One of the most favoured retouching tools that Photoshop users miss in GIMP is a Liquify filter. The existing iWarp filter has always been not very easy to use, and it lacks certain features. This is about to change thanks to Michael Muré who has been working on a new Warp Transform tool since May.

Feature-wise the Warp Transform is much like the iWarp filter. What's the difference then?

It's a real tool, it works right on canvas, so you work on the real thing instead of tiny preview. You can use Erase mode to partially remove warping you applied. Hardness option has been added to complement Strength and Size.

To illustrate all of that, Michael recorded a short demo that previews basic features of the tool:

So, let's summarize:

works on canvas;

has Move, Grow, Shrink and Swirl (CW and CCW) warping modes;

has Erase and Smooth modes to adjust changes you applied;

has Strength, Size and Hardness options for the "brush".

There are few limitations in the tool currently. The most visible ones are lack of undo/redo support and comparative slowness of processing. Both issues will be addressed as the project progresses.

As you probably remember, the GIMP team has set a ban on new tools that use old core, so just like Cage Transform tool introduced last year, the Warp Transform tool uses GIMP's new hi-end core, GEGL, as a backend. For that Michael created another GEGL operation that does all the calculations.

Apart from being useful for retouching the new tool plays another important role. What it does is introducing the first basic GEGL based brush-like tool. And while the Warp Transform tool doesn't currently use painting dynamics, there is no reason why it shouldn't be done later when the rest of painting functionality lands to GEGL.

One last thing to say here is that there is no decision yet whether Warp Transform tool will be part of GIMP 2.8. The core team isn't happy introducing a major new feature at this (late) stage of development. However, its still about half a year till release of v2.8, things might just change.

Edit (2014-11-11): The Warp transform tool has replaced the iWarp filter in the main development branch and will be available in GIMP 2.10.

The other new tool, Seamless Clone, developed as part of Google Summer of Code program, is also progressing. Stay tuned for more updates on all things GIMP.