floodfill算法的几种实现

<pre name="code" class="cpp">一、4-Way Recursive Method（FloodFill4） //Recursive 4-way floodfill, crashes if recursion stack is full void floodFill4(int x, int y, int newColor, int oldColor) {     if(x >= 0 && x < w && y >= 0 && y < h && screenBuffer[x][y] == oldColor && screenBuffer[x][y] != newColor)     {         screenBuffer[x][y] = newColor; //set color before starting recursion                floodFill4(x + 1, y,     newColor, oldColor);        floodFill4(x - 1, y,     newColor, oldColor);        floodFill4(x,     y + 1, newColor, oldColor);        floodFill4(x,     y - 1, newColor, oldColor);    }     } 二、8-Way Recursive Method（FloodFill8）//Recursive 8-way floodfill, crashes if recursion stack is fullvoid floodFill8(int x, int y, int newColor, int oldColor){    if(x >= 0 && x < w && y >= 0 && y < h && screenBuffer[x][y] == oldColor && screenBuffer[x][y] != newColor)    {        screenBuffer[x][y] = newColor; //set color before starting recursion!                floodFill8(x + 1, y,     newColor, oldColor);        floodFill8(x - 1, y,     newColor, oldColor);        floodFill8(x,     y + 1, newColor, oldColor);        floodFill8(x,     y - 1, newColor, oldColor);        floodFill8(x + 1, y + 1, newColor, oldColor);        floodFill8(x - 1, y - 1, newColor, oldColor);        floodFill8(x - 1, y + 1, newColor, oldColor);        floodFill8(x + 1, y - 1, newColor, oldColor);    }    }三、4-Way Method With Stack（FloodFill4Stack）//4-way floodfill using our own stack routinesvoid floodFill4Stack(int x, int y, int newColor, int oldColor){    if(newColor == oldColor) return; //avoid infinite loop    emptyStack();          if(!push(x, y)) return;     while(pop(x, y))    {        screenBuffer[x][y] = newColor;        if(x + 1 < w && screenBuffer[x + 1][y] == oldColor)        {                      if(!push(x + 1, y)) return;                   }            if(x - 1 >= 0 && screenBuffer[x - 1][y] == oldColor)        {            if(!push(x - 1, y)) return;                   }            if(y + 1 < h && screenBuffer[x][y + 1] == oldColor)        {            if(!push(x, y + 1)) return;                   }            if(y - 1 >= 0 && screenBuffer[x][y - 1] == oldColor)        {            if(!push(x, y - 1)) return;                   }        }     }四、8-Way Method With Stack（FloodFill8Stack）//4-way floodfill using our own stack routinesvoid floodFill4Stack(int x, int y, int newColor, int oldColor){    if(newColor == oldColor) return; //avoid infinite loop    emptyStack();          if(!push(x, y)) return;     while(pop(x, y))    {        screenBuffer[x][y] = newColor;        if(x + 1 < w && screenBuffer[x + 1][y] == oldColor)        {                      if(!push(x + 1, y)) return;        }            if(x - 1 >= 0 && screenBuffer[x - 1][y] == oldColor)        {            if(!push(x - 1, y)) return;        }            if(y + 1 < h && screenBuffer[x][y + 1] == oldColor)        {            if(!push(x, y + 1)) return;        }            if(y - 1 >= 0 && screenBuffer[x][y - 1] == oldColor)        {            if(!push(x, y - 1)) return;        }        if(x + 1 < w && y + 1 < h && screenBuffer[x + 1][y + 1] == oldColor)        {                  if(!push(x + 1, y + 1)) return;        }                if(x + 1 < w && y - 1 >= 0 && screenBuffer[x + 1][y - 1] == oldColor)        {              if(!push(x + 1, y - 1)) return;        }         if(x - 1 >= 0 && y + 1 < h && screenBuffer[x - 1][y + 1] == oldColor)        {                      if(!push(x - 1, y + 1)) return;        }        if(x - 1 >= 0 && y - 1 >= 0 && screenBuffer[x - 1][y - 1] == oldColor)        {            