only part of the logic for animating rectangular point and line generata as a series of strokes

pointAndConnectionAnimation.cpp

void FolkBodySpec::prepAnimation(){
	//start by identifying clusters
	auto groupColorings = fillCopies(itemTrayDimensionX*itemTrayDimensionY, 0);
	u8 nextColoring = 1;
	vector<Coord> centralNode;
	overRegion(itemTrayDimensionX, itemTrayDimensionY, [&](Coord c){
		uint ik = itemOffset(c);
		if(locatedItems[ik]){
			u8 gc;
			if(!groupColorings[ik]){
				centralNode.push_back(c);
				groupColorings[ik] = gc = nextColoring;
				++nextColoring;
			}else{
				gc = groupColorings[ik];
			}
			//extend coloring to connected ones
			if(horizontalConnectionFrom(c)){
				Coord right = c+Coord(1,0);
				groupColorings[itemOffset(right)] = gc;
			}
			if(verticalConnectionFrom(c)){
				Coord above = c+Coord(0,1);
				groupColorings[itemOffset(above)] = gc;
			}
			// centralNode[gc-1] = c;
		}
	});
	//from now on we'll use the groupColorings to flag visitedness. 0 means visited.
	//now, over each starting node
	for(Coord sn : centralNode){
		vector<pair<Coord,Coord>> remainders;
		if(horizontalConnectionFrom(sn)){
			remainders.push_back({sn, sn.east()});
		}
		if(verticalConnectionFrom(sn)){
			remainders.push_back({sn, sn.south()});
		}
		if(remainders.size() == 0){
			lineAnimations.push_back({{sn}});
		}else{
			vector<vector<Coord>> lines;
			//over each remainder until the lines are done
			do{
				vector<Coord> line;
				auto visit = [&](Coord p){
					line.push_back(p);
					groupColorings[itemOffset(p)] = 0;
				}
				auto p = remainders.pop();
				visit(p.first);
				Coord prev = p.first;
				Coord cur = p.second;
				while(true){
					visit(cur);
					while(true){
						//loop over neighbors connected to cur that aren't prev
						vector<Coord> neighbors;
						if(horizontalConnectionFrom(cur) && cur.east() != prev){ neighbors.push_back(cur.east()); }
						if(verticalConnectionFrom(cur) && cur.north() != prev){ neighbors.push_back(cur.north()); }
						if(verticalConnectionFrom(cur.south()) && cur.south() != prev){ neighbors.push_back(cur.south()); }
						if(horizontalConnectionFrom(cur.west()) && cur.west() != prev){ neighbors.push_back(cur.west()); }
						if(neighbors.size() == 0){
							goto doneLine;
						}else{
							bool foundOneUnvisitedNeighbor = false;
							for(Coord neigh : neighbors){
								if(groupColorings[itemOffset(neigh)]){
									if(foundOneUnvisitedNeighbor){
										remainders.push_back({cur, neigh});
									}else{
										prev = cur;
										cur = neigh;
										foundOneUnvisitedNeighbor = true;
									}
								}else{
									//remove the remainder connecting to that, I think there must have been one, I'd assert it if that were easy
									filterInPlace(remainders, [&](pair<Coord, Coord> p){ return p.first == neigh && p.second == cur; });
									visit(neigh);
									goto doneLine;
								}
							}
						}
					}
				}
				doneLine:
				lines.emplace_back(move(line));
			}while(!remainders.empty());
			lineAnimations.emplace_back(move(lines));
		}
	}
}