.y + offsetVec.y));
#endif
int steps = static_cast<int>(std::ceil(steps_per_rad_ * std::abs(angle))); // #448, #456
for (int i = 1; i < steps; ++i) // ie 1 less than steps
{
offsetVec = PointD(offsetVec.x * step_cos_ - step_sin_ * offsetVec.y,
offsetVec.x * step_sin_ + offsetVec.y * step_cos_);
#ifdef USINGZ
path_out.push_back(Point64(pt.x + offsetVec.x, pt.y + offsetVec.y, pt.z));
#else
path_out.push_back(Point64(pt.x + offsetVec.x, pt.y + offsetVec.y));
#endif
}
path_out.push_back(GetPerpendic(path[j], norms[j], group_delta_));
}
void ClipperOffset::OffsetPoint(Group& group, const Path64& path, size_t j, size_t k)
{
// Let A = change in angle where edges join
// A == 0: ie no change in angle (flat join)
// A == PI: edges 'spike'
// sin(A) < 0: right turning
// cos(A) < 0: change in angle is more than 90 degree
if (path[j] == path[k]) return;
double sin_a = CrossProduct(norms[j], norms[k]);
double cos_a = DotProduct(norms[j], norms[k]);
if (sin_a > 1.0) sin_a = 1.0;
else if (sin_a < -1.0) sin_a = -1.0;
if (deltaCallback64_) {
group_delta_ = deltaCallback64_(path, norms, j, k);
if (group.is_reversed) group_delta_ = -group_delta_;
}
if (std::fabs(group_delta_) <= floating_point_tolerance)
{
path_out.push_back(path[j]);
return;
}
if (cos_a > -0.999 && (sin_a * group_delta_ < 0)) // test for concavity first (#593)
{
// is concave (so insert 3 points that will create a negative region)
#ifdef USINGZ
path_out.push_back(Point64(GetPerpendic(path[j], norms[k], group_delta_), path[j].z));
#else
path_out.push_back(GetPerpendic(path[j], norms[k], group_delta_));
#endif
// this extra point is the only simple way to ensure that path reversals
// (ie over-shrunk paths) are fully cleaned out with the trailing union op.
// However it's probably safe to skip this whenever an angle is almost flat.
if (cos_a < 0.99) path_out.push_back(path[j]); // (#405)
#ifdef USINGZ
path_out.push_back(Point64(GetPerpendic(path[j], norms[j], group_delta_), path[j].z));
#else
path_out.push_back(GetPerpendic(path[j], norms[j], group_delta_));
#endif
}
else if (cos_a > 0.999 && join_type_ != JoinType::Round)
{
// almost straight - less than 2.5 degree (#424, #482, #526 & #724)
DoMiter(path, j, k, cos_a);
}
else if (join_type_ == JoinType::Miter)
{
// miter unless the angle is sufficiently acute to exceed ML
if (cos_a > temp_lim_ - 1) DoMiter(path, j, k, cos_a);
else DoSquare(path, j, k);
}
else if (join_type_ == JoinType::Round)
DoRound(path, j, k, std::atan2(sin_a, cos_a));
else if ( join_type_ == JoinType::Bevel)
DoBevel(path, j, k);
else
DoSquare(path, j, k);
}
void ClipperOffset::OffsetPolygon(Group& group, const Path64& path)
{
path_out.clear();
for (Path64::size_type j = 0, k = path.size() - 1; j < path.size(); k = j, ++j)
OffsetPoint(group, path, j, k);
solution->push_back(path_out);
}
void ClipperOffset::OffsetOpenJoined(Group& group, const Path64& path)
{
OffsetPolygon(group, path);
Path64 reverse_path(path);
std::reverse(reverse_path.begin(), reverse_path.end());
//rebuild normals
std::reverse(norms.begin(), norms.end());
norms.push_back(norms[0]);
norms.erase(norms.begin());
NegatePath(norms);
OffsetPolygon(group, reverse_path);
}
void ClipperOffset::OffsetOpenPath(Group& group, const Path64& path)
{
// do the line start cap
if (deltaCallback64_) group_delta_ = deltaCallback64_(path, norms, 0, 0);
if (std::fabs(group_delta_) <= floating_point_tolerance)
path_out.push_back(path[0]);
else
{
switch (end_type_)
{
case EndType::Butt:
