create/src/Mod/Path/libarea/AreaPocket.cpp

// AreaPocket.cpp
// implements CArea::MakeOnePocketCurve

/*==============================
Copyright (c) 2011-2015 Dan Heeks

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
==============================*/


#include "Area.h"

#include <map>
#include <set>

static const CAreaPocketParams* pocket_params = NULL;

class IslandAndOffset
{
public:
	const CCurve* island;
	CArea offset;
	std::list<CCurve> island_inners;
	std::list<IslandAndOffset*> touching_offsets;

	IslandAndOffset(const CCurve* Island)
	{
		island = Island;

		offset.m_curves.push_back(*island);
		offset.m_curves.back().Reverse();

		offset.Offset(-pocket_params->stepover);


		if(offset.m_curves.size() > 1)
		{
			for(std::list<CCurve>::iterator It = offset.m_curves.begin(); It != offset.m_curves.end(); It++)
			{
				if(It == offset.m_curves.begin())continue;
				island_inners.push_back(*It);
				island_inners.back().Reverse();
			}
			offset.m_curves.resize(1);
		}
	}
};

class CurveTree
{
	static std::list<CurveTree*> to_do_list_for_MakeOffsets;
	void MakeOffsets2();
	static std::list<CurveTree*> islands_added;

public:
	Point point_on_parent;
	CCurve curve;
	std::list<CurveTree*> inners;
	std::list<const IslandAndOffset*> offset_islands;
	CurveTree(const CCurve &c)
	{
		curve = c;
	}
	~CurveTree(){}

	void MakeOffsets();
};
std::list<CurveTree*> CurveTree::islands_added;

class GetCurveItem
{
public:
	CurveTree* curve_tree;
	std::list<CVertex>::iterator EndIt;
	static std::list<GetCurveItem> to_do_list;

	GetCurveItem(CurveTree* ct, std::list<CVertex>::iterator EIt):curve_tree(ct), EndIt(EIt){}

	void GetCurve(CCurve& output);
	CVertex& back(){std::list<CVertex>::iterator It = EndIt; It--; return *It;}
};

std::list<GetCurveItem> GetCurveItem::to_do_list;
std::list<CurveTree*> CurveTree::to_do_list_for_MakeOffsets;

void GetCurveItem::GetCurve(CCurve& output)
{
	// walk around the curve adding spans to output until we get to an inner's point_on_parent
	// then add a line from the inner's point_on_parent to inner's start point, then GetCurve from inner

	// add start point
	if(CArea::m_please_abort)return;
	output.m_vertices.insert(this->EndIt, CVertex(curve_tree->curve.m_vertices.front()));

	std::list<CurveTree*> inners_to_visit;
	for(std::list<CurveTree*>::iterator It2 = curve_tree->inners.begin(); It2 != curve_tree->inners.end(); It2++)
	{
		inners_to_visit.push_back(*It2);
	}

	const CVertex* prev_vertex = NULL;

	for(std::list<CVertex>::iterator It = curve_tree->curve.m_vertices.begin(); It != curve_tree->curve.m_vertices.end(); It++)
	{
		const CVertex& vertex = *It;
		if(prev_vertex)
		{
			Span span(prev_vertex->m_p, vertex);

			// order inners on this span
			std::multimap<double, CurveTree*> ordered_inners;
			for(std::list<CurveTree*>::iterator It2 = inners_to_visit.begin(); It2 != inners_to_visit.end();)
			{
				CurveTree *inner = *It2;
				double t;
				if(span.On(inner->point_on_parent, &t))
				{
					ordered_inners.insert(std::make_pair(t, inner));
					It2 = inners_to_visit.erase(It2);
				}
				else
				{
					It2++;
				}
				if(CArea::m_please_abort)return;
			}

			if(CArea::m_please_abort)return;
			for(std::multimap<double, CurveTree*>::iterator It2 = ordered_inners.begin(); It2 != ordered_inners.end(); It2++)
			{
				CurveTree& inner = *(It2->second);
				if(inner.point_on_parent.dist(back().m_p) > 0.01/CArea::m_units)
				{
					output.m_vertices.insert(this->EndIt, CVertex(vertex.m_type, inner.point_on_parent, vertex.m_c));
				}
				if(CArea::m_please_abort)return;

