Logo 
Search:

C++ Programming Articles

Submit Article
Home » Articles » C++ Programming » Computer GraphicsRSS Feeds

Program of scanfill algorithm

Posted By: Easy Tutor     Category: C++ Programming     Views: 3561

Write a program of scanfill algorithm.

Code for Program of scanfill algorithm in C++ Programming

# include <dos.h>
# include <stdio.h>
# include <graphics.h>
# include <iostream.h>
# include <conio.h>
# include <math.h>

struct Polygon
{
    int x;
    int y;
};

struct edRecord
{
    int YUpper;
    float XIntersect;
    float dxperscan;
    struct edRecord *Next;
};

typedef struct edRecord Edge;
typedef struct Polygon Nodes;
Edge  *Active;
Edge **Edges;
int Cntr=6;
Nodes NodesObj[6]={{100,100},{150,150},{150,200},{100,250},{50,200},{50,150}};

void Scanfill();
void InsertEdge(Edge*,Edge*);
void BuildEdgeList(int,Nodes*);
int YNext(int);
void MakeEdgeRec(Nodes,Nodes,int,Edge*);
void BulidActiveList(int);
void UpdateActiveList(int);
void DeleteAfter(Edge*);
void ResortActiveList(void);
void ResortActiveList(int);

//**************************************************************************void main()
{
    int gDriver = DETECT, gMode;
    int n,xArray[12];
    int iCntr,jCntr;

    initgraph(&gDriver,&gMode,"c:\\tc\\bgi");
        
    for(iCntr=0,jCntr=0;iCntr<12;iCntr+=2,jCntr++)
        xArray[iCntr] = NodesObj[jCntr].x;
    for(iCntr=1,jCntr=0;iCntr<12;iCntr+=2,jCntr++)
        xArray[iCntr] = NodesObj[jCntr].y;
    
    drawpoly(6,xArray);
    
    line(NodesObj[5].x,NodesObj[5].y,NodesObj[0].x,NodesObj[0].y);   //TO CLOSE POLYGON
    getch();
    
    Scanfill();
    getch();
    closegraph();
    restorecrtmode();
    return;
}

//**************************************************************************void Scanfill()
{
    int iCntr,Scan;
    //initialize edgelists with dummy nodes
    Edges=new Edge*[getmaxy()];
    for(iCntr=0;iCntr<getmaxy();iCntr++)
    {
        Edges[iCntr] = new Edge;
        Edges[iCntr]->Next = NULL;
    }
    //initialize Active edgeList with dummy nodes
    Active = new Edge;
    Active->Next = NULL;
    BuildEdgeList(Cntr,NodesObj);
    for(Scan=0;Scan<getmaxy();Scan++)
    {
        BulidActiveList(Scan);
        if (Active->Next != NULL)
        {
            ResortActiveList(Scan);
            UpdateActiveList(Scan);
            ResortActiveList();
        }
    }
}

//**************************************************************************void InsertEdge(Edge* edgeList,Edge* InitialEdge)
{
    Edge *PEdge,*QEdges;

    QEdges=edgeList;
    PEdge=QEdges->Next;
    while(PEdge!=NULL)
    if(InitialEdge->XIntersect < PEdge->XIntersect)
    PEdge=NULL;
    else
    {
        QEdges=PEdge;
        PEdge=PEdge->Next;
    }
    InitialEdge->Next = QEdges->Next;
    QEdges->Next = InitialEdge;
}

//**************************************************************************void BuildEdgeList(int Cntr,Nodes* Vertices)
{
    Edge* NewEdge;
    Nodes Vertex1,Vertex2;
    int YPrev,iCntr;
    Vertex1.x=Vertices[Cntr-1].x;
    Vertex1.y=Vertices[Cntr-1].y;
    YPrev = Vertices[Cntr-2].y;
    for(iCntr=0;iCntr<Cntr;iCntr++)
    {
        Vertex2.x = Vertices[iCntr].x;
        Vertex2.y = Vertices[iCntr].y;
        if(Vertex1.y != Vertex2.y)
        {
            NewEdge = new Edge;
            if(Vertex1.y < Vertex2.y)
                MakeEdgeRec(Vertex1,Vertex2,YNext(iCntr),NewEdge);
            else
                MakeEdgeRec(Vertex2,Vertex1,YPrev,NewEdge);
        }
        YPrev = Vertex1.y;
        Vertex1.x = Vertex2.x;
        Vertex1.y = Vertex2.y;
    }
}

