Animated Gif images are often used on web pages. They have a relatively small file size compared to video formats and can be easily embedded into web pages, but don't support sound and may result in poorer quality since they support a maximum of only 256 different colours. This restriction can be partially overcome by choosing appropriate colour reduction and dithering methods, described below.
Click 'Export Animation' in the File menu, select 'Gif (*.gif)' from the drop-down list of file types, specify a file name and click 'Save' to display the animated Gif options and save. After setting the options, click 'OK' and wait for the progress bar to reach the end.
Make sure that the speed of your animation is correct when playing before Exporting the animation because the same frame rate will be used when exporting the Gif. This can be adjusted using the scroll bar next to the Play and Stop buttons.
The Resize option allows you to specify a percentage to resize the dimensions of the animation. 50% is set by default since animated Gifs normally play better when small and have a smaller file size. Change the value to 100% if you want the resulting Gif to have the same dimensions as your animation.
The Super Sample option effects the quality of the resulting animated Gif by making the edges of lines and other objects smoother. The maximum value of 4 will result in the smoothest possible result, while the minimum value of 1 will give no smoothing, and will therefore make the figures appear as they do when playing in Pivot. The higher the value, the longer it will take to export the animation.
Super-sampling works by drawing each frame of the animation several times bigger than the resulting animation and then shrinking the image down to the correct size by averaging pixels. The resulting image is therefore anti-aliased and smoother.
The advanced options can be accessed by clicking the 'Advanced' button. The advanced options will automatically be set to try to maximise the quality and minimise the file size of the animated Gif. However, you may also like to adjust the advanced options manually, which may require some trial and error to find the best set of options.
The colour reduction option specifies the number of colours and the method for reducing the number of colours in the animated Gif. 'Quantize Optimal' gives the best possible result but also the largest file size. If your animation contains no colour then use 'Gray-scale (256 color)' since the result matches the animation perfectly and so no dithering is required. 'Monochrome (2 color)' results in just the colours black and white and produces the smallest file size.
The Dither Mode option can be used to improve the appearance of the animation when the animation contains a large number of colours and particularly when the animation contains gradients of gradually changing colours. Dithering is therefore often required when backgrounds or sprite images are used that are derived from photos.
The 'Nearest (no dithering)' option will result in no dithering applied to the Gif frames. The other options provide various different algorithms for dithering. 'Stucki' is selected by default if background or sprite images are used since it is a fast algorithm that results in clean and sharp images. Dithering always increases the file size of the resulting Gif.
Netscape colour mode with no dither (98KB) Quantize Optimal with Stucki dither (224KB)
Grey-scale colour mode with no dither (175KB) Monochrome with Stucki dither (136KB)
The optimization options help to further reduce the file size of the animated Gif file. However, they can result in artifacts and a reduction in quality and so they are disabled by default.
Merge Frames - Merge pixels with the same colour between frames.
Colour Palette - Sort colours by usage and remove unused entries.
Crop - Crop transparent areas for each frame. This will currently have no effect since transparency is not supported.