TRANSFORMÉE DE HOUGH: DÉTECTION DE DROITES

//*****************************************************************************************
//Author	MORARD Vincent 
//Date :	28/06/07 
//Contact:	vincent.morard@cpe.fr	
//WebSite:	pistol.petesampras.free.fr
//*****************************************************************************************

//Includes----------------------------------------------------------------------------------
#include "windows.h"
#include "cmugraphics.h"
#include "math.h"
#include <vector>
using namespace std;

//Define------------------------------------------------------------------------------------
#define SPACE_X1 100
#define SPACE_Y1 10
#define SPACE_X2 300
#define SPACE_Y2 210

#define SPACE_CENTER_X 200
#define SPACE_CENTER_Y 110

#define HOUGH_X1 50
#define HOUGH_Y1 230
#define HOUGH_X2 350
#define HOUGH_Y2 510

#define HOUGH_CENTER_X 50
#define HOUGH_CENTER_Y 370
const double Pi = 3.141592653589793238462643383279;

//Struct---------------------------------------------------------------------------------
struct Transform
{
	double X,Y,Theta,R;
	bool Inv_Transform;
};


//Header's function-----------------------------------------------------------------------
void DrawAxis(window &F,int Graph=-1);
void DrawCosinus(window &F,double R,double Theta);
void DrawLine(window &F,double X,double Y,double Theta);
void UpdateHough(window &F,vector<Transform> Vect);
void UpdateSpace(window &F,vector<Transform> Vect);
void ButtonDownAction(window &F,vector<Transform> *Vect,int MouseX,int MouseY,bool Final=0);
void UpdateCoord(window &F,vector<Transform> *Vect);
void DrawInterface(window &F,bool *Reset,bool *Exit,bool *Click);


//*******************************************************************************************

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)

{
	bool Exit=false;
	bool Reset=true;
	bool Click=false;
	int Cpt=0;
	window F(390,600,0,0);			//create a 390 width and 600 Height window 
									//at the position (0,0)
	F.SetWaitClose(false);			//Close the window when we exit
	F.SetBuffering(true);			//Allow double buffering
	F.ChangeTitle("Hough tranform");//Change title
	
	vector<Transform>Vect;			//Vector to stock all the parameters
	Vect.resize(0);					//init vector


	do
	{
		if(++Cpt==100)
		{
			MSG msg;
			if(!GetMessage(&msg, NULL, 0, 0))//On recoit le message de fin =>on a appuyé sur la croix
				exit(1);
			Cpt=0;
		}
		if(Reset)					//if Reset : we redraw axis
		{	
			Reset=false;
			DrawAxis(F);
			Vect.resize(0);			//And we resize to 0 the vector
		}
		UpdateCoord(F,&Vect);		//To update the points and theres transforms
		DrawInterface(F,&Reset,&Exit,&Click);		//Button
		F.UpdateBuffer();			
		Sleep(20);					//The process gives back the hand to an another process
									//during 20 ms
	}
	while(!Exit);
	exit(0);
	return 0;
}

//This function checks the mouse's event and calls the appropriate function
void UpdateCoord(window &F,vector<Transform>*Vect)
{
	int MouseX,MouseY;
	bool Click=false;
	
	F.GetMouseCoord(MouseX,MouseY);
	if(MouseY>540)
		return;
	//If the user clicks on the screen, he will see the result of Hough tranform in real time
	while(F.GetButtonState(LEFT_BUTTON,MouseX,MouseY)==BUTTON_DOWN)
	{	
		
		ButtonDownAction(F,Vect,MouseX,MouseY);		//temporary action
		F.UpdateBuffer();
	
		Sleep(30);
		Click=true;
	}
	if(Click)											//if we click the result keeps on the sreen
		ButtonDownAction(F,Vect,MouseX,MouseY,1);		
}


//This function takes back the coord of the mouse in the graph
//and calls the function to make a transformation into Hough's space.
void ButtonDownAction(window &F,vector<Transform> *Vect,int MouseX,int MouseY,bool Final)
{
	Transform Hough;		//this structure allow us to stock all the parameters of the Hough's transform
							//X and Y , R and theta

