You can find this filter through
→ → .This filter allows you to deform interactively some parts of the image and, thanks to its Animate option, to create the elements of a fade in/fade out animation between the original image and the deformed one, that you can play and use in a Web page.
To use it, first select a deform type then click on the Preview and drag the mouse pointer.
The Settings tab allows you to set parameters which will affect the preview you are working on. So, you can apply different deform modes to different parts of the preview.
Here, the Preview is your work space: You click on the Preview and drag mouse pointer. The underlying part of image will be deformed according to the settings you have chosen. If your work is not convenient, press the Reset button.
Move: Allows you to stretch parts of the image.
Remove: This remove the distortion where you drag the mouse pointer, partially or completely. This allows you to avoid pressing Reset button, working on the whole image. Be careful when working on an animation: this option will affect one frame only.
Grow: This option inflates the pointed pattern.
Shrink: Self explanatory.
Swirl CCW : Create a vortex counter clockwise.
Swirl CW : Create a vortex clockwise.
Defines the radius, in pixels (5-100), of the filter action circle around the pixel pointed by the mouse.
Sets how much out of shape your image will be put (0.0-1.0).
This option smoothes the IWarp effect.
This option renders a better image at the cost of increased calculation.
Max Depth: FIXME
Threshold: FIXME
This tab allows to generate several intermediate images between the original image and the final deformation of this image. You can play this animation thanks to the plugin Playback.
That's the number of images in your animation (2-100). These frames are stored as layers attached to your image. Use the XCF format when saving it.
This option plays the animation backwards.
When the animation ends one way, it goes backwards.