计算机图形学 区域填充算法的实现

实验四区域填充算法的实现

班级：信计二班学号：20080502076 姓名：刘刚分数：

一实验目的和要求

1 理解区域的表示和类型，能正确区分四连通和八连通的区域，了解区域填充的实现原理

2掌握光栅图形显示基本原理

3 熟悉区域填充的算法

二实验内容

1 利用画线函数，在屏幕上定义一个封闭区域

2 编程实现扫描线多边形填充算法，边填充算法，种子填充算法

三实验结果分析

1 本算法通过使用栈结构主要的实现了扫描线多边形填充算法，成功绘制出了四连通区域。算法要求区域是连通的，因为只有在连通的区域中，才能将种子点的颜色扩展到区域内的其他点。

2程序代码：

（区域填充的每一过程，每按回车健一次，就描一个点，一直按回车，就慢慢的演示填充了。）#include "stdio.h"

#include"stdlib.h"

#include "math.h"

#define pi 3.14159265

#include "Conio.h"

#include "graphics.h"

#include "malloc.h"

#define closegr closegraph

#define max 400

typedef struct Edge{

int ymax;

float x,deltax;

struct Edge *nextEdge;

}Edge;

typedef struct {

char *s,*t,*w,*v,*v1;

}string;

Edge *ET[max];

void initgr(void) /* BGI初始化*/

{int gd=DETECT,gm=0; /* 和gd=VGA,gm=VGAHI是同样效果*/

registerbgidriver(EGA VGA_driver);/* 注册BGI后可以驱动不需要.BGI文件的支持运行*/

initgraph(&gd,&gm,"");

}

void GetST(float x[5],float y[5],float a[5],float b[5],float radius)

{int i;

float r;

setcolor(BLUE);

for(i=0;i<5;i++)

{x[i]=radius*cos(i*0.4*pi+0.05*pi)-radius*sin(i*0.4*pi+0.05*pi)+450;

y[i]=radius*sin(i*0.4*pi+0.05*pi)+radius*cos(i*0.4*pi+0.05*pi)+200;

getch();

circle(x[i],y[i],1); fillellipse(x[i],y[i],1,1);

}

r=sin(0.1*pi)*radius/sin(126.0/180.0*pi);

for(i=0;i<5;i++)

{a[i]=r*cos(i*0.4*pi+0.25*pi)-r*sin(i*0.4*pi+0.25*pi)+450;

b[i]=r*sin(i*0.4*pi+0.25*pi)+r*cos(i*0.4*pi+0.25*pi)+200;

getch();

circle(a[i],b[i],1);

}

/*得到五角星的10个顶点*/

}

void Del_Node(int left,int top,int right,int bottom)

{int a[8];

a[0]=left;a[1]=top;a[2]=left;a[3]=bottom;a[4]=right;a[5]=bottom;a[6]=right;a[7]=top;

setcolor(WHITE);

fillpoly(4,a);

}

void Node_Rect(int left,int top,int right,int bottom,string a,int flag)

{int m;

rectangle(left,top,right,bottom);

for(m=1;m<4;m++) line(left+m*30,top,left+m*30,bottom);

if(flag==0){outtextxy(left+2,top+7,a.w); outtextxy(left+30+2,top+7,a.v); outtextxy(left+60+5,top+2,a.s);outtextxy(left+60+7,top+4,"_");

outtextxy(left+60+5,top+15,a.t); }

else {outtextxy(left+2,top+7,a.w); outtextxy(left+30+2,top+7,a.v1); outtextxy(left+60+2,top+4,"-");

outtextxy(left+60+10,top+2,a.s);outtextxy(left+60+11,top+4,"_");outtextxy(left+60+10,top+1

5,a.t);}

}

void CreatET(float x[5],float y[5],float a[5],float b[5])

{int n;