	//if the mouse is over the graph 1
	if(MouseX > SPACE_X1 && MouseX < SPACE_X2 && MouseY > SPACE_Y1 && MouseY < SPACE_Y2)
	{
		//We just have to tranform MouseX and MouseY to have the coord of the position of
		//the mouse on the graph
		Hough.X = MouseX-SPACE_CENTER_X;
		Hough.Y = SPACE_CENTER_Y-MouseY;
		//With X and Y we are able to get R and Theta in polar coord
		//R=sqrt(X² + Y²)
		//tan(Theta) = Y/X
		Hough.R = sqrt((double)(Hough.X*Hough.X+Hough.Y*Hough.Y));
		Hough.Theta = atan((double)Hough.Y/Hough.X)+Pi/2;
		if(Hough.X>0)
			Hough.Theta+=Pi;
		Hough.Inv_Transform = 0;		//Hough transform

		Vect->push_back(Hough);			//we push the new point
		UpdateHough(F,*Vect);			//and we update the transform
		if(!Final)
			Vect->pop_back();			//if we still click, we pop the new point
		else
		{
			F.SetPen(RED);				//if we stop clicking, we draw a circle on the screen
			F.SetBrush(RED);
			F.DrawCircle(MouseX,MouseY,3,FRAME);
	
		}
			

	}
	else if(MouseX >= HOUGH_X1 && MouseX < HOUGH_X2 && MouseY > HOUGH_Y1 && MouseY < HOUGH_Y2)
	{
		double Pas=Pi/(HOUGH_X2-HOUGH_X1);
		//We have got easily R and Theta 
		Hough.Theta = (MouseX-HOUGH_CENTER_X)*Pas;
		Hough.R = HOUGH_CENTER_Y-MouseY;
		//And we convert R and Theta in cartesien coord
		Hough.Y = Hough.R*cos(Hough.Theta);
		Hough.X = -Hough.R*sin(Hough.Theta);
		Hough.Inv_Transform = 1;		//Hough reverse

		Vect->push_back(Hough);
		UpdateSpace(F,*Vect);
		if(!Final)
			Vect->pop_back();
		else
		{
			F.SetBrush(GREEN);
			F.SetPen(GREEN);	
			F.DrawCircle(MouseX,MouseY,3,FILLED);
		}	
	}
}

void UpdateHough(window &F,vector<Transform> Vect)
{
	
	DrawAxis(F,2);
	F.SetPen(GREEN);
	F.SetBrush(GREEN);
	int Size=Vect.size();
	for(int i=0;i<Size;i++)
	{
		if(! Vect[i].Inv_Transform )
			DrawCosinus(F,Vect[i].R,Vect[i].Theta);
		else
			F.DrawCircle(Vect[i].Theta*(HOUGH_X2-HOUGH_X1)/Pi+HOUGH_CENTER_X,HOUGH_CENTER_Y-Vect[i].R,3);
			
	}
		
}
void UpdateSpace(window &F,vector<Transform> Vect)
{
	
	DrawAxis(F,1);
	F.SetPen(RED);
	F.SetBrush(RED);
	int Size=Vect.size();
	for(int i=0;i<Size;i++)
		if(Vect[i].Inv_Transform )
			DrawLine(F,Vect[i].X,Vect[i].Y,Vect[i].Theta);
		else
			F.DrawCircle(Vect[i].X+SPACE_CENTER_X,SPACE_CENTER_Y-Vect[i].Y,3);
			

}

void DrawCosinus(window &F,double R,double Theta)
{
	int Width=HOUGH_X2-HOUGH_X1;
	int Height=HOUGH_Y2-HOUGH_Y1;
	double x,y;
	double Pas=Pi/Width;		
	F.SetPen(GREEN);
	F.SetBrush(GREEN);
	//for each pixel of the graph, we evaluate the y coord with cosinus
	for(double i=HOUGH_X1;i<HOUGH_X2;i++)
	{
		x=i-HOUGH_CENTER_X;
		x*=Pas;					//conversion into radian
		y=R*cos(x-Theta);	
		F.DrawPixel(i,HOUGH_CENTER_Y-y);
	}		
}


//This function is able to draw a line with one point and one angle
void DrawLine(window &F,double X,double Y,double Theta)
{
	//Vecteur is the direction
	double Vecteur=tan(Theta);	

	X+=SPACE_CENTER_X;
	Y=SPACE_CENTER_Y-Y;
	if(X>SPACE_X2 || X<SPACE_X1 || Y>SPACE_Y2 || Y<SPACE_Y1)
		return;

	int LastX=X;
	int LastY=Y;
	double  i,j;
	
	F.SetPen(RED);
	F.SetBrush(RED);
	for(i=X;i<=SPACE_X2;i+=0.5)
	{
		if((j=Y-Vecteur*(i-X))>SPACE_Y2 || j<SPACE_Y1)
			break;
		
