GIMP has a great set of selection and transformation tools for editing your images – but the user interface sometimes makes it a bit difficult to use them the way you want. You probably know how to make a selection in GIMP, but what if you want to rotate that selection?
Before we get started, it’s important to point out that there are actually two different ideas here: you can select a part of your image and then rotate that selected part of the image, or you can actually rotate the selection area itself, for example, you can rotate the text.
They both have their uses, so I’ll explain how both options work in this quick tutorial. I’m going to assume that you’ve already made your selection, so we’ll skip right ahead to the rotation part of the process.
Rotate Your Image Selection in GIMP
If you want to rotate an image that you have selected, you’ll need to use either the Rotate tool or the Unified Transform tool. The Unified Transform tool is useful because it combines all possible transform operations in a single tool, but I generally recommend that new GIMP users stick to the specific transform tool they need.
Switch to the Rotate tool using the keyboard shortcut Shift + R. You can also find it nested under the Unified Transform tool with the other transform tools, you just have to right-click or long-press on the Unified Transform icon to see the full list (shown above).
The key setting that determines what part of your image gets rotated is right at the top of the Tool Options panel, once the Rotate tool is active. It’s definitely under-appreciated, but you want to make sure that it’s set to Layer, as it is in the example below.
Click anywhere in the main image window to begin the rotation process. In this example, I want to adjust the rotation of Wilber’s paintbrush bristles a little bit. Not for any particular reason, but just because I can. Image editing projects are like that sometimes, lol.
GIMP shows the Rotate tool popup in the top corner of the image window and adds a boundary around the part of the image that will be rotated. It also adds a quartered circle, which sets the pivot point. Any time you rotate an object in GIMP, it rotates around the pivot point.
I’ll move the pivot point to the base of the brush area, and the rotation looks much more natural. If you want to reset everything, simply click the Reset button. Once you’re satisfied with how it looks, click the Rotate button to finalize the transformation.
Rotate Your Selection Area in GIMP
It’s also possible to rotate just the selection that you’ve made, not the actual image data. Of course, I already gave the secret away in the section above: you just have to set the Transform setting to Selection instead of Layer.
Then you just follow the same steps to apply the rotation, except GIMP will only rotate your selection area instead of the actual image content itself.
This is useful in a lot of projects, even if you might not see the value at first. It’s useful when creating a new shadow behind an object or any other situation where you need to create a new element based on an existing shape in your image.
That’s everything you need to know about how to rotate a selection in GIMP!
About Thomas Boldt
Alan
Hello
I have an image in which the horizon runs across the centre but is not quite level. So I need to select an area slightly smaller than the full image, rotate the selection very slightly and then crop it. Can this not be done ‘on the fly’ in Gimp? Meaning select the crop tool, drag out a suitable area of the full size image, rotate that selection by grabbing a corner such that I can align the horizon visually, then hit the crop button and the job’s done. Seems like a 3 step process in Gimp, Select, Rotate, Crop. A lot of trial and error needed to get the rotation angle right. I’ve practically given up with it, way too much of a faff.
Thomas Boldt
Hi Alan, you’re right that things tend to be a bit more difficult in GIMP, and this is the perfect example. The process you want to use is available in most modern photo editing apps like Lightroom, but GIMP is behind the times when it comes to user experience design – though, of course, it’s free. Also, to be fair to GIMP, it is for general image manipulation, not just photos, so it’s not quite as focused on photo-specific processes like horizon leveling as other editors.
The best solution that I can suggest to you isn’t too much harder, though: use the Rotate tool on your entire image first to align the horizon, which will let you see the results in real time before applying them so you can get the alignment right on the first try. Then, you can crop out the section of the image that you want to keep.
Hope that helps!