This is more shocking of videos.

Split of D26901

When the size is smaller than KIconLoader::SizeEnormous it prevents to see a size difference between the preview size of a folder and the icon of a folder.
With D29002 the two always match in size.

Probably this patch fixes bug 390488.

In D29001#652832, @ngraham wrote:

Looks like this fixes https://bugs.kde.org/show_bug.cgi?id=408455!

It does not, this one is about the main files view.
But the fix will be quite similar.

Probably a candidate for the stable branch.

@elvisangelaccio
?

In D29001#653174, @elvisangelaccio wrote:

Please amend the commit message with whatever bug report(s) this fixes :)

Sure, done

Do we have a KF6 task for this to add support for dpr to this? Adding it to the PreviewJob should be straightforward, but we cannot really change the preview plug-ins class.

It does not, this one is about the main files view.
But the fix will be quite similar.

This approach is wrong though, for the main files view in particular. There's a difference between loading e.g. a 32px icon, and a 16px @2x scaling.
Doesn't really matter for the preview pane's large icon size but for the icon view it could have undesired side effects of using a non-symbolic icon when it should by symbolic, or having an icon with too small detail

In D29001#653284, @broulik wrote:

It does not, this one is about the main files view.
But the fix will be quite similar.

This approach is wrong though, for the main files view in particular. There's a difference between loading e.g. a 32px icon, and a 16px @2x scaling.
Doesn't really matter for the preview pane's large icon size but for the icon view it could have undesired side effects of using a non-symbolic icon when it should by symbolic, or having an icon with too small detail

Do you recommend me to abandon this then ?

In D29001#653282, @broulik wrote:

Do we have a KF6 task for this to add support for dpr to this? Adding it to the PreviewJob should be straightforward, but we cannot really change the preview plug-ins class.

I have tried to implement to add a setDevicePixelRatio to PreviewJob and in turn add it to the thumbnail ioslave and ThumbCreator.
I don't think we have to wait for KF6 for it, it won't break anything or at least we can implement it in a retro-compatible way.
But this requires some work.

Do you recommend me to abandon this then ?

I think in this particular instance is fine, but could lead to small text for text preview?

it won't break anything or at least we can implement it in a retro-compatible way.

If you have an idea how, sure. You can't add new virtuals to ThumbCreator class, though. Not too keen on having a V2, though.

In D29001#654410, @broulik wrote:

Do you recommend me to abandon this then ?

I think in this particular instance is fine, but could lead to small text for text preview?

it won't break anything or at least we can implement it in a retro-compatible way.

If you have an idea how, sure. You can't add new virtuals to ThumbCreator class, though. Not too keen on having a V2, though.

I was thinking modifying the virtual bool create(const QString &path, int width, int height, QImage &img) adding it a devicePixelRatio qreal parameter.
I am not sure it will break this way.
So that may we need a KF6 task indeed.