BOOL CPicDoc::LoadTgaFile(LPCTSTR lpszFileName)
{
  CFile file(lpszFileName, CFile::modeRead);
  BOOL bResult = FALSE;
  ////////////header
  BYTE tgaif[0x12];
  file.Read(tgaif, sizeof(tgaif));
  BYTE bHasPal = tgaif[1];//有无调色板
  BYTE type = tgaif[2];//图片类型
  WORD palEntries = *(WORD*)(tgaif + 0x05);//颜色表颜色个数
  WORD tgWidth = *(WORD*)(tgaif + 0x0c);//TGA宽
  WORD tgHeight = *(WORD*)(tgaif + 0x0e);//TGA高
  BYTE bitCount = *(BYTE*)(tgaif + 0x10);//TGA bit out
  int bmWidth = tgWidth % 4 == 0 ? tgWidth : tgWidth + 4 - (tgWidth % 4);//转换成4字节对齐的BMP宽
  DWORD bmBitsSize  = bmWidth * tgHeight * (bitCount / 8);//BMP图像流尺寸
  DWORD bmInfoSize  = sizeof(BITMAPINFOHEADER) + palEntries * sizeof(RGBQUAD);//BMP信息尺寸
  DWORD bmSize = sizeof(BITMAPFILEHEADER) + bmInfoSize + bmBitsSize;//BMP文件尺寸
  BITMAPFILEHEADER bmfh = {0x4d42, bmSize, 0, 0, sizeof(BITMAPFILEHEADER) + bmInfoSize};//BMP文件头
  BITMAPINFOHEADER bmih = {0x28, tgWidth, - tgHeight, 1, bitCount, 0, 0, 0, 0, palEntries, 0};//BMP信息头
  ///////////////////////////
  file.SeekToBegin();
  int tgSize = file.GetLength();
  BYTE* pTgBuf = new BYTE[tgSize];
  file.Read(pTgBuf, tgSize);
  m_pBmData = new BYTE[bmSize];
  memset(m_pBmData, 0, bmSize);
  memcpy(m_pBmData, &bmfh, sizeof(bmfh));//bitmap file header
  memcpy(m_pBmData + sizeof(bmfh), &bmih, sizeof(bmih));//bitmap info header
  BYTE* pTg = pTgBuf + 0x12 + *pTgBuf;
  BYTE* pBm = m_pBmData + sizeof(bmfh) + sizeof(bmih);
  if ((type == 1 || type == 9) && bHasPal == 1)
  {
    //////////palette
    for(int i = 0; i < palEntries; i ++)
    {
      BYTE* p  = pTg + i * 3;
      RGBQUAD rgb = {*p, *(p + 1), *(p + 2), 0};
      *(RGBQUAD*)(pBm + i * 4) = rgb;
    }
    /////////bits
    pTg += palEntries * 3;//TGA数据开始位置
    pBm += palEntries * sizeof(RGBQUAD);//BMP数据开始位置
    if (type == 1)
    {
      AlignDOWD(pBm, pTg, tgWidth, tgHeight, bitCount / 8);//对齐DWORD
    }
    else if (type == 9)
    {
      //decompress bits
      BYTE* pTempBits = new BYTE[bmBitsSize];
      BYTE* pTemp = pTempBits;
      while (pTg < pTgBuf + tgSize)
      {
        BYTE flags = *pTg;//标志
        int size = (flags & 0x7F) + 1;//长度
        pTg ++;
        if (flags > 0x7F)
        {
          memset(pTemp, *pTg, size);//重复size次
          pTg ++;
        }
        else
        {
          memcpy(pTemp, pTg, size);//拷贝size个原数
          pTg += size;
        }
        pTemp += size;//目的指针
      }
      AlignDOWD(pBm, pTempBits, tgWidth, tgHeight, bitCount / 8);//对齐DWORD
      delete pTempBits;
    }
    bResult = TRUE;
  }
  else if ((type == 2) && bHasPal == 0)
  {
    AlignDOWD(pBm, pTg, tgWidth, tgHeight, bitCount / 8);//对齐DWORD
    bResult = TRUE;
  }
  delete pTgBuf;

  return bResult;
}

void CPicDoc::AlignDOWD(BYTE *pDest, BYTE *pSrc, int nSrcWidth, int nSrcHeight, int nByte)
{
  if (nSrcWidth % 4 == 0)
  {
    memcpy(pDest, pSrc, nSrcWidth * nSrcHeight * nByte);
  }
  else
  {
    int nDestWidth = nSrcWidth + 4 - (nSrcWidth % 4);
    for (int rows = 0; rows < nSrcHeight; rows ++)
    {
      memcpy(pDest + rows * nDestWidth * nByte, pSrc + rows * nSrcWidth * nByte, nSrcWidth * nByte);
    }
  }
}

SIZE CPicDoc::GetPicSize()
{
  BITMAPINFOHEADER* p = (BITMAPINFOHEADER*)(m_pBmData + sizeof(BITMAPFILEHEADER));
  int cy = p->biHeight < 0 ? -p->biHeight : p->biHeight;
  SIZE sz = {p->biWidth, cy};
  return sz;
}

void CPicView::OnInitialUpdate()
{
  CScrollView::OnInitialUpdate();
  CPicDoc* pDoc = GetDocument();
  CSize sizeTotal = pDoc->GetPicSize();
  SetScrollSizes(MM_TEXT, sizeTotal);
}

void CPicView::OnDraw(CDC* pDC)
{
  CPicDoc* pDoc = GetDocument();
  HDC hDC = pDC->m_hDC;
  SIZE sizeTotal = pDoc->GetPicSize();
  BITMAPINFOHEADER* lpbmih = (BITMAPINFOHEADER*)(pDoc->m_pBmData + sizeof(BITMAPFILEHEADER));
  BYTE* lpbInit = pDoc->m_pBmData + ((BITMAPFILEHEADER*)pDoc->m_pBmData)->bfOffBits;

  ::StretchDIBits(hDC, 0, 0, sizeTotal.cx, sizeTotal.cy,
    0, 0, sizeTotal.cx, sizeTotal.cy, lpbInit, (BITMAPINFO*)lpbmih, DIB_RGB_COLORS, SRCCOPY);
}