music_library/backlog/tasks/ml-185.2 - Use-API-sized-covers-in-Presto.md

id, title, status, assignee, created_date, updated_date, labels, dependencies, documentation, modified_files, parent_task_id, priority, ordinal

id	title	status	assignee	created_date	updated_date	labels	dependencies	documentation	modified_files	parent_task_id	priority	ordinal
ML-185.2	Use API-sized covers in Presto	Done	Codex	2026-05-15 21:22	2026-05-15 21:53	presto artwork	ML-185.1	docs/project-conventions.md presto/AGENTS.md presto/README.md	presto/main.py presto/README.md presto/AGENTS.md presto/tests/conftest.py presto/tests/test_screens.py	ML-185	medium	21000

Description

Update the Presto application so it trusts the collection API to provide display-ready cover sizes.

Context for implementer: presto/main.py currently renders record-list covers at 80 px and record-detail covers at 480 px. It currently chooses among mini_cover_url, micro_cover_url, and thumb_url, then draw_jpeg/5 selects JPEG scale flags to fit images into a bounding box. After the API task is complete, records should expose named covers where small is the 80 px row cover and medium is the 460 px detail cover. Update the detail cover layout to draw the 460 px image centered in the 480 px display so it does not fill the full view width. Preserve existing cover byte caching, placeholder rendering, and the rule that drag redraws must not fetch images over the network.

Acceptance Criteria

• #1 Record-list rows fetch and draw the API-provided 80 px small cover variant.
• #2 Record-detail pages fetch and draw the API-provided 460 px medium cover variant centered within the 480 px display.
• #3 Presto image drawing no longer selects JPEG scale flags or resizes covers to fit a bounding box.
• #4 Missing or failed cover downloads still render placeholders, and drag redraws still avoid network fetches.
• #5 Presto README, Presto guidance, and smoke-test fixtures match the new named cover contract.
• #6 The Presto syntax check and smoke tests pass, with physical device verification only claimed if run on the device.

Implementation Plan

1. Add small helper(s) for reading the named cover object from API records, returning small for list rows and medium for detail pages.
2. Replace legacy mini_cover_url / micro_cover_url / thumb_url selection and preload checks with the new named cover helpers.
3. Simplify JPEG drawing so it decodes the already-sized image at the requested top-left coordinate and falls back to a placeholder on failures; remove _jpeg_scale_options and max-width/max-height fitting behavior.
4. Keep row and detail image cache keys separate and preserve the existing drag behavior that shows placeholders when data is not already cached.
5. Update presto/README.md, presto/AGENTS.md, and test mock records to describe and exercise the new contract.
6. Run python3 -c "import py_compile; py_compile.compile('main.py', cfile='/tmp/main.pyc', doraise=True)" from presto/ and mise run test for the Presto smoke suite.

Implementation Notes

Updated the Presto cover path to consume only the collection API covers object: row covers use covers.small, detail covers use covers.medium, and the detail cover layout is now 460 px wide and centered at x=10 on the 480 px display. Removed JPEG dimension probing and scale-selection logic so draw_jpeg decodes API-sized JPEGs at the requested position and uses the provided dimensions only for placeholder fallback. Preserved row/detail byte cache separation and drag-time placeholder behavior. Ran python3 -c "import py_compile; py_compile.compile('main.py', cfile='/tmp/main.pyc', doraise=True)" and mise run test from presto/; both passed. Physical Presto hardware was not tested.

Final Summary

Updated the Presto app to trust the API-provided cover sizes. Record rows now read covers.small, record detail pages read covers.medium, and the detail cover is 460 px wide and centered within the 480 px display.

Removed the JPEG dimension probing and scale-selection code from draw_jpeg; it now decodes API-sized JPEGs directly and only uses placeholder dimensions when a fetch or decode fails. Existing row/detail image caches and no-network-during-drag behavior are preserved.

Updated Presto guidance, README API examples, and smoke-test fixtures for the new cover contract, and added a focused smoke test assertion for the expected 80 px row cover and 460 px centered detail cover.

Tests run: Presto syntax check and mise run test from presto/ (8 passed). Physical device behavior was not verified on hardware.