Edge *e,*h;

n=(int)(y[3]+0.5);

e=(Edge*)malloc(sizeof(Edge));

e->ymax=(int)(b[3]+0.5);e->x=x[3];e->deltax=(a[3]-x[3])/(b[3]-y[3]); h=(Edge*)malloc(sizeof(Edge));

h->ymax=(int)(b[2]+0.5);h->x=x[3];h->deltax=(a[2]-x[3])/(b[3]-y[3]); e->nextEdge=h;h->nextEdge=NULL;

ET[n]=e;

n=(int)(b[2]+0.5);

e=(Edge*)malloc(sizeof(Edge));

e->ymax=(int)(b[1]+0.5);e->x=x[2];e->deltax=(a[1]-x[2])/(b[1]-y[2]); h=(Edge*)malloc(sizeof(Edge));

h->ymax=(int)(b[4]+0.5);h->x=x[4];h->deltax=(a[4]-x[4])/(b[4]-y[4]); e->nextEdge=h;h->nextEdge=NULL;

ET[n]=e;

n=(int)(b[1]+0.5);

e=(Edge*)malloc(sizeof(Edge));

e->ymax=(int)(y[1]+0.5);e->x=a[1];e->deltax=(x[1]-a[1])/(y[1]-b[1]); h=(Edge*)malloc(sizeof(Edge));

h->ymax=(int)(y[0]+0.5);h->x=a[4];h->deltax=(x[0]-a[4])/(y[0]-b[4]); e->nextEdge=h;h->nextEdge=NULL;

ET[n]=e;

n=(int)(b[0]+0.5);

e=(Edge*)malloc(sizeof(Edge));

e->ymax=(int)(y[1]+0.5);e->x=a[0];e->deltax=(x[1]-a[0])/(y[1]-b[0]); h=(Edge*)malloc(sizeof(Edge));

h->ymax=(int)(y[0]+0.5);h->x=a[0];h->deltax=(x[0]-a[0])/(y[0]-b[0]); e->nextEdge=h;h->nextEdge=NULL;

ET[n]=e;

}

void Free(float y[5],float b[5])

{int n;

n=(int)(y[3]+0.5);

ET[n]=NULL;

n=(int)(b[2]+0.5);

ET[n]=NULL;

n=(int)(b[1]+0.5);

ET[n]=NULL;

n=(int)(b[0]+0.5);

ET[n]=NULL;

}

void Arrow_Line(int leftx,int lefty,int rightx,int righty)

{line(leftx,lefty,rightx,righty);

line(rightx-5,righty+5,rightx,righty);line(rightx-5,righty-5,rightx,righty);

}

void Fillin(Edge *AEL,int bottom,int top )

{

char *s;

string str;

Edge *e;

Edge *p,*q;

int n,m,i=0,j=0,a[8];

AEL=(Edge*)malloc(sizeof(Edge));AEL->x=-1;

AEL->nextEdge=NULL;

for(n=bottom;n

{p=ET[n];

while(p)

{ getch();

setcolor(BLUE);

switch(n)

{case 59:str.s="31";str.t="97";str.w="146";str.v="200";str.v1="200";break;

case 156:str.s="83";str.t="60";str.w="207";str.v="66";str.v1="334";break;

case 217:str.s="31";str.t="97";str.w="314";str.v="148";str.v1="251";break;

case 254:str.s="83";str.t="60";str.w="314";str.v="200";str.v1="200";break;

default:break;

}

if(i%2==0)

{ if(n==59||n==217){

if(n==217) {setcolor(WHITE); line(60,390,70,390);line(70,390,70,410);line(70,410,50,410);line(50,410,50,430);

Arrow_Line(50,430,60,430);}

setcolor(BLUE);

Arrow_Line(60,390,150,390);

Node_Rect(150,380,250,405,str,0);

Arrow_Line(245,392,420,392); }

if(n==156){ setcolor(WHITE) ;Arrow_Line(60,390,150,390);

setcolor(BLUE);line(60,390,70,390);line(70,390,70,410);line(70,410,50,410);line(50,410,50,43 0);

