Implement progress bar

gfx/progress.lua

@@ -0,0 +1,77 @@
+local Element = require("gfx.element")
+local Orientation = require("gfx.prop.orientation")
+
+local BlankElement = Element:new()
+
+function BlankElement:draw()
+  local dirty = Element.draw(self)
+  if dirty then
+    self:_getWindow().clear()
+  end
+end
+
+local function round(value, biasDown)
+  local decimal = value % 1
+  return (((not biasDown) and decimal < 0.5) or ((not not biasDown) and decimal <= 0.5)) and math.floor(value) or math.ceil(value)
+end
+
+local Progress = Orientation.with(Element:new{
+  progress = 0.0,
+  active = nil,
+  inactive = nil
+})
+
+function Progress:new(o)
+  local obj = o or {}
+  obj.active = BlankElement:new()
+  obj.inactive = BlankElement:new()
+  return Element.new(self, obj)
+end
+
+function Progress:_updateProgress()
+  local width, height = self:getWidth(), self:getHeight()
+  if self:isVertical() then
+    self.active:resize(width, round(self:getProgress() * height))
+    self.inactive:resize(width, round((1 - self:getProgress()) * height, true))
+    self.inactive:setY(self.active:getY() + self.active:getHeight())
+  else
+    self.active:resize(round(self:getProgress() * width), height)
+    self.active:resize(round((1 - self:getProgress()) * width, true), height)
+    self.inactive:setX(self.active:setX() + self.active:getWidth())
+  end
+end
+
+function Progress:setProgress(progress)
+  self:setDirty()
+  self.progress = math.min(1, math.max(0, progress))
+  self:_updateProgress()
+end
+
+function Progress:getProgress()
+  return self.progress
+end
+
+function Progress:draw()
+  local dirty = Element.draw(self)
+  if dirty then
+    self.inactive:draw()
+    self.active:draw()
+  end
+  return dirty
+end
+
+function Progress:_isDirty()
+  return Element._isDirty(self) or self.active:_isDirty() or self.inactive:_isDirty()
+end
+
+function Progress:_reload()
+  Element._reload(self)
+
+  -- Reload child windows
+  local win = self:_getWindow()
+  self.active:setParent(win)
+  self.inactive:setParent(win)
+  self:_updateProgress()
+end
+
+return Progress