An MFC picture control to dynamically show pictures in a dialog

• Download control source - 2.61 KB
• Download demo - 2.19 MB

Introduction

This article describes an MFC control that makes it possible to display any picture in a standard image format (like BMP, GIF, JPEG, etc...) on a dialog.

Background

It took me some time to search for a picture control for MFC, but unfortunately, I found none that actually worked for me. So, I decided to make myself a flexible and lightweight picture control to display all types of images.

Using the code

This control internally uses the GDI+ library. So, please make sure to include GdiPlus.lib to your include libraries.

To use this control, create a static text control with the dialog designer of Visual C++. After that, assign a control member variable of type CPictureCtrl to it.

Now, you can load a picture on your control. Do that by calling one of the various CPictureCtrl::LoadFrom... functions. Use the one that suits your needs. The control should automatically update to the new image.

To clear the image, call CPictureCtrl::FreeImage.

Your image will be automatically sized to the size of your control, regardless of the aspect ratio.

class CPictureCtrl :
    public CStatic
{
public:

    //Constructor
    CPictureCtrl(void);

    //Destructor
    ~CPictureCtrl(void);

public:

    //Loads an image from a file
    BOOL LoadFromFile(CString &szFilePath);

    //Loads an image from an IStream interface
    BOOL LoadFromStream(IStream* piStream);

    //Loads an image from a byte stream;
    BOOL LoadFromStream(BYTE* pData, size_t nSize);

    //Loads an image from a Resource
//     BOOL LoadFromResource(HMODULE hModule, LPCTSTR lpName, LPCTSTR lpType);

    //Overload - Single load function
    BOOL Load(CString &szFilePath);
    BOOL Load(IStream* piStream);
    BOOL Load(BYTE* pData, size_t nSize);
//     BOOL Load(HMODULE hModule, LPCTSTR lpName, LPCTSTR lpType);

    //Frees the image data
    void FreeData();

protected:
    virtual void PreSubclassWindow();

    //Draws the Control
    virtual void DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct);
    virtual BOOL OnEraseBkgnd(CDC* pDC);

private:

    //Internal image stream buffer
    IStream* m_pStream;

    //Control flag if a pic is loaded
    BOOL m_bIsPicLoaded;

    //GDI Plus Token
    ULONG_PTR m_gdiplusToken;
};

Points of interest

The control is based on subclassing a CStatic control. Therefore, you will have all the functionality of this control, but it will not display any text. The usage of the GDI+ library makes it possible to work with many modern types of image files.

History

• 1.0 - Initial release.
• 1.1 - A bug when drawing the control without a loaded image was corrected.
• 1.2 - A bug when drawing the control was corrected.

Loading an image from a resource is disabled due to problems recognizing it correctly as an image.