Arrow_Line(50,430,60,430);

Node_Rect(60,420,160,445,str,0);Arrow_Line(155,430,490,430); }

if(n==254){setcolor(WHITE);Arrow_Line(245,392,420,392);

setcolor(BLUE);

line(245,390,260,390);line(260,390,260,410);line(260,410,210,410);line(210,410,210,430);

Arrow_Line(210,430,220,430);

Node_Rect(220,420,320,445,str,0); Arrow_Line(315,430,330,430);

}

Del_Node(10,j*80+70,119,j*80+95);}

else if(i%2!=0)

{ if(n==59)Node_Rect(420,380,520,405,str,1);

if(n==156) Node_Rect(490,420,590,445,str,1);

if(n==217)

{Node_Rect(420,380,520,405,str,1);line(515,390,530,390);line(530,390,530,410);

line(530,410,480,410);line(480,410,480,430);

Arrow_Line(480,430,490,430);}

if(n==254) {Node_Rect(330,420,430,445,str,1);

line(425,430,440,430);line(440,430,440,410);line(440,410,410,410);line(410,410,410,390);

Arrow_Line(410,390,420,390); }

Del_Node(120,j*80+70,220,j*80+95);

j+=1;}

i+=1;

e=AEL; q=AEL->nextEdge;

while(q)

{if(p->xx)break;

q=q->nextEdge;

e=e->nextEdge;}

q=p->nextEdge;

p->nextEdge=e->nextEdge;

e->nextEdge=p;

p=q;

}

p=AEL;q=AEL->nextEdge;

m=1;

getch();

while(q)

{ if(q->ymax==n)

{ /*outtextxy(2,i+10,"ScanLine have reached");

i+=10;

outtextxy(2,i+10,"one elem'ymax of AEL;");

i+=10;

outtextxy(2,i+10,"remove it from AEL;"); i+=20; */

setcolor(WHITE);

if(n==156){Del_Node(420,380,520,405);

getch();Arrow_Line(245,392,420,392);Del_Node(150,380,250,405); }

if(n==217) {Del_Node(490,420,590,445);line(515,390,530,390);line(530,390,530,410);

line(530,410,480,410);line(480,410,480,430);

Arrow_Line(480,430,490,430); getch();Arrow_Line(155,430,490,430); Del_Node(60,420,160,445);}

if(n==314)

{Del_Node(420,380,520,405);line(425,430,440,430);line(440,430,440,410);line(440,410,410,41 0);

line(410,410,410,390);Arrow_Line(410,390,420,390);

getch();Del_Node(330,420,430,445);Arrow_Line(315,430,330,430);getch();

Del_Node(220,420,320,445);

line(245,390,260,390);line(260,390,260,410);line(260,410,210,410);line(210,410,210,430);

Arrow_Line(210,430,220,430); getch();

Del_Node(150,380,250,405); Arrow_Line(60,390,150,390);}

i-=1;

p->nextEdge=q->nextEdge;

e=q;

q=q->nextEdge;free(e);

}

else{

if(p!=AEL&&m%2==0)

{setcolor(RED);

line((int)(p->x+0.5),n,(int)(q->x+0.5),n);

p->x+=p->deltax;

q->x+=q->deltax;}

p=p->nextEdge;

q=q->nextEdge;

m++;}

}

}

}

main()

{ char *s,*t,*w,*v,*v1;

string str;

int n,m ,i;

float x[5],y[5],a[5],b[5],r;

Edge *AEL;

initgr();/* BGI初始化*/

setbkcolor(WHITE);

setcolor(BLUE);

outtextxy(1,1,"Show Pentagram");

GetST(x,y,a,b,100); /*得到五角星的顶点*/ setcolor(9);

for(i=0;i<4;i++)

{getch();

line(x[i],y[i],a[i],b[i]);getch();

line(a[i],b[i],x[i+1],y[i+1]);

