图形填充之种子填充算法

编译器：VS2013

算法：在图形内选择一个点为种子，然后对这个种子四方位坐标未着色的入栈，出栈便着色，如此重复，等到栈内为空，则着色完成

代码：

#include "stdafx.h"
#include<stdio.h>
#include"graphics.h"
#include<stdlib.h>
#include<stack>

using namespace std;

//定义结构体存储像素坐标
struct Point
{
    int x;
    int y;
};

//函数声明
void Boundaryfilling(Point a[], int n);
void judgecolor(int x, int y, stack<int> &sx, stack<int> &sy);

int main()
{
    int gdriver = DETECT, gmode, n, i;

    printf("please input number of point:
");
    scanf_s("%d", &n);

    Point *p=(Point *)malloc(n*sizeof(Point));    //动态分配内存

    printf("please input point :
");
    for (i = 0; i < n; i++)
        scanf_s("%d%d", &p[i].x, &p[i].y);

    initgraph(&gdriver, &gmode, "");

    setcolor(BLUE);
    setbkcolor(BLACK);

    //画出多边形
    for (i = 0; i < n-1; i++)
        line(p[i].x, p[i].y, p[i + 1].x, p[i + 1].y);

    Boundaryfilling(p, n);

    system("pause");
    closegraph();

    return 0;
}

void Boundaryfilling(Point a[], int n)
{
    stack<int> sx,sy;
    int x=0 , y=0 ,x0,y0,i;

    for (i = 0; i < n; i++)
    {
        x += a[i].x;
        y += a[i].y;
    }

    x = x / (n-1);
    y = y / (n-1);

    sx.push(x);//x坐标入栈
    sy.push(y);//y坐标入栈

    while (!sx.empty())    //判断栈是否为空
    {
        x0 = sx.top();
        y0 = sy.top();

        putpixel(sx.top(), sy.top(), YELLOW);    //栈顶元素着色
        sx.pop();//栈顶元素出栈
        sy.pop();//栈顶元素出栈

        judgecolor(x0 - 1, y0, sx, sy);//左边点
        judgecolor(x0 + 1, y0, sx, sy);//右边点
        judgecolor(x0, y0 - 1, sx, sy);//下边点
        judgecolor(x0, y0 + 1, sx, sy);//上边点
    }
}

//判断该像素是否没有着色
void judgecolor(int x, int y,stack<int> &sx,stack<int> &sy)
{
    if (getpixel(x, y) == BLACK)
    {
        sx.push(x);
        sy.push(y);
    }
}

结果：