//**************************************************************************void BulidActiveList(int Scan)
{
    Edge *PEdge,*QEdges;
    PEdge=Edges[Scan]->Next;
    while(PEdge!=NULL)
    {
        QEdges=PEdge->Next;
        InsertEdge(Active,PEdge);
        PEdge=QEdges;
    }
}

//***************************************************************************void ResortActiveList(int Scan)
{
    Edge *iEdge,*jEdge;
    int iCntr;
    iEdge = Active->Next;
    while(iEdge!=NULL)
    {
        jEdge = iEdge->Next;
        for(iCntr=iEdge->XIntersect;iCntr<=jEdge->XIntersect-1;iCntr++)
            putpixel(iCntr,Scan,RED);
        iEdge=jEdge->Next;
    }
}
//***************************************************************************void UpdateActiveList(int Scan)
{
    Edge *PEdge,*QEdges;
    QEdges=Active;
    PEdge=Active->Next;
    while(PEdge!=NULL)
    {
        if(Scan>=PEdge->YUpper)
        {
            PEdge=PEdge->Next;
            DeleteAfter(QEdges);
        }
        else
        {
            PEdge->XIntersect+=PEdge->dxperscan;
            QEdges=PEdge;
            PEdge=PEdge->Next;
        }
    }
}
//***************************************************************************void ResortActiveList()
{
    Edge *PEdge,*QEdges;
    PEdge=Active->Next;
    Active->Next=NULL;
    while(PEdge!=NULL)
    {
        QEdges=PEdge->Next;
        InsertEdge(Active,PEdge);
        PEdge=QEdges;
    }
}

//***************************************************************************int YNext(int YCurr)
{
    int jCntr;
    if(YCurr+1>Cntr)
        jCntr=1;
    else
        jCntr=YCurr+1;
    while(NodesObj[YCurr].y == NodesObj[jCntr].y)
    {
        if(jCntr+1>Cntr)
            jCntr=1;
        else
            jCntr++;
    }
    return(NodesObj[jCntr].y);
}

//***************************************************************************void DeleteAfter(Edge* QEdges)
{
    Edge* PEdge;

    PEdge = QEdges->Next;
    QEdges->Next = PEdge->Next;
    delete PEdge;
}

//***************************************************************************void MakeEdgeRec(Nodes Lower,Nodes Upper,int YComp,Edge* CurrEdge)
{
    CurrEdge->dxperscan = (Upper.x - Lower.x) / (Upper.y - Lower.y);
    CurrEdge->XIntersect = Lower.x;
    if(Upper.y < YComp)
        CurrEdge->YUpper = Upper.y - 1;
    else
        CurrEdge->YUpper = Upper.y;
    InsertEdge(Edges[Lower.y],CurrEdge);
}
  
Share: 


Didn't find what you were looking for? Find more on Program of scanfill algorithm Or get search suggestion and latest updates.

Easy Tutor
Easy Tutor author of Program of scanfill algorithm is from United States. Easy Tutor says

Hello Friends,

I am Free Lance Tutor, who helped student in completing their homework.

I have 4 Years of hands on experience on helping student in completing their homework. I also guide them in doing their final year projects.

I have share many programs on this website for everyone to use freely, if you need further assistance, than please contact me on easytutor.2ya [at the rate] gmail [dot] com

I have special discount scheme for providing tutor services. I am providing tutor service to students from various contries, currently most of my students are from United States, India, Australia, Pakistan, Germany, UK and Canada.

I am also here to expand my technical network to receive more opportunity in my career, make friends to help them in resolving their technical problem, learn and share my knowledge, If you like to be my friend, Please send me friend request.

Thanks,
Happy Programming :)

 
View All Articles

 
Please enter your Comment

  • Comment should be atleast 30 Characters.
  • Please put code inside [Code] your code [/Code].

 
No Comment Found, Be the First to post comment!