osu! cursor smoke: skinning cursor-smoke.png, the element most skins forget
Hold the smoke key in osu! (C by default in stable) and the cursor leaves a trail of small particles behind it. People use it to draw on the playfield during breaks, to point at things in multiplayer and in replays, and to annotate patterns when teaching. It is drawn with a single image, cursor-smoke.png, which most skins never replace. The default smoke then clashes with an otherwise carefully styled cursor.
The file
cursor-smoke.png (plus cursor-smoke@2x.png) — one small particle, repeated along the cursor's path while the key is held.
Because the image is stamped many times per second, it behaves like a brush. A single 2-pixel speck gives a thin pencil line. A soft 16-pixel blob gives a thick marker.
Design tips
- Small and soft. Something between 8 and 24 pixels across (SD size) with soft edges draws a smooth line. Large or hard-edged particles draw a dotted, bumpy line.
- Match the cursor. If your cursor is a pink dot, a light pink smoke particle feels natural. A neutral white or light grey works with any cursor.
- Keep the centre bright. Smoke is often drawn quickly over busy backgrounds and replays. A bright centre with a faint edge stays visible without becoming a solid bar.
- Don't make it invisible by accident. A fully transparent smoke image removes a useful feature for people teaching or streaming with your skin. If you dislike smoke, a faint particle is a better compromise.
Where smoke matters
- Replays and teaching. Coaches draw circles around patterns while a replay is paused or slowed down.
- Multiplayer. In lobbies, players draw on the playfield during breaks. It is part of the social side of the game.
- Streaming. Viewers see smoke clearly, so a skin made for streaming should have smoke that reads well after video compression.
Testing
Reload the skin (Ctrl+Shift+Alt+S), start any map, wait for a break, then hold the smoke key and draw a circle, a fast zigzag and a slow line. Check that:
- fast movements still produce a continuous line, not separate dots;
- the line is visible on both a dark and a bright background;
- the smoke fades without leaving a distracting smear.
Related
Cursor smoke works best when it is designed alongside the cursor and cursor trail. The osuskins.org skin library lets you browse skins by their gameplay screenshots, and the install page explains how to try a skin quickly and switch back.
Notes by ZentaoLabs. Skin library: osuskins.org.