BansheeEngine/TreeView.txt

TreeView
  - Name editing
     - Detect mouse input in TreeView and if I double click over a GUILabel start rename
     - Or if I select it and hit F2 also start rename
     - Has callbacks with which it notifies TreeView of actual changes
  - Selecting
     - Clicking on a row of TreeView sets a flag that item is selected, and a GUIElement is created. 
     - Element is positioned in updateLayoutInternal and it shows a different colored background
  - Deleting
      - Simply track currently selected element and Delete event

TODO:
 - Add better TreeViewEditBox texture
 - In disableEdit make sure I actually apply name change
   - Use Undo/Redo system (TODO: Not implemented yet)
 - Clicking on an already selectecd element starts rename 
    - Will likely need some kind of check to ignore double-clicks?
 - Pressing F2 starts rename
 - Context menu with rename
 - Detect when I click outside of input box and disable edit (TODO: Need a way to easily detect this)
 - Delete
    - Needs Undo/Redo support


Implementation steps:
 - Selection
   - Clicking on element selects it, delete removes it, F2 renames is. Slow double click renames it.
   - Rename implementation to follow, just set up an empty method for now
   - Callback on selection
 - Rename implementation
   - When rename is initiated hide the objects label and replace it with an input-box with the same text as a label
   - Rename ends when user hits enter or click anywhere else but the rename box
 - Drag and drop
   - If a mouse drag is detected DragAndDropManager is activated
   - Element is not removed from its original position until drag is complete
   - Dragging over an element will make a highlight box appear around it
   - Dragging between elements will make a thick line appear between them
   - Releasing the drag changes the element parents
 - Auto scroll
    - Sliding over top or bottom of the tree view while dragging an element will search GUIElement parents to find a ScrollArea. If it finds one it will attempt to scroll up or down.

Detecting external clicks:
 - LostFocus event?
   - Triggered when I click on another control within my own windows, or when controls parent window loses the focus himself
   - Each GUIElement can implement acceptsMouseFocus event. If it does, then mouse click will cause a ReceivedFocus event.
     - Mouse click on any other element, or window losing focus will trigger LostFocus events
 - I can replace clumsy Selective Input with this approach
 - DropDownBox can also use the same approach although I will likely need to convert DropDownBox to a GUIElement - DO THIS AFTER TreeView implementation is working

 Other:
 - When dragging in tree view automatically expand mouse over elements
 - Ability to select and drag multiple elements
 - "Ping" effect
 - All operations should be undo-redoable
 - Context menu with copy/paste
 - Copy/Paste/Duplicate
   - This is more of a problem with actual copying of SceneObjects (It's not implemented). I should be able to serialize, and then de-serialize with a new parent as a form of copy.


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 SHORTCUT BRAINSTORM:

 Remove pre-defined GUICommandEvents and InputCommandType. They cannot be easily extended and I will need their functionality when I add support for shortcuts! 
INSTEAD:
 - Add GUIShortcutManager to BansheeEngine
 - Platform forwards all input commands to ShortcutManager instead of gInput (via a callback)
 - ShortcutManager checks if it has any registered shortcuts and if any are triggered it notifies GUIManager
 - Shortcuts change depending on active GUIElement
   - Each GUIELement can provide a list of shortcuts it listens to
   - OnFocusGained/OnFocusLost adds/removes items from the list
   - If multiple elements are in focus, all of their shortcuts are registered but the callbacks just don't get triggered on those elements that don't have the triggered shortcut
     - If two elements have the same shortcut, only one of them will trigger (undefined which)
 - (Obviously this functionality will need focusGained/focusLost functionality first)


TODO: Can I integrate this with the input manager somehow?
 - NO - Shortcut system should be GUI only, while in-game input and in-game shortcuts will be handled manually.

When I implement focus gained/lost system, send keyboard input to all elements with focus. Remove "acceptsKeyboardFocus". Elements can choose to ignore keyboard focus by ignoring keyboard events.
Remove Cut/Copy/Paste/Undo/Redo/Rename/SelectAll and similar shortcuts from InputCommands. Instead send generic shortcut commands whenever user presses some key (together with shift/ctrl/alt state).
  - Some shift/ctrl combinations might not be general shortcuts, like shift + arrows for selection, in which case we send them as specific shortcuts instead of generic ones
  - I should also add a GUIShortcutManager, as a centralized place for dealing with shortcuts (so that I my edit them at a later date)
   - TODO - Figure out how would this work