Frame Gallery - Background and Overlay Settings

Xara LX uses frames to create animated GIF files. Next to the frames listed in the Frame Gallery are two columns of switches. For each frame the left-hand switch indicates whether the frame is a background frame and the right-hand switch whether it overlays earlier frames. The settings of these switches can be changed simply by clicking on them.

Background

If this is set, then the frame covers all previous frames. This is useful if you want to create a background and then build up an animation on top of this background. Often the first frame in the animation is a Background frame.

If the first frame is not a background frame, the Animated GIF uses the page background as its background. In Xara LX you can set up the document background to the same color or bitmap as the final web page. This lets you create bitmaps that blend seamlessly with the web page background. For details see Changing the background.

Overlay

If this is set, then the frame overlays the previous frame.

Possible values are both off or one option on. Both on is invalid because a Background frame covers earlier frames and so nothing shows through - there is nothing to overlay.

B O

Off Off Render this frame over the current background.

On Off Render this frame on its own, overwriting all previous frames. This frame now becomes the current background and forms the background for all subsequent frames.

Off On Render this frame on top of the previous frame.

Examples

An animation that shows ‘A’, ‘B’, ‘C’ in sequence on a colored background. This requires four frames. Frame 1 is just the background and has Background on. Frame 2 shows ‘A’ and has both options off. Frames 3 and 4 show ‘B’ and ‘C’ and also have both options off.

An animation that builds up ‘A’, ‘AB’ ‘ABC’. Frame 1 shows the background and ‘A’ and has Background on. Frame 2 shows ‘B’ and has Overlay on. This overlays the frame over frame 1 and you see ‘AB’. Frame 3 shows ‘C’ and also has Overlay on. Building up an animation in this way is more efficient than making each frame a Background frame. The final animated GIF only needs to store the changes between frames and so frames 2 and 3 require less space than if they were Background frames.

Tip

To make a sequence of frames background or overlay, set the switch for the first frame and Shift-click on switch for the last frame. The background/overlay settings of all the frames in between change too.