Adjust the boundary to improve the plotting

[Gene0315]

PR #330 implemented new boundary treatment. However, apart from revising the NRBC method, it is also a nice way to make some other adjustments to improve the plotting.
For instance, add a half dx grid point outside the boundary and not show it on the figure.

[yungyuc]

@j8xixo12 This may be an opportunity to give the Euler 1D app a better architecture and absorb it into proper places in the GUI. What do you think?

[j8xixo12]

@yungyuc Since modmesh has mesh viewer which is able to read Gmsh and Plot3d mesh file and a Euler 1D solver. I think it's time to re-design the GUI!

But currently I have no idea how to design the new GUI. If the GUI should be designed based on a numerical analysis workflow, where the user first loads the mesh, then sets up the solver configuration likes boundary condition and convergence criteria...etc and then runs the simulation, these steps are guided by GUI. Or should it be divided by functionality, with each button corresponding to a specific function. I think this design is similar to the current design of modmesh, but it seems like lacking in integration. the previous design more like... Ansys workbench!

[yungyuc]

@j8xixo12 I outlined some ideas in #336 . At this stage, the key is to organize what we had in the proof-of-concept "Apps", and make the "Apps" a clear plugin system.

I am not sure how Ansys workbench looks like, and certainly did not reference it. In my vision, the GUI will be an integrated problem-solving environment. We will need to give it a cool name once putting it back to the mother solvcon code base.

[yungyuc]

@Gene0315 plans to update #338 (comment) by 8th June. We will review then.

[yungyuc]

@Gene0315 is there any progress made for this enhancement request?