File browsing

The file browser displays a list of files in the selected directory, along with some basic information on each file (type, size) and a list of subdirectories. If a file contains multiple HDUs (or equivalent), a list of HDU names is included. If a file is selected in the file browser, additional information is shown. A specific HDU of a file can be selected. When a subdirectory is selected, the file list is fetched for that subdirectory. When a file is loaded, the default image view is requested. A file can be loaded as a raster or contour image (not currently implemented), and can be appended to the current list of open files, or can replace all open files, in which case the frontend must first close all files using the CLOSE_FILE message with file_id = -1. Individual open files can be removed from the file list by calling CLOSE_FILE with an appropriate file_id field.

$skinparam style strictuml hide footbox title Change file browser sub-directory actor User box "Client-side" #EDEDED participant Frontend end box box "Server-side" #lightblue participant Backend end box activate Frontend User -> Frontend : Selects sub-directory Frontend -> Backend : FILE_LIST_REQUEST/ \n REGION_LIST_REQUEST activate Backend Backend -> Backend : Finds file in sub-directory Frontend <-- Backend : FILE_LIST_PROGRESS User -> Frontend : (Cancels the file/region list) Frontend -> Backend : (STOP_FILE_LIST) Frontend <-- Backend : FILE_LIST_RESPONSE/ \n REGION_LIST_RESPONSE deactivate Backend User <-- Frontend : Displays updated\n file browser deactivate Frontend$

$skinparam style strictuml hide footbox title Fetching file info actor User box "Client-side" #EDEDED participant Frontend end box box "Server-side" #lightblue participant Backend end box activate Frontend User -> Frontend : Selects file Frontend -> Backend : FILE_INFO_REQUEST activate Backend Backend -> Backend : Determines file info\n from header Frontend <-- Backend : FILE_INFO_RESPONSE deactivate Backend User <-- Frontend : Displays info\n for selected file deactivate Frontend$

$skinparam style strictuml hide footbox title Opening a file as a new frame (appending) actor User box "Client-side" #EDEDED participant Frontend end box box "Server-side" #lightblue participant Backend end box group File load User -> Frontend : Loads file\n(as new frame) activate Frontend Frontend -> Backend : OPEN_FILE activate Backend Backend -> Backend : Loads file Frontend <-- Backend : OPEN_FILE_ACK Frontend <-- Backend : REGION_HISTOGRAM_DATA deactivate Backend end group Image view Frontend -> Backend : SET_IMAGE_CHANNELS activate Backend Frontend <-- Backend : RASTER_TILE_DATA deactivate Backend User <-- Frontend: Displays image deactivate Frontend end$

$skinparam style strictuml hide footbox title Opening a file\n(replacing open files) actor User box "Client-side" #EDEDED participant Frontend end box box "Server-side" #lightblue participant Backend end box group File load User -> Frontend : Loads file\n(replace existing\nframes) activate Frontend Frontend -> Backend : CLOSE_FILE Frontend -> Frontend : Removes regions Backend -> Backend : Closes files and\n removes regions Frontend -> Backend : OPEN_FILE activate Backend Backend -> Backend : Loads file Frontend <-- Backend : OPEN_FILE_ACK Frontend <-- Backend : REGION_HISTOGRAM_DATA deactivate Backend end group Image view Frontend -> Backend : SET_IMAGE_CHANNELS activate Backend Frontend <-- Backend : RASTER_TILE_DATA deactivate Backend User <-- Frontend: Displays image deactivate Frontend end$