unified size rhythm for symbols (and probably also for text)

[matkoniecz]

from #710 (comment) - reported by @nebulon42

Having an unified size rhythm for symbols (and propably also for text) would be good. Currently there are symbols with 2 and 3 as base value for their size. A unified size rhythm would improve consistency and it would be easier to agree on a common symbol (SVG) base size like e.g. 16px.

Why this came to my attention: When working on #1108 I tried to represent all the various squares with a single SVG but could not find a suitable base size that would avoid scaling by e.g. 2.667 for some symbols. For this simple square I now chose a size of 1x1px, which can be scaled arbitrarily. For more complex symbols this is, of course, not possible.

[matthijsmelissen]

I agree.

Pay attention that the SJJB icons have a lot of whitespace around them, so we should make sure to define the size either explicitly with or without whitespace.

[matthijsmelissen]

Is this different from #974?

[nebulon42]

If I understand #974 correctly it is more about PNG versions of icons. This becomes obsolete when using SVG directly. This issue is about a common base canvas size of a SVG.
This could also include a common base size of text.

An example: if we choose 2px as size rhythm this would mean that icons could be e.g. 8px, 12px but not 15px, for text this would be the same.

[nebulon42]

#1165 is related

[gravitystorm]

We need to make sure that it's the "weight" of the icons that's similar, rather than just their width and height. For example, https://github.com/gravitystorm/openstreetmap-carto/blob/master/symbols/aerodrome.p.16.png has very little to it compared with a 16x16 solid square.

[kocio-pl]

Given my experience with icon design I would tell that it's not possible, at least within our framework - 14px matrix is not always enough (like in slipway) and some icons are intentionally made smaller to be less intrusive (like in trash). Trying to depict some ideas need very different shapes for the icon to be recognized, which is even more important factor here.

I'm not sure however about text rhythm - what does it mean?

[kocio-pl]

I guess this is mostly duplicate of #974 and it's not clear what we should do with text, so I'm closing it. It can be reopened later if needed.