Label variable ext size request

Hello,

I think it would be a beneficial feature to define a text size for different viewing distances for labels. For example, when defining the label, you may define text size 20 from distance A to B, size 18 from distance B to C, size 16 from distance C to D, etc. As the user zooms in and out, the label text size adjusts accordingly.

One example where this is helpful is if you have many entities close by. When you are zoomed close in, you may like a larger label. But as you zoom out and they are crunched together, the labels overlap each other and are visually unappealing and unreadable.

This could work very similarly to the translucencyByDistance property except with text size instead of translucency.

We’ve had an open issue for this for a while: https://github.com/AnalyticalGraphicsInc/cesium/issues/1075 Billboard already has scaleByDistance but doing the same thing with labels is actually tricky to pull off because Cesium renders labels as billboards of individual characters (instead of whole words) for both memory and performance reasons.

If someone wanted to work on this, we would definitely take a pull request for it, but it’s graphics problem that will have to be implemented at the shader level. It can’t be done exclusively on the CPU.