Examples

Complete, copy-pasteable integrations grouped by use case. Every example below ships in this repo as a single self-contained file you can read end-to-end.

For per-runtime install + setup snippets (CF Workers, Vercel Edge, Deno, Bun, browsers, Web Workers), see Installation. The examples here go further — full handlers with parameter parsing, error handling, and content negotiation.

API endpoints (Workers / Edge)

• Image resize API — accept an image POST or fetched URL, parse ?w=&h=&fit=&q=&format=, return the resized variant. The bread-and-butter Workers image endpoint.
• Open Graph card generator — 1200×630 social-card image rendered from query params (?title=&subtitle=&accent=). Drawn with Canvas 2D primitives.
• Avatar processing pipeline — multipart upload → autoOrient via EXIF → cover-crop to square → sharpen → JPEG. Worker / Vercel Edge.
• Watermark / branded screenshot — composite a logo overlay at gravity southeast over an input image. Worker shape and Node CLI shape.
• Format converter — any input → PNG / JPEG / BMP / raw based on the request's Accept header. Content negotiation done right.

Drawing-primitive recipes

• Document / invoice renderer — Canvas 2D drawing chops: gradients, Path2D, headers, rectangles, multi-column text. The "build a PDF page in a Worker" pattern.
• Bar chart from JSON — Worker endpoint that takes a JSON payload ({ labels, values, title }), renders a chart with axes, gridlines, and gradient bars, returns PNG.

Library integrations

simdra's createCanvas matches the node-canvas signature, so libraries that already accept "any node-canvas-shaped module" plug in cleanly. The three below have working code in the examples/ folder of the repo.

• SVG → PNG via canvg — Render any SVG to PNG at the edge. canvg + @xmldom/xmldom + simdra in a Cloudflare Worker. No headless browser, no Resvg, ~1 MB total bundle.
• PDF → PNG via pdfjs-serverless — Mozilla's pdf.js redistributed for edge runtimes, paired with a custom SimdraCanvasFactory. Renders any PDF page to PNG. Drop-in for Cloudflare / Vercel Edge / Deno Deploy.
• PDF → PNG via unpdf — Higher-level pdf.js wrapper (renderPageAsImage, extractText, extractImages). Less glue, fewer knobs. Same edge runtimes.

Where to go next

• Need to handle a use case not listed? Each example is structured so the input/output adapter (request parsing, response building) is small and replaceable. The image-processing core stays the same across runtimes.
• For deeper API references, see the Canvas 2D API and MicroSharp API pages.
• For deployment specifics — bundle limits, CPU budgets, async-offload via Service Bindings — see Installation.