A single simple event
The QViewer shows events in a virtual three-dimensional space. One of the three dimensions represents time and extends from the far past to the distant future. The other two dimensions form a plane that is used to organize and position categories of events.
Timeline files contain most of the information to organize and display events. The QEditor can be used to create and edit these files.
The simplest kind of event appears in the QViewer as an open-ended box whose open ends mark the start and end times of the event. The location and other dimensions of the box depend on the definition of the category to which the event is attached. A single event can be attached to more than one category.
A number of events drawn with extensions
Events don't have to look like the simple box. Extensions can be added to the event definition. These are small pieces of code that control drawing and other aspects of the event. Some useful extensions are included with distributions of Quotidian.
Categories provide the framework for displaying events. A timeline can have many categories which can be nested inside other categories. By themselves categories are not visible to the user, but they determine the size and shape of attached events, the events' relationship to events in other categories, and when attached events become invisible to avoid visual clutter.
A category can be defined with just a name. All the important category properties that deal with nesting, layout, and hiding have reasonable default values.
In general, timeline objects (such as events and categories) and their properties can be defined in any order. A warning or error message will appear in the Error Panel if a needed property is missing or incorrect.
There are two kinds of timeline files. One, relative timelines, contain only events with relative times, the other, called simply timelines, contains only events with dates and times.
Relative timelines contain events that have relative times for all their start and end times. To be displayed in the QViewer, a relative timeline must have a single origin datetime when it is loaded. All the relative times are added to this origin to produce a non-relative timeline. An origin can be assigned during editing, but more often it is given when the timeline is loaded.
Relative timelines are useful for series of events that are disconnected from an actual date and time or have only an incidental relation to the time at which the event occured. An examples of the former is a list of song files. The list can be loaded at any time, and when the QViewer is in real time mode it will start to play at that time. An example of the latter are records of the execution of a computer program. It may be useful to load the timelines generated by many executions relative to the same time and compare what occurred. The actual time that the execution of a program started is of less importance.