				// vertex add after GetCurve
				std::list<CVertex>::iterator VIt = output.m_vertices.insert(this->EndIt, CVertex(inner.point_on_parent));

				//inner.GetCurve(output);
				GetCurveItem::to_do_list.push_back(GetCurveItem(&inner, VIt));
			}

			if(back().m_p != vertex.m_p)output.m_vertices.insert(this->EndIt, vertex);
		}
		prev_vertex = &vertex;
	}

	if(CArea::m_please_abort)return;
	for(std::list<CurveTree*>::iterator It2 = inners_to_visit.begin(); It2 != inners_to_visit.end(); It2++)
	{
		CurveTree &inner = *(*It2);
		if(inner.point_on_parent != back().m_p)
		{
			output.m_vertices.insert(this->EndIt, CVertex(inner.point_on_parent));
		}
		if(CArea::m_please_abort)return;

		// vertex add after GetCurve
		std::list<CVertex>::iterator VIt = output.m_vertices.insert(this->EndIt, CVertex(inner.point_on_parent));

		//inner.GetCurve(output);
		GetCurveItem::to_do_list.push_back(GetCurveItem(&inner, VIt));

	}
}

class IslandAndOffsetLink
{
public:
	const IslandAndOffset* island_and_offset;
	CurveTree* add_to;
	IslandAndOffsetLink(const IslandAndOffset* i, CurveTree* a){island_and_offset = i; add_to = a;}
};

static Point GetNearestPoint(CurveTree* curve_tree, std::list<CurveTree*> &islands_added, const CCurve &test_curve, CurveTree** best_curve_tree)
{
	// find nearest point to test_curve, from curve and all the islands in 
	double best_dist;
	Point best_point = curve_tree->curve.NearestPoint(test_curve, &best_dist);
	*best_curve_tree = curve_tree;
	for(std::list<CurveTree*>::iterator It = islands_added.begin(); It != islands_added.end(); It++)
	{
		CurveTree* island = *It;
		double dist;
		Point p = island->curve.NearestPoint(test_curve, &dist);
		if(dist < best_dist)
		{
			*best_curve_tree = island;
			best_point = p;
			best_dist = dist;
		}
	}

	return best_point;
}

void CurveTree::MakeOffsets2()
{
	// make offsets

	if(CArea::m_please_abort)return;
	CArea smaller;
	smaller.m_curves.push_back(curve);
	smaller.Offset(pocket_params->stepover);

	if(CArea::m_please_abort)return;

	// test islands
	for(std::list<const IslandAndOffset*>::iterator It = offset_islands.begin(); It != offset_islands.end();)
	{
		const IslandAndOffset* island_and_offset = *It;

		if(GetOverlapType(island_and_offset->offset, smaller) == eInside)
			It++; // island is still inside
		else
		{
			inners.push_back(new CurveTree(*island_and_offset->island));
			islands_added.push_back(inners.back());
			inners.back()->point_on_parent = curve.NearestPoint(*island_and_offset->island);
			if(CArea::m_please_abort)return;
			Point island_point = island_and_offset->island->NearestPoint(inners.back()->point_on_parent);
			if(CArea::m_please_abort)return;
			inners.back()->curve.ChangeStart(island_point);
			if(CArea::m_please_abort)return;

			// add the island offset's inner curves
			for(std::list<CCurve>::const_iterator It2 = island_and_offset->island_inners.begin(); It2 != island_and_offset->island_inners.end(); It2++)
			{
				const CCurve& island_inner = *It2;
				inners.back()->inners.push_back(new CurveTree(island_inner));
				inners.back()->inners.back()->point_on_parent = inners.back()->curve.NearestPoint(island_inner);
				if(CArea::m_please_abort)return;
				Point island_point = island_inner.NearestPoint(inners.back()->inners.back()->point_on_parent);
				if(CArea::m_please_abort)return;
				inners.back()->inners.back()->curve.ChangeStart(island_point);
				to_do_list_for_MakeOffsets.push_back(inners.back()->inners.back()); // do it later, in a while loop
				if(CArea::m_please_abort)return;
			}

