South Korea shields

[1ec5]

Added shields for national expressways, national highways, and local highways in South Korea.

The national expressway shield is a little slice of home away from home. The shape is based on this sign blank on Wikimedia Commons, which is in the public domain. It’s very similar to the U.S. route shield, but the contours have subtle differences. It doesn’t leave very much room for the numerals, so ironically, local highways are much more prominent than national expressways.

The national highway shield is supposed to be an oval, even when a two-digit number would fit inside a circle, so I eschewed the roundedRectShield() function in favor of a custom image. Unfortunately, spritezero turns the ellipse into a hendecagon.

I’m unable to implement shields for metropolitan city roads and expressways. They are mapped as route relations, but the relations aren’t tagged with network. Instead, they’ve been added to network relations representing the highway system or the municipal government. We need them to be tagged with network=KR:* like the other route types so we can support them properly. The refs for Seoul’s special metropolitan city roads include both the signposted number and the non-signposted official number, which should go in unsigned_ref.

Along the way, this PR fixes an issue that caused routes with matching networks but missing refs to appear as blank shields.

Fixes #138.

[1ec5]

The national highway shield is supposed to be an oval, even when a two-digit number would fit inside a circle, so I eschewed the roundedRectShield() function in favor of a custom image. Unfortunately, spritezero turns the ellipse into a hendecagon.

Somehow I overlooked the circleShield() function. I added some options to specify the text color and fix the width, since the shield should always look like an oval:

[ZeLonewolf]

Because this PR uses a scaling variable, needs to be tested on 1x and 2x+ DPRs to ensure no scaling issues.

[1ec5]

1× simulation in Firefox:

[ZeLonewolf]

Looks great! Thanks for fixing that blank shield bug. Also confirmed that the Pittsburgh shields still work as expected.