How to find the vertical midpoint of a Gimp image or canvas?

Question

How can I locate the vertical midpoint of a gimp image? I searched online and found this post, but it didn't give me the simple, step-by-step solution I was looking for.

Answer 1

After a few more minutes searching, I found the answer. So for anyone else who has this question I want to post a simple concise step-by-step explanation.

Script-fu window for setting vertical or horizontal guides by percent

1. Make sure you have Gimp open with an image of some sort on the canvas.
2. Image > Guides > New Guide (By Percent).
3. If you don't see a Script-fu dialog box, switch between active windows until you find it (in Windows use ALT-TAB).
4. In the "Direction" drop-down choose "Vertical".
5. Ensure that "Positon" is set to 50% and click "OK".

And that's it! If you followed the instructions you should now have a vertical line bisecting your image, in the exact middle of the canvas.

PROTIP: If you follow the procedure again, but this time choose "Horizontal", you will now be able to locate the exact midpoint of your image in all directions.

Answer 2

Solution without explicit guides: several "Transform" tools (Scale, Shear, Rotate...) have built-in guides, and one of the option for these is "Center lines", so just start the Tool and just set the option (unless you need to know where the center is when using these tools).

Of course using real guides is often a good idea. If you find yourself routinely adding guides at the same place (center lines, for instance), have a look at ofn-preset-guides that lets you define your favorite guides sets and makes them available with a keyboard shortcut.