// This example was started by Guillaume Laurent.

 // It has become a place to dump code that tests parts of the

 // gnomemm canvas code. Little thought has been given to the

 // actual on-screen output.

 #include <libgnomecanvasmm.h>

 #include <libgnomecanvasmm/polygon.h>

 #include <iostream>

 class CanvasExample : public Gnome::Canvas::CanvasAA

 {

 	typedef Gnome::Canvas::CanvasAA Parent;

 public:

 	CanvasExample(double *, int);

 	virtual ~CanvasExample();

 private:

 	///Event handler function that handles dragging nodes of triangle

 	bool event_handler(GdkEvent* e, bool b);

 	///Event handler function that handles dragging triangle

 	bool tri_mover(GdkEvent* e, bool b);

 	///Coordinates of Weight Point of tirangle

 	Gnome::Art::Point * wp;

 	///Array of nodes of planefigure

 	Gnome::Canvas::Ellipse ** nodes;

 	///Sides of planefigure

 	Gnome::Canvas::Polygon * sides;

 	///Group of graphical elements of triangle

 	Gnome::Canvas::Group triangle;

 	///Indicates whether the button of mouse is pressed or not

 	bool isbutton;

 	///Number Of Elements - the number of nodes

 	int noe;

 	///At this location was the mousebutton pressed.

 	///It helps to calculate the distance of dragging.

 	double clicked_x, clicked_y;

 	///Remembers which Gnome::Canvas::Item was pressed.

 	///this variable is needed, because

 	///1. we cannot query the item at he cursor as fast as it could not cause a Segmentation Fault

 	///2. we would like to handle only ony item per movement, therefore quering it is not a working solution

 	Gnome::Canvas::Item * active_item;

 };

 ///When we click on the weight point we can drag the whole triangle. This function resolves it.

 bool CanvasExample::tri_mover(GdkEvent* e, bool b)

 {

 	b=b;

 	switch(e->type)

 	{

 		case GDK_BUTTON_PRESS:

 			clicked_x=e->button.x;

 			clicked_y=e->button.y;

 			isbutton=true;

 			break;

 		case GDK_BUTTON_RELEASE:

 			isbutton=false;

 			active_item=NULL;

 			break;

 		case GDK_MOTION_NOTIFY:

 			if(isbutton)

 			{

 				double dx=e->motion.x-clicked_x;

 				double dy=e->motion.y-clicked_y;

 				for(int i=0;i<=noe;i++)

 				{

 					nodes[i]->move(dx,dy);

 				}

 				clicked_x=e->motion.x;

 				clicked_y=e->motion.y;

 				Gnome::Canvas::Points coos;

 				for(int i=0;i<noe;i++)

 				{

 					double x1,y1,x2,y2;

 					nodes[i]->get_bounds(x1,y1,x2,y2);

 					double x=(x1+x2)/2;

 					double y=(y1+y2)/2;

 					coos.push_back(Gnome::Art::Point(x, y));

 				}

 				sides->property_points().set_value(coos);

 			}

 		default: break;

 	}

 	return true;

 }

 ///This function moves only one node of triangle,

 ///but recalculate the location of wight point,

 ///and also redraw the sides of the planefigure.

 bool CanvasExample::event_handler(GdkEvent* e, bool b)

 {

 	b=b;

 	switch(e->type)

 	{

 		case GDK_BUTTON_PRESS:

 			clicked_x=e->button.x;

 			clicked_y=e->button.y;

 			active_item=(get_item_at(e->button.x, e->button.y));

 			isbutton=true;

 			break;

 		case GDK_BUTTON_RELEASE:

 			isbutton=false;

 			active_item=NULL;

 			break;

 		case GDK_MOTION_NOTIFY:

 			if(isbutton)

 			{

 				//double x1, y1, x2, y2;

 				//(get_item_at(e->motion.x, e->motion.y))->get_bounds(x1, y1, x2, y2);

 				//printf("Item coos: %d %d %d %d\n", (int)x1, (int)y1, (int)x2, (int)y2);

 				//printf("Mouse is moved! %d %d\n",(int)e->motion.x,(int)e->motion.y);

 				double dx=e->motion.x-clicked_x;

 				double dy=e->motion.y-clicked_y;

 				active_item->move(dx, dy);

