Export UML diagrams to image files

You can export a UML document from Visual Studio to an image that is under program control. For example, you might want to do this as part of automatic document generation.

If you want to export a document to an image manually, you can copy and paste the shapes from a diagram into other programs such as Word. You can also print documents to XPS format. For more information, see Export diagrams as images.

Saving an Image

The following code defines a shortcut menu command, also known as a context menu command, that saves an image to a file.

The code first uses IShape.GetObject to get the Diagram of the underlying implementation. This type has a method CreateBitmap.

namespace SaveToImage
{
  using System.ComponentModel.Composition; // for [Import], [Export]
  using System.Drawing; // for Bitmap
  using System.Drawing.Imaging; // for ImageFormat
  using System.Linq; // for collection extensions
  using System.Windows.Forms; // for SaveFileDialog
  using Microsoft.VisualStudio.Modeling.Diagrams;
    // for Diagram
  using Microsoft.VisualStudio.Modeling.ExtensionEnablement;
    // for IGestureExtension, ICommandExtension, ILinkedUndoContext
  using Microsoft.VisualStudio.ArchitectureTools.Extensibility.Presentation;
    // for IDiagramContext
  using Microsoft.VisualStudio.ArchitectureTools.Extensibility.Uml;
    // for designer extension attributes

  /// <summary>
  /// Called when the user clicks the menu item.
  /// </summary>
  // Context menu command applicable to any UML diagram
  [Export(typeof(ICommandExtension))]
  [ClassDesignerExtension]
  [UseCaseDesignerExtension]
  [SequenceDesignerExtension]
  [ComponentDesignerExtension]
  [ActivityDesignerExtension]
  class CommandExtension : ICommandExtension
  {
    [Import]
    IDiagramContext Context { get; set; }

    public void Execute(IMenuCommand command)
    {
      // Get the diagram of the underlying implementation.
      Diagram dslDiagram = Context.CurrentDiagram.GetObject<Diagram>();
      if (dslDiagram != null)
      {
        string imageFileName = FileNameFromUser();
        if (!string.IsNullOrEmpty(imageFileName))
        {
          Bitmap bitmap = dslDiagram.CreateBitmap(
           dslDiagram.NestedChildShapes,
           Diagram.CreateBitmapPreference.FavorClarityOverSmallSize);
          bitmap.Save(imageFileName, GetImageType(imageFileName));
        }
      }
    }

    /// <summary>
    /// Called when the user right-clicks the diagram.
    /// Set Enabled and Visible to specify the menu item status.
    /// </summary>
    /// <param name="command"></param>
    public void QueryStatus(IMenuCommand command)
    {
      command.Enabled = Context.CurrentDiagram != null
        && Context.CurrentDiagram.ChildShapes.Count() > 0;
    }

    /// <summary>
    /// Menu text.
    /// </summary>
    public string Text
    {
      get { return "Save To Image..."; }
    }

    /// <summary>
    /// Ask the user for the path of an image file.
    /// </summary>
    /// <returns>image file path, or null</returns>
    private string FileNameFromUser()
    {
      SaveFileDialog dialog = new SaveFileDialog();
      dialog.AddExtension = true;
      dialog.DefaultExt = "image.bmp";
      dialog.Filter = "Bitmap ( *.bmp )|*.bmp|JPEG File ( *.jpg )|*.jpg|Enhanced Metafile (*.emf )|*.emf|Portable Network Graphic ( *.png )|*.png";
      dialog.FilterIndex = 1;
      dialog.Title = "Save Diagram to Image";
      return dialog.ShowDialog() == DialogResult.OK ? dialog.FileName : null;
    }

    /// <summary>
    /// Return the appropriate image type for a file extension.
    /// </summary>
    /// <param name="fileName"></param>
    /// <returns></returns>
    private ImageFormat GetImageType(string fileName)
    {
      string extension = System.IO.Path.GetExtension(fileName).ToLowerInvariant();
      ImageFormat result = ImageFormat.Bmp;
      switch (extension)
      {
        case ".jpg":
          result = ImageFormat.Jpeg;
          break;
        case ".emf":
          result = ImageFormat.Emf;
          break;
        case ".png":
          result = ImageFormat.Png;
          break;
      }
      return result;
    }
  }
}

See Also

Export diagrams as images Define a menu command on a modeling diagram