Follow Techotopia on Twitter

On-line Guides
All Guides
eBook Store
iOS / Android
Linux for Beginners
Office Productivity
Linux Installation
Linux Security
Linux Utilities
Linux Virtualization
Linux Kernel
System/Network Admin
Scripting Languages
Development Tools
Web Development
GUI Toolkits/Desktop
Mail Systems
Eclipse Documentation

How To Guides
General System Admin
Linux Security
Linux Filesystems
Web Servers
Graphics & Desktop
PC Hardware
Problem Solutions
Privacy Policy




Grokking The Gimp
Previous Page Home Next Page

1.5 Undoing and Redoing

An extremely useful feature of the GIMP is its ability to perform multiple undos and redos. The Undo  function is found in the Image:Edit menu, as is the Redo  function. These two functions are so useful and are employed so often that you will want to immediately memorize their keyboard shortcuts. These are C-z for undo and C-r for redo.

The number of undos that can be performed in the GIMP is controlled by the Interface branch of the Preferences dialog, and the Preferences  dialog is found in the Toolbox:File menu. Figure  1.12

Figure 1.12: Setting the Number of Undo Levels
Figure 1.12

illustrates the dialog with the Interface branch highlighted. The default value for the number of undos is 5, but for the size of images I work with and the amount of RAM I have available on my computer, I like to have 25 levels of undo. If I were working with large images with many layers, this would not be possible, and I would change the number of undos to a lower value. See Section  [*] in the README for more on how to budget your RAM.

An amazing feature of the GIMP is the Undo History function  found in the Image:View menu. When invoked, this function displays a palette of thumbnails, each representing an image state in the sequence of operations performed on your image. Figure  1.13

Figure 1.13: Working with the Undo History Dialog
Figure 1.13

illustrates such a sequence. Figures  1.13(a), (b), and (c) show the successive application of a selection, followed by a color fill. Figures  1.13(d), (e), and (f) show the respective entries in the Undo History dialog as the operations are performed.

In Figure  1.13, note how the highlighted thumbnail in the Undo History dialog indicates the current status of the image displayed in the image window. Performing an undo by typing C-z in the image window moves the highlighted thumbnail to a layer higher in the thumbnail stack, and performing redo with a C-r moves the highlighted thumbnail a layer lower. Furthermore, you can select any layer in the Undo History dialog at any time by clicking on it.

In this way, you have access to any prior version of the image available in the Undo History by one of two separate methods. The first is by repeatedly pressing C-z in the image window until arriving at the desired state. The second is by directly clicking on the corresponding thumbnail in the Undo History dialog.

Grokking The Gimp
Previous Page Home Next Page

  Published under the terms of the Open Publication License Design by Interspire