WIP: tabs, docking, dragdrop, settings, logging, harness

build/ImGui.linemap.json

@@ -0,0 +1 @@
+[[13, "imgui.lua"], [12931, "imgui_demo.lua"], [13824, "imgui_demo_2.lua"], [16712, "imgui_docking.lua"], [19839, "imgui_dragdrop.lua"], [20131, "imgui_draw.lua"], [25106, "imgui_h.lua"], [27260, "imgui_impl_roblox.lua"], [28016, "imgui_impl_roblox_fonts.lua"], [28794, "imgui_internal.lua"], [31943, "imgui_tables.lua"], [31990, "imgui_tabs.lua"], [33157, "imgui_widgets.lua"], [41247, "imstb_rectpack.lua"], [41693, "imstb_textedit.lua"], [42934, "imstb_truetype.lua"], [45402, "imstd_minstdio.lua"]]

imgui/imgui_dragdrop.lua

@@ -0,0 +1,289 @@
+--- ImGui Sincerely
+-- Drag and drop: 1:1 port of imgui.cpp [SECTION] DRAG AND DROP (docking branch)
+-- Payload `Data` is any Lua value (no copy is made). `data_size` is optional and only kept for API parity.
+
+function ImGui.IsDragDropActive()
+    return ImGui.GetCurrentContext().DragDropActive
+end
+
+function ImGui.ClearDragDrop()
+    local g = ImGui.GetCurrentContext()
+    g.DragDropActive = false
+    ImGuiPayload_Clear(g.DragDropPayload)
+    g.DragDropAcceptFlagsCurr = ImGuiDragDropFlags.None
+    g.DragDropAcceptIdCurr = 0
+    g.DragDropAcceptIdPrev = 0
+    g.DragDropAcceptIdCurrRectSurface = FLT_MAX
+    g.DragDropAcceptFrameCount = -1
+end
+
+function ImGui.BeginDragDropSource(flags)
+    if flags == nil then flags = 0 end
+    local g = ImGui.GetCurrentContext()
+    local window = g.CurrentWindow
+
+    local mouse_button = ImGuiMouseButton.Left
+
+    local source_drag_active = false
+    local source_id = 0
+    local source_parent_id = 0
+    if bit32.band(flags, ImGuiDragDropFlags.SourceExtern) == 0 then
+        source_id = g.LastItemData.ID
+        if source_id ~= 0 then
+            if g.ActiveId ~= source_id then return false end
+            if g.ActiveIdMouseButton ~= -1 then mouse_button = g.ActiveIdMouseButton end
+            if g.IO.MouseDown[mouse_button] == false or window.SkipItems then return false end
+            g.ActiveIdAllowOverlap = false
+        else
+            if g.IO.MouseDown[mouse_button] == false or window.SkipItems then return false end
+            if bit32.band(g.LastItemData.StatusFlags, ImGuiItemStatusFlags.HoveredRect) == 0 and (g.ActiveId == 0 or g.ActiveIdWindow ~= window) then
+                return false
+            end
+            if bit32.band(flags, ImGuiDragDropFlags.SourceAllowNullID) == 0 then
+                IM_ASSERT(false, "Use ImGuiDragDropFlags.SourceAllowNullID for items without an ID")
+                return false
+            end
+            source_id = window:GetIDFromRectangle(g.LastItemData.Rect)
+            g.LastItemData.ID = source_id
+            ImGui.KeepAliveID(source_id)
+            local is_hovered = ImGui.ItemHoverable(g.LastItemData.Rect, source_id, g.LastItemData.ItemFlags)
+            if is_hovered and g.IO.MouseClicked[mouse_button] then
+                ImGui.SetActiveID(source_id, window)
+                ImGui.FocusWindow(window)
+            end
+            if g.ActiveId == source_id then g.ActiveIdAllowOverlap = is_hovered end
+        end
+        if g.ActiveId ~= source_id then return false end
+        source_parent_id = window.IDStack.Data[window.IDStack.Size]
+        source_drag_active = ImGui.IsMouseDragging(mouse_button)
+
+        ImGui.SetActiveIdUsingAllKeyboardKeys()
+    else
+        window = nil
+        source_id = ImHashStr("#SourceExtern")
