Stroke Selection with Paint Dynamics in GIMP

In GIMP, you can stroke an active selection using a paint tool to create organic, hand-drawn contours instead of flat, uniform borders. By pairing dynamic brush presets with the stroke selection feature, the software automatically simulates pen pressure, speed variations, and tapering along the perimeter of your active marquee. This guide details how to configure your paint dynamics and execute the stroke operation to achieve realistic, pressure-sensitive outlines.

1. Prepare Your Canvas and Selection

  1. Use any selection tool (such as the Rectangle Select, Ellipse Select, or Free Select tool) to define your active selection area on the canvas.
  2. Create a new transparent layer via Layer > New Layer to ensure the stroke is rendered non-destructively separate from your background or source artwork.

2. Configure Your Paint Tool and Dynamics

Before executing the stroke, you must configure the tool GIMP will use along the path:

  1. Select the Paintbrush tool (or the Airbrush or Ink tool) from the Toolbox.
  2. In the Tool Options panel, choose your desired brush tip, base size, and color.
  3. Locate the Dynamics section within the Tool Options.
  4. Click the dynamics preset icon and choose a preset that incorporates pressure or velocity mapping, such as Pressure Opacity, Dynamics Random, or Pencil Generic. If you want lines that taper smoothly from thin to thick, select a dynamic profile that maps fading or pressure to the brush size.

3. Stroke the Active Selection

  1. With your selection still active, open the top menu and navigate to Edit > Stroke Selection....
  2. In the dialog box that appears, select the Stroke with a paint tool radio button.
  3. Set the dropdown menu to match the tool you configured (e.g., Paintbrush).
  4. Check the box labeled Emulate brush dynamics. This setting forces GIMP to calculate acceleration, distance, and simulated stylus pressure along the stroke path, applying the behavior defined in your active dynamics preset.
  5. Click the Stroke button.

GIMP will trace the boundary of your active selection, modulating line width, opacity, and texture according to your chosen dynamic profile.