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PrusaSlicer-NonPlainar/xs/src/libslic3r/Geometry.cpp
bubnikv c3af189045 Reduced some compiler warnings.
2016-11-16 22:09:00 +01:00

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#include "Geometry.hpp"
#include "ClipperUtils.hpp"
#include "ExPolygon.hpp"
#include "Line.hpp"
#include "PolylineCollection.hpp"
#include "clipper.hpp"
#include <algorithm>
#include <cassert>
#include <cmath>
#include <list>
#include <map>
#include <set>
#include <utility>
#include <stack>
#include <vector>
#ifdef SLIC3R_DEBUG
#include "SVG.hpp"
#endif
#ifdef SLIC3R_DEBUG
namespace boost { namespace polygon {
// The following code for the visualization of the boost Voronoi diagram is based on:
//
// Boost.Polygon library voronoi_graphic_utils.hpp header file
// Copyright Andrii Sydorchuk 2010-2012.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
template <typename CT>
class voronoi_visual_utils {
public:
// Discretize parabolic Voronoi edge.
// Parabolic Voronoi edges are always formed by one point and one segment
// from the initial input set.
//
// Args:
// point: input point.
// segment: input segment.
// max_dist: maximum discretization distance.
// discretization: point discretization of the given Voronoi edge.
//
// Template arguments:
// InCT: coordinate type of the input geometries (usually integer).
// Point: point type, should model point concept.
// Segment: segment type, should model segment concept.
//
// Important:
// discretization should contain both edge endpoints initially.
template <class InCT1, class InCT2,
template<class> class Point,
template<class> class Segment>
static
typename enable_if<
typename gtl_and<
typename gtl_if<
typename is_point_concept<
typename geometry_concept< Point<InCT1> >::type
>::type
>::type,
typename gtl_if<
typename is_segment_concept<
typename geometry_concept< Segment<InCT2> >::type
>::type
>::type
>::type,
void
>::type discretize(
const Point<InCT1>& point,
const Segment<InCT2>& segment,
const CT max_dist,
std::vector< Point<CT> >* discretization) {
// Apply the linear transformation to move start point of the segment to
// the point with coordinates (0, 0) and the direction of the segment to
// coincide the positive direction of the x-axis.
CT segm_vec_x = cast(x(high(segment))) - cast(x(low(segment)));
CT segm_vec_y = cast(y(high(segment))) - cast(y(low(segment)));
CT sqr_segment_length = segm_vec_x * segm_vec_x + segm_vec_y * segm_vec_y;
// Compute x-coordinates of the endpoints of the edge
// in the transformed space.
CT projection_start = sqr_segment_length *
get_point_projection((*discretization)[0], segment);
CT projection_end = sqr_segment_length *
get_point_projection((*discretization)[1], segment);
// Compute parabola parameters in the transformed space.
// Parabola has next representation:
// f(x) = ((x-rot_x)^2 + rot_y^2) / (2.0*rot_y).
CT point_vec_x = cast(x(point)) - cast(x(low(segment)));
CT point_vec_y = cast(y(point)) - cast(y(low(segment)));
CT rot_x = segm_vec_x * point_vec_x + segm_vec_y * point_vec_y;
CT rot_y = segm_vec_x * point_vec_y - segm_vec_y * point_vec_x;
// Save the last point.
Point<CT> last_point = (*discretization)[1];
discretization->pop_back();
// Use stack to avoid recursion.
std::stack<CT> point_stack;
point_stack.push(projection_end);
CT cur_x = projection_start;
CT cur_y = parabola_y(cur_x, rot_x, rot_y);
// Adjust max_dist parameter in the transformed space.
const CT max_dist_transformed = max_dist * max_dist * sqr_segment_length;
while (!point_stack.empty()) {
CT new_x = point_stack.top();
CT new_y = parabola_y(new_x, rot_x, rot_y);
// Compute coordinates of the point of the parabola that is
// furthest from the current line segment.
CT mid_x = (new_y - cur_y) / (new_x - cur_x) * rot_y + rot_x;
CT mid_y = parabola_y(mid_x, rot_x, rot_y);
// Compute maximum distance between the given parabolic arc
// and line segment that discretize it.
CT dist = (new_y - cur_y) * (mid_x - cur_x) -
(new_x - cur_x) * (mid_y - cur_y);
dist = dist * dist / ((new_y - cur_y) * (new_y - cur_y) +
(new_x - cur_x) * (new_x - cur_x));
if (dist <= max_dist_transformed) {
// Distance between parabola and line segment is less than max_dist.
point_stack.pop();
CT inter_x = (segm_vec_x * new_x - segm_vec_y * new_y) /
sqr_segment_length + cast(x(low(segment)));
CT inter_y = (segm_vec_x * new_y + segm_vec_y * new_x) /
sqr_segment_length + cast(y(low(segment)));
discretization->push_back(Point<CT>(inter_x, inter_y));
cur_x = new_x;
cur_y = new_y;
} else {
point_stack.push(mid_x);
}
}
// Update last point.
discretization->back() = last_point;
}
private:
// Compute y(x) = ((x - a) * (x - a) + b * b) / (2 * b).
