Set Polar Coordinates Depth and Angle in GIMP

This article explains how to locate and configure the Circle Depth Percentage and Mapping Angle parameters within GIMP’s GEGL-based Polar Coordinates filter. By properly adjusting these two core settings, you can control the intensity of circular distortion and dictate the rotational orientation of your transformed image.

Accessing the Filter

  1. Open your image in GIMP.
  2. Select the specific layer you want to distort.
  3. In the top menu, navigate to Filters > Distorts > Polar Coordinates...
  4. Ensure the Preview checkbox is enabled in the dialog window to see real-time updates as you adjust settings.

Configuring Circle Depth Percentage

The Circle depth in percent slider controls the degree to which the rectangular image transforms into a circular shape.

  • Default Behavior (100%): The image wraps fully into a circle or polar projection, bending the edges completely toward the center or perimeter.
  • Partial Distortion (0% to 99%): Decreasing the percentage reduces the curvature effect, creating a blend between the original rectangular orientation and a full polar warp. At 0%, no circular deformation occurs.
  • Adjustment: Drag the Circle depth in percent slider left or right, or type a precise numeric value directly into the text box to achieve the desired degree of roundness.

Configuring Mapping Angle (Offset Angle)

The rotational alignment of the distortion is managed via the Offset angle setting, which functions as the mapping angle for the transformation.

  • Default Behavior (0°): The top edge of the source image typically anchors at the top (12 o’clock position) or aligns with the zero-degree coordinate axis.
  • Custom Angles (0° to 359°): Adjusting this value rotates the origin point around the polar center. For example, setting the angle to 90°, 180°, or 270° rotates the starting point of the wrap by a quarter, half, or three-quarter turn, respectively.
  • Adjustment: Use the Offset angle slider to spin the projection, or enter a specific degree value to place key visual elements at an exact angle within the circular canvas.

Applying the Changes

Once you balance the curvature with the circle depth and rotate the projection using the offset angle, verify the result in the canvas preview and click OK to permanently apply the GEGL filter to your layer.