VC实现自绘图形输出到bmp文件
作者：江上飞鸟
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);
}