static CT parabola_y(CT x, CT a, CT b) {
return ((x - a) * (x - a) + b * b) / (b + b);
}
// Get normalized length of the distance between:
// 1) point projection onto the segment
// 2) start point of the segment
// Return this length divided by the segment length. This is made to avoid
// sqrt computation during transformation from the initial space to the
// transformed one and vice versa. The assumption is made that projection of
// the point lies between the start-point and endpoint of the segment.
template <class InCT,
template<class> class Point,
template<class> class Segment>
static
typename enable_if<
typename gtl_and<
typename gtl_if<
typename is_point_concept<
typename geometry_concept< Point<int> >::type
>::type
>::type,
typename gtl_if<
typename is_segment_concept<
typename geometry_concept< Segment<long> >::type
>::type
>::type
>::type,
CT
>::type get_point_projection(
const Point<CT>& point, const Segment<InCT>& segment) {
CT segment_vec_x = cast(x(high(segment))) - cast(x(low(segment)));
CT segment_vec_y = cast(y(high(segment))) - cast(y(low(segment)));
CT point_vec_x = x(point) - cast(x(low(segment)));
CT point_vec_y = y(point) - cast(y(low(segment)));
CT sqr_segment_length =
segment_vec_x * segment_vec_x + segment_vec_y * segment_vec_y;
CT vec_dot = segment_vec_x * point_vec_x + segment_vec_y * point_vec_y;
return vec_dot / sqr_segment_length;
}
template <typename InCT>
static CT cast(const InCT& value) {
return static_cast<CT>(value);
}
};
} } // namespace boost::polygon
#endif
using namespace boost::polygon; // provides also high() and low()
namespace Slic3r { namespace Geometry {
static bool
sort_points (Point a, Point b)
{
return (a.x < b.x) || (a.x == b.x && a.y < b.y);
}
/* This implementation is based on Andrew's monotone chain 2D convex hull algorithm */
Polygon
convex_hull(Points points)
{
assert(points.size() >= 3);
// sort input points
std::sort(points.begin(), points.end(), sort_points);
int n = points.size(), k = 0;
Polygon hull;
hull.points.resize(2*n);
// Build lower hull
for (int i = 0; i < n; i++) {
while (k >= 2 && points[i].ccw(hull.points[k-2], hull.points[k-1]) <= 0) k--;
hull.points[k++] = points[i];
}
// Build upper hull
for (int i = n-2, t = k+1; i >= 0; i--) {
while (k >= t && points[i].ccw(hull.points[k-2], hull.points[k-1]) <= 0) k--;
hull.points[k++] = points[i];
}
hull.points.resize(k);
assert( hull.points.front().coincides_with(hull.points.back()) );
hull.points.pop_back();
return hull;
}
Polygon
convex_hull(const Polygons &polygons)
{
Points pp;
for (Polygons::const_iterator p = polygons.begin(); p != polygons.end(); ++p) {
pp.insert(pp.end(), p->points.begin(), p->points.end());
}
return convex_hull(pp);
}
/* accepts an arrayref of points and returns a list of indices
according to a nearest-neighbor walk */
void
chained_path(const Points &points, std::vector<Points::size_type> &retval, Point start_near)
{
PointConstPtrs my_points;
std::map<const Point*,Points::size_type> indices;
my_points.reserve(points.size());
for (Points::const_iterator it = points.begin(); it != points.end(); ++it) {
my_points.push_back(&*it);
indices[&*it] = it - points.begin();
}
retval.reserve(points.size());
while (!my_points.empty()) {
Points::size_type idx = start_near.nearest_point_index(my_points);
start_near = *my_points[idx];
retval.push_back(indices[ my_points[idx] ]);
my_points.erase(my_points.begin() + idx);
}
}
void
chained_path(const Points &points, std::vector<Points::size_type> &retval)
{
if (points.empty()) return; // can't call front() on empty vector
chained_path(points, retval, points.front());
}
/* retval and items must be different containers */
template<class T>
void
chained_path_items(Points &points, T &items, T &retval)
{
std::vector<Points::size_type> indices;
chained_path(points, indices);
for (std::vector<Points::size_type>::const_iterator it = indices.begin(); it != indices.end(); ++it)
retval.push_back(items[*it]);
}
template void chained_path_items(Points &points, ClipperLib::PolyNodes &items, ClipperLib::PolyNodes &retval);
bool
directions_parallel(double angle1, double angle2, double max_diff)
{
double diff = fabs(angle1 - angle2);
max_diff += EPSILON;
return diff < max_diff || fabs(diff - PI) < max_diff;
}
template<class T>
bool
contains(const std::vector<T> &vector, const Point &point)
{
for (typename std::vector<T>::const_iterator it = vector.begin(); it != vector.end(); ++it) {
if (it->contains(point)) return true;
}
return false;
}
template bool contains(const ExPolygons &vector, const Point &point);
double
rad2deg(double angle)
{
return angle / PI * 180.0;
}
double
rad2deg_dir(double angle)
{
angle = (angle < PI) ? (-angle + PI/2.0) : (angle + PI/2.0);
if (angle < 0) angle += PI;
return rad2deg(angle);
}
double
deg2rad(double angle)
{
return PI * angle / 180.0;
}
void
simplify_polygons(const Polygons &polygons, double tolerance, Polygons* retval)
{
Polygons pp;
for (Polygons::const_iterator it = polygons.begin(); it != polygons.end(); ++it) {
Polygon p = *it;
p.points.push_back(p.points.front());
p.points = MultiPoint::_douglas_peucker(p.points, tolerance);
p.points.pop_back();
pp.push_back(p);
}
Slic3r::simplify_polygons(pp, retval);
}
double
linint(double value, double oldmin, double oldmax, double newmin, double newmax)
{
return (value - oldmin) * (newmax - newmin) / (oldmax - oldmin) + newmin;
}
#if 0
// Point with a weight, by which the points are sorted.
