IMGUI: Implement feature-parity with Qt GUI

[GPMueller]

General

• save the GUI layout and settings and read it back in on startup
• dockable and floatable windows

Visualisation

• take a screenshot and take screenshots of the entire chain
• camera (see, set, save and load), esp. FOV
• bounding box
• coordinate cross
• spin sphere
• arrows
• surface (including z-shift for 2D surfaces)
• isosurface
• colormap: selection, phase for HSV-map, set cardinal (i.e. symmetry-) axis, invert theta/phi
• light direction
• filter visualised spins by script (at least by "every N'th")

System controls

• start/stop button
• image selection and chain length setter
• method and solver selection, with solver only available where applicable
• (maybe) camera reset buttons: x/y/z/default

Methods with full set of parameters

• LLG
• MC
• GNEB
• MMF
• EMA
• for each, apply to current image
• for each, apply to all images

Hamiltonian Parameters

• Heisenberg
• (on corresp. branch) Micromagnetic
• Gaussian
• for each, apply to current image
• for each, apply to all images

Spin configurations window

• Settings: add noise, position, rect./cylindrical/spherical border, inverted, atom type, pinning
  Note: if we can implement this as scriptable, that might be even better, as it would allow for ellipses etc.
• Random, +z, -z
• Homogeneous: direction
• Domain wall (finally implement a proper one): width
• Spiral: angle, axis, q, q2, w.r.t. reciprocal lattice/real lattice/real space
• Skyrmion: radius, DW width, order, phase, up/down, R/L, achiral
• Hopfion: radius, order
• Homogeneous transition: add noise, range
• Increase chain length with interpolated images

Keybindings

UI controls

• F1-F4: Show help, settings, plots, log, ?
• F5-F7: toggle dragging, defects, pinning modes
• F10 or ctrl+f: toggle large visualisation (hide menu bar, requires functionality to restore it without keybinding)
• F11 or ctrl+shift+f: toggle fullscreen
• F12 or home: screenshot
• i: toggle info-widgets
• (maybe)ctrl+shift+v: toggle visualisation

Camera controls

• Left/right/scroll mouse
• wasdqe
• tfgh
• xyz: set camera direction (ctrl or shift to invert)

Control simulations

• space: start/stop
• (maybe) ctrl+m: cycle method
• (maybe) ctrl+s: cycle solver

Manipulate the current image

• ctrl+r: randomize
• ctrl+n: add noise
• enter: insert last used configuration

Manipulate the chain

• left/right arrows: switch between images
• ctrl+x: cut image
• ctrl+c: copy image
• ctrl+v: paste image at current image
• ctrl+left/right: insert image left/right of current image
• delete: delete current image

Visualisation:

• +/-: increment/decrement N, visualising every N'th spin
• 1: regular visualisation mode
• 2: isosurface visualisation mode
• 3-5: x/y/z slab visualisation
• /: cycle visualisation mode
• ,/., move slab (shift to go faster)

Log

Viewer

• display gathered log text
• select minimum level
• filter senders: "all"-button, checkboxes
• filter by image index: "all"-checkbox, "from"-index "to"-index

Settings

• accept level
• print level
• output folder

Menu

File

• save/load input config file
• save/load spin configuration
• save/load chains
• save/load eigenmodes
• save energy per spin, energies of chain, interpolated energies of chain

Edit

• cut/copy/paste, insert left/right, delete

Controls

• start/stop
• randomize
• toggle dragging/defect/pinning modes

View

• toggle widgets: info, settings, plots, configurations, geometry, visualisation, debug
• toggle camera projection
• switch visualisation modes: regular, isosurface, slab x/y/z
• toggle: visualisation, larger visualisation (hide menu bar), fullscreen visualisation

Help

• Keybindings
• About

[GPMueller]

When this GUI is more stable, it could be placed as an alternative to the mobile GUI, on https://spirit-code.github.io and the current web-UI would simply be the mobile variant.
Then, issues #12, #13, #14 and #15 could be closed.

Note, to be properly usable as a web-UI, it should support up-/downloading of images/chains. That would require some calls from C++ into the DOM to trigger what the current web-UI does to up-/download files.