diff -r 984723507b86 -r 6cc7b573b7b5 src/work/peter/magic_plane_figure.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/work/peter/magic_plane_figure.cc	Fri Apr 01 09:43:52 2005 +0000
@@ -0,0 +1,269 @@
+// 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>
+#include <lemon/list_graph.h>
+
+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, int b);
+
+	///Event handler function that handles dragging triangle
+	bool tri_mover(GdkEvent* e);
+
+	///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;
+
+	///Array of coordinates
+	double * coordinates;
+
+	///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)
+{
+	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;
+
+				Gnome::Canvas::Points coos;
+
+				for(int i=0;i<=noe;i++)
+				{
+					nodes[i]->move(dx,dy);
+
+					double x=(coordinates[2*i]+=dx);
+					double y=(coordinates[2*i+1]+=dy);
+
+					if(i!=noe)coos.push_back(Gnome::Art::Point(x,y));
+
+				}
+
+				clicked_x=e->motion.x;
+				clicked_y=e->motion.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, int 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);
+
+				coordinates[2*b]+=dx;
+				coordinates[2*b+1]+=dy;
+
+				Gnome::Canvas::Points coos;
+
+				double x_wp=0;
+				double y_wp=0;
+
+				for(int i=0;i<noe;i++)
+				{
+					coos.push_back(Gnome::Art::Point(coordinates[2*i], coordinates[2*i+1]));
+
+					x_wp+=coordinates[2*i];
+					y_wp+=coordinates[2*i+1];
+				}
+
+				sides->property_points().set_value(coos);
+
+				x_wp/=noe;
+				y_wp/=noe;
+
+				dx=x_wp-coordinates[noe*2];
+				dy=y_wp-coordinates[noe*2+1];
+				nodes[noe]->move(dx, dy);
+
+				coordinates[noe*2]+=dx;
+				coordinates[noe*2+1]+=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;
+
+	coordinates=new double [numofcoos+2];
+
+	double x_wp=0;
+	double y_wp=0;
+
+	Gnome::Canvas::Points coos;
+	for(int i=0;i<numofcoos;i+=2)
+	{
+		coordinates[i]=coosarray[i];
+		coordinates[i+1]=coosarray[i+1];
+		coos.push_back(Gnome::Art::Point(coordinates[i],
+						 coordinates[i+1]));
+
+		x_wp+=coordinates[i];
+		y_wp+=coordinates[i+1];
+
+	}
+
+	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),i));
+	}
+
+	coordinates[numofcoos]=x_wp/noe;
+	coordinates[numofcoos+1]=y_wp/noe;
+
+	wp=new Gnome::Art::Point(coordinates[numofcoos],coordinates[numofcoos+1]);
+
+	nodes[noe]= new Gnome::Canvas::Ellipse
+	(
+		triangle,
+		coordinates[numofcoos]-20,
+		coordinates[numofcoos+1]-20,
+		coordinates[numofcoos]+20,
+		coordinates[numofcoos+1]+20
+	);
+	*(nodes[noe]) << Gnome::Canvas::Properties::fill_color("blue");
+	*(nodes[noe]) << Gnome::Canvas::Properties::outline_color("black");
+	(nodes[noe])->signal_event().connect(sigc::mem_fun(*this, &CanvasExample::tri_mover));
+
+
+
+}
+
+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) )
+	{
+		double * coosarray=new double[argc];
+
+		for(int i=1;i<argc;i++)
+		{
+			coosarray[i-1]=atof(argv[i]);
+			printf("%g%c",coosarray[i-1],i%2?' ':'\n');
+		}
+
+		Gnome::Canvas::init();
+		Gtk::Main app(argc, argv);
+
+		MainWin mainwin("Magic Triangle",coosarray,argc-1);
+		app.run(mainwin);
+	}
+
+	return 0;
+}