DoBevel(path, 0, 0);
break;
case EndType::Round:
DoRound(path, 0, 0, PI);
break;
default:
DoSquare(path, 0, 0);
break;
}
}
size_t highI = path.size() - 1;
// offset the left side going forward
for (Path64::size_type j = 1, k = 0; j < highI; k = j, ++j)
OffsetPoint(group, path, j, k);
// reverse normals
for (size_t i = highI; i > 0; --i)
norms[i] = PointD(-norms[i - 1].x, -norms[i - 1].y);
norms[0] = norms[highI];
// do the line end cap
if (deltaCallback64_)
group_delta_ = deltaCallback64_(path, norms, highI, highI);
if (std::fabs(group_delta_) <= floating_point_tolerance)
path_out.push_back(path[highI]);
else
{
switch (end_type_)
{
case EndType::Butt:
DoBevel(path, highI, highI);
break;
case EndType::Round:
DoRound(path, highI, highI, PI);
break;
default:
DoSquare(path, highI, highI);
break;
}
}
for (size_t j = highI -1, k = highI; j > 0; k = j, --j)
OffsetPoint(group, path, j, k);
solution->push_back(path_out);
}
void ClipperOffset::DoGroupOffset(Group& group)
{
if (group.end_type == EndType::Polygon)
{
// a straight path (2 points) can now also be 'polygon' offset
// where the ends will be treated as (180 deg.) joins
if (!group.lowest_path_idx.has_value()) delta_ = std::abs(delta_);
group_delta_ = (group.is_reversed) ? -delta_ : delta_;
}
else
group_delta_ = std::abs(delta_);// *0.5;
double abs_delta = std::fabs(group_delta_);
join_type_ = group.join_type;
end_type_ = group.end_type;
if (group.join_type == JoinType::Round || group.end_type == EndType::Round)
{
// calculate the number of steps required to approximate a circle
// (see http://www.angusj.com/clipper2/Docs/Trigonometry.htm)
// arcTol - when arc_tolerance_ is undefined (0) then curve imprecision
// will be relative to the size of the offset (delta). Obviously very
//large offsets will almost always require much less precision.
double arcTol = (arc_tolerance_ > floating_point_tolerance ?
std::min(abs_delta, arc_tolerance_) :
std::log10(2 + abs_delta) * default_arc_tolerance);
double steps_per_360 = std::min(PI / std::acos(1 - arcTol / abs_delta), abs_delta * PI);
step_sin_ = std::sin(2 * PI / steps_per_360);
step_cos_ = std::cos(2 * PI / steps_per_360);
if (group_delta_ < 0.0) step_sin_ = -step_sin_;
steps_per_rad_ = steps_per_360 / (2 * PI);
}
//double min_area = PI * Sqr(group_delta_);
Paths64::const_iterator path_in_it = group.paths_in.cbegin();
for ( ; path_in_it != group.paths_in.cend(); ++path_in_it)
{
Path64::size_type pathLen = path_in_it->size();
path_out.clear();
if (pathLen == 1) // single point
{
if (deltaCallback64_)
{
group_delta_ = deltaCallback64_(*path_in_it, norms, 0, 0);
if (group.is_reversed) group_delta_ = -group_delta_;
abs_delta = std::fabs(group_delta_);
}
if (group_delta_ < 1) continue;
const Point64& pt = (*path_in_it)[0];
//single vertex so build a circle or square ...
if (group.join_type == JoinType::Round)
{
double radius = abs_delta;
size_t steps = steps_per_rad_ > 0 ? static_cast<size_t>(std::ceil(steps_per_rad_ * 2 * PI)) : 0; //#617
path_out = Ellipse(pt, radius, radius, steps);
#ifdef USINGZ
for (auto& p : path_out) p.z = pt.z;
#endif
}
else
{
int d = (int)std::ceil(abs_delta);
Rect64 r = Rect64(pt.x - d, pt.y - d, pt.x + d, pt.y + d);
path_out = r.AsPath();
#ifdef USINGZ
for (auto& p : path_out) p.z = pt.z;
#endif
}
solution->push_back(path_out);
continue;
} // end of offsetting a single point
if ((pathLen == 2) && (group.end_type == EndType::Joined))
end_type_ = (group.join_type == JoinType::Round) ?
