Partially fix unicode name truncation.

This fix ensures that name truncation always happens on codepoint
boundaries and that a name has exactly 5 visible codepoints. This should
cover all possible cases unless names can have grapheme clusters, afaik
this is not the case.

src/types/unitframe.lua

@@ -1,7 +1,7 @@
 -- Copyright 2023 <omicron.me@protonmail.com>
 --
 -- This file is part of Omicron Frames
--- 
+--
 -- Omicron Frames is free software: you can redistribute it and/or modify it
 -- under the terms of the GNU General Public License as published by the Free
 -- Software Foundation, either version 3 of the License, or (at your option)
@@ -13,7 +13,7 @@
 -- more details.
 --
 -- You should have received a copy of the GNU General Public License along with
--- Omicron Frames. If not, see <https://www.gnu.org/licenses/>. 
+-- Omicron Frames. If not, see <https://www.gnu.org/licenses/>.
 local omif = select(2, ...)
 local types = omif.GetModule("types")
 
@@ -35,24 +35,39 @@ types.UnitFrame = UnitFrame
 
 
 local colors = {
-    hostile = {0.5, 0.0, 0.0},
+    hostile = { 0.5, 0.0, 0.0 },
-    neutral = {0.7, 0.7, 0.0},
+    neutral = { 0.7, 0.7, 0.0 },
-    healthy = {0, 0.1, 0},
+    healthy = { 0, 0.1, 0 },
-    high = {0, 1.0, 0},
+    high = { 0, 1.0, 0 },
-    mid = {1.0, 1.0, 0},
+    mid = { 1.0, 1.0, 0 },
-    low = {1.0, 0.0, 0},
+    low = { 1.0, 0.0, 0 },
-    offline = {0.7, 0.7, 0.7},
+    offline = { 0.7, 0.7, 0.7 },
-    dead = {0.7, 0.7, 0.7},
+    dead = { 0.7, 0.7, 0.7 },
-    magic = {0.4, 0.4, 1.0},
+    magic = { 0.4, 0.4, 1.0 },
-    disease = {0.4, 0.2, 0.0},
+    disease = { 0.4, 0.2, 0.0 },
-    poison = {0.0, 0.7, 0.7},
+    poison = { 0.0, 0.7, 0.7 },
-    curse = {0.7, 0.0, 0.7},
+    curse = { 0.7, 0.0, 0.7 },
-    immune = {0.0, 0.2, 0.4},
+    immune = { 0.0, 0.2, 0.4 },
-    bomb = {1.0, 0.7, 0.7},
+    bomb = { 1.0, 0.7, 0.7 },
-    cyan = {0.0, 0.8, 0.8},
+    cyan = { 0.0, 0.8, 0.8 },
-    white = {1.0, 1.0, 1.0}
+    white = { 1.0, 1.0, 1.0 }
 }
 
+-- This trucates _codepoints_ not graphemes. If combination codepoints are
+-- contained in the string, it will not properly truncate and may return
+-- incorrect graphemes
+local function utf8_truncate(s, n)
+    local init = 0
+    for _ = 1, n do
+        local _, last = string.find(s, ".[\128-\191]*", init + 1)
+        if not last then
+            return s
+        end
+        init = last
+    end
+    return string.sub(s, 1, init)
+end
+
 ---@param unit string
 ---@param config table
 function UnitFrame:Init(unit, config)
@@ -127,7 +142,7 @@ function UnitFrame:StartRangeTicker()
     if self.rangeTicker then
         return
     end
-    local delta = 0.45 + (fastrandom(0, 100)/1000)
+    local delta = 0.45 + (fastrandom(0, 100) / 1000)
     self.rangeTicker = C_Timer.NewTicker(delta, function()
         self:UpdateRange()
     end)
@@ -157,7 +172,7 @@ end
 -- Returns
 --  true if the unit is in range
 --  false if the unit is not in range
---  nil if it could not be determined 
+--  nil if it could not be determined
 function UnitFrame:IsInRange()
     local unit = self.unit
     local friendlySpell = self.rangeFriendly
@@ -169,8 +184,8 @@ function UnitFrame:IsInRange()
     elseif enemySpell and UnitCanAttack("player", unit) then
         return IsSpellInRange(enemySpell, unit) == 1
     end
-    
+
-    -- Fall back to raid/party only range check 
+    -- Fall back to raid/party only range check
     local inRange, checkedRange = UnitInRange(unit)
     if checkedRange then
         return inRange
@@ -181,7 +196,7 @@ end
 