+        source_drag_active = true
+        mouse_button = g.IO.MouseDown[0] and 0 or -1
+        ImGui.KeepAliveID(source_id)
+        ImGui.SetActiveID(source_id, nil)
+    end
+
+    IM_ASSERT(g.DragDropWithinTarget == false)
+    if not source_drag_active then return false end
+
+    if not g.DragDropActive then
+        IM_ASSERT(source_id ~= 0)
+        ImGui.ClearDragDrop()
+        local payload = g.DragDropPayload
+        payload.SourceId = source_id
+        payload.SourceParentId = source_parent_id
+        g.DragDropActive = true
+        g.DragDropSourceFlags = flags
+        g.DragDropMouseButton = mouse_button
+        if payload.SourceId == g.ActiveId then g.ActiveIdNoClearOnFocusLoss = true end
+    end
+    g.DragDropSourceFrameCount = g.FrameCount
+    g.DragDropWithinSource = true
+
+    if bit32.band(flags, ImGuiDragDropFlags.SourceNoPreviewTooltip) == 0 then
+        local ret
+        if g.DragDropAcceptIdPrev ~= 0 and bit32.band(g.DragDropAcceptFlagsPrev, ImGuiDragDropFlags.AcceptNoPreviewTooltip) ~= 0 then
+            ret = ImGui.BeginTooltipHidden()
+        else
+            ret = ImGui.BeginTooltip()
+        end
+        IM_ASSERT(ret)
+    end
+
+    if bit32.band(flags, ImGuiDragDropFlags.SourceNoDisableHover) == 0 and bit32.band(flags, ImGuiDragDropFlags.SourceExtern) == 0 then
+        g.LastItemData.StatusFlags = bit32.band(g.LastItemData.StatusFlags, bit32.bnot(ImGuiItemStatusFlags.HoveredRect))
+    end
+    return true
+end
+
+function ImGui.EndDragDropSource()
+    local g = ImGui.GetCurrentContext()
+    IM_ASSERT(g.DragDropActive)
+    IM_ASSERT(g.DragDropWithinSource, "Not after a BeginDragDropSource()?")
+
+    if bit32.band(g.DragDropSourceFlags, ImGuiDragDropFlags.SourceNoPreviewTooltip) == 0 then
+        ImGui.EndTooltip()
+    end
+
+    if g.DragDropPayload.DataFrameCount == -1 then ImGui.ClearDragDrop() end
+    g.DragDropWithinSource = false
+end
+
+--- @param data any # any Lua value
+--- @return bool accepted
+function ImGui.SetDragDropPayload(type, data, data_size, cond)
+    local g = ImGui.GetCurrentContext()
+    local payload = g.DragDropPayload
+    if cond == nil or cond == 0 then cond = ImGuiCond.Always end
+
+    IM_ASSERT(type ~= nil)
+    IM_ASSERT(#type < 32, "Payload type can be at most 32 characters long")
+    IM_ASSERT(cond == ImGuiCond.Always or cond == ImGuiCond.Once)
+    IM_ASSERT(payload.SourceId ~= 0)
+
+    if cond == ImGuiCond.Always or payload.DataFrameCount == -1 then
+        payload.DataType = type
+        payload.Data = data
+        payload.DataSize = data_size or ((data ~= nil) and 1 or 0)
+    end
+    payload.DataFrameCount = g.FrameCount
+
+    return (g.DragDropAcceptFrameCount == g.FrameCount) or (g.DragDropAcceptFrameCount == g.FrameCount - 1)
+end
+
+function ImGui.BeginDragDropTargetCustom(bb, id)
+    local g = ImGui.GetCurrentContext()
+    if not g.DragDropActive then return false end
+
+    local window = g.CurrentWindow
+    local hovered_window = g.HoveredWindowUnderMovingWindow
+    if hovered_window == nil or window.RootWindowDockTree ~= hovered_window.RootWindowDockTree then return false end
+    IM_ASSERT(id ~= 0)
+    if not ImGui.IsMouseHoveringRect(bb.Min, bb.Max) or (id == g.DragDropPayload.SourceId) then return false end
+    if window.SkipItems then return false end
+
+    IM_ASSERT(g.DragDropWithinTarget == false and g.DragDropWithinSource == false)
+    g.DragDropTargetRect = ImRect(bb.Min, bb.Max)
