Wednesday, 24th May 2023
Instant colour fill with HTML Canvas
(via)
Shane O'Sullivan describes how to implement instant colour fill using HTML Canvas and some really clever tricks with Web Workers. A new technique to me is passing a canvas.getImageData() object to a Web Worker via worker.postMessage({action: "process", buffer: imageData.data.buffer}, [imageData.data.buffer]) where that second argument is a list of objects to "transfer ownership of" - then the worker can create a new ImageData(), populate it and transfer ownership of that back to the parent window.
REGENT: Coastal Travel. 100% Electric (via) As a long-time fan of ekranoplans this is very exciting to me: the REGENT Seaglider is a fully electric passenger carrying wing-in-ground-effect vehicle designed to serve coastal routes, operating at half the cost of an aircraft (and 1/10th the cost of a helicopter) and using hydrofoils to resolve previous problems with ekranoplans and wave tolerance. They’re a YC company and the founder has been answering questions on Hacker News today. They’ve pre-sold 467 vehicles already and expect them to start entering service in various locations around the world “mid-decade”.
The benefit of ground effects are: - 10-20% range extension (agreed, between 50% and 100% wingspan, which is where seagliders fly, the aerodynamic benefit of ground effect is reduced compared to near surface flight) - Drastic reduction in reserve fuel. This is a key limitation of electric aircraft because they need to sustain powered flight to another airport in the event of an emergency. We can always land on the water, therefore, we can count all of our batteries towards "mission useable" [...] Very difficult to distribute propulsion with IC engines or mechanical linkages. Electric propulsion technology unlocks the blown wing, which unlocks the use of hydrofoils, which unlocks wave tolerance and therefore operations of WIGs, which unlocks longer range of electric flight. It all works together.
— Billy Thalheimer, founder of REGENT
Migrating out of PostHaven. Amjith Ramanujam decided to migrate his blog content from PostHaven to a Markdown static site. He used shot-scraper (shelled out to from a Python script) to scrape his existing content using a snippet of JavaScript, wrote the content to a SQLite database using sqlite-utils, then used markdownify (new to me, a neat Python package for converting HTML to Markdown via BeautifulSoup) to write the content to disk as Markdown.