Re-organize Class Structure

[ebald19]

There is incentive in incorporating the functionality of AimIO into ScancoIO to improve header reading/writing functionality for ISQs, as well as add an AIM writer to ScancoIO.

I would like to propose a new structural format to help with further development by modularizing related functionality in the code. Below is a UML diagram of the changes I would like to implement. These changes would not change the user-facing functionality of the ScancoIO class. The metadata from the headers will still be able to be accessed and populated by dictionary from the ScancoIO class.

I would like to separate the reading of headers from the main image data into a designated header reader/writer module. The UML below outlines these as two separate modules, but this could easily be condensed into one IO module superclass that ScancoIO 'wraps' to use for header reading and writing.
[EDIT: After working with this I have moved it toward the condensed Header IO module format I mentioned possible above, to avoid overlapping functionality between readers/writers. See updated UML diagram below]

In this way, the functionality to incorporate from AimIO can be ported easily in it's associated module and be ported more seamlessly. This will also declutter the ScancoIO class. This format adds maintainability by separating the functionality of each file type and allows for easy addition of different header types [e.g: .RAD, .gobj]

The below image informally follows the UML class diagram format for class relationships and member descriptions [eg: association vs inheritance vs aggregation... and public vs private members]:

[ebald19]

@wallematthias any thoughts on this?

[wallematthias]

Hi, I second this! Just wondering, in your diagram where is the Image Data interface? It looks like this is handling headers only, or am I missing something?

+ReadImageData(infile)
+WriteImageData(outfile)

[ebald19]

Hi, I second this! Just wondering, in your diagram where is the Image Data interface? It looks like this is handling headers only, or am I missing something?

+ReadImageData(infile) +WriteImageData(outfile)

The data-specific IO is left out here as it is already implemented within the ScancoIO class. Since it is derived from the ImageIO ITK class I was going to leave data-related functionality within that class and have it subclass out for help with the specific header data. (Since it is so complicated and file-type specific).

Specifically, the Read(buffer) and Write(buffer) functions in ScancoIO are overrides from ImageIOBase and the reading/writing of image data has a lot of work done by that base class. (ie it looks like those buffers are manipulated elsewhere in an ITKImageFileReader). I haven't spent much time digging into what the base class does with it exactly but I am not sure if that work can be subclassed out within this module. Something like that can definitely be incorporated in the future if the need/ability is recognized but the scope of this specific issue I was focusing on headers only.

Hopefully that makes sense