			smaller.Subtract(island_and_offset->offset);

			std::set<const IslandAndOffset*> added;

			std::list<IslandAndOffsetLink> touching_list;
			for(std::list<IslandAndOffset*>::const_iterator It2 = island_and_offset->touching_offsets.begin(); It2 != island_and_offset->touching_offsets.end(); It2++)
			{
				const IslandAndOffset* touching = *It2;
				touching_list.push_back(IslandAndOffsetLink(touching, inners.back()));
				added.insert(touching);
			}

			while(touching_list.size() > 0)
			{
				IslandAndOffsetLink touching = touching_list.front();
				touching_list.pop_front();
				touching.add_to->inners.push_back(new CurveTree(*touching.island_and_offset->island));
				islands_added.push_back(touching.add_to->inners.back());
				touching.add_to->inners.back()->point_on_parent = touching.add_to->curve.NearestPoint(*touching.island_and_offset->island);
				Point island_point = touching.island_and_offset->island->NearestPoint(touching.add_to->inners.back()->point_on_parent);
				touching.add_to->inners.back()->curve.ChangeStart(island_point);
				smaller.Subtract(touching.island_and_offset->offset);

				// add the island offset's inner curves
				for(std::list<CCurve>::const_iterator It2 = touching.island_and_offset->island_inners.begin(); It2 != touching.island_and_offset->island_inners.end(); It2++)
				{
					const CCurve& island_inner = *It2;
					touching.add_to->inners.back()->inners.push_back(new CurveTree(island_inner));
					touching.add_to->inners.back()->inners.back()->point_on_parent = touching.add_to->inners.back()->curve.NearestPoint(island_inner);
					if(CArea::m_please_abort)return;
					Point island_point = island_inner.NearestPoint(touching.add_to->inners.back()->inners.back()->point_on_parent);
					if(CArea::m_please_abort)return;
					touching.add_to->inners.back()->inners.back()->curve.ChangeStart(island_point);
					to_do_list_for_MakeOffsets.push_back(touching.add_to->inners.back()->inners.back()); // do it later, in a while loop
					if(CArea::m_please_abort)return;
				}

				for(std::list<IslandAndOffset*>::const_iterator It2 = touching.island_and_offset->touching_offsets.begin(); It2 != touching.island_and_offset->touching_offsets.end(); It2++)
				{
					if(added.find(*It2)==added.end() && ((*It2) != island_and_offset))
					{
						touching_list.push_back(IslandAndOffsetLink(*It2, touching.add_to->inners.back()));
						added.insert(*It2);
					}
				}
			}

			if(CArea::m_please_abort)return;
			It = offset_islands.erase(It);

			for(std::set<const IslandAndOffset*>::iterator It2 = added.begin(); It2 != added.end(); It2++)
			{
				const IslandAndOffset* i = *It2;
				offset_islands.remove(i);
			}

			if(offset_islands.size() == 0)break;
			It = offset_islands.begin();
		}
	}

	CArea::m_processing_done += CArea::m_MakeOffsets_increment;
	if(CArea::m_processing_done > CArea::m_after_MakeOffsets_length)CArea::m_processing_done = CArea::m_after_MakeOffsets_length;

	std::list<CArea> separate_areas;
	smaller.Split(separate_areas);
	if(CArea::m_please_abort)return;
	for(std::list<CArea>::iterator It = separate_areas.begin(); It != separate_areas.end(); It++)
	{
		CArea& separate_area = *It;
		CCurve& first_curve = separate_area.m_curves.front();

