C / C++ / MFC

• GetDIBits Function (Windows)[^]
• SetDIBits Function (Windows)[^]

• pinvoke.net: BITMAPINFOHEADER (structures)[^]
• pinvoke.net: GetDIBits (GDI32)[^]
• pinvoke.net: SetDIBits (GDI32)[^]
• BITMAPINFO Structure (Windows)[^]

GAJERA wrote:

CDC *dc=NULL;
dc->Attach()

1. the CDC::Attach() method wants an HDC as parameter, then this code doesn't compile. To which HDC do you want to attach?
2. you have initialized dc to NULL and then you use that pointer to call one of its non-static members: this will give you a memory protection fault.

#ifndef CONSUMER_H
#define CONSUMER_H

#include <afx.h>
#include <afxwin.h>
#include <set>
using namespace std;

typedef set<CWnd*> ObserverListConsumerDef;

#include "ThreadMessages.h"

class CConsumer
{
public:
   CConsumer(void);
   virtual ~CConsumer(void);

// Thread Interface
public:
   bool Start(void); // Start the thread
   bool Stop (void) { m_bStop = true; return true; } // Stop  the thread
   bool Abort(void); // Stop the thread (brute force kill it)
   bool WaitForThread(DWORD dwWait); // Wait the thread to signal, i.e. to end
   // dwWait in milliseconds or INFINITE
   bool IsRunning() { return m_bIsRunning; }; // Is the thread running
   bool IsSuccess() { return m_bSuccess; }; // Was the run successful ?
   virtual bool Execute() = 0; // Override to provide functionality

// the thread itself
protected:
   static UINT ThreadFunc(LPVOID pVoid)
   {
      return( ((CConsumer*) pVoid)->LocalThreadFunc() );
   }

   UINT LocalThreadFunc(void);
   bool  m_bIsRunning;
   bool  m_bSuccess;
   bool  m_bStop;
   CWinThread* m_pThread;
   HANDLE      m_hThread;

// Observer Windows
public:
   void SetObserver(CWnd *pWnd);
   void DelObserver(CWnd *pWnd);

protected:
   ObserverListConsumerDef m_ObserverList;
   void SendMessageToObs(UINT nMsg, WPARAM wP, LPARAM lP);
};

#endif  // ! defined (CONSUMER_H)

1. explicitly delete the object:
   
   C++

   CConsumer pConsumer = new CConsumer;
   ...
   // Somewhere in your code, periodically do this:
   if (!pConsumer->IsRunning())
      delete pConsumer;

2. add auto-delete feature to CConsumer:
   
   C++

   class CConsumer
   {
      ...
   
   protected:
      static UINT ThreadFunc(LPVOID pVoid)
      {
         CConsumer* pConsumer = (CConsumer*)pVoid;
         UINT retVal = pConsumer->LocalThreadFunc();
         if (pConsumer->m_bAutoDelete)
            delete pConsumer;
         return retVal;
      }
   
      BOOL m_bAutoDelete;
   
      ...
   };