Canvas development: Difference between revisions

Canvas development (view source)

1,115 bytes added , 25 October 2016

m

→‎Adding new Placements: https://forum.flightgear.org/viewtopic.php?f=71&t=30642&p=297413#p297413

20,741

edits

@@ Line 1,937: / Line 1,937: @@
 === Adding new Placements ===
+{{WIP}}
+Let's assume, we'd like to a new type of placement, one for treating any Canvas as a raster image that can be fetched via the built-in httpd server, or even streamed as a MJPEG.
+For that to work, we need to be able fetch the Canvas, convert it to an osg::Image and then register the whole thing with the mongoose integration ($FG_SRC/Network/httpd), next we need to register a corresponding camera drawback to obtain the image, and notify the mongoose code to register a new handler and a class providing the corresponding image <ref>https://forum.flightgear.org/viewtopic.php?f=71&t=30642&p=297413#p297413</ref>.
+In Canvas terms, the way a Canvas is placed is handled by a so called '''Placement''', a placement is just another class that responds to placement-specific events, mainly relevant property updates.
+In this particular case, it wouldl make sense to support a handful of events/attributes:
+* output format (png, jpeg, mjpeg)
+* size of the image to be streamed (width/height)
+* color depth
+* name (to be used for requests)
+* update frequency (usually, once or twice per second should suffice)
 == Projections ==