		CurveTree* nearest_curve_tree = NULL;
		Point near_point = GetNearestPoint(this, islands_added, first_curve, &nearest_curve_tree);

		nearest_curve_tree->inners.push_back(new CurveTree(first_curve));

		for(std::list<const IslandAndOffset*>::iterator It = offset_islands.begin(); It != offset_islands.end();It++)
		{
			const IslandAndOffset* island_and_offset = *It;
			if(GetOverlapType(island_and_offset->offset, separate_area) == eInside)
				nearest_curve_tree->inners.back()->offset_islands.push_back(island_and_offset);
			if(CArea::m_please_abort)return;
		}

		nearest_curve_tree->inners.back()->point_on_parent = near_point;

		if(CArea::m_please_abort)return;
		Point first_curve_point = first_curve.NearestPoint(nearest_curve_tree->inners.back()->point_on_parent);
		if(CArea::m_please_abort)return;
		nearest_curve_tree->inners.back()->curve.ChangeStart(first_curve_point);
		if(CArea::m_please_abort)return;
		to_do_list_for_MakeOffsets.push_back(nearest_curve_tree->inners.back()); // do it later, in a while loop
		if(CArea::m_please_abort)return;
	}
}

void CurveTree::MakeOffsets()
{
	to_do_list_for_MakeOffsets.push_back(this);
	islands_added.clear();

	while(to_do_list_for_MakeOffsets.size() > 0)
	{
		CurveTree* curve_tree = to_do_list_for_MakeOffsets.front();
		to_do_list_for_MakeOffsets.pop_front();
		curve_tree->MakeOffsets2();
	}
}

void recur(std::list<CArea> &arealist, const CArea& a1, const CAreaPocketParams &params, int level)
{
	//if(level > 3)return;

    // this makes arealist by recursively offsetting a1 inwards
    
	if(a1.m_curves.size() == 0)
		return;
    
	if(params.from_center)
		arealist.push_front(a1);
	else
		arealist.push_back(a1);

    CArea a_offset = a1;
    a_offset.Offset(params.stepover);
    
    // split curves into new areas
	if(CArea::HolesLinked())
	{
		for(std::list<CCurve>::iterator It = a_offset.m_curves.begin(); It != a_offset.m_curves.end(); It++)
		{
            CArea a2;
			a2.m_curves.push_back(*It);
            recur(arealist, a2, params, level + 1);
		}
	}
    else
	{
        // split curves into new areas
		a_offset.Reorder();
        CArea* a2 = NULL;
       
		for(std::list<CCurve>::iterator It = a_offset.m_curves.begin(); It != a_offset.m_curves.end(); It++)
		{
			CCurve& curve = *It;
			if(curve.IsClockwise())
			{
				if(a2 != NULL)
					a2->m_curves.push_back(curve);
			}
			else
			{
				if(a2 != NULL)
					recur(arealist, *a2, params, level + 1);
				else
					a2 = new CArea();
                a2->m_curves.push_back(curve);
			}
		}

		if(a2 != NULL)
			recur(arealist, *a2, params, level + 1);
	}
}

#if 0
static CArea make_obround(const Point& p0, const Point& p1, double radius)
{
    Point dir = p1 - p0;
    dir.normalize();
    Point right(dir.y, -dir.x);
    CArea obround;
    CCurve c;
    if(fabs(radius) < 0.0000001)radius = (radius > 0.0) ? 0.002 : (-0.002);
    Point vt0 = p0 + right * radius;
    Point vt1 = p1 + right * radius;
    Point vt2 = p1 - right * radius;
    Point vt3 = p0 - right * radius;
    c.append(vt0);
    c.append(vt1);
    c.append(CVertex(1, vt2, p1));
    c.append(vt3);
    c.append(CVertex(1, vt0, p0));
    obround.append(c);
    return obround;
}
#endif

#if 0
static bool feed_possible(const CArea &area_for_feed_possible, const Point& p0, const Point& p1, double tool_radius)
{
    CArea obround = make_obround(p0, p1, tool_radius);
    obround.Subtract(area_for_feed_possible);
    return obround.m_curves.empty();
}
#endif

void MarkOverlappingOffsetIslands(std::list<IslandAndOffset> &offset_islands)
{
	for(std::list<IslandAndOffset>::iterator It1 = offset_islands.begin(); It1 != offset_islands.end(); It1++)
	{
		std::list<IslandAndOffset>::iterator It2 = It1;
		It2++;
		for(;It2 != offset_islands.end(); It2++)
		{
			IslandAndOffset &o1 = *It1;
			IslandAndOffset &o2 = *It2;

