VC实现自绘图形输出到bmp文件

作者：江上飞鸟

下载源代码

　　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);
}