How to Change Stroke Join Styles in GIMP

When stroking vector paths in GIMP, the appearance of sharp corners is governed by the Line Style settings within the Stroke Path dialog. By accessing these parameters, you can select between miter, round, and bevel corner joins, as well as configure the miter limit to control how excessively sharp angles behave.

Accessing the Stroke Path Dialog

To access the corner join settings, you must stroke a path using the dedicated dialog:

  1. Create or select your path using the Paths Tool (B).
  2. Open the stroke settings by navigating to Edit > Stroke Path... in the main menu, or by clicking the Paint along the path icon at the bottom of the Paths dockable dialog.
  3. In the dialog box that appears, select the Stroke line radio button.

Join Style Settings

Expand the Line Style dropdown section within the dialog to reveal the options governing corners:

  • Join Style: This is the direct setting that controls how corners are rendered where two path segments meet:
    • Miter: Extends the outer edges of the stroke lines until they intersect, creating a sharp, pointed corner.
    • Round: Rounds off the corner with a circular arc equal to the stroke width, producing smooth corners.
    • Bevel: Cuts the sharp point off flat across the corner, creating a squared-off angle.

The Miter Limit Setting

When using the Miter join style, the Miter limit setting directly governs sharp corners:

  • Purpose: At very acute (sharp) angles, a miter join can extend far beyond the actual corner of the path, creating an unwanted, excessively long spike.
  • Behavior: The miter limit defines the maximum allowed ratio of the miter length to the stroke width.
  • Effect: If the angle is so sharp that the miter extends past this ratio threshold, GIMP automatically converts that specific corner into a Bevel join to prevent spikes from ruining the artwork. Increasing the miter limit allows sharper corners to remain pointed, while decreasing it causes corners to bevel at wider angles.