Although a comparatively simple piece of software, a layout viewer is not only just a tool for the chip design engineer. Today design's complexity require not only a simple "viewer". Rather, a viewer is the microscope through which the engineer looks at the design.
There are numerous viewers available, but sadly there are not many which satisfy a few basic requirements. Most of them are commercial and expensive. If there is need for a simple, yet powerful viewer - here it is.
The main objective was to focus on the basic functionality but adding some useful features that many, even commercial viewers don't have.
First rarely any tool allows to place two or even more layout files over each other. It often happens that you receive some layers in one file, the other layers in another. Some tools allow to load multiple layouts and switch between the windows. Well, this may help - but still the possibility of overlaying two layouts offers much more comfort.
Sadly, almost no viewer is really precise. There is not much more annoying than a layout that changes when you zoom into it. Or placeholder shapes appearing at some zoom level and disappearing at the next, cell labels that cannot be caught because they jump around when you try to zoom them into view, and many other surprising ways or creative interpretation and optimization. This viewer shows the design as it is.
Only some viewers allow to make layers "transparent". Only this way, a stack of layers can be visualized effectively. In addition, this viewer can animate layers to make them blink or scroll the fill pattern. Animation is a good tool to highlight certain layers.
This viewer allows to display a layer "marked" by drawing a small cross on all shapes. There is no better way to visualize the distribution of a set of sparse error markers on a dense layout!
All comes wrapped in a nice, Qt based state of the art GUI. Usage of the viewer is simple and is similar to that of other tools.