EndType::Round :
EndType::Square;
BuildNormals(*path_in_it);
if (end_type_ == EndType::Polygon) OffsetPolygon(group, *path_in_it);
else if (end_type_ == EndType::Joined) OffsetOpenJoined(group, *path_in_it);
else OffsetOpenPath(group, *path_in_it);
}
}
#ifdef USINGZ
void ClipperOffset::ZCB(const Point64& bot1, const Point64& top1,
const Point64& bot2, const Point64& top2, Point64& ip)
{
if (bot1.z && ((bot1.z == bot2.z) || (bot1.z == top2.z))) ip.z = bot1.z;
else if (bot2.z && (bot2.z == top1.z)) ip.z = bot2.z;
else if (top1.z && (top1.z == top2.z)) ip.z = top1.z;
else if (zCallback64_) zCallback64_(bot1, top1, bot2, top2, ip);
}
#endif
size_t ClipperOffset::CalcSolutionCapacity()
{
size_t result = 0;
for (const Group& g : groups_)
result += (g.end_type == EndType::Joined) ? g.paths_in.size() * 2 : g.paths_in.size();
return result;
}
bool ClipperOffset::CheckReverseOrientation()
{
// nb: this assumes there's consistency in orientation between groups
bool is_reversed_orientation = false;
for (const Group& g : groups_)
if (g.end_type == EndType::Polygon)
{
is_reversed_orientation = g.is_reversed;
break;
}
return is_reversed_orientation;
}
void ClipperOffset::ExecuteInternal(double delta)
{
error_code_ = 0;
if (groups_.size() == 0) return;
solution->reserve(CalcSolutionCapacity());
if (std::abs(delta) < 0.5) // ie: offset is insignificant
{
Paths64::size_type sol_size = 0;
for (const Group& group : groups_) sol_size += group.paths_in.size();
solution->reserve(sol_size);
for (const Group& group : groups_)
copy(group.paths_in.begin(), group.paths_in.end(), back_inserter(*solution));
}
else
{
temp_lim_ = (miter_limit_ <= 1) ?
2.0 :
2.0 / (miter_limit_ * miter_limit_);
delta_ = delta;
std::vector<Group>::iterator git;
for (git = groups_.begin(); git != groups_.end(); ++git)
{
DoGroupOffset(*git);
if (!error_code_) continue; // all OK
solution->clear();
}
}
if (!solution->size()) return;
bool paths_reversed = CheckReverseOrientation();
//clean up self-intersections ...
Clipper64 c;
c.PreserveCollinear(false);
//the solution should retain the orientation of the input
c.ReverseSolution(reverse_solution_ != paths_reversed);
#ifdef USINGZ
auto fp = std::bind(&ClipperOffset::ZCB, this, std::placeholders::_1,
std::placeholders::_2, std::placeholders::_3,
std::placeholders::_4, std::placeholders::_5);
c.SetZCallback(fp);
#endif
c.AddSubject(*solution);
if (solution_tree)
{
if (paths_reversed)
c.Execute(ClipType::Union, FillRule::Negative, *solution_tree);
else
c.Execute(ClipType::Union, FillRule::Positive, *solution_tree);
}
else
{
if (paths_reversed)
c.Execute(ClipType::Union, FillRule::Negative, *solution);
else
c.Execute(ClipType::Union, FillRule::Positive, *solution);
}
}
void ClipperOffset::Execute(double delta, Paths64& paths)
{
paths.clear();
solution = &paths;
solution_tree = nullptr;
ExecuteInternal(delta);
}
void ClipperOffset::Execute(double delta, PolyTree64& polytree)
{
polytree.Clear();
solution_tree = &polytree;
solution = new Paths64();
ExecuteInternal(delta);
delete solution;
solution = nullptr;
}
void ClipperOffset::Execute(DeltaCallback64 delta_cb, Paths64& paths)
{
deltaCallback64_ = delta_cb;
Execute(1.0, paths);
}
} // namespace