if(!push(x - 1, y - 1)) return;        }    }}五、 Recursive Scanline Floodfill Algorithm(floodFillScanline)//stack friendly and fast floodfill algorithmvoid floodFillScanline(int x, int y, int newColor, int oldColor){    if(oldColor == newColor) return;    if(screenBuffer[x][y] != oldColor) return;          int y1;        //draw current scanline from start position to the top    y1 = y;    while(y1 < h && screenBuffer[x][y1] == oldColor)    {        screenBuffer[x][y1] = newColor;        y1++;    }            //draw current scanline from start position to the bottom    y1 = y - 1;    while(y1 >= 0 && screenBuffer[x][y1] == oldColor)    {        screenBuffer[x][y1] = newColor;        y1--;    }        //test for new scanlines to the left    y1 = y;    while(y1 < h && screenBuffer[x][y1] == newColor)    {        if(x > 0 && screenBuffer[x - 1][y1] == oldColor)         {            floodFillScanline(x - 1, y1, newColor, oldColor);        }         y1++;    }    y1 = y - 1;    while(y1 >= 0 && screenBuffer[x][y1] == newColor)    {        if(x > 0 && screenBuffer[x - 1][y1] == oldColor)         {            floodFillScanline(x - 1, y1, newColor, oldColor);        }        y1--;    }         //test for new scanlines to the right     y1 = y;    while(y1 < h && screenBuffer[x][y1] == newColor)    {        if(x < w - 1 && screenBuffer[x + 1][y1] == oldColor)         {                       floodFillScanline(x + 1, y1, newColor, oldColor);        }         y1++;    }    y1 = y - 1;    while(y1 >= 0 && screenBuffer[x][y1] == newColor)    {        if(x < w - 1 && screenBuffer[x + 1][y1] == oldColor)         {            floodFillScanline(x + 1, y1, newColor, oldColor);        }        y1--;    }}六、Scanline Floodfill Algorithm With Stack(floodFillScanlineStack)/The scanline floodfill algorithm using our own stack routines, fastervoid floodFillScanlineStack(int x, int y, int newColor, int oldColor){    if(oldColor == newColor) return;    emptyStack();        int y1;     bool spanLeft, spanRight;        if(!push(x, y)) return;        while(pop(x, y))    {            y1 = y;        while(y1 >= 0 && screenBuffer[x][y1] == oldColor) y1--;        y1++;        spanLeft = spanRight = 0;        while(y1 < h && screenBuffer[x][y1] == oldColor )        {            screenBuffer[x][y1] = newColor;            if(!spanLeft && x > 0 && screenBuffer[x - 1][y1] == oldColor)             {                if(!push(x - 1, y1)) return;                spanLeft = 1;            }            else if(spanLeft && x > 0 && screenBuffer[x - 1][y1] != oldColor)            {                spanLeft = 0;            }            if(!spanRight && x < w - 1 && screenBuffer[x + 1][y1] == oldColor)             {                if(!push(x + 1, y1)) return;                spanRight = 1;            }            else if(spanRight && x < w - 1 && screenBuffer[x + 1][y1] != oldColor)            {                spanRight = 0;            }             y1++;        }    }}cc bool pop(int&x, int &y) {     if(stackPointer > 0)     {         int p = stack[stackPointer];         x = p / h;         y = p % h;         stackPointer--;         return 1;     }         else     {         return 0;     }    }    bool push(int x, int y) {     if(stackPointer < stackSize - 1)     {         stackPointer++;         stack[stackPointer] = h * x + y;         return 1;     }         else     {         return 0;     }    }     void emptyStack() {     int x, y;     while(pop(x, y)); }void clearScreenBuffer(ColorRGB color) {     for(int x = 0; x < w; x++)     for(int y = 0; y < h; y++)     {         screenBuffer[x][y] = RGBtoINT(color);     }     }