Changes from the book to the final 2.4 release

The first edition of Beginning GIMP was written based on 2.3 development releases, and went to press more than a year before the final GIMP 2.4 was shipped. Because of that, there were some differences between the version described in the book and what's presented in the final release. Most of them are minor, but there are a few new features worth noting. (See the 2.4 Release Notes for other details and some sample videos.)

Here are some of the changes:

New Rectangular and Ellipse Selection Tools and Crop Tool

Chapter 2, on page 68, discusses the old (GIMP 2.0 and 2.2) ellipse selection tool, in which you can't adjust the selection after it's made. In GIMP 2.4, Ellipse Select now uses the new interface as well, so you no longer have to guess where to start a circular or elliptical selection.

These tools have been further improved since the book went to press: not only can you change the size of a selection by dragging a side or corner and move the selection by dragging inside the rectangle, you can also modify the size of an existing selection by clicking inside the selection.

The only disadvantage is that Shift and Ctrl no longer constrain the selection to a square or to expand from the center. Now you must use the tool options for that.

Some people also miss being able to move the contents of the selection simply by dragging it. To move the selection contents now, you have two options: press alt+ctrl before dragging (press the alt key first, before the ctrl key, otherwise it may not work), or use the menu item Select->Float to cut the selection contents onto a new floating layer (this is like using Cut then Paste except that Float keeps the selection in the same place in the image, while Paste centers it).

The options for constraining selections or crop rectangles to a specific aspect ratio (for example, for making desktop background images) have been greatly improved. If you make a lot of desktop backgrounds or other images with fixed aspect ratios, you'll love the new tools.

Redeye filter built in

The manual procedure described in Chapter 2 is no longer needed; GIMP now includes its own Redeye tool, in Make an approximate selection around the subject's eyes (to prevent the filter from acting on lips or other red areas), then run Filters->Enhance->Red eye removal.

Clipboard brush

GIMP 2.4 can now use the contents of the clipboard (whatever was most recently copied or cut) as a brush. Very nice! Read more about it in Karine's blog.

Spacebar in image windows now configurable

In 2.2, holding the space bar down (as if it was a shift key) temporarily switched to the Move tool, as a quick way of moving layers. That behavior is now optional in 2.4; by default, the space bar pans the image within the window. To configure the space bar's behavior, look for "Space Bar" in the Preferences dialog under Image Windows.

Dilate and Erode swapped as of GIMP 2.3.9

Beginning GIMP describes Dilate as enhancing dark areas of the image, reducing the size of light areas, and Erode as the reverse. This describes the behavior of GIMP 2.2 and earlier. But as of GIMP 2.3.9, the two tools have been reversed to follow standard image processing conventions. In 2.4, Dilate will make the image lighter, Erode will make it darker. (There's a more detailed discussion in GIMP bug 156545.)

New tools: Align, Healing Brush, Perspective Clone

These tools were still in development when Beginning GIMP went to press. It's used for aligning layers with each other or with the canvas. There's some documentation for them in the online GIMP manual: Align, Healing Brush, and Perspective Clone.

Startup and Preferences

GIMP 2.4 no longer asks a series of questions during the first startup; it sets all preferences to default values. GIMP will automatically migrate preferences from an older profile (GIMP 2.2 or 2.0) if it finds one; it no longer asks first. If you want a default profile, there's a Reset button in the Preferences dialog.

EXIF handling

In Chapter 2 I mention that a few versions of GIMP had bugs with EXIF handling. This no longer seems to be a problem; current versions of GIMP 2.3 preserve EXIF just fine. If you're having problems with EXIF preservation, or if you're seeing crashes when opening or saving JPEG files, check your version of libexif (which is separate from GIMP) and see if it's the newest available.
Save XMP is now a separate option from Save EXIF in the JPEG Advanced Preferences area.

Script-Fu language changes

GIMP 2.4 got a new script-fu engine shortly before release. Although the GIMP documentation page still references SIOD as the scheme implementation used, SIOD has been replaced by a different scheme module called Tiny-Fu, based on Tiny Scheme. Check the GIMP documentation pages for a list of the most important changes, and there's more migration information available as a wiki, which also offers general script-fu information.

Tiny Scheme unfortunately doesn't have much documentation itself, but it's apparently closer than SIOD was to the Scheme R5RS specification (PDF) (there may be more info at Schemers.org).