VC实现自绘图形输出到bmp文件

在用vc做程序时候，经常需要把输出的文本和图形保存到位图文件，当然可以有现成的控件来实现,但总不能如自己所愿，还是自己动手写吧！如下图：



一、实现方法

　　要把文本和图形保存到位图文件，只要对掌握位图结构有一定的了解，一切都ok呢。先必须要创建内存设备环境，然后内存设备环境创建的DIB区域，别忘了还要创建个CBitmap对象，CBitmap对象必须和DIB区域关联起来，把CBitmap对象选择到当前设备环境，然后在当前设备环境输出文本和图形就可以了。

二、具体实现代码如下

void CTestSaveBmpView::SaveAsBmp(CString filename)
{
 //定义图形大小
 int iWidth = 800;
 int iHeight = 600;
 int iPixel = 16;
 //图形格式参数
 LPBITMAPINFO lpbmih = new BITMAPINFO;
 lpbmih->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
 lpbmih->bmiHeader.biWidth = iWidth;
 lpbmih->bmiHeader.biHeight = iHeight;
 lpbmih->bmiHeader.biPlanes = 1;
 lpbmih->bmiHeader.biBitCount = iPixel;
 lpbmih->bmiHeader.biCompression = BI_RGB;
 lpbmih->bmiHeader.biSizeImage = 0;
 lpbmih->bmiHeader.biXPelsPerMeter = 0;
 lpbmih->bmiHeader.biYPelsPerMeter = 0;
 lpbmih->bmiHeader.biClrUsed = 0;
 lpbmih->bmiHeader.biClrImportant = 0;
 
 //创建位图数据
 HDC hdc,hdcMem;
 HBITMAP hBitMap = NULL;
 CBitmap *pBitMap = NULL;
 CDC *pMemDC = NULL;
 BYTE *pBits;
 
 hdc = CreateIC(TEXT("DISPLAY"),NULL,NULL,NULL);
 hdcMem = CreateCompatibleDC(hdc);
 hBitMap = CreateDIBSection(hdcMem,lpbmih,DIB_PAL_COLORS,(void **)&pBits,NULL,0);
 pBitMap = new CBitmap;
 pBitMap->Attach(hBitMap);
 pMemDC = new CDC;
 pMemDC->Attach(hdcMem);
 pMemDC->SelectObject(pBitMap);
 //
 CRect rc(0,0,iWidth,iHeight);
 pMemDC->SetBkMode(TRANSPARENT);
 //添加自绘图形 
 DrawCurve(pMemDC,rc);
 //保存到文件并创建位图结构
 BITMAPFILEHEADER bmfh;
 ZeroMemory(&bmfh,sizeof(BITMAPFILEHEADER));
 *((char *)&bmfh.bfType) = ''B'';
 *(((char *)&bmfh.bfType) + 1) = ''M'';
 bmfh.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
 bmfh.bfSize = bmfh.bfOffBits + (iWidth * iHeight) * iPixel / 8;
 
 TCHAR szBMPFileName[128];
 int iBMPBytes = iWidth * iHeight * iPixel / 8;
 strcpy(szBMPFileName,filename);
 CFile file;
 if(file.Open(szBMPFileName,CFile::modeWrite | CFile::modeCreate))
 {
  file.Write(&bmfh,sizeof(BITMAPFILEHEADER));
  file.Write(&(lpbmih->bmiHeader),sizeof(BITMAPINFOHEADER));
  file.Write(pBits,iBMPBytes);
  file.Close();
 }
 
 pMemDC->DeleteDC();
 delete pMemDC; pMemDC = NULL;
 delete pBitMap; pBitMap = NULL;
 delete lpbmih; lpbmih = NULL;
}

//输出文本和图形

void CTestSaveBmpView::DrawCurve(CDC *pDC, CRect rcClient)
{
 //页面背景色
 CBrush brushCtl;
 brushCtl.CreateSolidBrush(RGB(255,255,255));
 pDC->Rectangle(rcClient);
 pDC->FillRect(rcClient,&brushCtl) ;
 brushCtl.DeleteObject();
 
 CPen pen;
 pen.CreatePen(PS_SOLID, 1, RGB(255,0,0));
 CPen *oldPen = pDC->SelectObject(&pen); 
 
 double xMin = 10.00f, xMax = 100.00f;
 double yMin = 10.00f, yMax = 200.00f;
 
 double dbX1 = (xMax- xMin)/100 + xMin;
 double dbY1 = 600/dbX1 ;
 for (int i=1; i<100; i++) //曲线
 {
  double dbX2 = (xMax- xMin)*i/100 + xMin;
  double dbY2 = 600/dbX2 ;
  
  pDC->MoveTo(int(rcClient.left+(dbX1 - xMin)*rcClient.Width()/(xMax- xMin)), 
   int(rcClient.bottom-(dbY1- yMin)*rcClient.Height()/(yMax- yMin)));
  pDC->LineTo(int(rcClient.left+(dbX2 - xMin)*rcClient.Width()/(xMax- xMin)), 
   int(rcClient.bottom-(dbY2- yMin)*rcClient.Height()/(yMax- yMin))); 
  
  dbX1=dbX2;
  dbY1=dbY2;
 }
 pDC->SelectObject(oldPen); 
 pen.DeleteObject();
 oldPen = NULL;
}

//保存的实现
void CTestSaveBmpView::OnRButtonDown(UINT nFlags, CPoint point) 
{
 
 CFileDialog dlg(false,NULL,NULL,OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT,
  "位图文件(*.bmp)|*.bmp|",
  NULL);
 if (dlg.DoModal()!= IDOK) return;
 CString filename = dlg.GetFileName() + ".bmp";
 SaveAsBmp(filename); 
 
 CView::OnRButtonDown(nFlags, point);
}