[deodad]

Motivation

Ondine's SVG reads every color, the stroke width, the radius, and the font from CSS custom properties, and chart series mix colors with color-mix(). Renderers without CSS variables draw such an SVG black or not at all: resvg, librsvg, the SVG parsers of native apps, and email clients. Each host now flattens the SVG with its own string pass.

Changes

• Add the theme render option: an object of --ondine-* values in camel case (bg, fg, surfaceAlt, series1, radius, and so on). An empty object writes the defaults.
• Add crates/compiler/src/svg/resolve.rs, a final pass that replaces each var() in attributes with the host value, the root alias, or its fallback, and drops custom-property declarations. Text content is not changed.
• Evaluate color-mix(in srgb, …) to #rrggbb or #rrggbbaa (premultiplied, CSS Color 5 percentage rules). A mix reads hex, transparent, the 148 CSS named colors (sorted table, binary search), and rgb() or rgba() with comma or space syntax and an optional alpha.
• If a mix reads a host value in another form, such as hsl() or oklch(), render throws a RenderError with the new code unsupported that names the key. Unmixed values, such as border: 'hsl(…)', are written as given.
• Gate the pass and the option parser behind a new theme Cargo feature on compiler, forwarded by wasm. Only all.fast.generated.wasm (ondine/compiler, the CLI, and ondine/compiler/wasm/all.fast.wasm) and native builds enable it. The size-optimized per-type and all modules leave it out and return unsupported for theme.
• The image Worker keeps the size all module and its own flattening, since it must fit beside resvg under the 3 MB Worker limit. A later change can move it to theme if that budget allows.
• Keep the themed corner radius in the rx attribute when theme is set. Without theme, the output is byte-identical.
• Document the option, the color forms, and the unsupported code on the render, create, and RenderError API pages and in the theming guide.

Example

import { render } from 'ondine/compiler'

// Writes the theme as literal values
const { svg } = render('pie\n  "A" : 3\n  "B" : 2', { theme: { fg: 'rebeccapurple' } })
// Before: fill="var(--ondine-series-2,color-mix(in srgb,var(--_fg) 57%,var(--_bg)))"
// After:  fill="#a88bc5"

// Throws RenderError (unsupported): The theme value for "fg" cannot be mixed.
render('pie\n  "A" : 3', { theme: { fg: 'hsl(0 0% 0%)' } })

Validation

cargo fmt --all --check, cargo clippy --workspace --all-targets -- -D warnings (also wasm32 with flowchart only and all,theme), cargo test --workspace, pnpm build:wasm, pnpm vp test --run --project node (808 passed), pnpm check, and pnpm check:types. On this machine both builds use the stable toolchain (the pinned nightly has no rust-src). Against the base commit, per-type modules are 14 to 46 B smaller raw and 6 to 150 B larger gzip (flowchart +30 B, pie +35 B). They are not byte-identical, because of the unsupported error path. all.fast.wasm grows 27,341 B raw and 10,365 B gzip (1,265,581 to 1,275,946 B).