EMR_EXTFLOODFILL           = 53,

static extern bool ExtFloodFill(IntPtr hdc, int nXStart, int nYStart,

public static extern bool ExtFloodFill(IntPtr hdc, int nXStart, int nYStart,

    ExtFloodFill(vDC, 10, 10, GetPixel(vDC, 10, 10), FLOODFILLSURFACE);