GDI+ / C#: How to save an image as EMF?

Question

If you use Image.Save Method to save an image to a EMF/WMF, you get an exception (http://msdn.microsoft.com/en-us/library/ktx83wah.aspx)

Is there another way to save the image to an EMF/WMF? Are there any encoders available?

Answer 1

Image is an abstract class: what you want to do depends on whether you are dealing with a Metafile or a Bitmap.

Creating an image with GDI+ and saving it as an EMF is simple with Metafile. Per Mike's post:

var path = @"c:foo.emf"
var g = CreateGraphics(); // get a graphics object from your form, or wherever
var img = new Metafile(path, g.GetHdc()); // file is created here
var ig = Graphics.FromImage(img);
// call drawing methods on ig, causing writes to the file
ig.Dispose(); img.Dispose(); g.ReleaseHdc(); g.Dispose();

This is what you want to do most of the time, since that is what EMF is for: saving vector images in the form of GDI+ drawing commands.

You can save a Bitmap to an EMF file by using the above method and calling ig.DrawImage(your_bitmap), but be aware that this does not magically covert your raster data into a vector image.