3. Angre
| Kapittel 3. First Steps with Wilber |

## 3. Angre

Almost anything you do to an image in GIMP can be undone. You can undo the most recent action by choosing Edit → Undo from the image menu, but this is done so frequently that you really should memorize the keyboard shortcut, Ctrl+Z.

Du kan faktisk også angre angringane. Har du angra ein operasjon, og oppdagar at operasjonen likevel var betre før du angra, kan du finne fram Rediger → Gjenta i biletmenyen. Sidan du truleg vil bruke også denne funksjonen nokså mykje, vil det forenkla arbeidet dersom du lærer deg snartastkombinasjonen Ctrl+Y, som gjer det same. Ofte kan det vere nyttig å kunne kontrollera effekten av endringar ved å klikke att og fram mellom Angre og Gjenta. Dette vil til vanleg kunne gjerast nokså raskt, og legg ikkje beslag på maskinressursar. Heller ikkje endrar det angreloggen, så det er heilt ufarleg.

| Obs
If you undo one or more actions and then operate on the image in any way except by using Undo or Redo, it will no longer be possible to redo those actions: they are lost forever. The solution to this, if it creates a problem for you, is to duplicate the image and then test on the copy. ( Do Not test the original, because the undo/redo history is not copied when you duplicate an image.)

Har du stendig bruk for Angre og Gjenta, kan det vere enklare å arbeida med Angreloggen, ein dialog som viser ein kort omtale av kvart punkt i angreloggen. Du kan hente fram det aktuelle biletet ved å klikka på ønskt punkt i loggen.

Undo is performed on an image-specific basis: the "Undo History" is one of the components of an image. GIMP allocates a certain amount of memory to each image for this purpose. You can customize your Preferences to increase or decrease the amount, using the Environment page of the Preferences dialog. There are two important variables: the minimal number of undo levels, which GIMP will maintain regardless of how much memory they consume, and the maximum undo memory, beyond which GIMP will begin to delete the oldest items from the Undo History.

| Notat
Even though the Undo History is a component of an image, it is not saved when you save the image using GIMP's native XCF format, which preserves every other image property. When the image is reopened, it will have an empty Undo History.

GIMP's implementation of Undo is rather sophisticated. Many operations require very little Undo memory (e.g., changing visibility of a layer), so you can perform long sequences of them before they drop out of the Undo History. Some operations, such as changing layer visibility, are compressed, so that doing them several times in a row produces only a single point in the Undo History. However, there are other operations that may consume a lot of undo memory. Most filters are implemented by plug-ins, so the GIMP core has no efficient way of knowing what changed. As such, there is no way to implement Undo except by memorizing the entire contents of the affected layer before and after the operation. You might only be able to perform a few such operations before they drop out of the Undo History.

### 3.1. Ting du ikkje kan angra

Most actions that alter an image can be undone. Actions that do not alter the image generally cannot be undone. Examples include saving the image to a file, duplicating the image, copying part of the image to the clipboard, etc. It also includes most actions that affect the image display without altering the underlying image data. The most important example is zooming. There are, however, exceptions: toggling QuickMask on or off can be undone, even though it does not alter the image data.

Dei få, men viktige, unnataka som ikkje kan angrast, sjølv om dei gjer endringar i biletet er:

Å lukke vindauget

  The Undo History is a component of the image, so when the image is closed and all of its resources are freed, the Undo History is gone. Because of this, unless the image has not been modified since the last time it was saved, GIMP always asks you to confirm that you really want to close the image. (You can disable this in the Environment page of the Preferences dialog; if you do, you are assuming responsibility for thinking about what you are doing.)

Tilbakestill biletet

  “Reverting” means reloading the image from the file. GIMP actually implements this by closing the image and creating a new image, so the Undo History is lost as a consequence. Because of this, if the image is unclean, GIMP asks you to confirm that you really want to revert the image.

Handlingsdelar

  Noen av verktøya kan innehalde lange seriar med manipulasjonar, men bare det endelege resultatet blir registrert i angreloggen, ikkje dei einskilte stega. Den intelligente saksa krev at du merkar av ein del punkt på biletet og deretter klikkar innføre området for å lage eit utval. Det er ikkje råd å angre kvart einskild punkt. Klikkar du på Angre etter at du er ferdig med saksa, fører dette deg tilbake til biletet slik det var før du byrja å markera punkta. Arbeider du med tekst, kan du ikkje angre einskilde bokstavar. Angre vil ta bort heile det nye tekstlaget.

Filters, and other actions performed by plugins or scripts, can be undone just like actions implemented by the GIMP core, but this requires them to make correct use of GIMP's Undo functions. If the code is not correct, a plugin can potentially corrupt the Undo History, so that not only the plugin but also previous actions can no longer properly be undone. The plugins and scripts distributed with GIMP are all believed to be set up correctly, but obviously no guarantees can be given for plugins you obtain from other sources. Also, even if the code is correct, canceling a plugin while it is running may corrupt the Undo History, so it is best to avoid this unless you have accidentally done something whose consequences are going to be very harmful.

2.3. Dialogar og samlevindauge |  | 4. GIMP-kvikkasar