--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/classes/ReAnchor.lua	Tue Mar 20 21:25:29 2007 +0000
@@ -0,0 +1,314 @@
+--
+-- ReAnchor.lua
+--
+-- Provides drag-placement facilities for frames.
+--
+
+-- local constants
+local AceOO = AceLibrary("AceOO-2.0")
+
+local edges = { "BOTTOM", "TOP", "LEFT", "RIGHT" }
+
+local pointsOnEdge = {
+  BOTTOM = { "BOTTOM", "BOTTOMLEFT",  "BOTTOMRIGHT",  },
+  TOP    = { "TOP",    "TOPLEFT",     "TOPRIGHT",     },
+  RIGHT  = { "RIGHT",  "BOTTOMRIGHT", "TOPRIGHT",     },
+  LEFT   = { "LEFT",   "BOTTOMLEFT",  "TOPLEFT",      },
+}
+
+local edgeSelector = {
+  BOTTOM = 1,  -- select x of x,y
+  TOP    = 1,  -- select x of x,y
+  LEFT   = 2,  -- select y of x,y
+  RIGHT  = 2,  -- select y of x,y  
+}
+
+local oppositePoints = {
+  BOTTOMLEFT  = "TOPRIGHT",
+  BOTTOM      = "TOP",
+  BOTTOMRIGHT = "TOPLEFT",
+  RIGHT       = "LEFT",
+  TOPRIGHT    = "BOTTOMLEFT",
+  TOP         = "BOTTOM",
+  TOPLEFT     = "BOTTOMRIGHT",
+  LEFT        = "RIGHT",
+  CENTER      = "CENTER",
+}
+
+local insidePointOffsetFuncs = {
+  BOTTOMLEFT  = function(x, y) return x, y end,
+  BOTTOM      = function(x, y) return 0, y end,
+  BOTTOMRIGHT = function(x, y) return -x, y end,
+  RIGHT       = function(x, y) return -x, 0 end,
+  TOPRIGHT    = function(x, y) return -x, -y end,
+  TOP         = function(x, y) return 0, -y end,
+  TOPLEFT     = function(x, y) return x, -y end,
+  LEFT        = function(x, y) return x, 0 end,
+  CENTER      = function(x, y) return 0, 0 end,
+}
+
+local pointCoordFuncs = {
+  BOTTOMLEFT  = function(f) return f:GetLeft(),  f:GetBottom() end,
+  BOTTOM      = function(f) return nil,          f:GetBottom() end,
+  BOTTOMRIGHT = function(f) return f:GetRight(), f:GetBottom() end,
+  RIGHT       = function(f) return f:GetRight(), nil end,
+  TOPRIGHT    = function(f) return f:GetRight(), f:GetTop() end,
+  TOP         = function(f) return nil,          f:GetTop() end,
+  TOPLEFT     = function(f) return f:GetLeft(),  f:GetTop() end,
+  LEFT        = function(f) return f:GetLeft(),  nil end,
+  CENTER      = function(f) return f:GetCenter() end,
+}
+
+local edgeBoundsFuncs = {
+  BOTTOM = function(f) return f:GetLeft(), f:GetRight() end,
+  LEFT   = function(f) return f:GetBottom(), f:GetTop() end
+}
+edgeBoundsFuncs.TOP   = edgeBoundsFuncs.BOTTOM
+edgeBoundsFuncs.RIGHT = edgeBoundsFuncs.LEFT
+
+
+-- local utility functions
+
+-- Returns absolute coordinates x,y of the named point 'p' of frame 'f'
+local function GetPointCoords( f, p )
+  local x, y = pointCoordFuncs[p](f)
+  if not(x and y) then
+    local cx, cy = f:GetCenter()
+    x = x or cx
+    y = y or cy
+  end
+  return x, y
+end
+
+
+-- Returns true if frame 'f1' can be anchored to frame 'f2'
+local function CheckAnchorable( f1, f2 )
+  -- can't anchor a frame to itself or to nil
+  if f1 == f2 or f2 == nil then
+    return false
+  end
+  
+  -- can always anchor to UIParent
+  if f2 == UIParent then
+    return true
+  end
+  
+  -- also can't do circular anchoring of frames 
+  -- walk the anchor chain, which generally shouldn't be that expensive
+  -- (who nests draggables that deep anyway?)