+    g.DragDropTargetClipRect = ImRect(window.ClipRect.Min, window.ClipRect.Max)
+    g.DragDropTargetId = id
+    g.DragDropTargetFullViewport = 0
+    g.DragDropWithinTarget = true
+    return true
+end
+
+function ImGui.BeginDragDropTargetViewport(viewport, p_bb)
+    local g = ImGui.GetCurrentContext()
+    if not g.DragDropActive then return false end
+
+    local bb = p_bb or viewport:GetWorkRect()
+    local id = viewport.ID
+    if g.MouseViewport ~= viewport or not ImGui.IsMouseHoveringRect(bb.Min, bb.Max, false) or (id == g.DragDropPayload.SourceId) then
+        return false
+    end
+
+    IM_ASSERT(g.DragDropWithinTarget == false and g.DragDropWithinSource == false)
+    g.DragDropTargetRect = ImRect(bb.Min, bb.Max)
+    g.DragDropTargetClipRect = ImRect(bb.Min, bb.Max)
+    g.DragDropTargetId = id
+    g.DragDropTargetFullViewport = id
+    g.DragDropWithinTarget = true
+    return true
+end
+
+function ImGui.BeginDragDropTarget()
+    local g = ImGui.GetCurrentContext()
+    if not g.DragDropActive then return false end
+
+    local window = g.CurrentWindow
+    if bit32.band(g.LastItemData.StatusFlags, ImGuiItemStatusFlags.HoveredRect) == 0 then return false end
+    local hovered_window = g.HoveredWindowUnderMovingWindow
+    if hovered_window == nil or window.RootWindowDockTree ~= hovered_window.RootWindowDockTree or window.SkipItems then return false end
+
+    local display_rect = (bit32.band(g.LastItemData.StatusFlags, ImGuiItemStatusFlags.HasDisplayRect) ~= 0) and g.LastItemData.DisplayRect or g.LastItemData.Rect
+    local id = g.LastItemData.ID
+    if id == 0 then
+        id = window:GetIDFromRectangle(display_rect)
+        ImGui.KeepAliveID(id)
+    end
+    if g.DragDropPayload.SourceId == id then return false end
+
+    IM_ASSERT(g.DragDropWithinTarget == false and g.DragDropWithinSource == false)
+    g.DragDropTargetRect = ImRect(display_rect.Min, display_rect.Max)
+    local clip = (bit32.band(g.LastItemData.StatusFlags, ImGuiItemStatusFlags.HasClipRect) ~= 0) and g.LastItemData.ClipRect or window.ClipRect
+    g.DragDropTargetClipRect = ImRect(clip.Min, clip.Max)
+    g.DragDropTargetId = id
+    g.DragDropWithinTarget = true
+    return true
+end
+
+function ImGui.IsDragDropPayloadBeingAccepted()
+    local g = ImGui.GetCurrentContext()
+    return g.DragDropActive and g.DragDropAcceptIdPrev ~= 0
+end
+
+--- @return ImGuiPayload?
+function ImGui.AcceptDragDropPayload(type, flags)
+    if flags == nil then flags = 0 end
+    local g = ImGui.GetCurrentContext()
+    local payload = g.DragDropPayload
+    IM_ASSERT(g.DragDropActive)
+    IM_ASSERT(payload.DataFrameCount ~= -1)
+    if type ~= nil and not ImGuiPayload_IsDataType(payload, type) then return nil end
+
+    local was_accepted_previously = (g.DragDropAcceptIdPrev == g.DragDropTargetId)
+    local r = g.DragDropTargetRect
+    local r_surface = r:GetWidth() * r:GetHeight()
+    if r_surface > g.DragDropAcceptIdCurrRectSurface then return nil end
+
+    g.DragDropAcceptFlagsCurr = flags
+    g.DragDropAcceptIdCurr = g.DragDropTargetId
+    g.DragDropAcceptIdCurrRectSurface = r_surface
+
+    payload.Preview = was_accepted_previously
+    flags = bit32.bor(flags, bit32.band(g.DragDropSourceFlags, ImGuiDragDropFlags.AcceptNoDrawDefaultRect))
+    local draw_target_rect = payload.Preview and bit32.band(flags, ImGuiDragDropFlags.AcceptNoDrawDefaultRect) == 0
+    if draw_target_rect and g.DragDropTargetFullViewport ~= 0 then
+        ImGui.RenderDragDropTargetRectForViewport(g.DragDropTargetFullViewport, g.DragDropTargetRect)
+    elseif draw_target_rect then
+        ImGui.RenderDragDropTargetRectForItem(r)
+    end
+
+    g.DragDropAcceptFrameCount = g.FrameCount
+    if bit32.band(g.DragDropSourceFlags, ImGuiDragDropFlags.SourceExtern) ~= 0 and g.DragDropMouseButton == -1 then
+        payload.Delivery = was_accepted_previously and (g.DragDropSourceFrameCount < g.FrameCount)
+    else
+        payload.Delivery = was_accepted_previously and not ImGui.IsMouseDown(g.DragDropMouseButton)
+    end
+    if not payload.Delivery and bit32.band(flags, ImGuiDragDropFlags.AcceptBeforeDelivery) == 0 then return nil end
+    return payload
+end
+
+function ImGui.RenderDragDropTargetRectForItem(bb)
+    local g = ImGui.GetCurrentContext()
+    local window = g.CurrentWindow
+    local bb_display = ImRect(bb.Min, bb.Max)
+    bb_display:ClipWith(g.DragDropTargetClipRect)
+    bb_display:Expand(g.Style.DragDropTargetPadding)
+    local push_clip_rect = not window.ClipRect:Contains(bb_display)
+    if push_clip_rect then window.DrawList:PushClipRectFullScreen() end
+    ImGui.RenderDragDropTargetRectEx(window.DrawList, bb_display, g.Style.DragDropTargetRounding)
+    if push_clip_rect then window.DrawList:PopClipRect() end
+end
+
+function ImGui.RenderDragDropTargetRectForViewport(viewport_id, bb)
+    local g = ImGui.GetCurrentContext()
+    local viewport = ImGui.FindViewportByID(viewport_id)
+    IM_ASSERT(viewport ~= nil)
+    local bb_padded = ImRect(bb.Min, bb.Max)
+    bb_padded:Expand(-g.Style.DragDropTargetPadding)
+    ImGui.RenderDragDropTargetRectEx(ImGui.GetForegroundDrawList(viewport), bb_padded, g.Style.DragDropTargetRounding)
+end
+
+function ImGui.RenderDragDropTargetRectEx(draw_list, bb, rounding)
+    local g = ImGui.GetCurrentContext()
+    draw_list:AddRectFilled(bb.Min, bb.Max, ImGui.GetColorU32(ImGuiCol.DragDropTargetBg), rounding, 0)
+    draw_list:AddRect(bb.Min, bb.Max, ImGui.GetColorU32(ImGuiCol.DragDropTarget), rounding, 0, g.Style.DragDropTargetBorderSize)
+end
+
+--- @return ImGuiPayload?
+function ImGui.GetDragDropPayload()
+    local g = ImGui.GetCurrentContext()
+    return (g.DragDropActive and g.DragDropPayload.DataFrameCount ~= -1) and g.DragDropPayload or nil
+end
+
+function ImGui.EndDragDropTarget()
+    local g = ImGui.GetCurrentContext()
+    IM_ASSERT(g.DragDropActive)
+    IM_ASSERT(g.DragDropWithinTarget)
+    g.DragDropWithinTarget = false
+    if g.DragDropPayload.Delivery then ImGui.ClearDragDrop() end
+end
+
+-- Payload methods (C++ ImGuiPayload members): payload:IsDataType(t) etc. also work through these globals
+function ImGui.PayloadIsDataType(payload, t) return ImGuiPayload_IsDataType(payload, t) end
+
+return true

imgui/imgui_draw.lua

@@ -137,6 +137,8 @@ function ImGui.StyleColorsDark(dst)
     colors[ImGuiCol.TabDimmed]                 = ImLerpV4V4F(colors[ImGuiCol.Tab],          colors[ImGuiCol.TitleBg], 0.80)
     colors[ImGuiCol.TabDimmedSelected]         = ImLerpV4V4F(colors[ImGuiCol.TabSelected],  colors[ImGuiCol.TitleBg], 0.40)
     colors[ImGuiCol.TabDimmedSelectedOverline] = ImVec4(0.50, 0.50, 0.50, 0.00)
+    colors[ImGuiCol.DockingPreview] = ImVec4(colors[ImGuiCol.HeaderActive].x, colors[ImGuiCol.HeaderActive].y, colors[ImGuiCol.HeaderActive].z, colors[ImGuiCol.HeaderActive].w * 0.7)
+    colors[ImGuiCol.DockingEmptyBg] = ImVec4(0.20, 0.20, 0.20, 1.00)
     colors[ImGuiCol.PlotLines]                 = ImVec4(0.61, 0.61, 0.61, 1.00)
     colors[ImGuiCol.PlotLinesHovered]          = ImVec4(1.00, 0.43, 0.35, 1.00)
     colors[ImGuiCol.PlotHistogram]             = ImVec4(0.90, 0.70, 0.00, 1.00)
@@ -205,6 +207,8 @@ function ImGui.StyleColorsClassic(dst)
     colors[ImGuiCol.TabDimmed]                 = ImLerpV4V4F(colors[ImGuiCol.Tab],          colors[ImGuiCol.TitleBg], 0.80)
     colors[ImGuiCol.TabDimmedSelected]         = ImLerpV4V4F(colors[ImGuiCol.TabSelected],  colors[ImGuiCol.TitleBg], 0.40)
     colors[ImGuiCol.TabDimmedSelectedOverline] = ImVec4(0.53, 0.53, 0.87, 0.00)
+    colors[ImGuiCol.DockingPreview] = ImVec4(colors[ImGuiCol.Header].x, colors[ImGuiCol.Header].y, colors[ImGuiCol.Header].z, colors[ImGuiCol.Header].w * 0.7)
+    colors[ImGuiCol.DockingEmptyBg] = ImVec4(0.20, 0.20, 0.20, 1.00)
     colors[ImGuiCol.PlotLines]                 = ImVec4(1.00, 1.00, 1.00, 1.00)
     colors[ImGuiCol.PlotLinesHovered]          = ImVec4(0.90, 0.70, 0.00, 1.00)
     colors[ImGuiCol.PlotHistogram]             = ImVec4(0.90, 0.70, 0.00, 1.00)
@@ -274,6 +278,8 @@ function ImGui.StyleColorsLight(dst)
     colors[ImGuiCol.TabDimmed]                 = ImLerpV4V4F(colors[ImGuiCol.Tab],          colors[ImGuiCol.TitleBg], 0.80)
     colors[ImGuiCol.TabDimmedSelected]         = ImLerpV4V4F(colors[ImGuiCol.TabSelected],  colors[ImGuiCol.TitleBg], 0.40)
     colors[ImGuiCol.TabDimmedSelectedOverline] = ImVec4(0.26, 0.59, 1.00, 0.00)
+    colors[ImGuiCol.DockingPreview] = ImVec4(colors[ImGuiCol.Header].x, colors[ImGuiCol.Header].y, colors[ImGuiCol.Header].z, colors[ImGuiCol.Header].w * 0.7)
+    colors[ImGuiCol.DockingEmptyBg] = ImVec4(0.68, 0.69, 0.73, 1.00)
     colors[ImGuiCol.PlotLines]                 = ImVec4(0.39, 0.39, 0.39, 1.00)
     colors[ImGuiCol.PlotLinesHovered]          = ImVec4(1.00, 0.43, 0.35, 1.00)
     colors[ImGuiCol.PlotHistogram]             = ImVec4(0.90, 0.70, 0.00, 1.00)
@@ -328,6 +334,18 @@ function ImGui.ShadeVertsLinearColorGradientKeepAlpha(draw_list, vert_start_idx,
     end
 end
 
+-- Rotate and translate vertices [vert_start_idx, vert_end_idx) (1-based, like _VtxCurrentIdx)
+function ImGui.ShadeVertsTransformPos(draw_list, vert_start_idx, vert_end_idx, pivot_in, cos_a, sin_a, pivot_out)
+    local data = draw_list.VtxBuffer.Data
+    local pix, piy, pox, poy = pivot_in.x, pivot_in.y, pivot_out.x, pivot_out.y
+    for i = vert_start_idx, vert_end_idx - 1 do
+        local pos = data[i][1]
+        local x, y = pos[1] - pix, pos[2] - piy
+        pos[1] = x * cos_a - y * sin_a + pox
+        pos[2] = x * sin_a + y * cos_a + poy
+    end
+end
+
 -- Distribute UV over (a, b) rectangle
 --- @param draw_list      ImDrawList
 --- @param vert_start_idx int
@@ -3145,7 +3163,7 @@ function MT.ImDrawList:_ClearFreeMemory()
     self._TextureStack:clear()
     -- self._CallbacksDataBuf:clear()
     self._Path:clear()
-    -- self._Splitter.ClearFreeMemory()
+    self._Splitter:ClearFreeMemory()
 end
 
 function MT.ImDrawList:AddDrawCmd()
@@ -3312,6 +3330,184 @@ function MT.ImDrawList:_OnChangedVtxOffset()
     curr_cmd.VtxOffset = self._CmdHeader.VtxOffset
 end
 
+----------------------------------------------------------------
+-- [SECTION] ImDrawListSplitter
+----------------------------------------------------------------
+-- Lua: channels swap ImVector objects with the draw list (C++ memcpy of the vector headers).
+-- Channel 0 holds nothing while it is the current channel (its buffers live in the draw list).
+
+-- Copy ClipRect, TexRef, VtxOffset (TexRef is assigned by reference, never mutated)
+local function ImDrawCmd_HeaderCopyRef(dst, src)
+    ImVec4_Copy(dst.ClipRect, src.ClipRect)
+    dst.TexRef = src.TexRef
+    dst.VtxOffset = src.VtxOffset
+end
+
+function MT.ImDrawListSplitter:Clear()
+    self._Current = 0
+    self._Count = 1
+end
+
+function MT.ImDrawListSplitter:ClearFreeMemory()
+    for i = 1, self._Channels.Size do
+        local ch = self._Channels.Data[i]
+        if i - 1 == self._Current then
+            -- Current channel is a copy of CmdBuffer/IdxBuffer, don't destruct again
+            self._Channels.Data[i] = ImDrawChannel()
+        else
+            ch._CmdBuffer:clear()
+            ch._IdxBuffer:clear()
+        end
+    end
+    self._Current = 0
+    self._Count = 1
+    self._Channels:clear()
+end
+
+--- @param draw_list      ImDrawList
+--- @param channels_count int
+function MT.ImDrawListSplitter:Split(draw_list, channels_count)
+    IM_ASSERT(self._Current == 0 and self._Count <= 1, "Nested channel splitting is not supported. Please use separate instances of ImDrawListSplitter.")
+    local old_channels_count = self._Channels.Size
+    if old_channels_count < channels_count then
+        self._Channels:reserve(channels_count)
+        self._Channels:resize(channels_count)
+    end
+    self._Count = channels_count
+
+    -- Channel 0 is the draw list itself (memset to 0 in C++)
+    local channels = self._Channels.Data
+    channels[1] = { _CmdBuffer = nil, _IdxBuffer = nil }
+    for i = 2, channels_count do
+        if i > old_channels_count or channels[i] == nil then
+            channels[i] = ImDrawChannel()
+        else
+            channels[i]._CmdBuffer:resize(0)
+            channels[i]._IdxBuffer:resize(0)
+        end
+    end
+end
+
+--- @param draw_list ImDrawList
+function MT.ImDrawListSplitter:Merge(draw_list)
+    -- Note that we never use or rely on _Channels.Size because it is merely a buffer that we never shrink back to 0 to keep all sub-buffers ready for use.
+    if self._Count <= 1 then
+        return
+    end
+
+    self:SetCurrentChannel(draw_list, 0)
+    draw_list:_PopUnusedDrawCmd()
+
+    -- Calculate our final buffer sizes. Also fix the incorrect IdxOffset values in each command.
+    local new_cmd_buffer_count = 0
+    local new_idx_buffer_count = 0
+    local last_cmd = (self._Count > 0 and draw_list.CmdBuffer.Size > 0) and draw_list.CmdBuffer.Data[draw_list.CmdBuffer.Size] or nil
+    local idx_offset = last_cmd and (last_cmd.IdxOffset + last_cmd.ElemCount) or 0
+    local channels = self._Channels.Data
+    for i = 2, self._Count do
+        local ch = channels[i]
+        local cmds = ch._CmdBuffer
+        if cmds.Size > 0 and cmds.Data[cmds.Size].ElemCount == 0 and cmds.Data[cmds.Size].UserCallback == nil then -- Equivalent of PopUnusedDrawCmd()
+            cmds:pop_back()
+        end
+
+        if cmds.Size > 0 and last_cmd ~= nil then
+            -- Do not include ImDrawCmd_AreSequentialIdxOffset() in the compare as we rebuild IdxOffset values ourselves.
+            -- Manipulating IdxOffset (e.g. by reordering draw commands like done by RenderDimmedBackgroundBehindWindow()) is not supported within a splitter.