			if(GetOverlapType(o1.offset, o2.offset) == eCrossing)
			{
				o1.touching_offsets.push_back(&o2);
				o2.touching_offsets.push_back(&o1);
			}
		}
	}
}

void CArea::MakeOnePocketCurve(std::list<CCurve> &curve_list, const CAreaPocketParams &params)const
{
	if(CArea::m_please_abort)return;
#if 0  // simple offsets with feed or rapid joins
	CArea area_for_feed_possible = *this;

	area_for_feed_possible.Offset(-params.tool_radius - 0.01);
	CArea a_offset = *this;

	std::list<CArea> arealist;
	recur(arealist, a_offset, params, 0);

	bool first = true;

	for(std::list<CArea>::iterator It = arealist.begin(); It != arealist.end(); It++)
	{
		CArea& area = *It;
		for(std::list<CCurve>::iterator It = area.m_curves.begin(); It != area.m_curves.end(); It++)
		{
			CCurve& curve = *It;
			if(!first)
			{
				// try to join these curves with a feed move, if possible and not too long
				CCurve &prev_curve = curve_list.back();
				const Point &prev_p = prev_curve.m_vertices.back().m_p;
				const Point &next_p = curve.m_vertices.front().m_p;

				if(feed_possible(area_for_feed_possible, prev_p, next_p, params.tool_radius))
				{
					// join curves
					prev_curve += curve;
				}
				else
				{
					curve_list.push_back(curve);
				}
			}
			else
			{
				curve_list.push_back(curve);
			}
			first = false;
		}
	}
#else
	pocket_params = &params;
	if(m_curves.size() == 0)
	{
		CArea::m_processing_done += CArea::m_single_area_processing_length;
		return;
	}
	CurveTree top_level(m_curves.front());

	std::list<IslandAndOffset> offset_islands;

	for(std::list<CCurve>::const_iterator It = m_curves.begin(); It != m_curves.end(); It++)
	{
		const CCurve& c = *It;
		if(It != m_curves.begin())
		{
			IslandAndOffset island_and_offset(&c);
			offset_islands.push_back(island_and_offset);
			top_level.offset_islands.push_back(&(offset_islands.back()));
			if(m_please_abort)return;
		}
	}

	MarkOverlappingOffsetIslands(offset_islands);

	CArea::m_processing_done += CArea::m_single_area_processing_length * 0.1;

	double MakeOffsets_processing_length = CArea::m_single_area_processing_length * 0.8;
	CArea::m_after_MakeOffsets_length = CArea::m_processing_done + MakeOffsets_processing_length;
	double guess_num_offsets = sqrt(GetArea(true)) * 0.5 / params.stepover;
	CArea::m_MakeOffsets_increment = MakeOffsets_processing_length / guess_num_offsets;

	top_level.MakeOffsets();
	if(CArea::m_please_abort)return;
	CArea::m_processing_done = CArea::m_after_MakeOffsets_length;

	curve_list.push_back(CCurve());
	CCurve& output = curve_list.back();

	GetCurveItem::to_do_list.push_back(GetCurveItem(&top_level, output.m_vertices.end()));

	while(GetCurveItem::to_do_list.size() > 0)
	{
		GetCurveItem item = GetCurveItem::to_do_list.front();
		item.GetCurve(output);
		GetCurveItem::to_do_list.pop_front();
	}

	// delete curve_trees non-recursively
	std::list<CurveTree*> CurveTreeDestructList;
	for(std::list<CurveTree*>::iterator It = top_level.inners.begin(); It != top_level.inners.end(); It++)
	{
		CurveTreeDestructList.push_back(*It);
	}
	while(CurveTreeDestructList.size() > 0)
	{
		CurveTree* curve_tree = CurveTreeDestructList.front();
		CurveTreeDestructList.pop_front();
		for(std::list<CurveTree*>::iterator It = curve_tree->inners.begin(); It != curve_tree->inners.end(); It++)
		{
			CurveTreeDestructList.push_back(*It);
		}
		delete curve_tree;
	}

	CArea::m_processing_done += CArea::m_single_area_processing_length * 0.1;
#endif
}