The Visio file format

Since the 2013 edition, Visio files are Open Packaging Convention compliant, which means that most of the contents are accessible for programmers using some standard techniques. This means that package parts can be more easily extracted, and even modified, without recourse to the Visio type library. Before the 2013 version, Visio files were either binary or monolithic XML files (which were approximately 10 times the size of the binary files). Now that Visio files are zipped-up XML packages, there is greater scope for extensibility. For example, the Visio Web Access control in SharePoint 2010 used XAML to render the graphics on a layer over the top of the Visio binary file. The files had to be published as Visio Web Drawings (*.vdw) to be used, and only the linked Data Graphics content was automatically refreshable. Since the 2013 version, native Visio files are rendered in the Visio Web Access control without needing Silverlight, and any shape cell that is referenced...