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);

}