A simple Windows Forms image viewer

• Download source files - 12 Kb
• Download demo project - 38 Kb

Introduction

This is a simple viewer application which allows you to apply basic operation on images such as Rotate, Flip, ROI (Region of interest) zoom and Panning. It offers a sample example for the powerful Matrix class use and the way to have unclassical forms look. A simple windowing method is implemented using middle muse button (available for grayscale image).

Using the code

The interesting code is based on the DisplayPort class which acts as a viewport. A command mechanism is also develop to allow multiple DisplayPort to interact with the user cooperatively. Adding new behaviour such as displaying and designing graphics above the image is easy. See the DisplayLinkRind class which is a manager of simple text overlays.

To add a DisplayPort to a WindowsForm just add a member like this and chain the MouseDown event:

public LimfWnd()
{
    this.ClientSize = new System.Drawing.Size(464, 344);

    this.m_DisplayPort = new DisplayPort();

    InitializeComponent();

    this.m_DisplayPort.MouseDown += new MouseEventHandler(LimfWnd_MouseDown);

            ...

Then add the controls to the form:

private void InitializeComponent()
{
    // 
    // LimfWnd
    // 
    this.AllowDrop = true;
    this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
    this.BackColor = System.Drawing.SystemColors.WindowText;

    this.ClientSize = new System.Drawing.Size(SystemInformation.WorkingArea.Width/2, 
                                              SystemInformation.WorkingArea.Height/2);

    this.Controls.AddRange(new System.Windows.Forms.Control[] {this.m_DisplayPort,
                                                                          this.splitter1});

            ...

Add image to the DisplayPort:

private void LoadImage(object sender, System.EventArgs e)
{
    FileDialog  Boite = new OpenFileDialog();
    Boite.ShowDialog();

    if(Boite.FileName.Length > 0)
    {
        Image Img = Image.FromFile(Boite.FileName);
        m_DisplayPort.SetImage(Img);
    }
}
            ...

Chain the menu list event:

private void LimfWnd_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
    if(e.Button == MouseButtons.Right)
    {
        CMenuActionList CommandsLst;

        if(sender.GetType() == m_DisplayPort.GetType())
            CommandsLst = ((DisplayPort) sender).GetCommand(null);
        else
            CommandsLst = new CMenuActionList();

        if(CommandsLst == null)
            CommandsLst = new CMenuActionList();

        CommandsLst.AddMenu(1, "Quit", 1, new System.EventHandler(Quit));

Points of Interest

The main difficulty was to create the basic rotate/flip routines to manage the coordinate converter. The only limit I found regarding the use of GDI+ was the 16 bits per pixel format which is not implemented, so no use for such images.

History

Version 1.0 is the first release.