Application for diagram rendering based on GTK+ 3

[Козлов Кирилл <admin sdusi ru>]

Hello,

I need to develop an application with an area for rendering diagrams. In the area there will be objects which 
can be connected via lines, can be moved, deleted (like it's done in Dia, for example).
Please give me an advice on what modern GTK+ 3 objects should be used to implement this functionality (design 
area, the grid, drawing object, markers for changing size of an object). Any help or shared experience will 
be appreciated.

Best regards,
Kirill Kozlov