// If the points have the same weight, sort them lexicographically by their positions.
struct ArrangeItem {
ArrangeItem() {}
Pointf pos;
coordf_t weight;
bool operator<(const ArrangeItem &other) const {
return weight < other.weight ||
((weight == other.weight) && (pos.y < other.pos.y || (pos.y == other.pos.y && pos.x < other.pos.x)));
}
};
Pointfs arrange(size_t num_parts, const Pointf &part_size, coordf_t gap, const BoundingBoxf* bed_bounding_box)
{
// Use actual part size (the largest) plus separation distance (half on each side) in spacing algorithm.
const Pointf cell_size(part_size.x + gap, part_size.y + gap);
const BoundingBoxf bed_bbox = (bed_bounding_box != NULL && bed_bounding_box->defined) ?
*bed_bounding_box :
// Bogus bed size, large enough not to trigger the unsufficient bed size error.
BoundingBoxf(
Pointf(0, 0),
Pointf(cell_size.x * num_parts, cell_size.y * num_parts));
// This is how many cells we have available into which to put parts.
size_t cellw = size_t(floor((bed_bbox.size().x + gap) / cell_size.x));
size_t cellh = size_t(floor((bed_bbox.size().y + gap) / cell_size.y));
if (num_parts > cellw * cellh)
CONFESS(PRINTF_ZU " parts won't fit in your print area!\n", num_parts);
// Get a bounding box of cellw x cellh cells, centered at the center of the bed.
Pointf cells_size(cellw * cell_size.x - gap, cellh * cell_size.y - gap);
Pointf cells_offset(bed_bbox.center() - 0.5 * cells_size);
BoundingBoxf cells_bb(cells_offset, cells_size + cells_offset);
// List of cells, sorted by distance from center.
std::vector<ArrangeItem> cellsorder(cellw * cellh, ArrangeItem());
for (size_t j = 0; j < cellh; ++ j) {
// Center of the jth row on the bed.
coordf_t cy = linint(j + 0.5, 0., double(cellh), cells_bb.min.y, cells_bb.max.y);
// Offset from the bed center.
coordf_t yd = cells_bb.center().y - cy;
for (size_t i = 0; i < cellw; ++ i) {
// Center of the ith column on the bed.
coordf_t cx = linint(i + 0.5, 0., double(cellw), cells_bb.min.x, cells_bb.max.x);
// Offset from the bed center.
coordf_t xd = cells_bb.center().x - cx;
// Cell with a distance from the bed center.
ArrangeItem &ci = cellsorder[j * cellw + i];
// Cell center
ci.pos.x = cx;
ci.pos.y = cy;
// Square distance of the cell center to the bed center.
ci.weight = xd * xd + yd * yd;
}
}
// Sort the cells lexicographically by their distances to the bed center and left to right / bttom to top.
std::sort(cellsorder.begin(), cellsorder.end());
cellsorder.erase(cellsorder.begin() + num_parts, cellsorder.end());
// Return the (left,top) corners of the cells.
Pointfs positions;
positions.reserve(num_parts);
for (std::vector<ArrangeItem>::const_iterator it = cellsorder.begin(); it != cellsorder.end(); ++ it)
positions.push_back(Pointf(it->pos.x - 0.5 * part_size.x, it->pos.y - 0.5 * part_size.y));
return positions;
}
#else
class ArrangeItem {
public:
Pointf pos;
size_t index_x, index_y;
coordf_t dist;
};
class ArrangeItemIndex {
public:
coordf_t index;
ArrangeItem item;
ArrangeItemIndex(coordf_t _index, ArrangeItem _item) : index(_index), item(_item) {};
};
bool
arrange(size_t total_parts, const Pointf &part_size, coordf_t dist, const BoundingBoxf* bb, Pointfs &positions)
{
positions.clear();
Pointf part = part_size;
// use actual part size (the largest) plus separation distance (half on each side) in spacing algorithm
part.x += dist;
part.y += dist;
Pointf area;
if (bb != NULL && bb->defined) {
area = bb->size();
} else {
// bogus area size, large enough not to trigger the error below
area.x = part.x * total_parts;
area.y = part.y * total_parts;
}
// this is how many cells we have available into which to put parts
size_t cellw = floor((area.x + dist) / part.x);
size_t cellh = floor((area.y + dist) / part.y);
if (total_parts > (cellw * cellh))
return false;
// total space used by cells
Pointf cells(cellw * part.x, cellh * part.y);
// bounding box of total space used by cells
BoundingBoxf cells_bb;
cells_bb.merge(Pointf(0,0)); // min
cells_bb.merge(cells); // max
// center bounding box to area
cells_bb.translate(
(area.x - cells.x) / 2,
(area.y - cells.y) / 2
);
// list of cells, sorted by distance from center
std::vector<ArrangeItemIndex> cellsorder;
// work out distance for all cells, sort into list
