Two things kept a scanned `.tif` off the wall, and both had to be fixed for
its tile to come out as a picture.
CanvasKit was never up on the catalogue's route: the studio boots it when the
workspace mounts, but a visitor who only ever opens the library never does, so
the JPEG inside the file had no decoder and the tile was drawn as nothing. The
`.tif` branch now brings the engine up itself.
And the pixels were being read out of that JPEG through an image `readPixels`
handed a buffer of ours, which CanvasKit answers by throwing rather than
filling — the frame came back black to a check on the return value. It now
takes the buffer CanvasKit hands back, the form the canvas calls in this repo
have always used. Measured in the browser on a 5472x3648 JPEG-compressed scan:
the tile went from 2378 bytes of solid black to 68670 bytes at mean 189.2 sd
74.6, against the 189.3/74.6 the same picture's uncompressed copy yields.
`scripts/tiff-decode-check.mjs` gains the fixture that was broken — a
JPEG-compressed strip — judged by how far a channel strays from the libvips
reference rather than by equality, since that strip is lossy. Its bundle now
re-exports the shim alongside the reader so the two are one module instance and
the fixture's JPEG has a decoder behind it.
3dtours
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