castbar: mark a cast that none of your interrupts can stop

ClassicAPI carries notInterruptible on C_Spell.UnitCastingInfo (arg 8) and
UnitChannelInfo (arg 7); both call sites already stepped over it positionally.
The target, focus and nameplate bars now paint it.

There is no shield art to hang on the icon -- this client ships three
CastingBar textures (Border, Flash, Spark), and Blizzard's shield arrived in
3.x -- so the state is carried by color instead: the bar and the icon's
border both take a new appearance.castbar.shieldcolor, which keeps it legible
on a bar configured without an icon. One api helper paints both so the two
modules cannot drift apart on it.

Dusty rose (.8,.45,.45) rather than a steel grey. Grey is the retail
convention, but pfUI's casting color is already a near-grey pale blue, so the
two separated on brightness alone and washed out against the bar texture. The
rose sits above failcolor in luminance and well below it in saturation, and
the two are further told apart by motion: a failed cast flashes the bar full
and fades, a shielded one fills normally and tints the icon border, which
failcolor never touches.

Not on the player's own bar. The flag is measured against the reader's own
interrupts and silences, so on your own cast it answers a question nobody
asked.

Stamped once at cast start, with the rest of the cast data, rather than
re-polled. ClassicAPI evaluates lazily from the caster's live auras but does
not yet fire the 3.3.5 UNIT_SPELLCAST_INTERRUPTIBLE / _NOT_INTERRUPTIBLE
change events, and polling per frame would undo the event-driven rework these
bars just got -- so a caster who bubbles mid-cast keeps the bar it started
with until the next one.

Two limits worth knowing when it stays dark. The value is relative to your own
kit -- with no interrupt and no silence known it is never reported, whatever
the cast -- and a creature's built-in interrupt immunity lives in
creature_template, which 1.12's SMSG_SPELL_START does not carry, so a boss
with that immunity reads interruptible while your kick still fails on it.

api/api.lua

@@ -1333,6 +1333,32 @@ function pfUI.api.CreateBackdropShadow(f)
   f.backdrop_shadow:SetBackdropBorderColor(0, 0, 0, tonumber(pfUI_config.appearance.border.shadow_intensity))
 end
 
+-- [ Set Castbar Shield ]
+-- Colors a castbar for a cast that none of the player's own interrupts or
+-- silences can stop. The bar and the icon's border both take the shield color,
+-- so the state still reads on a bar configured without an icon. Not shielded
+-- restores the normal cast/channel color and the configured border.
+-- 'bar'        [frame]     the castbar statusbar
+-- 'icon'       [frame]     the icon frame, or nil for a bar without one
+-- 'shielded'   [bool]      whether the cast is uninterruptible
+-- 'isChannel'  [bool]      selects the unshielded color
+function pfUI.api.SetCastbarShield(bar, icon, shielded, isChannel)
+  if shielded then
+    bar:SetStatusBarColor(pfUI.api.GetStringColor(C.appearance.castbar.shieldcolor))
+  else
+    bar:SetStatusBarColor(pfUI.api.GetStringColor(C.appearance.castbar[isChannel and "channelcolor" or "castbarcolor"]))
+  end
+
+  local iconborder = icon and icon.backdrop
+  if not iconborder then return end
+
+  if shielded then
+    iconborder:SetBackdropBorderColor(pfUI.api.GetStringColor(C.appearance.castbar.shieldcolor))
+  else
+    iconborder:SetBackdropBorderColor(pfUI.api.GetStringColor(C.appearance.border.color))
+  end
+end
+
 -- [ Bar Layout Options ] --
 -- 'barsize'  size of bar in number of buttons
 -- returns:   array of options as strings for pfUI.gui.bar

api/config.lua

@@ -156,6 +156,7 @@ function pfUI:LoadConfig()
   pfUI:UpdateConfig("appearance", "castbar",     "castbarcolor",     ".7,.7,.9,.8")
   pfUI:UpdateConfig("appearance", "castbar",     "channelcolor",     ".9,.9,.7,.8")
   pfUI:UpdateConfig("appearance", "castbar",     "failcolor",        "1,.2,.2,.8")
+  pfUI:UpdateConfig("appearance", "castbar",     "shieldcolor",      ".8,.45,.45,.8")
   pfUI:UpdateConfig("appearance", "castbar",     "texture",          "Interface\\AddOns\\pfUI\\img\\bar")
   pfUI:UpdateConfig("appearance", "infight",     "screen",           "0")
   pfUI:UpdateConfig("appearance", "infight",     "aggro",            "0")

modules/castbar.lua

@@ -86,7 +86,7 @@ pfUI:RegisterModule("castbar", function ()
 
