继续求助,继续给分,还是种子填充的问题.

[lihobby]

种子填充算法的递归实现
填充区域可以是 多边形区域 也可以是圆形区域.
用C 语言 描述的数据结构 写这个程序,要详细点 谢谢 谢谢!!!

[寻开心]

/*
* fill.c : simple seed fill program
* Calls pixelread() to read pixels, pixelwrite() to write pixels.
*/

typedef struct { /* window: a discrete 2-D rectangle */
int x0, y0; /* xmin and ymin */
int x1, y1; /* xmax and ymax (inclusive) */
} Window;

typedef int Pixel; /* 1-channel frame buffer assumed */

Pixel pixelread();

typedef struct {short y, xl, xr, dy;} Segment;
/*
* Filled horizontal segment of scanline y for xl<=x<=xr.
* Parent segment was on line y-dy. dy=1 or -1
*/

#define MAX 10000 /* max depth of stack */

#define PUSH(Y, XL, XR, DY) /* push new segment on stack */ \
if (sp<stack+MAX && Y+(DY)>=win->y0 && Y+(DY)<=win->y1) \
{sp->y = Y; sp->xl = XL; sp->xr = XR; sp->dy = DY; sp++;}

#define POP(Y, XL, XR, DY) /* pop segment off stack */ \
{sp--; Y = sp->y+(DY = sp->dy); XL = sp->xl; XR = sp->xr;}

/*
* fill: set the pixel at (x,y) and all of its 4-connected neighbors
* with the same pixel value to the new pixel value nv.
* A 4-connected neighbor is a pixel above, below, left, or right of a pixel.
*/

fill(x, y, win, nv)
int x, y; /* seed point */
Window *win; /* screen window */
Pixel nv; /* new pixel value */
{
int l, x1, x2, dy;
Pixel ov; /* old pixel value */
Segment stack[MAX], *sp = stack; /* stack of filled segments */

ov = pixelread(x, y); /* read pv at seed point */
if (ov==nv || x<win->x0 || x>win->x1 || y<win->y0 || y>win->y1) return;
PUSH(y, x, x, 1); /* needed in some cases */
PUSH(y+1, x, x, -1); /* seed segment (popped 1st) */

while (sp>stack) {
/* pop segment off stack and fill a neighboring scan line */
POP(y, x1, x2, dy);
/*
* segment of scan line y-dy for x1<=x<=x2 was previously filled,
* now explore adjacent pixels in scan line y
*/
for (x=x1; x>=win->x0 && pixelread(x, y)==ov; x--)
pixelwrite(x, y, nv);
if (x>=x1) goto skip;
l = x+1;
if (l<x1) PUSH(y, l, x1-1, -dy); /* leak on left? */
x = x1+1;
do {
for (; x<=win->x1 && pixelread(x, y)==ov; x++)
pixelwrite(x, y, nv);
PUSH(y, l, x-1, dy);
if (x>x2+1) PUSH(y, x2+1, x-1, -dy); /* leak on right? */
skip: for (x++; x<=x2 && pixelread(x, y)!=ov; x++);
l = x;
} while (x<=x2);
}
}

[寻开心]

这个例子是填充一个矩形，对于其它形状的只要修改边界检查条件就可以了。

[BlueSky2008]

计算机图形学书上不都有吗？