Show the full image in the sidebar preview

[dschmidt]

Initial Checklist

• I understand this is a user story and questions should be posted in the Community Discussions
• I searched issues and couldn’t find anything (or linked relevant results below)

User Story

As a user, I want the preview in the details panel of the right sidebar to show the whole image, so that I can see what the file actually looks like without opening it.

User Value

• The sidebar preview is the larger of the two previews, so it should show more of the image than the tile, not a different crop of it.
• Today the tile and the sidebar show two different cutouts of the same image, which is confusing.
• Cropping stays acceptable in the tiles, where a uniform grid matters more than completeness.

Acceptance Criteria

• The preview in the file details panel shows the complete image, without cropping, in its original aspect ratio.
• The preview is scaled down to fit the available preview area and is never upscaled beyond that area or distorted.
• Portrait, landscape and square images are all shown completely, centered in the preview area.
• The height of the preview area stays stable, so the details below it do not jump when switching between files.
• Tiles and list thumbnails keep their current cropping behaviour.
• The motion photo badge and the loading spinner keep working on the preview.

Related

• Make Sidebar preview 16:9 #497 introduced the 16:9 sidebar preview. This story revises it: consistent sizing of the preview area stays, cropping the image goes.

Notes

• The file details panel requests its preview without a processor, so it falls back to the cropping thumbnail processor. The space details panel already requests fit for the space image.
• Testing: cover this in the existing unit tests of the file details panel, asserting the requested processor and that the image is rendered contained instead of cropped.

Visual

Bad:

[dschmidt]

after I complained a bunch of times about the behavior, @kulmann asked me to open this ticket, so we can discuss :)

[AlexAndBear]

Thats kinda weird, It shouldn't be like this, instead the whole image should be shown, not a cropped selection. I "fixed" this long time ago, but seems not to be sufficient for all cases

Can you upload you test image ?

[dschmidt]

AAH! That's good to hear it's not the intended behavior. I talked to @JammingBen and @kulmann and they both couldn't remember what you agreed on. The linked story also just talks about landscape images and I understood what I'm seeing is intended.
Thanks @AlexAndBear!

I thought I had seen this before on standard builds, but now it seems I've run into this only because I'm on a build based on opencloud-eu/opencloud#3397.

Debugging... Closing it for now and will reopen once if it's not the imagor PR's fault

[dschmidt]

Reopening: it is not the imagor PR's fault.

Measured against the current release build, at the size the sidebar requests (448):

source	box the server picks	aspect, source vs box
2268x4032 portrait	280x500	0.5625 vs 0.560
4080x3072 landscape	500x280	1.333 vs 1.786

So landscape images lose about a quarter of their height in the sidebar on the release today. Portrait photos survive only because the portrait box is itself close to 9:16, which is also why my screenshots looked like a branch-only problem: opencloud-eu/opencloud#3397 additionally matches square requests against a landscape box, so there a portrait photo gets 500x280 and the crop becomes dramatic.

The cause is the one from the notes above: the panel passes no processor, so it falls back to the cropping thumbnail. details-preview has no CSS of its own, the image is sized by h-[160px] with automatic width, so nothing is cropped in the layout. The crop is entirely the processor.

[dschmidt]

This is before my PR

This is after

While I somehow agree that 16:9 looks more beautiful in a way, I find it utterly confusing if the image is cut off in the sidebar. Especially if it's cut off differently than in the tile, e.g. with this picture when the sidebar removes the legs that can be seen on the tile