Drop shadow for animated GIF

Question

Briefly

I don't know, how I can to make shadow effect for animated GIF. For me good solution in any open source/free program, not Photoshop.

Detail

For PNG images I make shadow effect. Example:

But how I can to make similar effect for animated GIF? Example GIF:

I don't need to edit GIF, I only need add shadow in borders of animated GIF. Perhaps, correct its effect not named «shadow».

Did not help

For PNG I use ShareX and Greenshot programs, but if I try add shadow for GIF like for PNG, output black image for me. I not find answer for my question in Google.

Answer 1

For GIF the drop shadow is going to be complicated for two reasons:

1. The drop shadow on your PNG relies on partial opacity to blend the shadow with the page background. But the GIF format doesn't support that, in GIF the opacity a pixel is either completely opaque or completely transparent. You can at best simulate a blend to a background of a specific color using Layer>Transparency>Semi-flatten

2. The semi-flatten above will create a lot of intermediate tones that will be included in the 256-color limit of GIF and reduce the number of colors available elsewhere (for the anti-aliasing of the edges of text for instance). This will have a negative impact on the overall image quality.

Answer 2

Simply enlarge your document, add a background color as the background color where the GIF will be placed, then add your shadow to your GIF. This is the only way.

If your output is for the web, you can add a CSS property to it and will look better than exporting the shadow in the GIF directly (will be better quality).

Answer 3

Since v2.19, ScreenToGif lets you add dropshadows to your recordings/animations.

You can manually add the shadows while editing:

Or you can set a task to add the shadow after recording:

These are the exported animations (Gif and Apng):