Zoomed to 1:1 or past it, the develop canvas showed a smoothed blur
rather than the photograph's pixels, so focus and noise could not be
judged at the magnification meant for judging them.
Two things caused it. The canvas only switched to nearest-neighbour
strictly past 1:1, with a margin, so the 1:1 inspection itself stayed
smooth. And the switch mostly had nothing to act on: the pipeline
rendered a viewport-sized frame at every zoom, so past 1:1 it was the
pipeline doing the enlarging - bilinearly whenever a straightening angle
or lens correction was in the chain - and the detail stage then sharpened
and denoised those invented pixels at radii scaled up to match. The
texture reached the canvas already blurred and was presented 1:1.
Now, from 1:1 on, the visible region is rendered at the source's own
resolution (render::render_size) and the canvas enlarges it with
nearest-neighbour, so the blocks on screen are the pixels an export would
have; it is also less shading. The decision lives in two small
functions, render::magnification and render::shows_source_pixels,
measured in physical pixels like one_to_one_zoom, with a half-percent
tolerance so the inspection zoom counts as 1:1 even where fit() rounded
the other edge. Below 1:1 the render and the smooth filter are unchanged.
dtourolle
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