A looping background is a moving background that simulates camera panning, and that seamlessly repeats itself. It is a standard animation technique.
There are multiple ways to do looping backgrounds in Synfig. The one presented here is simple, minimizes manual work and repetition, and doesn't use keyframes.
The background can be a bitmap or a vector graphics. In order to be usable as a looping background, the requirements are the same. Imagine duplicating the image and putting the duplicate next to the original in an horizontal line: the left edge must seamlessly blend with the right edge.
This tutorial uses a vector graphics background, but the same workflow can be applied for bitmap images.
If you already have a background, skip to the next section.
In Synfig Studio, create a new canvas with File | New.
- Prepare or gather background.
- Mention trick to keep same size when importing a sif file.
- Mention trick to keep the two ends the same (exported, decomposed vector).
- Import background.
- Genete's trick of the Zoom layer.
- Duplicate encapsulated background. Say bounding box width is L pixels.
- Move center of the duplicate L pixels towards the direction of the loop.
- Add translation layer.
- Record mode. Move translation layer opposite direction of loop, L pixels. Two waypoints, one at time 0, one at time T. Exit from record mode.
- Add Timed Loop layer. Set duration to T.