   -- Stamp the bar with cast data and render text/icon/lag once. OnUpdate
   -- then animates the fill from this state without touching C_Spell.
-  local function StampBar(cb, name, tex, startMs, endMs, spellID, isChannel, delayMs, isTradeskill, rank)
+  local function StampBar(cb, name, tex, startMs, endMs, spellID, isChannel, delayMs, isTradeskill, rank, noInterrupt)
     cb.startTime = startMs
     cb.endTime = endMs
     cb.isChannel = isChannel
@@ -97,7 +97,10 @@ pfUI:RegisterModule("castbar", function ()
     cb:SetAlpha(1)
     cb.fadeout = nil
 
-    cb.bar:SetStatusBarColor(GetStringColor(C.appearance.castbar[isChannel and "channelcolor" or "castbarcolor"]))
+    -- Shield an uninterruptible cast. Not on the player's own bar: the flag is
+    -- measured against the reader's own interrupts and silences, so on your own
+    -- cast it answers a question nobody asked.
+    SetCastbarShield(cb.bar, cb.icon, noInterrupt and cb.unitstr ~= "player", isChannel)
 
     -- Rank: prefer the value the UNIT_SPELLCAST_* event delivered (arg5, passed
     -- through by RefreshBar). Only the retarget re-poll has no event in hand, so
@@ -152,10 +155,10 @@ pfUI:RegisterModule("castbar", function ()
       ClearBar(cb)
       return
     end
-    local name, _, tex, startMs, endMs, isTradeskill, _, _, spellID, _, delayMs = C_Spell.UnitCastingInfo(query)
+    local name, _, tex, startMs, endMs, isTradeskill, _, noInterrupt, spellID, _, delayMs = C_Spell.UnitCastingInfo(query)
     local isChan
     if not name then
-      name, _, tex, startMs, endMs, _, _, spellID = C_Spell.UnitChannelInfo(query)
+      name, _, tex, startMs, endMs, _, noInterrupt, spellID = C_Spell.UnitChannelInfo(query)
       isChan = true
     end
     -- Synthetic fallback for abilities the engine treats as instant-cast but
@@ -169,7 +172,7 @@ pfUI:RegisterModule("castbar", function ()
       end
     end
     if name and startMs and endMs then
-      StampBar(cb, name, tex, startMs, endMs, spellID, isChan, delayMs, isTradeskill, rank)
+      StampBar(cb, name, tex, startMs, endMs, spellID, isChan, delayMs, isTradeskill, rank, noInterrupt)
     else
       ClearBar(cb)
     end

modules/gui.lua

@@ -2792,6 +2792,7 @@ pfUI:RegisterModule("gui", function ()
       CreateConfig(nil, T["Use Unit Fonts"], C.castbar, "use_unitfonts", "checkbox")
       CreateConfig(nil, T["Casting Color"], C.appearance.castbar, "castbarcolor", "color")
       CreateConfig(nil, T["Channeling Color"], C.appearance.castbar, "channelcolor", "color")
+      CreateConfig(nil, T["Uninterruptible Color"], C.appearance.castbar, "shieldcolor", "color")
       CreateConfig(nil, T["Castbar Texture"], C.appearance.castbar, "texture", "dropdown", pfUI.gui.dropdowns.uf_bartexture)
       CreateConfig(nil, T["Disable Blizzard Castbar"], C.castbar.player, "hide_blizz", "checkbox")
     end)

modules/nameplates.lua

@@ -77,10 +77,10 @@ pfUI:RegisterModule("nameplates", function ()
   -- vs channel itself. Never called per frame.
   local function PollCastInfo(unit)
     if not unit then return nil end
-    local name, _, texture, startMs, endMs, _, _, _, spellID = C_Spell.UnitCastingInfo(unit)
+    local name, _, texture, startMs, endMs, _, _, noInterrupt, spellID = C_Spell.UnitCastingInfo(unit)
     local isChannel
     if not name then
-      name, _, texture, startMs, endMs, _, _, spellID = C_Spell.UnitChannelInfo(unit)
+      name, _, texture, startMs, endMs, _, noInterrupt, spellID = C_Spell.UnitChannelInfo(unit)
       isChannel = true
     end
     if not name or not startMs or not endMs then return nil end
@@ -92,6 +92,7 @@ pfUI:RegisterModule("nameplates", function ()
       endTime   = endMs / 1000,
       duration  = (endMs - startMs) / 1000,
       isChannel = isChannel,
+      noInterrupt = noInterrupt,
     }
   end
 
@@ -1751,7 +1752,7 @@ nameplates:RegisterEvent("PLAYER_GUILD_UPDATE")
       -- Relative 0..duration range to avoid float precision loss with large
       -- absolute timestamps.
       nameplate.castbar:SetMinMaxValues(0, duration)
-      nameplate.castbar:SetStatusBarColor(GetStringColor(C.appearance.castbar[(isChannel and "channelcolor" or "castbarcolor")]))
+      SetCastbarShield(nameplate.castbar, nameplate.castbar.icon, castInfo.noInterrupt, isChannel)
       if castInfo.icon then
         nameplate.castbar.icon.tex:SetTexture(castInfo.icon)
         nameplate.castbar.icon.tex:SetTexCoord(.1,.9,.1,.9)