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nitidnitid

How it gets fast

Speed here is not a faster decoder — it is a different order of operations:

  1. The embedded EXIF thumbnail is decoded in single-digit milliseconds and drawn immediately.
  2. The full image decodes on a background thread and replaces it without a flicker.
  3. Neighbouring files in the folder are prefetched, so arrow keys never wait.

Measured on a 24-megapixel JPEG, from process start:

window created at    11 ms
gpu ready at        118 ms
thumbnail up at     128 ms   <- the picture is on screen here
first pixels in     146 ms

The full decode of that same image takes about 120 ms and lands afterwards, replacing the thumbnail in place. Most of what remains is the graphics driver starting up, not work nitid controls — which is why the order of operations matters more than decoder benchmarks.

Run with NITID_STARTUP_REPORT=1 to get that breakdown for your own machine. The numbers are held to a threshold by tests/startup.rs, so a change that puts a full decode back on the startup path fails the build rather than quietly costing a tenth of a second.