for (size_t i = 0; i <= cellw-1; ++i) {
for (size_t j = 0; j <= cellh-1; ++j) {
coordf_t cx = linint(i + 0.5, 0, cellw, cells_bb.min.x, cells_bb.max.x);
coordf_t cy = linint(j + 0.5, 0, cellh, cells_bb.min.y, cells_bb.max.y);
coordf_t xd = fabs((area.x / 2) - cx);
coordf_t yd = fabs((area.y / 2) - cy);
ArrangeItem c;
c.pos.x = cx;
c.pos.y = cy;
c.index_x = i;
c.index_y = j;
c.dist = xd * xd + yd * yd - fabs((cellw / 2) - (i + 0.5));
// binary insertion sort
{
coordf_t index = c.dist;
size_t low = 0;
size_t high = cellsorder.size();
while (low < high) {
size_t mid = (low + ((high - low) / 2)) | 0;
coordf_t midval = cellsorder[mid].index;
if (midval < index) {
low = mid + 1;
} else if (midval > index) {
high = mid;
} else {
cellsorder.insert(cellsorder.begin() + mid, ArrangeItemIndex(index, c));
goto ENDSORT;
}
}
cellsorder.insert(cellsorder.begin() + low, ArrangeItemIndex(index, c));
}
ENDSORT: ;
}
}
// the extents of cells actually used by objects
coordf_t lx = 0;
coordf_t ty = 0;
coordf_t rx = 0;
coordf_t by = 0;
// now find cells actually used by objects, map out the extents so we can position correctly
for (size_t i = 1; i <= total_parts; ++i) {
ArrangeItemIndex c = cellsorder[i - 1];
coordf_t cx = c.item.index_x;
coordf_t cy = c.item.index_y;
if (i == 1) {
lx = rx = cx;
ty = by = cy;
} else {
if (cx > rx) rx = cx;
if (cx < lx) lx = cx;
if (cy > by) by = cy;
if (cy < ty) ty = cy;
}
}
// now we actually place objects into cells, positioned such that the left and bottom borders are at 0
for (size_t i = 1; i <= total_parts; ++i) {
ArrangeItemIndex c = cellsorder.front();
cellsorder.erase(cellsorder.begin());
coordf_t cx = c.item.index_x - lx;
coordf_t cy = c.item.index_y - ty;
positions.push_back(Pointf(cx * part.x, cy * part.y));
}
if (bb != NULL && bb->defined) {
for (Pointfs::iterator p = positions.begin(); p != positions.end(); ++p) {
p->x += bb->min.x;
p->y += bb->min.y;
}
}
return true;
}
#endif
#ifdef SLIC3R_DEBUG
// The following code for the visualization of the boost Voronoi diagram is based on:
//
// Boost.Polygon library voronoi_visualizer.cpp file
// Copyright Andrii Sydorchuk 2010-2012.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
namespace Voronoi { namespace Internal {
typedef double coordinate_type;
typedef boost::polygon::point_data<coordinate_type> point_type;
typedef boost::polygon::segment_data<coordinate_type> segment_type;
typedef boost::polygon::rectangle_data<coordinate_type> rect_type;
// typedef voronoi_builder<int> VB;
typedef boost::polygon::voronoi_diagram<coordinate_type> VD;
typedef VD::cell_type cell_type;
typedef VD::cell_type::source_index_type source_index_type;
typedef VD::cell_type::source_category_type source_category_type;
typedef VD::edge_type edge_type;
typedef VD::cell_container_type cell_container_type;
typedef VD::cell_container_type vertex_container_type;
typedef VD::edge_container_type edge_container_type;
typedef VD::const_cell_iterator const_cell_iterator;
typedef VD::const_vertex_iterator const_vertex_iterator;
typedef VD::const_edge_iterator const_edge_iterator;
static const std::size_t EXTERNAL_COLOR = 1;
inline void color_exterior(const VD::edge_type* edge)
{
if (edge->color() == EXTERNAL_COLOR)
return;
edge->color(EXTERNAL_COLOR);
edge->twin()->color(EXTERNAL_COLOR);
const VD::vertex_type* v = edge->vertex1();
if (v == NULL || !edge->is_primary())
return;
v->color(EXTERNAL_COLOR);
const VD::edge_type* e = v->incident_edge();
do {
color_exterior(e);
e = e->rot_next();
} while (e != v->incident_edge());
}
inline point_type retrieve_point(const std::vector<segment_type> &segments, const cell_type& cell)
{
assert(cell.source_category() == SOURCE_CATEGORY_SEGMENT_START_POINT || cell.source_category() == SOURCE_CATEGORY_SEGMENT_END_POINT);
return (cell.source_category() == SOURCE_CATEGORY_SEGMENT_START_POINT) ? low(segments[cell.source_index()]) : high(segments[cell.source_index()]);
}
inline void clip_infinite_edge(const std::vector<segment_type> &segments, const edge_type& edge, coordinate_type bbox_max_size, std::vector<point_type>* clipped_edge)
{
const cell_type& cell1 = *edge.cell();
const cell_type& cell2 = *edge.twin()->cell();
point_type origin, direction;
// Infinite edges could not be created by two segment sites.
