Zwabel’s Weblog

April 9, 2009

Nicer Direcory Thumbnails, and Thumbnail Sequences

Filed under: KDE — zwabel @ 8:41 pm

When I did my last blog post, there were some comments that said that the folder previews didn’t look as nice as they could. I agree, luckily, one day later Fredrik Höglund came up with a patch to do some more complex and nicer painting on the items. Now the previews are layed out like a bunch of physical photos, with some random rotations, a white border, and drop shadows:
folder_previews_new

In my opinion, this looks very nice. The fact that the items are rotated randomly takes away some of the regularity that tends to be annoying, and the borders and shadows make it look like “real” objects.

I had some more ideas how the folder-previews, and previews in general, could be made even more useful.

Typically the problem with automatically generated previews for “sequence items”(Like folders, videos, etc., as opposed to simple images) is that you can never be sure that you pick a part of the sequence that is really useful to describe the content.

For example a video thumbnail taken right at the beginning of a movie, will most probably just show an empty black surface. A folder preview may show pictures that are not useful for describing the folder content. Now on several places on the internet, they have found a simple solution: When moving the cursor over the item, jump through different thumbnails from alternative locations in the sequence, to get a better description of the item.

This seems very reasonable, since the probability that one of the sequence items shows something “interesting” is a lot higher than it is for the part chosen automatically for the initial thumbnail, so I’ve spent some of the evenings this week bringing this functionality to KDE.

When an file/directory is hovered, the sequence of thumbnails generated for that item is alternated, showing another thumbnail every second, using a fast fade animation that is friendly to the eye. Currently the only thumb-creator that supports this feature is the one that creates thumbnails for directories, but once there is thumbnailers for videos again, I hope the developers will also implement the interface to support this feature. Since I’m too lazy to do a screencast, I will just attach another screenshot:
folder_previews_iteration1
Actually all you can see here, is that the icon under the cursor shows different preview pictures than the unhovered version above. You get the Idea.

April 6, 2009

KDE for Painters

Filed under: KDE — zwabel @ 11:40 am
Tags: , , , , , ,

My mother is an artist(A painter, see website). Since me and my brother have to administrate her computer, and she’s using Windows XP, we always have to deal with all kinds of problematic implications that come from this. Linux is a lot better suitable for remote administration
, and since she’s already using Thunderbird and Firefox, one should think that this isn’t such a hard switch.

So we tried it, and we nearly got her go crazy. Because she was using Windows Explorer before to manage her pictures, she has accumulated a really strange structure for them: Hundrets of folders, each with between 5 and 50 pictures, and all in a flat tree, and all badly named.

There is only one way of keeping at least a minimum level of overview in this mess: By recognizing the content of the folders using folder previews. Although this isn’t such a complicated thing, there seems to be no linux file manager that has this feature, until now.

I’ve implemented this feature within the KDE preview generator, so it works within all KDE applications now:
folder_previews
Isn’t it beautiful? Actually, the fact that it is beautiful is due to Peter Penz, who put the previews into the folder icon after I implemented the actual previewing. Now all we need is some more speed in preview generation, and it would be perfect.

This is one of the killer features my mother needs, and there is one more. She usually takes photographs of her paintings. The photographs tend to also show the borders, and are never perfectly even. Now there is a proprietary application on windows where you can just select the borders, and have the application perfectly map the picture into a rectangular and correctly scaled form.

Gimp comes relatively close to this with its inverse perspective transform tool, but it doesn’t change the pixel-size of the image to correctly reflect the size of the selected rectangle. Also it is a too complicated tool for such simple tasks.

However digikam also has a perspective transform tool in showfoto, and showfoto seems generally to be a very good and simple application for doing simple image adjustments like brightness/contrast etc., so this application would be a perfect match. However that tool also didn’t support inverse transform and resizing the image to the content yet.

Since it as well lives in the KDE source tree, this was also a simple attacking point for me. Here you can see the result, already present in the current digikam beta release:
Here you select the area that will be inversely mapped into a rectangular shape(I didn’t have an actual painting available):
inverse_transform_pre
And the result:
inverse_transform_post

So to make it short: If you’re a painter, then KDE 4.3 is for you. 🙂

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