Timelines allow Sophie objects to be animated over time. Examples of Sophie objects include Sophie frames, audio files and pages. Example frame content include text, images and video frames.

Timelines can control the visibility of a frame, or if a movie is playing or not. The author can use Timelines to control a movie that is on a template spanning pages of a book, and also to change the current page of the book as the movie plays.

Issues with Sophie 1 timelines

Referencing Objects

Sophie 1 timeline events kept hard references to frames and audio. This meant that if a timeline that spanned 1000 pages were to be loaded, every page and thus every object on those pages were loaded. This could cause severe memory issues. Sophie 2 should use a lazy approach to referencing objects, maybe through the ResourceRef class.

Timeline Scope

There are two types of timelines in Sophie 1, normal and page timelines. The difference is that a page timeline had a page channel. A page channel was a special channel that could only contain page events for changing the current page.

A normal timeline would only reference objects on one page, or should have but Sophie never enforced this. It was very easy to create a broken timeline. In a large project, an Author should be able to attach a timeline to a particular page or template and thus, only see those timelines when filtered. This will help in timeline management on huge books.

UI Issues

Boyan mentioned that we may want to ditch the page timeline concept and allow any object to be placed on any channel. We'll have to decide if an author can understand the ramifications of coalescing timeline events in this manner.

How will be handle a timeline with page events and now allow a user to drag an event for a frame that exits on page 1 into the area of the timeline that corresponds to page 15?

Design

• Events should be pluggable
• Events should weak reference the objects they control
• Examples of events include:
  • hide/show a frame
  • Start/stop media
  • Go to an object (page, maybe a frame also?)
  • Animate a frame
    • translate
    • tween?
• Synchronizing - Sophie should make sure media on timelines remain in sync