How do you rotate a layer in GIMP?

To rotate a layer in GIMP, you can use the Arbitrary Rotation tool, which is accessible through a menu option or a keyboard shortcut.

Rotating a Layer: Methods

Here are the ways you can rotate a layer in GIMP:

Using the Menu:
1. Select the layer you want to rotate.
2. Go to the image menubar.
3. Click on Layer.
4. Select Transform.
5. Choose Arbitrary Rotation.
Using the Keyboard Shortcut:
1. Select the layer you want to rotate.
2. Press Shift + R on your keyboard. This will directly open the Arbitrary Rotation dialog.

Once you have initiated the Arbitrary Rotation tool through either method, a dialog box will appear. This dialog allows you to adjust:

Rotation Angle: You can manually enter the desired rotation angle in degrees.
Interpolation Method: Choose the interpolation method to control the quality of the rotation. Common options include Cubic, Linear, or None.
Rotation Center: You can change the pivot point for the rotation. By default, it rotates from the center of the layer, but you can select a different point as the center if needed.

For simple rotations of 90 or 180 degrees, you can also use the Layer → Transform → Rotate menu for predefined rotation options, like rotate by 90 degrees clockwise or counterclockwise.
When performing rotations that result in a larger layer size, you may need to enlarge your canvas. This can be done by going to Image → Canvas Size to avoid clipping.
Always try to use the Cubic Interpolation Method to get the best possible image quality after the rotation. This minimizes potential pixilation that can occur with the other methods.
You can also utilize the rotation tool in the tool panel in a visual manner. This allows you to dynamically adjust the rotation angle directly on the canvas, but the Arbitrary Rotation dialog offers more precision.