if (cell1.contains_point() && cell2.contains_point()) {
point_type p1 = retrieve_point(segments, cell1);
point_type p2 = retrieve_point(segments, cell2);
origin.x((p1.x() + p2.x()) * 0.5);
origin.y((p1.y() + p2.y()) * 0.5);
direction.x(p1.y() - p2.y());
direction.y(p2.x() - p1.x());
} else {
origin = cell1.contains_segment() ? retrieve_point(segments, cell2) : retrieve_point(segments, cell1);
segment_type segment = cell1.contains_segment() ? segments[cell1.source_index()] : segments[cell2.source_index()];
coordinate_type dx = high(segment).x() - low(segment).x();
coordinate_type dy = high(segment).y() - low(segment).y();
if ((low(segment) == origin) ^ cell1.contains_point()) {
direction.x(dy);
direction.y(-dx);
} else {
direction.x(-dy);
direction.y(dx);
}
}
coordinate_type koef = bbox_max_size / (std::max)(fabs(direction.x()), fabs(direction.y()));
if (edge.vertex0() == NULL) {
clipped_edge->push_back(point_type(
origin.x() - direction.x() * koef,
origin.y() - direction.y() * koef));
} else {
clipped_edge->push_back(
point_type(edge.vertex0()->x(), edge.vertex0()->y()));
}
if (edge.vertex1() == NULL) {
clipped_edge->push_back(point_type(
origin.x() + direction.x() * koef,
origin.y() + direction.y() * koef));
} else {
clipped_edge->push_back(
point_type(edge.vertex1()->x(), edge.vertex1()->y()));
}
}
inline void sample_curved_edge(const std::vector<segment_type> &segments, const edge_type& edge, std::vector<point_type> &sampled_edge, coordinate_type max_dist)
{
point_type point = edge.cell()->contains_point() ?
retrieve_point(segments, *edge.cell()) :
retrieve_point(segments, *edge.twin()->cell());
segment_type segment = edge.cell()->contains_point() ?
segments[edge.twin()->cell()->source_index()] :
segments[edge.cell()->source_index()];
::boost::polygon::voronoi_visual_utils<coordinate_type>::discretize(point, segment, max_dist, &sampled_edge);
}
} /* namespace Internal */ } // namespace Voronoi
static inline void dump_voronoi_to_svg(const Lines &lines, /* const */ voronoi_diagram<double> &vd, const ThickPolylines *polylines, const char *path)
{
const double scale = 0.2;
const std::string inputSegmentPointColor = "lightseagreen";
const coord_t inputSegmentPointRadius = coord_t(0.09 * scale / SCALING_FACTOR);
const std::string inputSegmentColor = "lightseagreen";
const coord_t inputSegmentLineWidth = coord_t(0.03 * scale / SCALING_FACTOR);
const std::string voronoiPointColor = "black";
const coord_t voronoiPointRadius = coord_t(0.06 * scale / SCALING_FACTOR);
const std::string voronoiLineColorPrimary = "black";
const std::string voronoiLineColorSecondary = "green";
const std::string voronoiArcColor = "red";
const coord_t voronoiLineWidth = coord_t(0.02 * scale / SCALING_FACTOR);
const bool internalEdgesOnly = false;
const bool primaryEdgesOnly = false;
BoundingBox bbox = BoundingBox(lines);
bbox.min.x -= coord_t(1. / SCALING_FACTOR);
bbox.min.y -= coord_t(1. / SCALING_FACTOR);
bbox.max.x += coord_t(1. / SCALING_FACTOR);
bbox.max.y += coord_t(1. / SCALING_FACTOR);
::Slic3r::SVG svg(path, bbox);
if (polylines != NULL)
svg.draw(*polylines, "lime", "lime", voronoiLineWidth);
// bbox.scale(1.2);
// For clipping of half-lines to some reasonable value.
// The line will then be clipped by the SVG viewer anyway.
const double bbox_dim_max = double(bbox.max.x - bbox.min.x) + double(bbox.max.y - bbox.min.y);
// For the discretization of the Voronoi parabolic segments.
const double discretization_step = 0.0005 * bbox_dim_max;
// Make a copy of the input segments with the double type.
std::vector<Voronoi::Internal::segment_type> segments;
for (Lines::const_iterator it = lines.begin(); it != lines.end(); ++ it)
segments.push_back(Voronoi::Internal::segment_type(
Voronoi::Internal::point_type(double(it->a.x), double(it->a.y)),
Voronoi::Internal::point_type(double(it->b.x), double(it->b.y))));
// Color exterior edges.
for (voronoi_diagram<double>::const_edge_iterator it = vd.edges().begin(); it != vd.edges().end(); ++it)
if (!it->is_finite())
Voronoi::Internal::color_exterior(&(*it));
// Draw the end points of the input polygon.
for (Lines::const_iterator it = lines.begin(); it != lines.end(); ++it) {
svg.draw(it->a, inputSegmentPointColor, inputSegmentPointRadius);
svg.draw(it->b, inputSegmentPointColor, inputSegmentPointRadius);
}
// Draw the input polygon.
