Question

我一直在使用Paul Heckbert的优秀种子填充算法（可用here和书Graphic Gems (1990)）。

因为算法可能会出现问题。它构思精良，速度快！不幸的是，它只适用于4个连接的空间。

我正在寻找一个设计良好，快速的8连接空间算法（沿对角线泄漏）。有什么想法吗？

对于此问题，递归访问或反复将每个单元格抛出到堆栈中将不被认为是精心设计的。伪代码中可用的算法非常受欢迎（Heckbert的代码和伪代码都可用）。

谢谢！

为了完整性，将赫克伯特的算法复制到此处：

/*
 * 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);
    }
}

Answer 1

从cvFloodFill()框架中检查OpenCV。 flags 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)

Answer 2

https://github.com/DanBloomberg/leptonica/blob/master/src/conncomp.c具有Heckbert算法的4连接和8连接变体。

uprice是您需要的功能。

高效的8连接洪水填充

2 个答案: