Dear ImGui for Roblox - not yet ported / known gaps
====================================================
Upstream reference: tools/test/upstream/ (ocornut/imgui docking branch, 1.93 WIP).
Re-check with: python3 tools/test/missing.py [imgui|widgets|tables|draw]  and  python3 tools/test/undefined.py --no-demo
(missing.py also lists names the port defines differently, e.g. the *V printf variants and DragFloat2..4 / DragInt2..4,
which exist as ImGui.DragFloat2 = DragFloatN(2) etc. Those are NOT gaps.)


FEATURES NOT PORTED / PARTIAL
-----------------------------
- ImFont::AddRemapCodepointToGlyphIndex / FontSrcGetGlyphIndexFromCodepoint (needs the 1.93 font loader split).
- Default compressed font data (GetDefaultCompressedFontDataTTF / ProggyClean/ProggyForever embedded data):
  AddFontFromMemoryCompressedTTF works, but the default font comes from fonts/ instead.
- DebugLogSkippedErrors / DebugDrawIdConflicts* (Metrics error-recovery and ID-conflict debug tools).
- ImGuiDataType.S64/U64: supported, but values are Luau doubles: exact only within +-2^53 (LLONG_MAX/ULLONG_MAX
  round up to 2^63/2^64; U64 max prints as 18446744073709551615 via a special case).
- ImDrawList::AddCallback(userdata_size > 0): "copy" = shallow copy of a table userdata (no raw bytes in Lua).
- stb_truetype: cmap format 2 (high-byte mapping) asserts -- same as upstream stb_truetype ("@TODO").
- GetAllocatorFunctions (n/a in Luau).

WON'T DO (platform)
-------------------
- Multi-viewports / platform windows: Roblox has one window. Viewport API exists for the main viewport only.
- Gamepad navigation via a real gamepad backend (keyboard navigation works).
- IME / non-ASCII keyboard text input (backend sends printable ASCII only).

NOT VERIFIED LINE BY LINE AGAINST UPSTREAM
------------------------------------------
- Demo: Layout & Scrolling, Popups & Modal windows, Inputs & Focus.

KNOWN ISSUES
------------
- Tables > "Columns flags": disabling every column asserts in TableUpdateLayout (upstream asserts too).
- ImTriangulator ([Luau] deviation, imgui_draw.lua ImTriangulator_IsReflex): only strictly counter-clockwise corners are
  reflex (upstream: also collinear/duplicate points), so polygons with duplicate points triangulate differently (no
  overlapping-triangle fallback).

PLANNED EXTENSIONS
------------------
- ImGuizmo, ImNodes, ImGuiColorTextEdit, ImPlot, ImPlot3D (as separate extensions/, built with a --with flag).