Add no-crop thumbnails rendering in images preview

[pasnox]

Describe the bug

Image preview is broken.
It regularly produce thumbnails that truncate most of the images and make the previewing in Space useless.

Steps to reproduce

Steps to reproduce the behavior:

1. Create a space
2. Upload a bunch of landscape and portrait photos
3. Preview them, in most occasion the thumbnail produced is truncated

Expected behavior

The image is always entirely visible, downscaling it if needed to fit in the client screen

Actual behavior

Thumbnails seems to be cropped instead of downscaled

Setup

OCIS_URL="https://host.com:8888" \
OCIS_CONFIG_DIR="${HOME}/ocis/config" \
OCIS_BASE_DATA_PATH="${HOME}/ocis/data" \
OCIS_INSECURE=false \
PROXY_TRANSPORT_TLS_KEY="/etc/pki/host.com/private/csr.key" \
PROXY_TRANSPORT_TLS_CERT="/etc/pki/host.com/certificates/certificate-fullchain.crt" \
PROXY_HTTP_ADDR="0.0.0.0:8888" \
WEB_HTTP_ADDR="0.0.0.0:8431" \
ocis server

[pasnox]

So, after some investigation, it seems the preview thumbnails used depend the client resolution and how works the thumbnailer by default.
So the thumbnailer by default only generate landscape cropped thumbnails, so if the client size is lower that the image size, you would get a highly truncated image.
To workaround (but not fix it), you can request the thumbnailer to thumbnails also in portrait mode, extending the default

from:
THUMBNAILS_RESOLUTIONS="16x16,32x32,64x64,128x128,1920x1080,3840x2160,7680x4320"

to:
THUMBNAILS_RESOLUTIONS="16x16,32x32,64x64,128x128,1920x1080,3840x2160,7680x4320,1080x1920,2160x3840,4320x7680"

Please add those portrait mode in default, and ensure downscaled instead of cropped is used by the thumbnailer.

[micbar]

@C0rby Can you take a look if this is a bug?

[kulmann]

There is a ticket in web for this, see owncloud/web#7728 - but we need some kind of nocrop query option for the thumbnailer service, so that web can request a preview cropped or downscaled as needed.

We intended to have a cropped thumbnail for the file list, but downscaled for the right sidebar Details panel, for the preview app (which shows the images in larger dimensions) and for the upcoming tiles view.

[C0rby]

Please add those portrait mode in default

You are more than welcome to add the missing resolutions to the default config and open a PR.

and ensure downscaled instead of cropped is used by the thumbnailer.

As @kulmann already stated that was a deliberate decision but we could add a nocrop query parameter.
For that one would need to:

• adapt the webdav service

  ocis/services/webdav/pkg/dav/requests/thumbnail.go

  Line 53 in 4b18930

  func ParseThumbnailRequest(r *http.Request) (*ThumbnailRequest, error) {

• Add a nocrop parameter to the thumbnails service

  ocis/protogen/proto/ocis/services/thumbnails/v0/thumbnails.proto

  Line 41 in b8a90b5

  message GetThumbnailRequest {

• Add the parameter to all the requests in https://github.com/owncloud/ocis/blob/master/services/webdav/pkg/service/v0/service.go
• And implement the parameter in the thumbnails service, probably somewhere in the generator file: https://github.com/owncloud/ocis/blob/master/services/thumbnails/pkg/thumbnail/generator.go

https://pkg.go.dev/github.com/disintegration/imaging#Resize could be used for that since it doesn't crop as opposed to https://pkg.go.dev/github.com/disintegration/imaging#Thumbnail, which we are using right now.

[micbar]

Removing the bug label because this is an enhancement.

[jacobgkau]

Removing the bug label because this is an enhancement.

This is a blocking issue for resolving a bug (impossible to view a full photo without downloading) in web.

[pasnox]

Hi, I just migrated to 4.0.4, and it seems not fixed.
I still have cropped landscape images. Also, you dd not said how I would enable the no-crop mode ?
Can you please give more information ?
Also, just found owncloud/web#9806 claiming to fix it, but does not seems, or not yet in a released version ?
Thanks,

[kulmann]

Hi, I just migrated to 4.0.4, and it seems not fixed.
I still have cropped landscape images. Also, you dd not said how I would enable the no-crop mode ?
Can you please give more information ?
Also, just found owncloud/web#9806 claiming to fix it, but does not seems, or not yet in a released version ?
Thanks,

It will be available as part of the ocis v5.0.0 release early next year. There are alpha versions available if you want to check - the web ui utilizes the new option automatically in the preview app. First beta is planned for next Tuesday.