#25 cherry-pick slider component

druid/base/slider.lua

@@ -0,0 +1,82 @@
+--- Druid slider component
+-- @module base.slider
+
+local helper = require("druid.helper")
+local const = require("druid.const")
+
+local M = {}
+M.interest = {
+	const.ON_SWIPE
+}
+
+
+local function on_change_value(self)
+	if self.callback then
+		self.callback(self.parent.parent, self.value)
+	end
+end
+
+
+function M.init(self, node, end_pos, callback)
+	self.node = helper.get_node(node)
+
+	self.start_pos = gui.get_position(self.node)
+	self.pos = gui.get_position(self.node)
+	self.target_pos = self.pos
+	self.end_pos = end_pos
+
+	self.dist = self.end_pos - self.start_pos
+	self.is_drag = false
+	self.value = 0
+	self.callback = callback
+
+	assert(self.dist.x == 0 or self.dist.y == 0, "Slider for now can be only vertical or horizontal")
+end
+
+
+function M.on_input(self, action_id, action)
+	if action_id ~= const.ACTION_TOUCH then
+		return false
+	end
+
+	if gui.pick_node(self.node, action.x, action.y) then
+		if action.pressed then
+			self.pos = gui.get_position(self.node)
+			self.is_drag = true
+		end
+	end
+
+	if self.is_drag and not action.pressed then
+		-- move
+		self.pos.x = self.pos.x + action.dx
+		self.pos.y = self.pos.y + action.dy
+
+		local prev_x = self.target_pos.x
+		local prev_y = self.target_pos.y
+
+		self.target_pos.x = helper.clamp(self.pos.x, self.start_pos.x, self.end_pos.x)
+		self.target_pos.y = helper.clamp(self.pos.y, self.start_pos.y, self.end_pos.y)
+
+		gui.set_position(self.node, self.target_pos)
+
+		if prev_x ~= self.target_pos.x or prev_y ~= self.target_pos.y then
+
+			if self.dist.x > 0 then
+				self.value = (self.target_pos.x - self.start_pos.x) / self.dist.x
+			end
+
+			if self.dist.y > 0 then
+				self.value = (self.target_pos.y - self.start_pos.y) / self.dist.y
+			end
+
+			on_change_value(self)
+		end
+	end
+
+	if action.released then
+		self.is_drag = false
+	end
+end
+
+
+return M

druid/druid.lua

@@ -15,6 +15,7 @@ M.comps = {
 	progress = require("druid.base.progress"),
 	grid = require("druid.base.grid"),
 	scroll = require("druid.base.scroll"),
+	slider = require("druid.base.slider"),
 
 	progress_rich = require("druid.rich.progress_rich"),
 }