- OnionSkinSettings (editor view state): enabled, frames_before/after (default 2/2),
opacity (0.35), warm past / cool future tints, linear falloff. Threaded App →
SharedPaneState (gated off during playback) → VelloRenderContext.
- Toggle: View ▸ Onion Skinning + the `O` shortcut (AppAction::ToggleOnionSkin).
- Tint: packed an RGB multiply into the canvas-blit matrix uniform's unused .w slots
(1,1,1 = no tint for all normal blits); BlitTransform::with_tint. Shader multiplies.
- Render: for the ACTIVE raster layer only, blit the N neighbouring keyframes (full
texture if resident, else the low-res proxy — uploaded on demand) tinted + faint,
composited behind the current frame. Off during playback.
Next: a settings panel (frame count/opacity) and vector-layer ghosts.
Skyler Lehmkuhl