How to Make a MFC Paint Brush Application

This article will walk you through the steps to write a simple paint brush application using the Microsoft Foundation Class (MFC) library. The program will convert your mouse into a drawing instrument on a window. When the left mouse button is pressed and dragged, a line is drawn. When the button is released, the line stops.

Things You'll Need

• Microsoft Visual C++ development environment

Instructions

1. Launch Microsoft Visual C++. Then click File, New and Projects. Select "Win32 Application," give the project a name and click OK. Check "An empty project" and click "Finish."

2. Add a source file to the project. Click Project, "Add To Project," New and then "C++ Source File." Name the source file.

3. Copy and paste the following source code onto the file of Step 2: //begin MFC Paint Brush #include class CWindow :public CFrameWnd { CPoint mBegAny, mEndAny; public: CWindow() { Create(NULL,"Paintbrush Window"); } void OnLButtonDown(UINT flags, CPoint any); void OnLButtonUp(UINT flags, CPoint any); DECLARE_MESSAGE_MAP() }; BEGIN_MESSAGE_MAP( CWindow, CFrameWnd) ON_WM_LBUTTONDOWN() //macro that maps left button click ON_WM_LBUTTONUP() //macro that maps left button END_MESSAGE_MAP() void CWindow::OnLButtonDown(UINT flags, CPoint any) { CFrameWnd::OnLButtonDown(flags, any); mBegAny = any; } void CWindow::OnLButtonUp(UINT flags, CPoint any) { CFrameWnd::OnLButtonDown(flags, any); mEndAny = any; CClientDC dc(this); dc.MoveTo(mBegAny); dc.LineTo(mEndAny); } class MyApp :public CWinApp { CWindow *wnd; public: BOOL InitInstance() { wnd = new CWindow(); m_pMainWnd = wnd; m_pMainWnd->ShowWindow(1); return 1; } }; MyApp theApp; //end MFC Paint Brush

4. Understand what the code means. Class CFrameWnd is used to create a window. The coordinates of the mouse are stored in variables mBegAny and mEndAny of type CPoint. This occurs inside events OnLButtonDown and OnLButtonUp that correspond to a mouse click or release, respectively. Class CWinApp is the MFC equivalent of the main() function. It controls the initialization, running and termination of a Windows Application.

5. Build the application. To build press F7 or click Build and then "Build file_name.exe" or click on the Build icon. Run the application. Press Ctrl+F5 or click Build then "Execute file_name.exe" or click the Run icon.

Tips & Warnings

• A class called CMetaFileDC (device context class) will solve the problems listed under Warnings.

• You can't draw curves with this application.

• A window resize will erase the lines drawn.

Resources

• DevCentral has articles and tutorials with easy to understand examples.
• FunctionX provides tutorials and links on various computer languages.
• Code Beach offers free and open source code and tutorials.