CPaintDC develish slow

[S van Leent]

Hi all, I am currently doing a project where I need to be able to have a imaging framework. Although the framework itself runs pretty smooth, the CPaintDC of MFC kills me. The SetPixelV is extremely slow, so I want to use another way of doing this. I know it is possible to create a CDC in memory, but how can I put a bitmap created from this CDC put on the surface a CWnd subclassed control? Any suggestions? LPCTSTR Dutch = TEXT("Double Dutch :-)");

[basementman]

bitblt. Code snippet to help you (heavily edited and content deleted):

BOOL DoChart(CallContextObj *pCallContextObj)
{
CDC oMemDC;
CBitmap *pOldBmp;
CBitmap oBmp;

long lWidth = 300;
long lHeight = 200;
pCallContextObj->GetParameterValue("ChartWidth",&lWidth);
pCallContextObj->GetParameterValue("ChartHeight",&lHeight);

CRect oBmpSize(0,0,lWidth,lHeight);

oMemDC.CreateCompatibleDC(NULL);
int iOldMapMode = oMemDC.SetMapMode(MM_TEXT);

CWindowDC dcScreen(NULL);

oBmp.CreateCompatibleBitmap(&dcScreen,oBmpSize.Width(), oBmpSize.Height());

pOldBmp = oMemDC.SelectObject(&oBmp);

WORD wChartType = 88;
pCallContextObj->GetParameterValue("ChartType",&wChartType);

BOOL bRetval = FALSE;
char caHeaders[512];
strcpy(caHeaders,"Invalid Chart Type");

switch (wChartType)
{
case 0:
bRetval = DoLineChart(pCallContextObj,&oMemDC,caHeaders,oBmpSize);
break;

  case 1:
    bRetval = DoBarChart(FALSE,pCallContextObj,&oMemDC,caHeaders,oBmpSize);
    break;

  case 2:
    bRetval = DoBarChart(TRUE,pCallContextObj,&oMemDC,caHeaders,oBmpSize);
    break;

  case 3:
    bRetval = DoOpenHiLowCloseChart(pCallContextObj,&oMemDC,caHeaders,oBmpSize);
    break;

  case 4:
    bRetval = DoPieChart(pCallContextObj,&oMemDC,caHeaders,oBmpSize);
    break;
}

if (bRetval)
{
LPSTR cpBuf = pCallContextObj->GetOutputBufferPtr();

  long lQuality = 75;
  pCallContextObj->GetParameterValue("ImageQuality",&lQuality);

  char caContentType\[256\];

  long lDataSize = WriteImage(oBmp,cpBuf,pCallContextObj->GetOutputBufferSize(),caHeaders,(DWORD)lQuality);
  if (lDataSize > 0)
    {
      pCallContextObj->SuppressHeaders();
      // pCallContextObj->GetMimeType("x.bmp",caContentType);
      pCallContextObj->GetMimeType("x.jpg",caContentType);

      sprintf(caHeaders,"Content-Type: %s%sContent-Length: %d%s%s",caContentType,cpCRLF,lDataSize,cpCRLF,cpCRLF);

      // write out our custom headers
      if (pCallContextObj->ServerSupportFunction(HSE\_REQ\_SEND\_RESPONSE\_HEADER,"200 OK",0,(LPDWORD)caHeaders) || ::GetLastError() == 10054)
        pCallContextObj->WriteClient((LPVOID)cpBuf,(LPDWORD)&lDataSize);

      \*cpBuf = 0;
    }
  else
    bRetval = FALSE;
}

oMemDC.SetMapMode(iOldMapMode);
oMemDC.SelectObject(pOldBmp);

oMemDC.DeleteDC();