Basalt2/docs/references/elements/Tree.md

local VisualElement = require("elements/VisualElement") local tHex = require("libraries/colorHex")

---@class Tree : VisualElement local Tree = setmetatable({}, VisualElement) Tree.__index = Tree

Tree.defineProperty(Tree, "nodes", {default = {}, type = "table", canTriggerRender = true}) Tree.defineProperty(Tree, "selectedNode", {default = nil, type = "table", canTriggerRender = true}) Tree.defineProperty(Tree, "expandedNodes", {default = {}, type = "table", canTriggerRender = true}) Tree.defineProperty(Tree, "scrollOffset", {default = 0, type = "number", canTriggerRender = true}) Tree.defineProperty(Tree, "nodeColor", {default = colors.white, type = "number"}) Tree.defineProperty(Tree, "selectedColor", {default = colors.lightBlue, type = "number"})

Tree.listenTo(Tree, "mouse_click") Tree.listenTo(Tree, "mouse_scroll")

function Tree.new() local self = setmetatable({}, Tree):__init() self.set("width", 30) self.set("height", 10) self.set("z", 5) return self end

function Tree:init(props, basalt) VisualElement.init(self, props, basalt) self.set("type", "Tree") return self end

function Tree:setNodes(nodes) self.set("nodes", nodes) if #nodes > 0 then self.get("expandedNodes")[nodes[1]] = true end return self end

function Tree:expandNode(node) self.get("expandedNodes")[node] = true self:updateRender() return self end

function Tree:collapseNode(node) self.get("expandedNodes")[node] = nil self:updateRender() return self end

function Tree:toggleNode(node) if self.get("expandedNodes")[node] then self:collapseNode(node) else self:expandNode(node) end return self end

local function flattenTree(nodes, expandedNodes, level, result) result = result or {} level = level or 0

for _, node in ipairs(nodes) do
    table.insert(result, {node = node, level = level})
    if expandedNodes[node] and node.children then
        flattenTree(node.children, expandedNodes, level + 1, result)
    end
end
return result

end

function Tree:mouse_click(button, x, y) if not VisualElement.mouse_click(self, button, x, y) then return false end

local relX, relY = self:getRelativePosition(x, y)
local flatNodes = flattenTree(self.get("nodes"), self.get("expandedNodes"))
local visibleIndex = relY + self.get("scrollOffset")

if flatNodes[visibleIndex] then
    local nodeInfo = flatNodes[visibleIndex]
    local node = nodeInfo.node

    if relX <= nodeInfo.level * 2 + 2 then
        self:toggleNode(node)
    end

    self.set("selectedNode", node)
    self:fireEvent("node_select", node)
end
return true

end

function Tree:onSelect(callback) self:registerCallback("node_select", callback) return self end

function Tree:mouse_scroll(direction) local flatNodes = flattenTree(self.get("nodes"), self.get("expandedNodes")) local maxScroll = math.max(0, #flatNodes - self.get("height")) local newScroll = math.min(maxScroll, math.max(0, self.get("scrollOffset") + direction))

self.set("scrollOffset", newScroll)
return true

end

function Tree:render() VisualElement.render(self)

local flatNodes = flattenTree(self.get("nodes"), self.get("expandedNodes"))
local height = self.get("height")
local selectedNode = self.get("selectedNode")
local expandedNodes = self.get("expandedNodes")
local scrollOffset = self.get("scrollOffset")

for y = 1, height do
    local nodeInfo = flatNodes[y + scrollOffset]
    if nodeInfo then
        local node = nodeInfo.node
        local level = nodeInfo.level
        local indent = string.rep("  ", level)
        
        -- Expand/Collapse Symbol
        local symbol = " "
        if node.children and #node.children > 0 then
            symbol = expandedNodes[node] and "\31" or "\16"
        end

        local bg = node == selectedNode and self.get("selectedColor") or self.get("background")
        local text = indent .. symbol .." " .. (node.text or "Node")
        
        self:blit(1, y, text .. string.rep(" ", self.get("width") - #text),
            string.rep(tHex[self.get("nodeColor")], self.get("width")),
            string.rep(tHex[bg], self.get("width")))
    else
        -- Leere Zeile
        self:blit(1, y, string.rep(" ", self.get("width")),
            string.rep(tHex[self.get("foreground")], self.get("width")),
            string.rep(tHex[self.get("background")], self.get("width")))
    end
end

end

return Tree