我一直在使用paul heckbert的优秀种子填充算法(可在here和Graphic Gems (1990)一书中找到)。
由于算法可能出现卷积。它构思得很好而且速度很快!不幸的是,它只适用于4连通空间。
我正在寻找一个设计良好,快速算法8连通空间(沿对角线泄漏)。有什么想法吗?
递归地访问或重复地将每个单元格扔到堆栈上不会被认为是为解决此问题而精心设计的。最受赞赏的是伪代码中可用的算法(Heckbert的算法在代码和伪代码中都可用)。
谢谢!
为了完整起见,在此复制Heckbert的算法:
/*
* A Seed Fill Algorithm
* by Paul Heckbert
* from "Graphics Gems", Academic Press, 1990
*
* user provides pixelread() and pixelwrite() routines
*/
/*
* fill.c : simple seed fill program
* Calls pixelread() to read pixels, pixelwrite() to write pixels.
*
* Paul Heckbert 13 Sept 1982, 28 Jan 1987
*/
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);
}
}
最佳答案
从cvFloodFill()框架中检查OpenCVflags参数似乎用于设置此值:
void cvFloodFill(CvArr* image,
CvPoint seed_point,
CvScalar new_val,
CvScalar lo_diff=cvScalarAll(0),
CvScalar up_diff=cvScalarAll(0),
CvConnectedComp* comp=NULL,
int flags=4,
CvArr* mask=NULL)