Implement abstract element properties

gfx/prop/children.lua

@@ -0,0 +1,85 @@
+local Prop = require("gfx.prop")
+local Children = Prop:new{ defaultState = {} }
+
+function Children:with(elementType)
+  local propSelf = self
+  function elementType:_iterateChildren(opts)
+    local func, tbl, start = ipairs(propSelf:getState(self))
+    return function(t, i)
+        if i == opts.to then
+            return nil, nil
+        end
+        return func(t, i)
+    end, tbl, (opts and opts.from) or start
+  end
+
+  function elementType:childCount()
+    return #propSelf:getState(self)
+  end
+
+  function elementType:_childAt(index)
+    return propSelf:getState()[elementType:_validChildIndex(index)]
+  end
+
+  function elementType:_validChildIndex(from)
+    return math.max(1, math.min((from or self:childCount()) + 1, self:childCount() + 1))
+  end
+
+  function elementType:_triggerChildChanged(index)
+    if type(self.onChildrenChanged) == "function" then
+        self:onChildrenChanged(index)
+    end
+    self:_reload()
+  end
+
+  function elementType:_addChild(child, index)
+    index = self:_validChildIndex(index)
+    table.insert(propSelf:getState(self), index, child)
+    self:_triggerChildChanged(index)
+  end
+
+  function elementType:_removeChild(locator)
+    local index = nil
+    local locatorType = type(locator)
+    if locatorType == "table" then
+      for i,v in self:_iterateChildren() do
+        if v == locator then
+          index = i
+          break
+        end
+      end
+    elseif locatorType == "string" then
+      for i,v in self:_iterateChildren() do
+        if v:getId() == locator then
+          index = i
+          break
+        end
+      end
+    else--if locatorType == "number" then
+      index = self:_validChildIndex(locator)
+    end
+
+    -- Child not found
+    if index == nil then
+        return false, nil
+    end
+
+    local result = table.remove(propSelf:getState(self), index)
+    self:_triggerChildChanged(index)
+    return true, result
+  end
+
+  function elementType:findChildById(id)
+    for _,child in self:_iterateChildren() do
+      local result = child:findById(id)
+      if result then
+          return result
+      end
+    end
+    return nil
+  end
+
+  return elementType
+end
+
+return Children

gfx/prop/init.lua

@@ -0,0 +1,24 @@
+local Prop = {}
+Prop.__index = Prop
+
+function Prop:getState(element)
+  return element[self]
+end
+
+function Prop:setState(element, state)
+  element[self] = state
+end
+
+function Prop.attach(elementType, prop, defaultState)
+  prop:setState(elementType, defaultState or prop.defaultState)
+  return prop:with(elementType)
+end
+
+function Prop:new(o)
+  local obj = o or {}
+  setmetatable(obj, Prop)
+  obj.__index = obj
+  return obj
+end
+
+return Prop

gfx/prop/orientation.lua

@@ -0,0 +1,25 @@
+local Prop = require("gfx.prop")
+local Orientation = Prop:new{ defaultState = false }
+
+function Orientation:with(elementType)
+  local propSelf = self
+  function elementType:setVertical(vertical)
+    local state = self:isVertical()
+    if state ~= vertical then
+        self:setDirty()
+        propSelf:setState(self, vertical)
+    end
+  end
+
+  function elementType:isVertical()
+    return propSelf:getState(self)
+  end
+
+  function elementType:isHorizontal()
+    return not self:isVertical()
+  end
+
+  return elementType
+end
+
+return Orientation