Changing view parameters

Contours must be re-calculated by the server when the contour parameters (levels, mode or smoothness) change. However, as contour rendering is done on the frontend, any changes to the contour rendering parameters (visibility, opacity, thickness, colour, line style) do not require any server interaction.

$skinparam style strictuml hide footbox title Updating contour parameters actor User box "Client-side" #EDEDED participant Frontend end box box "Server-side" #lightblue participant Backend end box User -> Frontend: Changes contour\nparameters activate Frontend Frontend -> Backend : SET_CONTOUR_PARAMETERS activate Backend Frontend <-- Backend : CONTOUR_IMAGE_DATA deactivate Backend User <-- Frontend: Displays updated image User -> Frontend: Changes rendering\nparameters User <-- Frontend: Displays updated image deactivate Frontend$

Similarly for raster images: As all the rendering is done on the frontend, any changes to the raster rendering configuration (colour map, range, scaling type) do not require any interaction between frontend and backend:

$skinparam style strictuml hide footbox title Changing colour maps, range or scaling type\n(no server interaction required) actor User box "Client-side" participant "GPU" participant Frontend end box box "Server-side" #lightblue participant Backend end box User -> Frontend : Changes parameter activate Frontend Frontend -> GPU : Shader parameters deactivate Frontend activate GPU GPU -> GPU : Render image\n(Color mapping,\ncomposition etc) User <-- GPU : Display image deactivate GPU$

Vector overlay rendering requires image data for both the vector angle (normally calculated from polarization angle PA) and length/intensity (normally calculated from polarized intensity PI). The image data is first downsampled on the backend using block downsampling with an even block width, and then masked with a threshold value. Adjusting the block width or threshold value will require the data to be recalculated and streamed by the backend. The backend streams data tile-by-tile.

$skinparam style strictuml hide footbox title Updating vector overlay parameters actor User box "Client-side" #EDEDED participant Frontend end box box "Server-side" #lightblue participant Backend end box User -> Frontend: Changes vector overlay\nparameters activate Frontend Frontend -> Backend: SET_VECTOR_OVERLAY_PARAMETERS activate Backend Backend -> Backend: Reads required\ndata from disk Backend -> Backend: Generates PA/PI tiles Backend -> Backend: Compresses using ZFP Frontend <-- Backend: VECTOR_OVERLAY_TILE_DATA\n(progress < 1.0) Frontend -> Frontend: Processes tile and\ngenerates vertices User <-- Frontend: Displays partial\noverlay image Frontend <-- Backend: VECTOR_OVERLAY_TILE_DATA\n(progress < 1.0) Frontend -> Frontend: Processes tile and\ngenerates vertices User <-- Frontend: Displays partial\noverlay image Frontend <-- Backend: VECTOR_OVERLAY_TILE_DATA\n(progress = 1.0) deactivate Backend Frontend -> Frontend: Processes tile and\ngenerates vertices User <-- Frontend: Dispalys complete\noverlay image deactivate Frontend$