.ANI

Introduction

An ANI file is an animated mouse pointer for Windows, such as the spinning busy cursor. It holds a series of frames, each a complete cursor or icon, and the time to show each one. Pointer schemes in the Windows Mouse settings still use them.

The frames inside are ordinary ICO and CUR images, so each frame can have several sizes and its own hotspot.

Structure

An ANI file is a RIFF file with the form type ACON. Like every RIFF file, it is a series of chunks, each a four-letter ID, a little-endian length and the data, padded to an even length.

The anih chunk is the header: 36 bytes giving the number of frames, the number of steps in the animation, the default display rate in jiffies (sixtieths of a second) and flags. The frames are icon chunks inside a LIST chunk of type fram. An optional rate chunk gives a display time for each step, and an optional seq chunk gives the order in which frames are shown, so a frame can be reused. A LIST chunk of type INFO can carry a title and an author.

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