How to: Enumerate Drawing Content of a Visual

The Drawing object provide an object model for enumerating the contents of a Visual.

Example

The following example uses the GetDrawing method to retrieve the DrawingGroup value of a Visual and enumerate it.

Note:
When you are enumerating the contents of the visual, you are retrieving Drawing objects, and not the underlying representation of the render data as a vector graphics instruction list. For more information, see Windows Presentation Foundation Graphics Rendering Overview.

public void RetrieveDrawing(Visual v)
{
    DrawingGroup dGroup = VisualTreeHelper.GetDrawing(v);
    EnumDrawingGroup(dGroup);

}

 // Enumerate the drawings in the DrawingGroup.
 public void EnumDrawingGroup(DrawingGroup drawingGroup)
 {
     DrawingCollection dc = drawingGroup.Children;

     // Enumerate the drawings in the DrawingCollection.
     foreach (Drawing drawing in dc)
     {
         // If the drawing is a DrawingGroup, call the function recursively.
         if (drawing.GetType() == typeof(DrawingGroup))
         {
             EnumDrawingGroup((DrawingGroup)drawing);
         }
         else if (drawing.GetType() == typeof(GeometryDrawing))
         {
             // Perform action based on drawing type.  
         }
         else if (drawing.GetType() == typeof(ImageDrawing))
         {
             // Perform action based on drawing type.
         }
         else if (drawing.GetType() == typeof(GlyphRunDrawing))
         {
             // Perform action based on drawing type.
         }
         else if (drawing.GetType() == typeof(VideoDrawing))
         {
             // Perform action based on drawing type.
         }
     }
 }

See Also

Reference

Drawing
DrawingGroup
VisualTreeHelper

Concepts

Drawing Objects Overview
Windows Presentation Foundation Graphics Rendering Overview