nfFrameExtras.lua

-- Depends on: nfAddon


-- Grab host namespace
  local _,mod = ...


-- Frame signals
  -- Gives frame objects :Listen and :Update, a system for sending and receiving
  -- signals to a parent frame and all its children. Useful for scenarios like
  -- unit frames that may have many children/regions that want to update for
  -- specific scenarios. I use this in nfUnitFrames so the event which listens
  -- to health changes can then do something like:
  --   units['player']:Update('health',current,max)
  -- 
  -- Then, children/regions of the base player frame can update their health
  -- display like:
  --   playerframe.statusbar:Listen('health',function(self,current,max)
  --     self:SetValue(current/max)
  --   end)
  
  local function Listen(self,event,func)
    mod:argcheck(event,1,'string')
    mod:argcheck(func,2,'function')
    
    -- :Update is called on the parent, so insert it into their registry.
    local parent = self._nfparent
    local signal_registry = parent._nfsigreg
    local sigtbl = signal_registry[event]
    if not sigtbl then
      sigtbl = {}
      signal_registry[event] = sigtbl
    end
    sigtbl[#sigtbl+1] = function(...) func(self,...) end
  end
  
  local function Update(self,event,...)
    mod:argcheck(event,1,'string')
    
    local sigtbl = self._nfsigreg[event]
    if sigtbl then
      local succ,err
      for i = 1,#sigtbl do
        succ,err = pcall(sigtbl[i],...)
        if not succ then
          mod:softerror(err)
        end
      end
    end
  end
  
  local function HasUpdate(self,event)
    return (not not self._nfsigreg[event])
  end


-- Z-levels
  -- Transparently creates container holders to allow for infinite fine-grained
  -- z-level positioning of regions. Simply: Texture:SetZLevel(n). Regions in a
  -- higher `n` always appear layered above those in a lower `n`. An `n` of <=
  -- 0 places the region directly on the parent (lowest Z level).
  
  local function SetZLevel(self,lvl)
    mod:argcheck(lvl,1,'number')
    
    local parent = self._nfparent
    if lvl <= 0 then
      self:SetParent(parent)
    else
      local zlevels = parent._nfzlevels
      if lvl > #zlevels then
        for i = #zlevels+1,lvl do
          zlevels[i] = CreateFrame('Frame',nil,(zlevels[i-1] or parent))
          zlevels[i]:SetAllPoints(true)
        end
      end
      self:SetParent(zlevels[lvl])
    end
  end


-- Creation wrapper
  local function CreateTexture(self,...)
    local r = self:_nfCreateTexture(...)
    r._nfparent = self
    r.Listen = Listen
    r.SetZLevel = SetZLevel
    return r
  end
  
  local function CreateFontString(self,...)
    local r = self:_nfCreateFontString(...)
    r._nfparent = self
    r.Listen = Listen
    r.SetZLevel = SetZLevel
    return r
  end
  
  function mod:CreateFrame(...)
    local f = CreateFrame(...)
    
    f._nfsigreg = {}
    f.Listen = Listen
    f.Update = Update
    f.HasUpdate = HasUpdate
    
    f._nfzlevels = {}
    
    f._nfCreateTexture = f.CreateTexture
    f.CreateTexture = CreateTexture
    f._nfCreateFontString = f.CreateFontString
    f.CreateFontString = CreateFontString
    
    return f
  end