for (Lines::const_iterator it = lines.begin(); it != lines.end(); ++it)
svg.draw(Line(Point(coord_t(it->a.x), coord_t(it->a.y)), Point(coord_t(it->b.x), coord_t(it->b.y))), inputSegmentColor, inputSegmentLineWidth);
#if 1
// Draw voronoi vertices.
for (voronoi_diagram<double>::const_vertex_iterator it = vd.vertices().begin(); it != vd.vertices().end(); ++it)
if (! internalEdgesOnly || it->color() != Voronoi::Internal::EXTERNAL_COLOR)
svg.draw(Point(coord_t(it->x()), coord_t(it->y())), voronoiPointColor, voronoiPointRadius);
for (voronoi_diagram<double>::const_edge_iterator it = vd.edges().begin(); it != vd.edges().end(); ++it) {
if (primaryEdgesOnly && !it->is_primary())
continue;
if (internalEdgesOnly && (it->color() == Voronoi::Internal::EXTERNAL_COLOR))
continue;
std::vector<Voronoi::Internal::point_type> samples;
std::string color = voronoiLineColorPrimary;
if (!it->is_finite()) {
Voronoi::Internal::clip_infinite_edge(segments, *it, bbox_dim_max, &samples);
if (! it->is_primary())
color = voronoiLineColorSecondary;
} else {
// Store both points of the segment into samples. sample_curved_edge will split the initial line
// until the discretization_step is reached.
samples.push_back(Voronoi::Internal::point_type(it->vertex0()->x(), it->vertex0()->y()));
samples.push_back(Voronoi::Internal::point_type(it->vertex1()->x(), it->vertex1()->y()));
if (it->is_curved()) {
Voronoi::Internal::sample_curved_edge(segments, *it, samples, discretization_step);
color = voronoiArcColor;
} else if (! it->is_primary())
color = voronoiLineColorSecondary;
}
for (std::size_t i = 0; i + 1 < samples.size(); ++i)
svg.draw(Line(Point(coord_t(samples[i].x()), coord_t(samples[i].y())), Point(coord_t(samples[i+1].x()), coord_t(samples[i+1].y()))), color, voronoiLineWidth);
}
#endif
if (polylines != NULL)
svg.draw(*polylines, "blue", voronoiLineWidth);
svg.Close();
}
#endif /* SLIC3R_DEBUG */
// Euclidian distance of two boost::polygon points.
template<typename T>
T dist(const boost::polygon::point_data<T> &p1,const boost::polygon::point_data<T> &p2)
{
T dx = p2.x() - p1.x();
T dy = p2.y() - p1.y();
return sqrt(dx*dx+dy*dy);
}
// Find a foot point of "px" on a segment "seg".
template<typename segment_type, typename point_type>
inline point_type project_point_to_segment(segment_type &seg, point_type &px)
{
typedef typename point_type::coordinate_type T;
const point_type &p0 = low(seg);
const point_type &p1 = high(seg);
const point_type dir(p1.x()-p0.x(), p1.y()-p0.y());
const point_type dproj(px.x()-p0.x(), px.y()-p0.y());
const T t = (dir.x()*dproj.x() + dir.y()*dproj.y()) / (dir.x()*dir.x() + dir.y()*dir.y());
assert(t >= T(-1e-6) && t <= T(1. + 1e-6));
return point_type(p0.x() + t*dir.x(), p0.y() + t*dir.y());
}
template<typename VD, typename SEGMENTS>
inline const typename VD::point_type retrieve_cell_point(const typename VD::cell_type& cell, const SEGMENTS &segments)
{
assert(cell.source_category() == SOURCE_CATEGORY_SEGMENT_START_POINT || cell.source_category() == SOURCE_CATEGORY_SEGMENT_END_POINT);
return (cell.source_category() == SOURCE_CATEGORY_SEGMENT_START_POINT) ? low(segments[cell.source_index()]) : high(segments[cell.source_index()]);
}
template<typename VD, typename SEGMENTS>
inline std::pair<typename VD::coord_type, typename VD::coord_type>
measure_edge_thickness(const VD &vd, const typename VD::edge_type& edge, const SEGMENTS &segments)
{
typedef typename VD::coord_type T;
const typename VD::point_type pa(edge.vertex0()->x(), edge.vertex0()->y());
const typename VD::point_type pb(edge.vertex1()->x(), edge.vertex1()->y());
const typename VD::cell_type &cell1 = *edge.cell();
const typename VD::cell_type &cell2 = *edge.twin()->cell();
if (cell1.contains_segment()) {
if (cell2.contains_segment()) {
// Both cells contain a linear segment, the left / right cells are symmetric.
// Project pa, pb to the left segment.
const typename VD::segment_type segment1 = segments[cell1.source_index()];
const typename VD::point_type p1a = project_point_to_segment(segment1, pa);
const typename VD::point_type p1b = project_point_to_segment(segment1, pb);
return std::pair<T, T>(T(2.)*dist(pa, p1a), T(2.)*dist(pb, p1b));
} else {
// 1st cell contains a linear segment, 2nd cell contains a point.
// The medial axis between the cells is a parabolic arc.
// Project pa, pb to the left segment.
const typename VD::point_type p2 = retrieve_cell_point<VD>(cell2, segments);
return std::pair<T, T>(T(2.)*dist(pa, p2), T(2.)*dist(pb, p2));
}
} else if (cell2.contains_segment()) {
// 1st cell contains a point, 2nd cell contains a linear segment.
