How to Use the Cage Transform Tool in GIMP

Before vs after perspective correction using GIMP's Cage Transformtool

GIMP's Cage Transform Tool offers a powerful, versatile way to transform photos and areas within photos. For photographers, it's a useful way to reduce perspective distortion.

Perspective distortion occurs when the camera lens has to be inclined so that it can fit the entire subject in the frame, such as a when shooting a tall building.

The photo here was shot from a low position so that the top of the door appears to be narrower than the bottom. Follow the tutorial to learn how to correct this distortion with the Cage Transform Tool.

  1. Go to File > Open and select the file that you're going to work with. Press Open.

    GIMP File > Open
  2. Select the Cage Transform Tool in the toolbox.

    Select Cage Transform tool in GIMP
  3. Click to place as many anchor points as necessary around the area that you wish to transform. Click the initial anchor to close the cage.

    Cage point selection in GIMP
  4. If you wish to change the position of an anchor, select Create or adjust the cage below the Toolbox and drag the anchors to new positions. Select Deform the cage again before you transform the image.

    The more accurately you place these anchors, the better the result will be; however, the result is usually not perfect. You might need to correct additional distortion or areas where parts of the image overlay others oddly.

  5. Drag each anchor to adjust the image to your liking. When you're satisfied, press Enter to commit the transformation.

    Cage-transformed image in GIMP
  6. Check the image for distortions, overlaps, and other flaws that you might have introduced in this process. After you've corrected them as desired, save your image.