Users expect a magnifier to tell them the counts, which the follower view could
not do: it has the rendered pixels but not the numbers behind them.
Take them from the detector's int32 buffer directly, the same source the main
view colours from, so no float copy of the image is needed - the magnifier
still holds nothing full-size of its own, only a shared_ptr to the frame and
one to the reader image.
The labels are painted in drawForeground() rather than as scene items. The main
view creates up to 5000 QGraphicsSimpleTextItems per overlay rebuild for this;
here they are just drawn, so there is no item churn and no scene invalidation.
Text is laid out in viewport pixels so it stays a constant readable size, and
black/white is chosen from the luminance of the rendered pixel underneath, as
the main view does.
Threshold is the same 30x as the main view, so the default 12x magnification
shows no labels until the user wheels in; a cap keeps pathological window sizes
from drawing thousands of them.
Verified in the GUI at 32x: counts drawn per pixel with white text over the
dark centre of a Bragg peak and black elsewhere, and "Gap" across a module gap.
Main image panel still pixel-identical to the pre-series baseline.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
The magnifier and the main view are two views of the same image at different
position and zoom, but the magnifier ran the whole pipeline again on its own
copy: it wrapped the same int32 buffer in a SimpleImage, converted it to float,
coloured every pixel and kept its own full-size QImage. That is a second
conversion and two extra full-detector buffers (20 MB at 2.8 Mpx, 138 MB at
18 Mpx) to feed a 320x320 window.
Separate producing a frame from displaying one:
- JFJochImage keeps the rendered frame in a shared_ptr<QImage> (the pointer is
stable for the widget's lifetime; only the contents change, so the existing
buffer reuse is unaffected), publishes it via Frame() and announces new
pixels with frameRendered().
- JFJochImageItem holds that shared_ptr instead of a reference to a member of
its owner, which also removes a lifetime coupling.
- JFJochFollowerImage is a small read-only view of such a frame with its own
zoom and centre. It shows only the image: overlays, ROI tools and per-pixel
labels belong to the view that owns the data.
- The magnifier becomes one of those, fed from frameRendered().
Consequences beyond the saving: the magnifier now agrees with the main view on
colour map, contrast and HDR mode, which it never did -- it was wired to
neither, so it always drew with its own defaults. And the visibility guard
added in 6d1af4921 is gone: there is no longer any per-frame work to skip, so
nothing needs guarding. That guard was a workaround for this design.
Stepping 30 frames with the magnifier open: 5550 -> 4810 ms CPU, which is what
it costs with the magnifier closed (4770 ms) -- it is now free either way.
Verified: main image panel and a drag-pan stay pixel-identical to the
pre-refactor binary (AE=0); the magnifier follows the cursor, updates on a new
frame, and now tracks a colour-map change.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 5