--[[

# Explorer Panel

A GUI panel that displays the game hierarchy.


## Selection Bindables

- `Function GetSelection ( )`

	Returns an array of objects representing the objects currently
	selected in the panel.

- `Function SetSelection ( Objects selection )`

	Sets the objects that are selected in the panel. `selection` is an array
	of objects.

- `Event SelectionChanged ( )`

	Fired after the selection changes.


## Option Bindables

- `Function GetOption ( string optionName )`

	If `optionName` is given, returns the value of that option. Otherwise,
	returns a table of options and their current values.

- `Function SetOption ( string optionName, bool value )`

	Sets `optionName` to `value`.

	Options:

	- Modifiable

		Whether objects can be modified by the panel.

		Note that modifying objects depends on being able to select them. If
		Selectable is false, then Actions will not be available. Reparenting
		is still possible, but only for the dragged object.

	- Selectable

		Whether objects can be selected.

		If Modifiable is false, then left-clicking will perform a drag
		selection.

## Updates

- 2013-09-18
	- Fixed explorer icons to match studio explorer.

- 2013-09-14
	- Added GetOption and SetOption bindables.
		- Option: Modifiable; sets whether objects can be modified by the panel.
		- Option: Selectable; sets whether objects can be selected.
	- Slight modification to left-click selection behavior.
	- Improved layout and scaling.

- 2013-09-13
	- Added drag to reparent objects.
		- Left-click to select/deselect object.
		- Left-click and drag unselected object to reparent single object.
		- Left-click and drag selected object to move reparent entire selection.
		- Right-click while dragging to cancel.

- 2013-09-11
	- Added explorer panel header with actions.
		- Added Cut action.
		- Added Copy action.
		- Added Paste action.
		- Added Delete action.
	- Added drag selection.
		- Left-click: Add to selection on drag.
		- Right-click: Add to or remove from selection on drag.
	- Ensured SelectionChanged fires only when the selection actually changes.
	- Added documentation and change log.
	- Fixed thread issue.

- 2013-09-09
	- Added basic multi-selection.
		- Left-click to set selection.
		- Right-click to add to or remove from selection.
	- Removed "Selection" ObjectValue.
		- Added GetSelection BindableFunction.
		- Added SetSelection BindableFunction.
		- Added SelectionChanged BindableEvent.
	- Changed font to SourceSans.

- 2013-08-31
	- Improved GUI sizing based off of `GUI_SIZE` constant.
	- Automatic font size detection.

- 2013-08-27
	- Initial explorer panel.


## Todo

- Sorting
	- by ExplorerOrder
	- by children
	- by name
- Drag objects to reparent

]]

local ENTRY_SIZE = GUI_SIZE + ENTRY_PADDING*2
local ENTRY_BOUND = ENTRY_SIZE + ENTRY_MARGIN
local HEADER_SIZE = ENTRY_SIZE*2

local FONT = 'SourceSans'
local FONT_SIZE do
	local size = {8,9,10,11,12,14,18,24,36,48}
	local s
	local n = math.huge
	for i = 1,#size do
		if size[i] <= GUI_SIZE then
			FONT_SIZE = i - 1
		end
	end
end

local GuiColor = {
	Background      = Color3.new(233/255, 233/255, 233/255);
	Border          = Color3.new(149/255, 149/255, 149/255);
	Selected        = Color3.new( 96/255, 140/255, 211/255);
	BorderSelected  = Color3.new( 86/255, 125/255, 188/255);
	Text            = Color3.new(  0/255,   0/255,   0/255);
	TextDisabled    = Color3.new(128/255, 128/255, 128/255);
	TextSelected    = Color3.new(255/255, 255/255, 255/255);
	Button          = Color3.new(221/255, 221/255, 221/255);
	ButtonBorder    = Color3.new(149/255, 149/255, 149/255);
	ButtonSelected  = Color3.new(255/255,   0/255,   0/255);
	Field           = Color3.new(255/255, 255/255, 255/255);
	FieldBorder     = Color3.new(191/255, 191/255, 191/255);
	TitleBackground = Color3.new(178/255, 178/255, 178/255);
}