Hi, in Testbed 15 we are asked to implement a way to set the map background color in the style itself, at least for styles that are meant to be used as basemaps.
The SLD specification does not allow for that, which makes sense in the context of "overlay" WMS, with a client deciding the set of layers to be displayed, and controlling the background color from the GetMap itself. However, the need to set the background color is real and we have seen in GeoServer since the beginning: anyone forgot about the "giant_polygon" layer used in the NYC demo layer group? :-D Looking at the MBStyles code I see a similar solution, the code is taking the bgcolor specification found in Mapbox GL and turning it into a inline user style with a GML giant polygon defined inside. The giant polygon approach has been labelled as clumsy and ineffective, and indeed, I have to agree: - Why expose a dedicated, user visible layer with a massive polygon just to set the color of the painting canvas - Reprojection issues abund when going to local projections, the advanced projection handling help here by cutting the geometry, but it's not available for all projections The idea proposed in the testbed is to add a BGColor element inside UserStyle that would allow setting the background color for the entire style (imagine a multi-layer stylesheet, also known as style group, in GeoServer): <UserStyle> <BGColor>FFAA00</BGColor> ... </UserStyle> The idea seems useful and has no backwards compatibility issues, so I'd like to implement it, at least in the SLD parser, to give a simple solution to.. well... a simple problem. The renderer would then simply use the information to paint the canvas with the first bgcolor found in the layer stack. If the map is requested to be transparent (&transparent=true) then it would ignore the bgcolor, allowing the layers to be used both as suitable backgrounds but also as overlays Objections? :) Cheers Andrea == GeoServer Professional Services from the experts! Visit http://goo.gl/it488V for more information. == Ing. Andrea Aime @geowolf Technical Lead GeoSolutions S.A.S. Via di Montramito 3/A 55054 Massarosa (LU) phone: +39 0584 962313 fax: +39 0584 1660272 mob: +39 339 8844549 http://www.geo-solutions.it http://twitter.com/geosolutions_it ------------------------------------------------------- *Con riferimento alla normativa sul trattamento dei dati personali (Reg. UE 2016/679 - Regolamento generale sulla protezione dei dati “GDPR”), si precisa che ogni circostanza inerente alla presente email (il suo contenuto, gli eventuali allegati, etc.) è un dato la cui conoscenza è riservata al/i solo/i destinatario/i indicati dallo scrivente. Se il messaggio Le è giunto per errore, è tenuta/o a cancellarlo, ogni altra operazione è illecita. Le sarei comunque grato se potesse darmene notizia. This email is intended only for the person or entity to which it is addressed and may contain information that is privileged, confidential or otherwise protected from disclosure. We remind that - as provided by European Regulation 2016/679 “GDPR” - copying, dissemination or use of this e-mail or the information herein by anyone other than the intended recipient is prohibited. If you have received this email by mistake, please notify us immediately by telephone or e-mail.*
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