[Wishlist] Drawing only a portion of an image

[luiscubal]

I'd like to have new DrawImage overloads in Xwt.Drawing.Context:

These overloads would be the "source rectangle" on the image, effectively drawing only a portion of the image on the widget.

Equivalent feature in other toolkits:

• WinForms: http://msdn.microsoft.com/en-us/library/ms142040.aspx
• AWT/Swing: http://docs.oracle.com/javase/1.4.2/docs/api/java/awt/Graphics.html#drawImage%28java.awt.Image,%20int,%20int,%20int,%20int,%20int,%20int,%20int,%20int,%20java.awt.image.ImageObserver%29