a 40% size reduction in WASM binary size

• completed the removal of the mongoose networking library from the server-side C code
• replaced the WCSLIB by WCSTools in the client-side WebAssembly, reducing the WASM binary size from 1.1MB to 676KB

minor improvements

• interleaving a video frame preparation in FORTRAN with x265 encoding and WebSocket transmission in C
• interleaving a P-V Diagram preparation in FORTRAN with ZFP compression and WebSocket transmission in C
• recompiled the client-side WebAssembly with the latest emscripten compiler

improved server-side efficiency

• added handling of /cluster_heartbeat/id to the libmicrohttpd HTTP server part
• server-side optimisations: removed the Unix pipe and the accompanying request/response POSIX threads from three WebSocket event loop functions: <ws_event_loop>, <video_event_loop> and <pv_event_loop>
• upgraded the libx265 library version

compressed size reduction

• reduced the compressed size of the WebGL GSLS archive from 26kB to 20kB by replacing the LZ4HC compressor with BZIP2

optimisations

• reduced the long-poll interval for the image/spectrum from 500ms to 250ms
• coalesced the WebGL GLSL shaders into a single LZ4-compressed file (164kB down to 26kB), significantly cutting the number of HTTP requests to the CDN

WebGL GLSL off-load to CDN

• asynchronous (non-blocking) fetching of WebGL GLSL shaders from the Content Delivery Network (CDN) in the client-side JavaScript
• further reduced the compressed size of the initial web page response down to 1.73kB by off-loading the GLSL shaders to the CDN

reduced web page loading times

• switched to a versioned Font Awesome Kit in order to take advantage of a browser cache
• compress the main web page response, reducing the trasmitted size from 173kB to 35kB

page loading speed-ups

• removed fetching of the binned PNG background image from the JVO server whilst the FITS dataset is being loaded (saves several hundred kilobytes in Internet traffic)
• removed preloading of the metadata for three MP4 help video files (saves three HTTP requests to the CDN)
• optimised loading from the browser cache of the zero-md JavaScript library + dependencies, used to display the CHANGELOG

even faster web page loading

• further improved asynchronous loading of WebAssembly

faster web page loading

• asynchronous (non-blocking) loading of WebAssembly to speed up the initial web page loading