+  for i = 1, f2:GetNumPoints() do
+    local _, f = f2:GetPoint(i)
+    return CheckAnchorable(f1,f)
+  end
+  
+  return true
+end
+
+-- Returns true if frames f1 and f2 specified edges overlap
+local function CheckEdgeOverlap( f1, f2, e )
+  local l1, u1 = edgeBoundsFuncs[e](f1)
+  local l2, u2 = edgeBoundsFuncs[e](f2)
+  return l1 <= l2 and l2 <= u1 or l2 <= l1 and l1 <= u2
+end
+
+-- Returns true if point p1 on frame f1 overlaps edge e2 on frame f2
+local function CheckPointEdgeOverlap( f1, p1, f2, e2 )
+  local l, u = edgeBoundsFuncs[e2](f2)
+  local x, y = GetPointCoords(f1,p1)
+  x = select(edgeSelector[e2], x, y)
+  return l <= x and x <= u
+end
+
+-- Returns the distance between corresponding edges. It is 
+-- assumed that the passed in edges e1 and e2 are the same or opposites
+local function GetEdgeDistance( f1, f2, e1, e2 )
+  local x1, y1 = pointCoordFuncs[e1](f1)
+  local x2, y2 = pointCoordFuncs[e2](f2)
+  return math.abs((x1 or y1) - (x2 or y2))
+end
+
+-- Returns interior offsets (specified absolutely) from a point
+local function GetInteriorOffsetsToPoint(p, x, y)
+  return insidePointOffsetFuncs[p](x,y)
+end
+
+
+
+
+
+-- ReAnchor is a Mixin which provides some anchoring and 
+-- placement methods for frames.
+-- An object with the ReAnchor mixin must support the 
+-- IAnchorable interface (implicitly or explicitly).
+-- The mixin methods also require arguments to support
+-- that interface.
+
+-- In the method prototypes, 'IRObjs' is used to refer to a
+-- table of objects which support the IAnchorable interface.
+
+
+ReAnchor = AceOO.Mixin {
+  "GetClosestVisibleEdge",
+  "GetClosestVisiblePoint",
+  "GetClosestPointSnapped",
+  "DisplaySnapIndicator",
+  "HideSnapIndicator",
+}
+
+---------------------------------------------------------
+-- Constants and classes that are not exported via mixin
+---------------------------------------------------------
+ReAnchor.IAnchorable = AceOO.Interface {
+  GetFrame = "function",
+  GetAnchorage = "function",  -- return ReAnchor.anchorInside or .anchorOutside
+}
+
+ReAnchor.anchorInside  = { inside = true }
+ReAnchor.anchorOutside = { outside = true }
+
+ReAnchor.snapIndicator1 = CreateFrame("Frame",nil,UIParent,"ReAnchorSnapIndicatorTemplate")
+ReAnchor.snapIndicator2 = CreateFrame("Frame",nil,UIParent,"ReAnchorSnapIndicatorTemplate")
+
+
+
+
+--------------------
+-- Mixin methods
+--------------------
+
+-- returns:
+--  (1) o : the closest IRObj
+--  (2) e1 : the point (edge) on self:GetFrame()
+--  (3) e2 : the point (edge) on o:GetFrame()
+function ReAnchor:GetClosestVisibleEdge( IRObjs )
+  local f1 = self:GetFrame()
+  local r, o, e1, e2
+  for _, o2 in pairs(IRObjs) do
+    local f2 = o2:GetFrame()
+    local a = o2:GetAnchorage()
+    if f2:IsVisible() and CheckAnchorable(f1,f2) then
+      for _, e in pairs(edges) do
+        local opp = a.inside and e or oppositePoints[e]
+        if CheckEdgeOverlap(f1,f2,e) then
+          local d = GetEdgeDistance(f1, f2, e, opp)
+          if not r or d < r then
+            r, o, e1, e2 = d, o2, e, opp
+          end
+        end
+      end
+    end
+  end
