创建调色板、计算颜色表长度

Code:
// 创建逻辑调色板
void MakePalette(int nColorTableLength, LPRGBQUAD lpColorTable, HPALETTE hPalette)
{
    // 如果是真彩色就不用创建
    if (nColorTableLength == 0)
        return;

    // 删除旧的逻辑调色板
    if (hPalette != NULL)
        DeleteObject(hPalette);
    //
    LPLOGPALETTE pLogPal = (LPLOGPALETTE) new char[2*sizeof(WORD)+
        nColorTableLength*sizeof(PALETTEENTRY)];


    pLogPal->palVersion = 0x300;
    pLogPal->palNumEntries = nColorTableLength;
    LPRGBQUAD lpDibQuad = (LPRGBQUAD)lpColorTable;
    for (int i = 0; i<nColorTableLength; i++)
    {
        pLogPal->palPalEntry[i].peRed = lpDibQuad->rgbRed;
        pLogPal->palPalEntry[i].peGreen = lpDibQuad->rgbGreen;
        pLogPal->palPalEntry[i].peBlue = lpDibQuad->rgbBlue;
        pLogPal->palPalEntry[i].peFlags = 0;
        lpDibQuad++;
    }

    // 创建逻辑调色板
    hPalette = CreatePalette(pLogPal);
    delete pLogPal;
}

// 计算颜色表长度
int ComputeColorTableLength(int nBCount)
{
 printf("/nbit:%d/n", nBCount);
 int nColorLength;
 switch(nBCount)
 {
 case 1:
  nColorLength = 2;
  break;

 case 4:
  nColorLength = 16;
  break;
 case 8:
  nColorLength = 256;
  break;
 case 16:
 case 24:
 case 32:
  nColorLength = 0;
  break;
 default:
 assert(FALSE);//断言它的条件返回错误，则终止程序执行
 }
 assert((nColorLength>=0) && (nColorLength <=256));
 return nColorLength;
}