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displaydev: one-call canvas blits, and WorkerDisplay for Python in a Web Worker - #207
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…ay for an OffscreenCanvas in a Web Worker PSDisplay.blit_rect converted RGB565 one pixel at a time through the Python-to-JavaScript bridge, four calls a pixel: about two seconds for a full 1280x720 LVGL frame. It now converts the whole buffer in one JavaScript call, byte for byte the same pixels. The drawing and the input handling move into two shared helpers (_webcanvas, _webinput) so a second canvas display can use them: WorkerDisplay draws on an OffscreenCanvas the page transfers to a Web Worker and takes its input from events the page relays. A board config, board_configs/workerdisplay, pairs them, and LVGL's display_driver runs on it unchanged.
Without a pyscript module, a Pyodide Web Worker fell through to wake sources that never fire there, so timers (LVGL's display_driver loop among them) armed and never ran.
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Faster PyScript drawing
PSDisplay.blit_rectconverted RGB565 to RGBA one pixel at a time through the Python-to-JavaScript bridge, four calls a pixel. A full 1280x720 LVGL frame took about two seconds. It now hands the whole buffer to JavaScript once and converts it there: about 60 ms for the same frame in Chrome, with byte-for-byte the same pixels (checked against the old lookup table on random data).Python in a Web Worker
A long redraw on the page's main thread holds up everything else the page has to do on time.
displaydev.workerdisplay.WorkerDisplaylets your Python run in a Web Worker instead: the page transfers its canvas as anOffscreenCanvasand relays pointer, wheel and key events, andget_eventshands them out exactly asPSDisplaydoes, soappdevand LVGL'sdisplay_driverwork unchanged.board_configs/workerdisplaypairs them. The module docstring has the page-side JavaScript and the event format.To share code between the two, the canvas drawing moves into
displaydev/_webcanvas.pyand the input handling intodisplaydev/_webinput.py(neither touchesdocument, so both import in a worker).PSDisplay's public behaviour is unchanged. Both new helpers are listed inpydevices-desktop.tomlandmip-split.toml.Tests
tests/test_workerdisplay.py: one JavaScript call per blit, bounds checks, mouse events in CSS pixels, touch mapped to framebuffer pixels, keys with auto-repeat dropped, wheel. The existing display tests pass.