When you’re doing any kind of design work in GIMP, having complete control over your layers makes the job much easier. Alignment tools are a major timesaver for designers, preventing you from having to calculate pixel offsets and other tedious things that the computer is much better at doing – at least, it’s usually better.
The Quick Guide to Center A Layer in GIMP (3 Steps)
The fastest way to align a layer to the center in GIMP is by using the Alignment tool. Here are the three quick steps:
Step 1: Switch to the Alignment tool by pressing Q.
Step 2: Select the image element you want to center by clicking on it directly.
Step 3: In the Tool Options panel, make sure the Relative to setting is set to Image, then click the Align center of target button.
That’s all there is to it!
If you’ve been following along with my other guides, you probably know enough to be getting on with your project now, but if you want to learn more about your centering options and how you can sometimes use guides to get a better alignment result than the computer, read on!
Centering With Alignment Tools
If you’re not quite comfortable with GIMP yet, let’s take a slower path through the process of centering a layer, and I’ll explain all your options along the way.
Option 1: The Alignment Tool
This is definitely the easiest step, as long as you use the keyboard shortcut Q to activate the Alignment tool. If you look for it in the toolbox, you might have a hard time locating it at first, because it is stacked under the Move tool. Click and hold or right-click to see all stacked tools.
You can also access the tool by opening the Tools menu, selecting Transform Tools, and then clicking Align.
Option 2: Selecting Your Image Element
Actually, this one might be the easiest step – simply click on the image element you want to center, and GIMP will place a handle at each of the four corners of the layer boundary to show it’s selected, as you can see below.
The only trick is that you’ll have to click on a visible pixel in order for GIMP to select your object properly. If you click on a transparent pixel right next to your desired object, GIMP will select the next layer below that has a visible pixel in that spot.
If you want to select multiple objects for centering, hold down the Shift key and continue clicking to select additional objects. GIMP will add the same handles around the edges of each layer that is selected this way.
Option 3: Alignment Settings
This one gets a bit more complex, but only a little bit. The key setting you need to watch for centering layers is the Relative to dropdown menu setting. By default, this should be set to Image, which will center the layer to the image boundaries.
Most of the time, this is fine – but if you want to center a layer relative to another object, you’ll have to use the Shift key to select multiple image objects, as I just mentioned above in Step Two.
Change the Relative to setting to First object, and you’ll be able to center one layer against another layer. There are also options for aligning to a selection, or to an active layer, channel, or path, but we don’t need to worry about those at the moment.
Of course, this is all just set up for one last button push: the Align center to target button, which is what sets everything in motion and aligns everything instantly with pixel-perfect precision.
This will all become second nature to you fairly quickly, especially if you’ve already got experience in other image editing programs. Editing programs often share some basic general principles that let you transfer skills a bit more easily between them, once you’re familiar with the basics of how they work.
Advanced Tip: Centering With Guides
As you saw in the example above, Wilber is technically centered in terms of pixel dimensions, but he doesn’t really look visually centered. Most of Wilber’s image is his head, but the paintbrush sticking out of his mouth throws off the balance.
If you focus too much on the numbers and ignore how it looks, you’ll get a less-than-perfect result.
Instead, I think I could get a better image by centering Wilber’s head over the text and letting the paintbrush stick off to the side. Even though it would be technically off-center, it should look more centered because the balance seems more natural to the eye.
The computer actually can’t calculate this for us, unless we do something needlessly complex involving separate layers, removing the brush from Wilber’s mouth, centering it again, then recomposing the image with a new layer containing the paintbrush-equipped version of Wilber overtop of the old one.
Yawn – sounds super boring. Let’s just use guides!
Click on the vertical ruler at the edge of the image window and drag overtop of your image. GIMP will show you a blue overlay of a guide, which will stay fixed in place once you release the mouse button. These just act as temporary visual aids, and don’t appear in your final saved image.
With a guide on either side of my text, I can use them to center Wilber’s head above it without having to worry about whether or not the computer can calculate it properly. You might not be able to get it exactly pixel-perfect the way the computer would, but because the balance is slightly off anyways, it will be virtually impossible to notice.
There is a bit of subjective decision-making here too, which will depend on what layer you’re centering. Because of the exact shape of the curve that forms the bottom of Wilber’s jaw and ear, he might actually be better a bit farther over to the left than I placed him – but you’ll have to make that choice yourself.
One of the most important things to learn when you’re developing your skills as an image editor is when to trust the computer’s calculations and when it’s better to trust your own eye. If you were doing technical work, trust the computer every time – but for visual quirks like this one, trust your eye.
That’s everything you need to know to center a layer in GIMP – and a bit of extra knowledge on top! I hope that it helps you sharpen your skills.
If you’ve got a centering trick that I didn’t include, be sure to let us know in the comments =)About Thomas Boldt