basic implementation of grid (#19)

* basic implementation of grid

* add dirty example of grid

druid/base/grid.lua

@@ -0,0 +1,86 @@
+local helper = require("druid.helper")
+
+local M = {}
+
+--- Sort and placing nodes
+-- Plans: placing by max width, placing with max in_row
+-- Allow different node sizes, allow animation with node insert
+
+
+function M.init(instance, parent, element, in_row)
+	instance.parent = helper.get_node(parent)
+	instance.nodes = {}
+
+	instance.offset = vmath.vector3(0)
+	instance.anchor = vmath.vector3(0)
+	instance.in_row = in_row or 1
+	instance.node_size = gui.get_size(helper.get_node(element))
+	instance.border = vmath.vector4(0)
+end
+
+
+local function check_border(instance, pos)
+	local size = instance.node_size
+	local W = pos.x - size.x/2
+	local E = pos.x + size.x/2
+	local N = pos.y + size.y/2
+	local S = pos.y - size.y/2
+
+	instance.border.x = math.min(instance.border.x, W)
+	instance.border.y = math.max(instance.border.y, N)
+	instance.border.z = math.max(instance.border.z, E)
+	instance.border.w = math.min(instance.border.w, S)
+end
+
+
+local temp_pos = vmath.vector3(0)
+local function get_pos(instance, index)
+	local row = math.ceil(index / instance.in_row) - 1
+	local col = (index - row * instance.in_row) - 1
+
+	temp_pos.x = col * (instance.node_size.x + instance.offset.x)
+	temp_pos.x = temp_pos.x + (0.5 - instance.anchor.x) * instance.node_size.x
+	temp_pos.y = -row * (instance.node_size.y + instance.offset.y)
+	temp_pos.y = temp_pos.y - (0.5 - instance.anchor.y) * instance.node_size.y
+
+	return temp_pos
+end
+
+
+local function update_pos(instance)
+	for i = 1, #instance.nodes do
+		local node = instance.nodes[i]
+		gui.set_position(node, get_pos(instance, i))
+	end
+end
+
+
+function M.set_offset(instance, offset)
+	instance.offset = offset
+	update_pos(instance)
+end
+
+
+function M.set_anchor(instance, anchor)
+	instance.anchor = anchor
+	update_pos(instance)
+end
+
+
+function M.add(instance, item, index)
+	index = index or (#instance.nodes + 1)
+	table.insert(instance.nodes, index, item)
+	gui.set_parent(item, instance.parent)
+
+	local pos = get_pos(instance, index)
+	check_border(instance, pos)
+	gui.set_position(item, pos)
+end
+
+
+function M.get_size(instance)
+	return instance.border
+end
+
+
+return M

druid/druid.lua

@@ -13,6 +13,7 @@ M.comps = {
 	text = require("druid.base.text"),
 	timer = require("druid.base.timer"),
 	progress = require("druid.base.progress"),
+	grid = require("druid.base.grid"),
 
 	progress_rich = require("druid.rich.progress_rich"),
 }