fill_point.rar_扫描线 填充算法_扫描线 种子填充_扫描线填充_种子填充_种子填充算法

extern int nMinX, nMaxX, nMinY, nMaxY; typedef struct { int x1, x2, y, dy; } LINESEGMENT; #define MAXDEPTH 10000 #define PUSH(XL, XR, Y, DY) \ if( sp < stack+MAXDEPTH && Y+(DY) >= nMinX && Y+(DY) <= nMaxY ) \ { sp->xl = XL; sp->xr = XR; sp->y = Y; sp->dy = DY; ++sp; } #define POP(XL, XR, Y, DY) \ { --sp; XL = sp->xl; XR = sp->xr; Y = sp->y+(DY = sp->dy); } // Fill background with given color void SeedFill_4(int x, int y, COLORREF new_color) { int left, x1, x2, dy; COLORREF old_color; LINESEGMENT stack[MAXDEPTH], *sp = stack; old_color = GetPixel(x, y); if( old_color == new_color ) return; if( x < nMinX || x > nMaxX || y < nMinX || y > nMaxY ) return; PUSH(x, x, y, 1); /* needed in some cases */ PUSH(x, x, y+1, -1); /* seed segment (popped 1st) */ while( sp > stack ) { POP(x1, x2, y, dy); for( x = x1; x >= nMinX && GetPixel(x, y) == old_color; --x ) SetPixel(x, y, new_color); if( x >= x1 ) goto SKIP; left = x+1; if( left < x1 ) PUSH(y, left, x1-1, -dy); /* leak on left? */ x = x1+1; do { for( ; x<=nMaxX && GetPixel(x, y) == old_color; ++x ) SetPixel(x, y, new_color); PUSH(left, x-1, y, dy); if( x > x2+1 ) PUSH(x2+1, x-1, y, -dy); /* leak on right? */ SKIP: for( ++x; x <= x2 && GetPixel(x, y) != old_color; ++x ) {;} left = x; } while( x<=x2 ); } }