/*

	polyspan.h

	Polyspan Header

	Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley

	Copyright (c) 2007, 2008 Chris Moore

	Copyright (c) 2012-2013 Carlos López

	......... ... 2015 Ivan Mahonin

	This package is free software; you can redistribute it and/or

	modify it under the terms of the GNU General Public License as

	published by the Free Software Foundation; either version 2 of

	the License, or (at your option) any later version.

	This package is distributed in the hope that it will be useful,

	but WITHOUT ANY WARRANTY; without even the implied warranty of

	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

	General Public License for more details.

*/

#ifndef _POLYSPAN_H_

#define _POLYSPAN_H_

#include <vector>

#include "geometry.h"

class Polyspan {

public:

	struct PenMark {

		int y, x;

		Real cover, area;

		PenMark(): y(), x(), cover(), area() { }

		PenMark(int xin, int yin, Real c, Real a):

			y(yin), x(xin), cover(c), area(a) { }

		void set(int xin, int yin, Real c, Real a)

			{ y = yin; x = xin; cover = c; area = a; }

		void setcoord(int xin, int yin)

			{ y = yin; x = xin;	}

		void setcover(Real c, Real a)

			{ cover	= c; area = a; }

		void addcover(Real c, Real a)

			{ cover += c; area += a; }

		bool operator < (const PenMark &rhs) const

			{ return y == rhs.y ? x < rhs.x : y < rhs.y; }

	};

	typedef	std::vector<PenMark> cover_array;

	//for assignment to flags value

	enum PolySpanFlags {

		NotSorted = 0x8000,

		NotClosed =	0x4000

	};

	enum {

		MAX_SUBDIVISION_SIZE = 64,

		MIN_SUBDIVISION_DRAW_LEVELS = 4

	};

private:

	Vector			arc[3*MAX_SUBDIVISION_SIZE + 1];

	cover_array		covers;

	PenMark			current;

	int				open_index;

	//ending position of last primitive

	Real			cur_x;

	Real			cur_y;

	//starting position of current primitive list

	Real			close_x;

	Real			close_y;

	//flags for the current segment

	int				flags;

	//the window that will be drawn (used for clipping)

	ContextRect		window;

	//add the current cell, but only if there is information to add

	void addcurrent();

	//move to the next cell (cover values 0 initially), keeping the current if necessary

	void move_pen(int x, int y);

	static bool clip_conic(const Vector *p, const ContextRect &r);

	static Real max_edges_conic(const Vector *p);

	static void subd_conic_stack(Vector *arc);

	static bool clip_cubic(const Vector *p, const ContextRect &r);

	static Real max_edges_cubic(const Vector *p);

	static void subd_cubic_stack(Vector *arc);

public:

	Polyspan();

	const ContextRect& get_window() const { return window; }

	const cover_array& get_covers() const { return covers; }

	bool notclosed() const

		{ return (flags & NotClosed) || (cur_x != close_x) || (cur_y != close_y); }

	//0 out all the variables involved in processing

	void clear();

	void init(const ContextRect &window)

		{ clear(); this->window = window; }

	void init(int minx, int miny, int maxx, int maxy)

	{

		clear();

		window.minx = minx;

		window.miny = miny;

		window.maxx = maxx;

		window.maxy = maxy;

	}

	//close the primitives with a line (or rendering will not work as expected)

	void close();

	// Not recommended - destroys any separation of spans currently held

	void merge_all();

	//will sort the marks if they are not sorted

	void sort_marks();

	//encapsulate the current sublist of marks (used for drawing)

	void encapsulate_current();

	//move to start a new primitive list (enclose the last primitive if need be)

	void move_to(Real x, Real y);

	//primitive_to functions

	void line_to(Real x, Real y);

	void conic_to(Real x1, Real y1, Real x, Real y);

	void cubic_to(Real x1, Real y1, Real x2, Real y2, Real x, Real y);

	void draw_scanline(int y, Real x1, Real y1, Real x2, Real y2);

	void draw_line(Real x1, Real y1, Real x2, Real y2);

	Real extract_alpha(Real area, bool evenodd) const;

};

#endif