Commons:Graphics village pump/November 2014

File:Van Halen - Diver Down.jpg - replace with PNG version?

For the File:Van Halen - Diver Down.jpg image, would it be worthwhile to upload the PNG version of the album cover at this page as a preferred alternative? --Gazebo (talk) 08:37, 28 October 2014 (UTC)

 Done @Gazebo I've uploaded a SVG version, the PNG was better but also not that good. ↔ User: Perhelion (Commons: = crap?) 11:27, 5 November 2014 (UTC)

One remark Perhelion: When you use a viewBox to clip an object to the correct size (like the white bar in this image) you should probably specify an absolute size (width/height) on the root SVG element. Otherwise when viewed in a browser width/height="100%" is assumed. Since the aspect ratio of the image will not match that of the browser window in most cases, the size of the viewBox is automatically increased along one dimension (to preserve aspect ratio without cutting any content). This will result in the "hidden" contents becoming visible again which is not desired (in this image probably not visible in most browsers as they use a white background anyway, but it's pretty obvious with my Firefox add-on Nicer Media Pages installed, as it changes the background color).
Despite setting an absolute width/height I can only think of using a clip path in the size of the viewBox and really cut away all unwanted content as a workaround, but probably the former is cleaner and easier. If anybody has any other idea on how to solve this, I'm happy to hear! --Patrick87 (talk) 19:09, 5 November 2014 (UTC)

Thanks Patrick87, I've added the absolute size and a High Contrast addon to my Chrome (it also reduce the energy cost of your display and increase the life time ^^). ↔ User: Perhelion (Commons: = crap?) 20:57, 5 November 2014 (UTC)

Time zone maps

Hi! The file:Standard time zones of the world.png has multiple issues (see also its talk page). Part of Brazil moved to a different time zone last year and Russia has reverted back to its original 11 time zones a few weeks ago. An SVG version and some derivates might need updating as well. Any volunteers? Richardw (talk) 08:32, 13 November 2014 (UTC)

@Richardw Can you please give a reference how it should be exactly look!? ↔ User: Perhelion (Commons: = crap?) 17:55, 13 November 2014 (UTC)

Hi Perhelion! As for Brazil, I only know what is on the talk page. As for Russia: I don't have the exact boundaries for you, but I know they went back to how it was "before". However, when I look at the history of file:World Time Zones Map.png, the most recent changes seem to have been implemented in that image. Does that help you? Richardw (talk) 08:49, 14 November 2014 (UTC)

"Correcting" perspective of 3D object photographs

Here are two examples[1][2][3] where editors have attempted to "correct" the perspective of photos of 3D objects taken at angles, or with weird perspective. But as far as I understand perspective, this is impossible, since you can't compensate for parts of the objects that are unseen on the original photos, and you can't "rotate" the objects on them, therefore the result becomes even more skewed (especially the objects on the edges of the first example). Anyone else have thoughts on this? Should it be discouraged? It is of course different with photos of 2D objects. FunkMonk (talk) 21:26, 21 November 2014 (UTC)

@FunkMonk: First of all, I'm very uncomfortable with the expression "perspective correction" because perspective is a physical parameter (or a combination of several, if you think about focal lengths etc.) of the picture taking process that – as you point out correctly – can't be changed afterwards. All you can do once the picture has been taken is try to make it appear as if is was taken from a different perspective. This can work rather well with flat objects such as paintings, but as soon as things are starting to become three-dimensional, you run into problems (think about a relief or maybe even a painting with thick paint and visible brush strokes shot from the side).

When it comes to buildings, there are some people around preaching that verticals must be vertical. There has been a recent discussion on this at the QIC talk page (mostly in german, with no real conclusion). There are cases where a certain amount of "correction" makes sense. For example, if a building is shot from below with a very wide angle lens, the verticals may converge much more in the image then they would appear to the human eye. Tuning down that "exaggeration" produced by the lens to a level where it looks natural often makes sense. On the other hand, you have presented some examples that show how such a "correction" can lead to really absurd results.

So no, I don't think manipulations like this should be discouraged in general. Instead I think that some guidance material on what amount of manipulation may be appropriate under what circumstances should be developed. Huge pile of work, though, if you want to do it right … --El Grafo (talk) 13:40, 25 November 2014 (UTC)