Recipe: Pixel-perfect line art

Free-hand pencil strokes that look "professional" — no L-shaped staircases, no double-pixels at corners. The editor has a built-in filter that handles this for you.

![Screenshot: side-by-side comparison of a freehand diagonal — left "raw" with L-shape artifacts, right "pixel-perfect" with clean single-pixel diagonal — placeholder]

Goal

A clean line that looks like a vector stroke at small sizes. The trade-off: the filter only runs at brush size 1, and it removes pixels from L-shaped corners as you draw.

Steps

1. Pick the pencil

Hotkey B or click the pencil tile in the Tools panel.

2. Set brush size to 1

Brush section → Size = 1. The pixel-perfect checkbox below the size slider activates only at size 1 (it's about removing pixels, which makes no sense for thicker brushes).

3. Enable pixel-perfect

Tools panel → Brush → Pixel-perfect checkbox.

The L-filter runs as you stroke: when three consecutive pixels form a corner (e.g., right-then-down at the same speed), the middle one is automatically removed.

4. Draw

Free-hand strokes now produce clean diagonals. The filter is trail-based — it watches your last few pixels and retracts mid-stroke. If you change direction, the previous corner is fixed up before the next pixel lands.

The filter respects the original colour. When a corner pixel is retracted, the editor restores whatever colour was underneath, not transparent. This means pixel-perfect plays nicely with shading: drawing a dark line over a coloured fill leaves the fill intact at the retracted positions.

5. Combine with symmetry

For symmetric line art (faces, characters), turn on vertical symmetry as well. The L-filter runs per branch — each mirrored stroke gets its own filter pass, so both sides come out clean.

When pixel-perfect doesn't help

• Slow, deliberate strokes. If you're placing pixels one by one with intent, the filter might remove a pixel you wanted. Disable it for that stroke or use a larger brush.
• Thick line art (> 1 px). No L-filter. Use the line tool (L) for straight runs and clean up corners by hand.
• Curves with tight bends. The filter removes one pixel of a 3-pixel corner — for very tight curves you may want both pixels to stay.

Tips

• Toggle live with the checkbox. Drawing → toggle off → fix a specific corner → toggle on → continue. The filter only runs on new strokes, so old pixels aren't re-evaluated.
• Same workflow with eraser. Pixel-perfect also applies to size-1 eraser strokes. Useful for cleaning up rough fill edges.
• Use the status bar. The hex of the pixel under the cursor is shown in the status bar, so you can verify which colour will be restored if pixel-perfect retracts.

See also

• Pixel-perfect mode — full reference.
• Drawing tools — all the brush options.
• Symmetry — mirror strokes across axes.