Render exercise art

Serve an exercise illustration frame from its stable URL, with a silhouette standing in until the drawing is published.

Show the exercise being performed, in the same drawn style as the muscle figures. Use the image template returned in an exercise record’s frames array and replace {publishableKey} with the publishable half of your key.

GET /v1/{publishableKey}/exercises/{id}/{figure}/{frame}.webp

HTML

<img
  src="https://cdn.gymassets.dev/v1/{key}/exercises/myfv/male/start.webp"
  alt="Curl with barbell, start position"
/>

Response · image/webp 200

content-type: image/webp
cache-control: public, max-age=3600
access-control-allow-origin: *
access-control-expose-headers: x-art-status, x-quota-status

Path parameters

Parameter	Behavior
`publishableKey`	Authorizes the image request and assigns it to the Exercise art allowance
`id`	The `id` field of an exercise record: its identity, permanent by design
`figure`	`male` or `female`
`frame`	`start` or `finish`

Formats are webp and png. Any other extension returns 400 unsupported_format with the supported list, and a path missing one of the segments returns 400 with the expected shapes.

Silhouette stand-ins

A frame whose drawing is not yet published returns 200 with a neutral silhouette of the requested figure and this header:

x-art-status: coming-soon

The header is exposed to browser JavaScript. A response without it carries the finished drawing. Finished artwork is published to the same URL, and appears without any change to the requesting page.

The frames array on the exercise record lists only published drawings, and GET /v1/exercises?drawn=true returns only exercises that have them. An interface that should not show silhouettes filters there instead of probing image URLs.

Muscle masks

Each drawn frame publishes the mask layers used to highlight the worked muscles on the illustration:

Leaf	Contents
`{frame}-mask-primary.png`	The primary muscles, as an alpha layer aligned to the frame
`{frame}-mask-secondary.png`	The secondary muscles — present only when the record lists any

The record’s frames array carries a template for every mask that exists. A mask request for an undrawn frame returns 404 not_found — there is no silhouette stand-in for a mask — and the response names the collection that lists drawn exercises:

{
  "error": "not_found",
  "key": "exercises/uqgq/male/start-mask-primary.png",
  "exercises": "https://api.gymassets.dev/v1/exercises?drawn=true"
}

Caching

Responses state their window in cache-control. A finished drawing is cacheable for one hour. A silhouette stand-in is cacheable for five minutes, and a newly published drawing therefore appears within minutes with no cache to purge.

Allowance

When the Exercise art allowance for the key is crossed, images keep serving and the response carries x-quota-status: exhausted. An end user never meets a broken image because of an account limit.