Image cropping doesn't work for small areas

[caesarsgrunt]

Image cropping works for JPEG images, but not for PNGs. The crop button is disabled.

Rev.179738

Works fine with this file...

​http://www.semiologic.com/media/2009/11/26/turkey-day/Turkey-Day.png

The crop button is disabled until you actually select the area that you're meaning to crop. Possible UI niggle? How is this done in Flickr?

Odd - for me it's disabled even after electing the area. As I say, though, it works fine for jpegs. I'll do some more testing.

it might be an 8-bit png vs 24-bit png problem or some weird thing like that.

Ok, it seems I misreported the bug. Didn't do enough testing.

The actual bug is that the crop button is disabled if the area selected is smaller than the default thumbnail size set in the Media preferences.

Real-life example of when this is a problem - I want to make small thumbnails from a small area of the image for a couple of the images on my site. The rest want to be big thumbs of the whole image; hence a largish default size.

I can't see any reason for disabling the button for small areas; is there a reason?

Discussing with Andrew, Mark, Ryan and Peter IRL right now. Popular opinion seems to be that it's generally reasonable to have a minimum size. Potential cases where it would be useful to go smaller would be if you want to insert little accent images like icons or something, but this seems a bit edge case to delay a release for since there's no patch. Moving to 3.0 with intention of addressing earlyish.

Note: Please do not change back to 2.9 unless a) there's a use case in which this is a blocker that we are missing, and b) there is a patch, since we are already in Beta 2.

Don't think there's a case in which it's a blocker, though it is very annoying to have a minimum of the standard thumb size.

If it is decided that this should be fixed I can provide a patch instantly; it's just a couple of lines need removing. Perhaps I'll add a patch anyway.

Hmm, turns out not to be as easy as I thought. Enabling the button is easy, but saving a small image returns a PHP error message. I'll investigate later.

Just ran into this problem myself. Took a while to figure out that it wasn't a bug and was designed this way because it gave no feedback.

(Personal pet peeve: "Grayed-out and disabled anything because even though the grayed-out tells the user they can't do something it doesn't tell them why not or how to fix it. I'd much prefer to see nothing grayed-out (or at least nothing disabled) and to instead have it when click to launch a pop-up that explains why the user can't do whatever and that tells them how to fix it. But I digress...)

Anyway, here's a good reference on why this use-case is important (I know, Jane already blessed it, but this is still a good reference):

• Look for the sub-head: ​Image Reduction: Better Thumbnails

I just ran into this "bug" as well - not being able to re-crop an image to generate a new thumbnail if the image has either x or y dimensions smaller than the thumbnail size as specified in Media settings.

I'd be happy to submit a patch today to "fix" this if someone authoritative can speak to what functionality would be acceptable.

I came across this and it took me ages to work out why I couldn't crop - this really is unintuitive. Here is a proposed patch - it doesn't disable the button but issues an alert telling you what's up. Thoughts?

I'm going to need help with i10n-ifying the Javascript, because my attempts to get that to work failed miserably.

Replying to solarissmoke:

I came across this and it took me ages to work out why I couldn't crop - this really is unintuitive. Here is a proposed patch - it doesn't disable the button but issues an alert telling you what's up. Thoughts?

Agreed. I had the same experience.