You'll need: FontCreator (Windows and macOS), and comfort drawing and selecting contours in the Glyph Edit window.

A monoline font — and many other letterforms — is easiest to think about as a skeleton — a thin centerline — with a pen of some width run along it. In this font editor, FontCreator's stroke feature lets you design exactly that way: draw a path, give it a stroke, and FontCreator builds the filled outline (the envelope) for you. The path stays a centerline you can keep editing — change the width, swap the cap, nudge a node — and the filled shape updates live. When you're done you either bake it to plain outlines or just export: FontCreator expands strokes to outlines automatically.

This is great for a monoline font or geometric design, a calligraphic font, icon sets, and any glyph where adjusting one width beats redrawing two edges by hand.

Note: This is not the same as a single-line / engraving font. There, you deliberately keep paths open so a CNC tool follows the centerline (see Single-Line Fonts for Engraving and Cutting). Here, you stroke the centerline and export a normal filled font.

Stroke a path (the monoline font workflow)

1. Draw your skeleton — for an l, a single vertical path; for an e, the eye and the curve as one or two paths.
2. Select the path.
3. Turn the path into a stroke: right-click in the glyph editor and choose Stroke (or tick the Stroked box in the stroke bar that appears below the editor). The stroke bar then exposes the attributes:

- W: and H: — the pen width and height. Equal values give a uniform (round-pen) stroke; different values give a calligraphic broad-nib effect (see the tip below). - Pos: — where the pen sits relative to the path: Center, Left, or Right. Center is the usual choice; the edge positions are handy when the skeleton sits on a design boundary. - Start: and End: — how each open end is finished, set independently (next section). - Fill — keep this ticked to draw the solid envelope.

Corners are turned automatically: FontCreator uses a sharp (miter) outer corner and falls back to a clean bevel on very acute angles, so there's no separate join control to set.

FontCreator immediately shows the filled envelope while keeping the centerline editable. Drag a node or change the width and the filled shape follows.

Tip: For a calligraphic broad-nib pen, give W: and H: different values — a wide W with a small H mimics a flat nib. Equal W and H values give a uniform (round-pen) stroke.

Caps: how open ends are finished

Caps apply to the ends of open paths. FontCreator offers five:

• Butt — a flat end, flush with the last node.
• Round — a half-circle, extending past the end by half the width.
• Square — a flat end extended past the node by half the width.
• Inset Round — a rounded end nestled inside the stroke body (a soft, slightly tucked terminal).
• Calligraphic — an angled, pen-like end for calligraphic styles.

Tip: Round and Square extend the stroke beyond the last node by half the width — keep that in mind when you place endpoints near the cap height or baseline.

Corners: how bends are turned

You don't set a join style by hand — FontCreator turns every corner automatically. It uses a sharp (miter) outer corner where the angle allows, and falls back to a clean bevel where a miter would spike out too far. In practice this means corners just look right: gentle bends stay crisp, and very acute angles are trimmed instead of growing a long spike.

Pen position, open vs closed

• Pos: lets the same skeleton sit centered on the path or hug the left or right side — useful when your centerline is actually a design edge.
• Strokes work on open and closed paths. An open path becomes a stroke with two caps; a closed path becomes a band (think of an O drawn as one circular centerline stroked into a ring).

Keep it editable, then expand stroke to outline

The path stays a stroked centerline — fully editable — until you decide to turn it into plain geometry, i.e. expand the stroke to an outline. Two ways to bake:

• Glyph → Decompose → Stroke — expands just the stroked paths on the active layer into their envelope outlines.
• Glyph → Decompose → Flatten Outlines — the full bake: it resolves path decorations, expands strokes, decomposes components, applies masks, and removes overlaps in one step.

Tip: Save your project before baking. Decompose Stroke is one-way for that glyph — the centerline + width become ordinary points.

You don't have to bake before export

When you export, FontCreator expands every stroked path to its envelope automatically, per master — so a project full of stroked centerlines exports as a perfectly normal filled TTF/OTF/CFF2/UFO. Baking is only for when you want the authored glyph to be plain outlines (handoff to another tool, manual cleanup, or simplifying a finished glyph).

(The Open Contours export setting is a separate thing — it governs any paths you leave open and unstroked; see Export a Font (Export Fonts Correctly) and the single-line tutorial.)

Strokes in variable fonts

You can design variable fonts with strokes — for example, a weight axis that's really just a changing stroke width over the same skeleton. Two things to know:

• Highest quality = leave it stroked. If you keep the paths stroked and let the font stay variable, the renderer strokes the interpolated centerline at runtime — clean at every weight.
• Baking is per-master and approximate. A stroke envelope is a non-linear function of the path, so once you flatten to outlines, interpolating between the baked masters is an approximation. Keep the source paths as compatible as possible across masters, and add an intermediate master if you see buckling near former corners.

Watch out: In the editor, a glyph whose masters differ only in stroke width (identical centerline coordinates) can look static when you scrub the variation slider. That's a known preview limitation — the exported variable font is correct, because export expands each master's stroke before computing the deltas. Use Test Web Font to confirm.

Troubleshooting

Frequently asked questions

What is a monoline font? A monoline font is one whose letters have a uniform stroke width — the same thickness everywhere, with no thick-and-thin contrast. In FontCreator you design one by drawing each glyph as a skeleton centerline and giving it a single stroke width.

How do I expand a stroke to an outline? Use Glyph → Decompose → Stroke to expand just the stroked paths on the active layer into their envelope outlines, or Glyph → Decompose → Flatten Outlines for the full bake. You don't have to do this before export — FontCreator expands every stroked path to its outline automatically when you export.

Monoline vs single-line (engraving) — what's the difference? A monoline font is stroked and exports as a normal filled font with closed outlines. A single-line (engraving) font deliberately keeps paths open so a CNC or laser tool follows the centerline directly — see Single-Line Fonts for Engraving and Cutting.

What to read next

• Single-Line Fonts for Engraving and Cutting — when you want to keep paths open for CNC instead of stroking them.
• Path Decorations (Reusable Corners, Serifs & Caps) — add designed terminals to stroked open paths.
• Export a Font (Export Fonts Correctly) — how strokes and the Open Contours setting behave at export.
• Fix Variable Font Compatibility — keep interpolation clean when baking strokes.