* ui: blur media by resampling the preview, not a per-frame effect
Modifier.blur put a BlurEffect on a display-sized graphics layer, so the
Gaussian was re-evaluated on every frame the media was drawn. It also
requires RenderEffect, which Android applies only from API 31, so below
Android 12 media was drawn unblurred while the setting read as on.
A blur and a downscale discard the same thing - detail finer than their
radius - so the preview is now resampled to about one pixel per radius and
stretched back. That runs once when the item composes, needs no
RenderEffect, and removes the detail irreversibly rather than convolving
it. The first resampling step bounds both sides, so no image, however
shaped, can produce a large intermediate.
While the blur hides the media the file is also left unread, so an image
scrolled past is no longer read, decoded at its full size and kept in the
image cache only to be hidden again. blurHidesMedia() is the single
definition that both the drawing and the loading decision use, so they
cannot disagree about whether the media is on screen.
* plans: blur media by resampling the preview
* ui: shorten comments in media blur
* ui: smooth the media blur and match its strength to the old one
Stretching the resampled preview straight to the screen showed its pixel grid. Double it back
up until its longest side is at least half the reference width before drawing, so the last
stretch is short and the tents compose into a bell. The reference width moves from 360 to 400:
fitted against Gaussians, 360 blurred 5-75% more than Modifier.blur did, 400 is within 10% at
every setting.
Narasimha-sc
c0344a9a61