// The medial axis between the cells is a parabolic arc.
const typename VD::point_type p1 = retrieve_cell_point<VD>(cell1, segments);
return std::pair<T, T>(T(2.)*dist(pa, p1), T(2.)*dist(pb, p1));
} else {
// Both cells contain a point. The left / right regions are triangular and symmetric.
const typename VD::point_type p1 = retrieve_cell_point<VD>(cell1, segments);
return std::pair<T, T>(T(2.)*dist(pa, p1), T(2.)*dist(pb, p1));
}
}
// Converts the Line instances of Lines vector to VD::segment_type.
template<typename VD>
class Lines2VDSegments
{
public:
Lines2VDSegments(const Lines &alines) : lines(alines) {}
typename VD::segment_type operator[](size_t idx) const {
return typename VD::segment_type(
typename VD::point_type(typename VD::coord_type(lines[idx].a.x), typename VD::coord_type(lines[idx].a.y)),
typename VD::point_type(typename VD::coord_type(lines[idx].b.x), typename VD::coord_type(lines[idx].b.y)));
}
private:
const Lines &lines;
};
void
MedialAxis::build(ThickPolylines* polylines)
{
construct_voronoi(this->lines.begin(), this->lines.end(), &this->vd);
/*
// DEBUG: dump all Voronoi edges
{
for (VD::const_edge_iterator edge = this->vd.edges().begin(); edge != this->vd.edges().end(); ++edge) {
if (edge->is_infinite()) continue;
ThickPolyline polyline;
polyline.points.push_back(Point( edge->vertex0()->x(), edge->vertex0()->y() ));
polyline.points.push_back(Point( edge->vertex1()->x(), edge->vertex1()->y() ));
polylines->push_back(polyline);
}
return;
}
*/
typedef const VD::vertex_type vert_t;
typedef const VD::edge_type edge_t;
// collect valid edges (i.e. prune those not belonging to MAT)
// note: this keeps twins, so it inserts twice the number of the valid edges
this->valid_edges.clear();
{
std::set<const VD::edge_type*> seen_edges;
for (VD::const_edge_iterator edge = this->vd.edges().begin(); edge != this->vd.edges().end(); ++edge) {
// if we only process segments representing closed loops, none if the
// infinite edges (if any) would be part of our MAT anyway
if (edge->is_secondary() || edge->is_infinite()) continue;
// don't re-validate twins
if (seen_edges.find(&*edge) != seen_edges.end()) continue; // TODO: is this needed?
seen_edges.insert(&*edge);
seen_edges.insert(edge->twin());
if (!this->validate_edge(&*edge)) continue;
this->valid_edges.insert(&*edge);
this->valid_edges.insert(edge->twin());
}
}
this->edges = this->valid_edges;
// iterate through the valid edges to build polylines
while (!this->edges.empty()) {
const edge_t* edge = *this->edges.begin();
// start a polyline
ThickPolyline polyline;
polyline.points.push_back(Point( edge->vertex0()->x(), edge->vertex0()->y() ));
polyline.points.push_back(Point( edge->vertex1()->x(), edge->vertex1()->y() ));
polyline.width.push_back(this->thickness[edge].first);
polyline.width.push_back(this->thickness[edge].second);
// remove this edge and its twin from the available edges
(void)this->edges.erase(edge);
(void)this->edges.erase(edge->twin());
// get next points
this->process_edge_neighbors(edge, &polyline);
// get previous points
{
ThickPolyline rpolyline;
this->process_edge_neighbors(edge->twin(), &rpolyline);
polyline.points.insert(polyline.points.begin(), rpolyline.points.rbegin(), rpolyline.points.rend());
polyline.width.insert(polyline.width.begin(), rpolyline.width.rbegin(), rpolyline.width.rend());
polyline.endpoints.first = rpolyline.endpoints.second;
}
assert(polyline.width.size() == polyline.points.size()*2 - 2);
// prevent loop endpoints from being extended
if (polyline.first_point().coincides_with(polyline.last_point())) {
polyline.endpoints.first = false;
polyline.endpoints.second = false;
}
// append polyline to result
polylines->push_back(polyline);
}
#ifdef SLIC3R_DEBUG
{
static int iRun = 0;
dump_voronoi_to_svg(this->lines, this->vd, polylines, debug_out_path("MedialAxis-%d.svg", iRun ++).c_str());
printf("Thick lines: ");
for (ThickPolylines::const_iterator it = polylines->begin(); it != polylines->end(); ++ it) {
ThickLines lines = it->thicklines();
for (ThickLines::const_iterator it2 = lines.begin(); it2 != lines.end(); ++ it2) {
printf("%f,%f ", it2->a_width, it2->b_width);
}
}
printf("\n");
}
#endif /* SLIC3R_DEBUG */
}
void
MedialAxis::build(Polylines* polylines)
{
ThickPolylines tp;
this->build(&tp);
polylines->insert(polylines->end(), tp.begin(), tp.end());
}
void
MedialAxis::process_edge_neighbors(const VD::edge_type* edge, ThickPolyline* polyline)
{
while (true) {
// Since rot_next() works on the edge starting point but we want
// to find neighbors on the ending point, we just swap edge with
// its twin.
