Tree

This is the tree class. It provides a hierarchical view of nodes that can be expanded and collapsed, with support for selection and scrolling.

Extends: VisualElement

Examples (Executable)

local basalt = require("basalt")
local main = basalt.getMainFrame()

local fileTree = main:addTree()
:setPosition(2, 2)
:setSize(15, 15)
:setBackground(colors.black)
:setForeground(colors.white)
:setSelectedBackgroundColor(colors.blue)
:setSelectedForegroundColor(colors.white)
:setScrollBarColor(colors.lightGray)
:setScrollBarBackgroundColor(colors.gray)

-- Build a file system-like tree structure
local treeData = {
{
text = "Root",
children = {
{
text = "Documents",
children = {
{text = "report.txt"},
{text = "notes.txt"},
{text = "todo.txt"}
}
},
{
text = "Pictures",
children = {
{text = "vacation.png"},
{text = "family.jpg"},
{
text = "Archive",
children = {
{text = "old_photo1.jpg"},
{text = "old_photo2.jpg"},
{text = "old_photo3.jpg"}
}
}
}
},
{
text = "Music",
children = {
{text = "song1.mp3"},
{text = "song2.mp3"},
{text = "song3.mp3"},
{text = "song4.mp3"}
}
},
{
text = "Videos",
children = {
{text = "movie1.mp4"},
{text = "movie2.mp4"}
}
},
{
text = "Projects",
children = {
{
text = "ProjectA",
children = {
{text = "src"},
{text = "tests"},
{text = "README.md"}
}
},
{
text = "ProjectB",
children = {
{text = "main.lua"},
{text = "config.lua"}
}
}
}
}
}
}
}

fileTree:setNodes(treeData)
local textLabel = main:addLabel()
:setPosition(2, 18)
:setForeground(colors.yellow)
:setText("Selected: None")

-- Handle node selection
fileTree:onSelect(function(self, node)
textLabel
:setText("Selected: " .. node.text)
:setPosition(2, 18)
:setForeground(colors.yellow)
end)

-- Info label
main:addLabel()
:setText("Click nodes to expand/collapse | Scroll to navigate")
:setPosition(2, 1)
:setForeground(colors.lightGray)

basalt.run()

Properties

Property	Type	Default	Description
nodes	table	{}	The tree structure containing node objects with {text, children} properties
expandedNodes	table	{}	Table of nodes that are currently expanded
offset	number	0	Current vertical scroll position
horizontalOffset	number	0	Current horizontal scroll position
selectedForegroundColor	color	white	foreground color of selected node
selectedBackgroundColor	color	lightBlue	background color of selected node
showScrollBar	boolean	true	Whether to show the scrollbar when nodes exceed height
scrollBarSymbol	string	"	" Symbol used for the scrollbar handle
scrollBarBackground	string	"\127"	Symbol used for the scrollbar background
scrollBarColor	color	lightGray	Color of the scrollbar handle
scrollBarBackgroundColor	color	gray	Background color of the scrollbar

Functions

Method	Returns	Description
Tree:expandNode	Tree	Expands a node to show its children
Tree:collapseNode	Tree	Collapses a node to hide its children
Tree:toggleNode	Tree	Toggles between expanded and collapsed state
Tree:onSelect	Tree	Registers a callback for when a node is selected
Tree:getNodeSize	number, number	Gets the size of the tree

Tree:expandNode(node)

Expands a node

Parameters

• node table The node to expand

Returns

• Tree self The Tree instance

Tree:collapseNode(node)

Collapses a node

Parameters

• node table The node to collapse

Returns

• Tree self The Tree instance

Tree:toggleNode(node)

Toggles a node's expanded state

Parameters

• node table The node to toggle

Returns

• Tree self The Tree instance

Tree:onSelect(callback)

Registers a callback for when a node is selected

Parameters

• callback function The callback function

Returns

• Tree self The Tree instance

Tree:getNodeSize()

Gets the size of the tree

Returns

• number width The width of the tree
• number height The height of the tree