+  return o, e1, e2
+end
+
+-- returns:
+--  (1) o:  the closest IRObj
+--  (1) p:  the point on self:GetFrame()
+--  (2) rp: the relativePoint on o:GetFrame()
+--  (3) x:  x offset
+--  (4) y:  y offset
+-- such that self:GetFrame():SetPoint(p,o:GetFrame(),rp,x,y) preserves the current location
+function ReAnchor:GetClosestVisiblePoint( IRObjs )
+  local f1 = self:GetFrame()
+  local o, e1, e2 = self:GetClosestVisibleEdge( IRObjs )
+  local f2 = o:GetFrame()
+  local rsq, p, rp, x, y
+  -- iterate pointsOnEdge in order and use < to prefer edge centers to corners
+  for _, p1 in ipairs(pointsOnEdge[e1]) do
+    if CheckPointEdgeOverlap(f1,p1,f2,e2) then
+      local p2 = o:GetAnchorage().outside and oppositePoints[p1] or p1
+      local x1, y1 = GetPointCoords(f1,p1)
+      local x2, y2 = GetPointCoords(f2,p2)
+      local dx = x1 - x2
+      local dy = y1 - y2
+      local rsq2 = dx*dx + dy*dy
+      if not rsq or rsq2 < rsq then
+        rsq, p, rp, x, y = rsq2, p1, p2, dx, dy
+      end
+    end
+  end
+  return o, p, rp, x, y
+end
+
+
+-- Calls self:GetClosestVisiblePoint() and then snaps to the specified
+-- offsets if within the given range in x and y (as appropriate)
+-- Return semantic is the same as GetClosestVisiblePoint(). Returns nil
+-- if no snap can be done.
+function ReAnchor:GetClosestPointSnapped(IRObjs, r, xOff, yOff)
+  local f1 = self:GetFrame()
+  local o, p, rp, x, y = self:GetClosestVisiblePoint(IRObjs)
+  local s = false
+  
+  if r then
+    local sx, sy = GetInteriorOffsetsToPoint(p, xOff or 0, yOff or 0)
+    local xx, yy = pointCoordFuncs[p](f1)
+    if xx and yy then
+      if math.abs(x) <= r then
+        x = sx
+        s = true
+      end
+      if math.abs(y) <= r then
+        y = sy
+        s = true
+      end
+    elseif xx then
+      if math.abs(x) <= r then
+        x = sx
+        s = true
+        if math.abs(y) <= r then
+          y = sy
+        end
+      end
+    elseif yy then
+      if math.abs(y) <= r then
+        y = sy
+        s = true
+        if math.abs(x) <= r then
+          x = sx
+        end
+      end
+    end
+  end
+  
+  if s then
+    return o, p, rp, x, y
+  end
+end
+
+
+
+-- shows anchor-indicators on the associated frame and the target frame
+-- when a snap is warranted.
+function ReAnchor:DisplaySnapIndicator( IRObjs, r, xOff, yOff )
+  local o, p, rp, x, y, snap = self:GetClosestPointSnapped(IRObjs, r, xOff, yOff)
+  local si1 = ReAnchor.snapIndicator1
+  local si2 = ReAnchor.snapIndicator2
+  if o then
+    si1:ClearAllPoints()
+    si2:ClearAllPoints()
+    si1:SetPoint("CENTER", self:GetFrame(), p, 0, 0)
+    local xx, yy = pointCoordFuncs[rp](o:GetFrame())
+    x = math.abs(x) <=r and xx and 0 or x
+    y = math.abs(y) <=r and yy and 0 or y
+    si2:SetPoint("CENTER", o:GetFrame(), rp, x, y)
+    si1:Show()
+    si2:Show()
+  else
+    if si1:IsVisible() then
+      si1:Hide()
+      si2:Hide()
+    end
+  end
+end
+
+
+function ReAnchor:HideSnapIndicator()
+  local si1 = ReAnchor.snapIndicator1
+  local si2 = ReAnchor.snapIndicator2
+  if si1:IsVisible() then
+    si1:Hide()
+    si2:Hide()
+  end
+end
+