Increase default quality for previews to e.g. 90 or 95

[maddylliieeee]

Re-Opened owncloud/gallery#465

Steps to reproduce

Upload a bunch of photos to your OC
Open the Gallery app for these photos
Open a single photo (slideshow view)

Expected behaviour

Assuming uploaded photos had proper resolution a sharp photo should appear.

Actual behaviour

The resolution of the displayed photo fits (so this is not a duplicate to those issues pointing to resolution) but compression artifacts are visible.
Probably due to a low quality on JPEG compression?

Server configuration

** Operating system: **
Ubuntu 14.04 LTS
** Web server: **
Apache/2.4.7 (Ubuntu)
** Database: **
MySQL
** PHP version: **
PHP/5.5.9-1ubuntu4.14 OpenSSL/1.0.1f configured
** ownCloud version: ** (see ownCloud admin page)
8.2.1

Updated from an older ownCloud or fresh install:

from 8.1.4, didn't test before 8.2.1 however

Request/Suggestion

Increase preview quality from 75 to at least 90, better 95. Because in full screen as well as in previews already lot's of artifacts are visible.

[karlitschek]

@georgehrke What do you think?

[georgehrke]

@georgehrke What do you think?

Sounds reasonable, especially for retina screens.

Open a single photo (slideshow view)

@oparoz Does the gallery app use thumbnails for full screen preview?

[oparoz]

@georgehrke - The Gallery app uses the cached previews in order to not serve a 20MP photo to a 1024x768 tablet. The original can always be downloaded and there is also a plan to download it in the background if the user zooms in.

I think the change is trivial, but it should be a config setting. That way people wanting better quality could change the settings and re-generate all thumbnails.

Since I think it would be difficult to detect a setting change, we would have to let users manually re-generate thumbnails.

[maddylliieeee]

A config-setting would be perfect, really!

[MorrisJobke]

Since I think it would be difficult to detect a setting change, we would have to let users manually re-generate thumbnails.

No. Please no setting for such stuff. We should do it in the correct way and not hide this behind yet another setting. Everybody wants sharp images not only the people who know a magic setting.

[georgehrke]

Yep, I'd say go without a setting as well.

[maddylliieeee]

What about increasing the default but provide a setting to reduce it again? Some people may still like the option to reduce the size of the images.

[oparoz]

No. Please no setting for such stuff. We should do it in the correct way and not hide this behind yet another setting.

OK, the correct way is to use a better default for the max preview, but then you'l have to introduce a check and use a lower value for previews smaller than 256x256 per example. That way you still have proper thumbnails.

[oparoz]

It doesn't change the fact that this will have zero effect on existing installations.

[Jaimy85]

You can change line 321 in lib/private/image.php to
$res = imagejpeg($this->resource, NULL, 95);

[MorrisJobke]

ge.php to
$res = imagejpeg($this->resource, NULL, 95);

#21437

[meisterleise]

okay, it's an old post, but the image quality is still bad with this plugin.
Can someone please tell me where I can find this line $res to change the quality?
I can't find it!

[maddylliieeee]

I found it here: lib/private/legacy/image.php

But is that still being used?

[stale]

This issue has been automatically closed.