 function UnitFrame:UpdateRange()
     local unit = self.unit
-    
+
     if UnitIsDeadOrGhost(unit) then
         self.secureFrame:SetAlpha(1.0)
         return
@@ -235,7 +250,7 @@ function UnitFrame:PrepareWheelBinds(bindings)
     -- scroll wheel to the current unit frame button when the mouse enters and
     -- to unbind it when the mouse leaves. When the keybind is triggered the
     -- button will receive a click with a custom button name
-    
+
     -- Build a table with all lines of the scroll wheel + modifier combinations
     -- we want to bind, then concat it with newlines into a full script
     local unit = self.unit
@@ -247,13 +262,13 @@ function UnitFrame:PrepareWheelBinds(bindings)
             local prefix = ModifiersToPrefix(bind.mods)
             local button = bind.button == "wheel-up" and "MOUSEWHEELUP" or "MOUSEWHEELDOWN"
             table.insert(bindScript,
-                string.format([[self:SetBindingClick(false, "%s%s", "OmicronSecureFrame%s", "%s%s")]], 
+                string.format([[self:SetBindingClick(false, "%s%s", "OmicronSecureFrame%s", "%s%s")]],
                     prefix, button, unit, prefix, bind.button
-                ) 
+                )
             )
         end
     end
-    
+
     local secure = self.secureFrame
     local bindScript = table.concat(bindScript, "\n")
 
@@ -272,7 +287,7 @@ function UnitFrame:SetMouseBinds(binds)
 
     secure:RegisterForClicks("AnyDown")
     self:PrepareWheelBinds(binds)
-    
+
     for _, bind in ipairs(binds) do
         local prefix = ModifiersToPrefix(bind.mods)
         local button
@@ -295,7 +310,7 @@ function UnitFrame:SetMouseBinds(binds)
         if bind.kind == "macro" then
             self:SetMacroAction(button, bind.data)
         elseif bind.kind == "spell" then
-            self:SetSpellAction(button, bind.data) 
+            self:SetSpellAction(button, bind.data)
         else
             secure:SetAttribute(button, bind.kind)
         end
@@ -455,7 +470,7 @@ end
 
 function UnitFrame:ROLE_CHANGED_INFORM(name, changer, old, new)
     if UnitName(self.unit) == name then
-         self:UpdateRole(new)
+        self:UpdateRole(new)
     end
 end
 
@@ -563,7 +578,7 @@ function UnitFrame:UpdateHealthColor()
     elseif isFriend and pct >= 0.90 then
         self.hp:SetColor(unpack(colors.healthy))
     elseif isFriend and pct >= 0.75 then
-        local progress = (pct - 0.75) / (0.90-0.75)
+        local progress = (pct - 0.75) / (0.90 - 0.75)
         self.hp:SetInterpolatedColor(colors.mid, colors.high, progress)
     else
         local progress = pct / 0.75
@@ -580,25 +595,10 @@ function UnitFrame:UpdateName()
         -- TODO: UnitClass can return Unknown and the color can be nil. Having
         -- the unit exist but not fully loaded is possibly a state we want to
         -- handle more generally
-        local color = RAID_CLASS_COLORS[class] or {r=1, g=1, b=1}
+        local color = RAID_CLASS_COLORS[class] or { r = 1, g = 1, b = 1 }
         self.name:SetTextColor(color.r, color.g, color.b)
     else
         self.name:SetTextColor(1, 1, 1)
     end
-    self.name:SetText(UnitName(self.unit):sub(1, 5))
+    self.name:SetText(utf8_truncate((UnitName(self.unit)), 5))
 end
-
---[[
-    -- UNIT_AURA
-    -- UNIT_CLASSIFICATION_CHANGED
-    -- UNIT_COMBAT
-    -- UNIT_CONNECTION
-    -- UNIT_DISPLAYPOWER
-    -- UNIT_FACTION
-    -- UNIT_FLAGS
-    -- UNIT_LEVEL
-    -- UNIT_MANA
-    -- UNIT_HEALTH_PREDICTION
-    -- UNIT_PHASE
-]]--
-