const VD::edge_type* twin = edge->twin();
// count neighbors for this edge
std::vector<const VD::edge_type*> neighbors;
for (const VD::edge_type* neighbor = twin->rot_next(); neighbor != twin;
neighbor = neighbor->rot_next()) {
if (this->valid_edges.count(neighbor) > 0) neighbors.push_back(neighbor);
}
// if we have a single neighbor then we can continue recursively
if (neighbors.size() == 1) {
const VD::edge_type* neighbor = neighbors.front();
// break if this is a closed loop
if (this->edges.count(neighbor) == 0) return;
Point new_point(neighbor->vertex1()->x(), neighbor->vertex1()->y());
polyline->points.push_back(new_point);
polyline->width.push_back(this->thickness[neighbor].first);
polyline->width.push_back(this->thickness[neighbor].second);
(void)this->edges.erase(neighbor);
(void)this->edges.erase(neighbor->twin());
edge = neighbor;
} else if (neighbors.size() == 0) {
polyline->endpoints.second = true;
return;
} else {
// T-shaped or star-shaped joint
return;
}
}
}
bool
MedialAxis::validate_edge(const VD::edge_type* edge)
{
// construct the line representing this edge of the Voronoi diagram
const Line line(
Point( edge->vertex0()->x(), edge->vertex0()->y() ),
Point( edge->vertex1()->x(), edge->vertex1()->y() )
);
// discard edge if it lies outside the supplied shape
// this could maybe be optimized (checking inclusion of the endpoints
// might give false positives as they might belong to the contour itself)
if (this->expolygon != NULL) {
if (line.a.coincides_with(line.b)) {
// in this case, contains(line) returns a false positive
if (!this->expolygon->contains(line.a)) return false;
} else {
if (!this->expolygon->contains(line)) return false;
}
}
// retrieve the original line segments which generated the edge we're checking
const VD::cell_type* cell_l = edge->cell();
const VD::cell_type* cell_r = edge->twin()->cell();
const Line &segment_l = this->retrieve_segment(cell_l);
const Line &segment_r = this->retrieve_segment(cell_r);
/*
SVG svg("edge.svg");
svg.draw(*this->expolygon);
svg.draw(line);
svg.draw(segment_l, "red");
svg.draw(segment_r, "blue");
svg.Close();
*/
/* Calculate thickness of the cross-section at both the endpoints of this edge.
Our Voronoi edge is part of a CCW sequence going around its Voronoi cell
located on the left side. (segment_l).
This edge's twin goes around segment_r. Thus, segment_r is
oriented in the same direction as our main edge, and segment_l is oriented
in the same direction as our twin edge.
We used to only consider the (half-)distances to segment_r, and that works
whenever segment_l and segment_r are almost specular and facing. However,
at curves they are staggered and they only face for a very little length
(our very short edge represents such visibility).
Both w0 and w1 can be calculated either towards cell_l or cell_r with equal
results by Voronoi definition.
When cell_l or cell_r don't refer to the segment but only to an endpoint, we
calculate the distance to that endpoint instead. */
coordf_t w0 = cell_r->contains_segment()
? line.a.distance_to(segment_r)*2
: line.a.distance_to(this->retrieve_endpoint(cell_r))*2;
coordf_t w1 = cell_l->contains_segment()
? line.b.distance_to(segment_l)*2
: line.b.distance_to(this->retrieve_endpoint(cell_l))*2;
if (cell_l->contains_segment() && cell_r->contains_segment()) {
// calculate the relative angle between the two boundary segments
double angle = fabs(segment_r.orientation() - segment_l.orientation());
if (angle > PI) angle = 2*PI - angle;
assert(angle >= 0 && angle <= PI);
// fabs(angle) ranges from 0 (collinear, same direction) to PI (collinear, opposite direction)
// we're interested only in segments close to the second case (facing segments)
// so we allow some tolerance.
// this filter ensures that we're dealing with a narrow/oriented area (longer than thick)
// we don't run it on edges not generated by two segments (thus generated by one segment
// and the endpoint of another segment), since their orientation would not be meaningful
if (PI - angle > PI/8) {
// angle is not narrow enough
// only apply this filter to segments that are not too short otherwise their
// angle could possibly be not meaningful
if (w0 < SCALED_EPSILON || w1 < SCALED_EPSILON || line.length() >= this->min_width)
return false;
}
} else {
if (w0 < SCALED_EPSILON || w1 < SCALED_EPSILON)
return false;
}
if (w0 < this->min_width && w1 < this->min_width)
return false;
if (w0 > this->max_width && w1 > this->max_width)
return false;
this->thickness[edge] = std::make_pair(w0, w1);
this->thickness[edge->twin()] = std::make_pair(w1, w0);
return true;
}
const Line&
MedialAxis::retrieve_segment(const VD::cell_type* cell) const
{
return this->lines[cell->source_index()];
}
const Point&
MedialAxis::retrieve_endpoint(const VD::cell_type* cell) const
{
const Line& line = this->retrieve_segment(cell);
if (cell->source_category() == SOURCE_CATEGORY_SEGMENT_START_POINT) {
return line.a;
} else {
return line.b;
}
}
} }
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