		LastX=i;				//We get the coord of the point whith cut the graph's window
		LastY=j;
	}
	F.DrawLine((int)X,(int)Y,LastX,LastY);
	LastX=X;
	LastY=Y;

	//We do the same thing in the other way
	for(i=X;i>=SPACE_X1;i-=0.5)
	{
		if((j=j=Y-Vecteur*(i-X))>SPACE_Y2 || j<SPACE_Y1)
			break;
		
		LastX=i;
		LastY=j;
	}
	F.DrawLine((int)X,(int)Y,LastX,LastY);


}


void DrawInterface(window &F,bool *Reset,bool *Exit,bool *Click)
{
	int MouseX,MouseY;
	F.SetFont(20,BOLD,SWISS);
	F.SetPen(WHITE);
	F.SetBrush(WHITE);
	F.DrawRectangle(100,540,400,590);


	F.SetPen(NAVYBLUE,2);
	//F.DrawRectangle(210,545,270,575);
	F.DrawString(110,550,"Reset");
	F.DrawString(220,550,"Quit");

	if(F.GetButtonState(LEFT_BUTTON,MouseX,MouseY)==BUTTON_DOWN)
	{
		if(MouseX>=80 && MouseX<180 && MouseY>545 && MouseY<575)
			*Click=true;
		if(MouseX>=210 && MouseX<270 && MouseY>545 && MouseY<575)
			*Click=true;
	}
	else if (*Click)
	{
		*Click=false;
		if(MouseX>=80 && MouseX<180 && MouseY>545 && MouseY<575)
			*Reset=true;
		if(MouseX>=210 && MouseX<270 && MouseY>545 && MouseY<575)
			*Exit=true;


	}
	else
		*Click=false;

}

void DrawAxis(window &F,int Graph)
{
	
	F.SetBrush(WHITE);
	F.SetFont(15,BOLD,SWISS);
	if(Graph!=2)			//We do not draw again graph 2
	{
		F.SetPen(DARKRED,3);
		F.DrawRectangle(SPACE_X1,SPACE_Y1,SPACE_X2,SPACE_Y2);
		F.SetPen(BLACK);
		//y-axis
		F.DrawLine(SPACE_CENTER_X,SPACE_Y1,SPACE_CENTER_X,SPACE_Y2);
		//x-axis
		F.DrawLine(SPACE_X1,SPACE_CENTER_Y,SPACE_X2,SPACE_CENTER_Y);
		//Arrows
		F.DrawLine(SPACE_CENTER_X-5,SPACE_Y1+9,SPACE_CENTER_X,SPACE_Y1);
		F.DrawLine(SPACE_CENTER_X+5,SPACE_Y1+9,SPACE_CENTER_X,SPACE_Y1);
		F.DrawLine(SPACE_X2-5,SPACE_CENTER_Y+3,SPACE_X2,SPACE_CENTER_Y);
		F.DrawLine(SPACE_X2-5,SPACE_CENTER_Y-3,SPACE_X2,SPACE_CENTER_Y);
		//Legende
		F.DrawString(SPACE_CENTER_X,SPACE_Y1-16,"y");
		F.DrawString(SPACE_X2+10,SPACE_CENTER_Y,"x");
	}
	if(Graph!=1)			//We do not draw again graph 1
	{
		F.SetPen(DARKGREEN,3);
		F.DrawRectangle(HOUGH_X1,HOUGH_Y1,HOUGH_X2,HOUGH_Y2);
		F.SetPen(BLACK);
		//y-axis
		F.DrawLine(HOUGH_CENTER_X,HOUGH_Y1,HOUGH_CENTER_X,HOUGH_Y2);
		//x-axis
		F.DrawLine(HOUGH_X1,HOUGH_CENTER_Y,HOUGH_X2,HOUGH_CENTER_Y);
		//Arrows
		F.DrawLine(HOUGH_CENTER_X-5,HOUGH_Y1+9,HOUGH_CENTER_X,HOUGH_Y1);
		F.DrawLine(HOUGH_CENTER_X+5,HOUGH_Y1+9,HOUGH_CENTER_X,HOUGH_Y1);
		F.DrawLine(HOUGH_X2-5,HOUGH_CENTER_Y+3,HOUGH_X2,HOUGH_CENTER_Y);
		F.DrawLine(HOUGH_X2-5,HOUGH_CENTER_Y-3,HOUGH_X2,HOUGH_CENTER_Y);
		//Legende
		F.DrawString(HOUGH_CENTER_X,HOUGH_Y1-16,"Theta");
		F.DrawString(HOUGH_X2+8,HOUGH_CENTER_Y,"R");
	}
	
}