/*
    Trasarea segmentelor de dreapta in spatiul discret
	DDA line drawing algorithm
*/

#include <iostream>
#include <graphics.h>
#include <math.h>
struct punct
{
    int x,y;
};


void BresGeneral(int, int, int, int);

punct waitForLeftMouseClick2();

int culoareCreion = GREEN;
int culoareHartie = WHITE;
void patr(int x,int y);
void waitForLeftMouseClick();

void DDALine(int x1,int y1,int x2,int y2,int iColor);

int x,y;            // coordonate mouse
int latp=10;        // marimea patratului
punct A,B;
int X,Y;            // coordonate patrat
int Xa,Ya;
int main()
{
    int x1,x2,y1,y2,iColor;



    x1 = 78;
    y1 = 120;
    x2 = 210;
    y2 = 350;

    initwindow(800,800); //open a 400x300 graphics window
    setcolor(GREEN);
 for(int i=0;i<=50;i++) line(50,50+i*latp,550,50+i*latp);
 for(int j=0;j<=50;j++) line(50+j*latp,50,50+j*latp,550);

while(1){

    A=waitForLeftMouseClick2();
    B=waitForLeftMouseClick2();
    BresGeneral((A.x-50)/latp,(A.y-50)/latp,(B.x-50)/latp,(B.y-50)/latp);
}
    //waitForLeftMouseClick();
    return 0;
}
void patr(int i,int j){
// determin pozitia in grila
    int xp,yp;
    xp = 50 + i*latp;
    yp = 50 + j*latp;

// determin culoarea celulei
if(getpixel(xp+1,yp+1)==BLACK) setcolor(YELLOW);
    else setcolor(BLACK);

    for(int k=1;k<latp;k++) line(xp+k,yp+1,xp+k,yp+latp);

    setcolor(GREEN);

}

void DDALine(int x1,int y1,int x2,int y2,int iColor)
{

    float dX,dY,iSteps;
    float xInc,yInc,iCount,x,y;

    dX = x1 - x2;
    dY = y1 - y2;

    if (fabs(dX) > fabs(dY))
        iSteps = fabs(dX);
    else
        iSteps = fabs(dY);

    xInc = dX/iSteps;
    yInc = dY/iSteps;

    x = x1;
    y = y1;
    circle((int)x,(int)y,1);

    for (iCount=1; iCount<=iSteps; iCount++)
    {
        putpixel((int)x,(int)y,iColor);
        x -= xInc;
        y -= yInc;
    }
    circle((int)x,(int)y,1);
    return;
}


void waitForLeftMouseClick()
{
    clearmouseclick(WM_LBUTTONDOWN);
    const int DELAY = 50; // Milliseconds of delay between checks
    int x, y;
    while (!ismouseclick(WM_LBUTTONDOWN))
        delay(DELAY);
    getmouseclick(WM_LBUTTONDOWN, x, y);
}

punct waitForLeftMouseClick2()
{
    clearmouseclick(WM_LBUTTONDOWN);
    const int DELAY = 50; // Milliseconds of delay between checks
    punct p;
    while (!ismouseclick(WM_LBUTTONDOWN))
        delay(DELAY);
    getmouseclick(WM_LBUTTONDOWN, p.x, p.y);
    return p;
}



// Bresenham generalizat
void BresGeneral(
    int x1, int y1, int x2, int y2)
{

    int oct, dx,dy, absdx, absdy,c1,c2,t;
    int culoare = culoareCreion;

    int x,y,i;
    if(x1==x2) // vertical
    {
        if (y1>y2)
        {
            y=y1;
            y1=y2;
            y2=y;
        }
        for(y=y1; y<=y2; y++)
            patr(x1,y);
        return;
    }

    if(y1==y2) // orizontal
    {
        if (x1>x2)
        {
            x=x1;
            x1=x2;
            x2=x;
        }
        for(x=x1; x<=x2; x++)
            patr(x,y1);
        return;
    }

    dx=x2-x1;
    dy=y2-y1;

    absdx=abs(dx);
    absdy=abs(dy);
    if(dx>0)  // oct=1,2,7,8
    {
        if(dy>0) // oct 1,2
            if(dx>=dy)
                oct=1;
            else
                oct=2;
        else if(dx>=absdy)
            oct=8;
        else
            oct=7;
    }
    else // 3,4,5,6
    {
        if(dy>0) // oct 3,4
            if(absdx>=dy)
                oct=4;
            else
                oct=3;
        else if(absdx>=absdy)
            oct=5;
        else
            oct=6;
    }

    if(absdy>absdx)
    {
        x=absdx;
        absdx=absdy;
        absdy=x;
    }

    c1=absdy<<1;
    c2=c1-(absdx<<1);
    t=c1-absdx;
    patr(x1,y1);

    for(i=1, x=x1, y=y1; i<absdx; i++)
    {
        if(t<0) // deplasament O
        {
            t+=c1;
            switch(oct)
            {
            case 1:
            case 8:
                x++;
                break;
            case 4:
            case 5:
                x--;
                break;
            case 2:
            case 3:
                y++;
                break;
            case 6:
            case 7:
                y--;
                break;
            }
        }
        else
        {
            t+=c2;  // deplasament D
            switch(oct)
            {
            case 1:
            case 2:
                x++;
                y++;
                break;
            case 3:
            case 4:
                x--;
                y++;
                break;
            case 5:
            case 6:
                x--;
                y--;
                break;
            case 7:
            case 8:
                x++;
                y--;
                break;
            }
        }
        patr(x,y);
    }
    patr(x2,y2);
}