}

getch();

line(x[4],y[4],a[4],b[4]); getch();

line(a[4],b[4],x[0],y[0]);

/*画出五角星*/

getch();

line(x[3]-170,10,x[3]+170,10);

line(x[3]+170-5,5,x[3]+170,10);

line(x[3]+170-5,15,x[3]+170,10);

line(x[3]-170,10,x[3]-170,360);

line(x[3]-170-5,355,x[3]-170,360);

line(x[3]-170+5,355,x[3]-170,360); outtextxy(x[3]-170-5,5,"0"); /*画坐标*/ for(i=10;i<350;i+=10)

{if(i%50==0)

{

line(x[3]-170+i,10,x[3]-170+i,20);

if(i==50) s=ecvt(i,2,1,1);

else s=ecvt(i,3,1,1);

outtextxy(x[3]-170-25,i-5,s);}

else

line(x[3]-170+i,10,x[3]-170+i,15);

}

for(i=10;i<350;i+=10)

{if(i%50==0)

{line(x[3]-170,i,x[3]-170+15,i);

if(i==50) s=ecvt(i,2,1,1);

else s=ecvt(i,3,1,1);

outtextxy(x[3]-170+i-10,2,s);

}

else

line(x[3]-170,i,x[3]-170+5,i);

}

/*标坐标轴刻度*/

setcolor(RED);

getch();

outtextxy(x[3]-170-20,58,"49"); getch();

line(x[3]-170,58,x[3]+100,58); outtextxy(x[3]+102,58,"ET[49]"); getch();

outtextxy(x[3]-170-25,156,"146"); getch();

line(x[3]-170,156,x[3]+150,156); outtextxy(x[3]+132,148,"ET[146]"); getch();

outtextxy(x[3]-170-25,217,"207"); getch();

line(x[3]-170,217,x[3]+100,217); outtextxy(x[3]+102,217,"ET[207]"); getch();

outtextxy(x[3]-170-25,254,"244"); getch();

line(x[3]-170,254,x[3]+120,254); outtextxy(x[3]+122,254,"ET[244]"); getch();

/*划分类边*/

getch();

outtextxy(10,20,"Edge Table:"); getch();

for(i=0;i<4;i++)

{ rectangle(10,40+i*80,80,i*80+60);

line(70,i*80+50,90,i*80+50);line(90,i*80+50,90,i*80+65);

line(90,i*80+65,20,i*80+65);

line(20,i*80+65,20,i*80+70);

line(18,i*80+68,20,i*80+70);line(22,i*80+68,20,i*80+70);

}

outtextxy(15,45,"ET[49]"); outtextxy(15,125,"ET[146]");

outtextxy(15,205,"ET[207]"); outtextxy(15,285,"ET[244]");

for(i=0;i<4;i++)

{switch(i)

{case 0:str.s="31";str.t="97";str.w="146";str.v="200";str.v1="200";break;

case 1:str.s="83";str.t="60";str.w="207";str.v="66";str.v1="334";break;

case 2:str.s="31";str.t="97";str.w="314";str.v="148";str.v1="251";break;

case 3:str.s="83";str.t="60";str.w="314";str.v="200";str.v1="200";break;

default:break;

}

Node_Rect(10,i*80+70,110,i*80+95,str,0);

line(105,i*80+85,120,i*80+85);line(118,i*80+83,120,i*80+85);line(118,i*80+87,120,i*80+85); Node_Rect(120,i*80+70,220,i*80+95,str,1);

}

/*画分类表*/

n=(int)(y[3]+0.5);

m=(int)(y[1]+0.5);

getch();

CreatET(x,y,a,b);

setcolor(BLUE); outtextxy(10,360,"Active Edge List:");

rectangle(20,380,60,400); outtextxy(25,385,"AEL");

Fillin(AEL,n,m); /*填充*/

outtextxy(200,400,"Fillin Finished!");

getch();

closegr(); /* 恢复TEXT屏幕模式*/

}

3运行结果：