 				Gnome::Canvas::Points coos;

 				double x_wp=0;

 				double y_wp=0;

 				for(int i=0;i<noe;i++)

 				{

 					double x1,y1,x2,y2;

 					nodes[i]->get_bounds(x1,y1,x2,y2);

 					double x=(x1+x2)/2;

 					double y=(y1+y2)/2;

 					coos.push_back(Gnome::Art::Point(x, y));

 					x_wp+=x;

 					y_wp+=y;

 				}

 				sides->property_points().set_value(coos);

 				x_wp/=noe;

 				y_wp/=noe;

 				double x1,y1,x2,y2;

 				nodes[noe]->get_bounds(x1,y1,x2,y2);

 				double x=(x1+x2)/2;

 				double y=(y1+y2)/2;

 				dx=x_wp-x;

 				dy=y_wp-y;

 				nodes[noe]->move(dx, dy);

 				clicked_x=e->motion.x;

 				clicked_y=e->motion.y;

 			}

 		default: break;

 	}

 	return true;

 }

 CanvasExample::CanvasExample(double * coosarray, int numofcoos):triangle(*(root()), 0, 0),isbutton(false),active_item(NULL)

 {

 	noe=numofcoos/2;

 	double x_wp=0;

 	double y_wp=0;

 	Gnome::Canvas::Points coos;

 	for(int i=0;i<numofcoos;i++)

 	{

 		double x=coosarray[i++];

 		double y=coosarray[i];

 		coos.push_back(Gnome::Art::Point(x, y));

 		x_wp+=x;

 		y_wp+=y;

 	}

 	sides=new Gnome::Canvas::Polygon(triangle, coos);

 	*sides << Gnome::Canvas::Properties::outline_color("green");

 	sides->property_width_pixels().set_value(10);

 	nodes=new Gnome::Canvas::Ellipse* [noe+1];

 	for(int i=0; i<noe;i++)

 	{

 		nodes[i]= new Gnome::Canvas::Ellipse(triangle, coos[i].get_x()-20, coos[i].get_y()-20, coos[i].get_x()+20, coos[i].get_y()+20);

 		*(nodes[i]) << Gnome::Canvas::Properties::fill_color("blue");

 		*(nodes[i]) << Gnome::Canvas::Properties::outline_color("black");

 		(nodes[i])->signal_event().connect(sigc::bind(sigc::mem_fun(*this, &CanvasExample::event_handler),true));

 	}

 	wp=new Gnome::Art::Point(x_wp/noe,y_wp/noe);

 	nodes[noe]= new Gnome::Canvas::Ellipse(triangle, wp->get_x()-20, wp->get_y()-20, wp->get_x()+20, wp->get_y()+20);

 	*(nodes[noe]) << Gnome::Canvas::Properties::fill_color("blue");

 	*(nodes[noe]) << Gnome::Canvas::Properties::outline_color("black");

 	(nodes[noe])->signal_event().connect(sigc::bind(sigc::mem_fun(*this, &CanvasExample::tri_mover),true));

 }

 CanvasExample::~CanvasExample()

 {

 }

 //MainWin:

 class MainWin : public Gtk::Window

 {

 public:

 	MainWin(const std::string& title, double *, int);

 protected:

 	//Member widgets:

 	CanvasExample m_canvas;

 };

 MainWin::MainWin(const std::string& title, double * coosarray, int noc):m_canvas(coosarray, noc)

 {

 	set_title (title);

 	add(m_canvas);

 	set_default_size(900,600);

 	show_all();

 }

 //main():

 int main(int argc, char *argv[])

 {

 	if((argc>=7)&&( (argc/2)!=( (argc+1)/2 ) ) )

 	{

 		double * coosarray=new double[argc];

 		for(int i=1;i<argc;i++)

 		{

 			coosarray[i-1]=atof(argv[i]);

 		}

 		Gnome::Canvas::init();

 		Gtk::Main app(argc, argv);

 		MainWin mainwin("Magic Triangle",coosarray,argc-1);

 		app.run(mainwin);

 	}

 	return 0;

 }