Disclaimer: I'm particularly biased here as I wrote some documentation for Kivio and the program's author, Peter Simonsonn, has fixed every single bug I reported.
Kivio is an example of how applications can suddenly become usable. Kivio had languished as poorly supported application in KOffice for ages. You couldn't do much with it as it didn't come with any stencils. The user interface was appalling, cluttered and off putting. A couple of new people took over, did a clean-up on the UI, added some stencils and fixed the bugs. Suddenly Kivio is a very capable application.
Kivio is designed for creating diagram and flowcharts. It comes with a several sets of pre-drawn symbols, stencils, that can be arranged on a page and linked together. Any Kivio document can contain several pages. Stencils are grouped into sets covering various fields including: flowcharting, electronics and computer networks.
All stencils in Kivo can be resized to any proportions and have text assigned to them. You can change the line width, colour and fill colour of all objects. Tools are also provided for aligning and grouping objects.
Stencils can be linked together with connectors, this is a line between the object that tracks the object as it is moved.
Arrowheads of various types can be added to each end of a connector.
Editing is quick and easy with most of the options being accessible from the toolbars. Multiple objects can be selected and formatting changes made to all of them simultaneously.
Stencils can be precisely sized and positioned by entering exact values. Like the rest of KOffice, sizes have to be entered in whatever units have been chosen for the document. You can lock stencils to avoid accidental changes. Most of this functionality is accessible via a number of small panels, known as dockers, that can be positioned around the editing window and pop-out when the mouse is moved over them. This allows the functionality to be accessed quickly without cluttering up the window.
Dockers aren't used by any of the other KOffice applications.
Pages can be divided into several layers so entire groups of stencils can be displayed or hidden. For example, you could have a basic office layout as the bottom layer and create layers for the plumbing, electrical wiring, computer networking on top of it.
Once you've created a drawing you can print it or export it as a bitmap. Many image formats are supported but there is no control over the size of the image, only which stencils are included.
Although Kivio shares code with KOffice it is not very well integrated. Attempting to copy a drawing into KWord resulted in a load of XML text being displayed. Kivio is a KPart so you can embed Kivio drawings into other KOffice applications although you can't embed other KParts into Kivio itself.
There is also a little bit of flickering present.