The default mouse manager used in the GraphStream graph view is hard to base from and its missing few features we would love to use.

TODO

• Selecting single element (ui.selected attribute)
• Selecting area of elements
• Extending/ selection when holding shift (both single/area; RTS-like)
• Moving single element
• Moving selection of elements (would be impossible without the rewrite)
• Clicking single element (ui.clicked attribute)
• Hover detection (ui.mouseOver attribute)
• Prevent unselecting on right click
• Mark preselected elements (ui.preselected attribute)

Other

• Snaping to grids
• Rotate selected elements positions around the point (while holding R?)
• Spread selected elements positions on line (while holding L?)
• Scale selected elements positions away from the point (while holding S?)
• Gravity move selected elements positions towards the point (while holding G?)
• There might be way to implement a bit smoother scaling and moving around the graph (as the mouse manager runs on the thread used to display graph)

Nazwy łuków mogą być przeciągane tylko wzdłuż nich, mimo ze pojawiają się poza nimi.
Gdy nazwę łuku przeciągniemy na Place bądź Transition nie da się ponownie zmienić jego położenia.

Przykład:

Jak widać powyżej nazwa łuku wchodzi na Place uniemożliwiając zmianę jej miejsca. Przemieszczenie Place'a nic nie daje gdyż nazwa jest zbyt blisko niego.

Możliwe rozwiązania:
-uniemożliwić przemieszczanie nazwy łuku(-),
-uniemożliwić przemieszczanie nazwy łuku tak blisko Place bądź Transition(+),
-umożliwić "chwytanie" nazwy łuku gdy jest tak blisko(-),

UPDATE 1:
Po ostatnim hotfixie Adriana nazwy łuków można schować pod Place. Co do Transition to nazwy są na nich. W obu przypadkach nie ma opcji "wyciągnięcia" ich stamtąd.(Oczywiście jest opcja kliknięcie leyaut ale to zmienia ułożenie całości)

Przykład:

In editor mode, user can add, delete and modify net elements.
These actions can be performed using assigned buttons in the toolbar.

RUN / EDIT mode

CenterPanel class has a field called ObjectProperty<EditorMode> editorMode. It is observable and can be bound to.

User can only interact with tools in the toolbar if editorMode is EditorMode.EDIT!

Add and delete

Tools

• Place (create new Place)
• Transition (create new Transition)
• Arc (connect Place with Transition (or Transition with Place) with an Arc)
• Delete (??) (delete existing Places, Arcs and Transitions)
• Cursor (no tool)

Create tools

User should have an indication that the tool is active. Preferably a Ghost should appear on the screen showing where the new Element would be inserted.

Adding Arc

One (or both) of two options:

1. User clicks input Node, then output Node.
2. User clicks input Node, then output Node. After successful Arc creation, output Node becomes new input Node.

User should have an visual indicator (graph bg / cursor shape / other) that he is in add Arc mode. After clicking the first Node, Arc (Arrow) ghost appears and is following mouse. Nodes that can be connected highlight on hover. If user clicks a Node that cannot be connected, nothing happens OR he is prompted about it.

Option 2.

This is useful when user wants to connect multiple Nodes one after another. Maybe have a toggle for this mode?

Delete tools

User must have a clear visual indication that the action he is about to perform is potentially destructive.
Possible indicators:

• Graph bg
• Graph area outline
• Cursor shape

When user deletes an Element of the net, all inputs and outputs should be updated to reflect these changes
When user deletes Place or Transition with inputs and/or outputs, those Arcs should be also deleted.

Modify

When user selects (clicks or box select) one or more Elements, then in the Properties Tab a list of the common properties should appear.

User should be able to see a list of selected Elements and deselect them using mouse.

In the Properties Tab, user should be able to modify selected Elements' properties. If more than one is selected, all are modified simultaneously.

I think we should release current state as v3.0.0-alpha
What do you think?

Any editor need this essential thing.

TODO

• System to store changes (hybrid generative and save state¹)
• Menu "Edit" with "Undo" and "Redo" (possibly with minimalistic description what about)
• Keyboard shortcuts
• Basic usage (moving nodes for now)
• Allow grouping undoable actions (will come handy for cumulative actions)

Known issues

(checked = fixed)

• Keyboard shortcuts doesn't work all the time
• Limit undo history length (or group old actions into larger chunks using save state) to prevent higher memory usage in intensive session
• Prevent undo while network is being simulated (running).

Extra features

• Sound alert when no more actions to undo/redo.

Classes

• UndoHistory
• UndoableAction (provides way to undo it)
• HardlyUndoableAction (can't provide way to undo it, state needs to be read from saved)
• MoveNodeAction
• UndoableGroup

Useful resources

Adding Arcs do not work in continuous mode.
After the first Arc is added, next cannot be created until the Arc button is deselected and selected again.

Nets need to be easy to be made easy to read without user moving each node pixel perfect...

TODO

• "Net layout" menu (or submenu in "View" or "Organize"/"Edit" menu)
• Automatic layout strategies
• Grids
• Direction
• Distances
• Minimalizing edges, bends
• Grouping elements by type (places and transitions)
• Allow partial layout applying (only to selection)
• Push layout employment to history stack to allow Ctrl+Z (grouped, not as individual node moves)
• Grouping elements by tags (or common styles? common names?)

Layout strategies ideas

• TBA

Useful resources

• https://www.baeldung.com/cs/graph-auto-layout-algorithm
• https://www.yworks.com/pages/interactive-showcase-of-graph-layouts
• https://www.mindfusion.eu/graph-layout.html
• https://live.yworks.com/demos/layout/layoutstyles/