+            local next_cmd = cmds.Data[1]
+            if ImDrawCmd_HeaderCompare(last_cmd, next_cmd) and last_cmd.UserCallback == nil and next_cmd.UserCallback == nil then
+                -- Merge previous channel last draw command with current channel first draw command if matching.
+                last_cmd.ElemCount = last_cmd.ElemCount + next_cmd.ElemCount
+                idx_offset = idx_offset + next_cmd.ElemCount
+                cmds:erase(1) -- FIXME-OPT: Improve for multiple merges.
+            end
+        end
+        if cmds.Size > 0 then
+            last_cmd = cmds.Data[cmds.Size]
+        end
+        new_cmd_buffer_count = new_cmd_buffer_count + cmds.Size
+        new_idx_buffer_count = new_idx_buffer_count + ch._IdxBuffer.Size
+        for cmd_n = 1, cmds.Size do
+            cmds.Data[cmd_n].IdxOffset = idx_offset
+            idx_offset = idx_offset + cmds.Data[cmd_n].ElemCount
+        end
+    end
+    local cmd_write = draw_list.CmdBuffer.Size + 1
+    local idx_write = draw_list.IdxBuffer.Size + 1
+    draw_list.CmdBuffer:resize(draw_list.CmdBuffer.Size + new_cmd_buffer_count)
+    draw_list.IdxBuffer:resize(draw_list.IdxBuffer.Size + new_idx_buffer_count)
+
+    -- Write commands and indices in order (they are fairly small structures, we don't copy vertices only indices)
+    local dst_cmds = draw_list.CmdBuffer.Data
+    local dst_idx = draw_list.IdxBuffer.Data
+    for i = 2, self._Count do
+        local ch = channels[i]
+        local src_cmds = ch._CmdBuffer.Data
+        for n = 1, ch._CmdBuffer.Size do
+            dst_cmds[cmd_write] = src_cmds[n]
+            src_cmds[n] = nil -- ownership moved to the draw list
+            cmd_write = cmd_write + 1
+        end
+        local src_idx = ch._IdxBuffer.Data
+        for n = 1, ch._IdxBuffer.Size do
+            dst_idx[idx_write] = src_idx[n]
+            idx_write = idx_write + 1
+        end
+    end
+    draw_list._IdxWritePtr = idx_write
+
+    -- Ensure there's always a non-callback draw command trailing the command-buffer
+    if draw_list.CmdBuffer.Size == 0 or draw_list.CmdBuffer.Data[draw_list.CmdBuffer.Size].UserCallback ~= nil then
+        draw_list:AddDrawCmd()
+    end
+
+    -- If current command is used with different settings we need to add a new command
+    local curr_cmd = draw_list.CmdBuffer.Data[draw_list.CmdBuffer.Size]
+    if curr_cmd.ElemCount == 0 then
+        ImDrawCmd_HeaderCopyRef(curr_cmd, draw_list._CmdHeader) -- Copy ClipRect, TexRef, VtxOffset
+    elseif not ImDrawCmd_HeaderCompare(curr_cmd, draw_list._CmdHeader) then
+        draw_list:AddDrawCmd()
+    end
+
+    self._Count = 1
+end
+
+--- @param draw_list ImDrawList
+--- @param idx       int # 0-based channel index
+function MT.ImDrawListSplitter:SetCurrentChannel(draw_list, idx)
+    IM_ASSERT(idx >= 0 and idx < self._Count)
+    if self._Current == idx then
+        return
+    end
+
+    -- Overwrite ImVector (12/16 bytes), four times. This is merely a silly optimization instead of doing .swap()
+    local channels = self._Channels.Data
+    local cur = channels[self._Current + 1]
+    cur._CmdBuffer = draw_list.CmdBuffer
+    cur._IdxBuffer = draw_list.IdxBuffer
+    self._Current = idx
+    local ch = channels[idx + 1]
+    draw_list.CmdBuffer = ch._CmdBuffer
+    draw_list.IdxBuffer = ch._IdxBuffer
+    draw_list._IdxWritePtr = draw_list.IdxBuffer.Size + 1
+
+    -- If current command is used with different settings we need to add a new command
+    local curr_cmd = (draw_list.CmdBuffer.Size == 0) and nil or draw_list.CmdBuffer.Data[draw_list.CmdBuffer.Size]
+    if curr_cmd == nil then
+        draw_list:AddDrawCmd()
+    elseif curr_cmd.ElemCount == 0 then
+        ImDrawCmd_HeaderCopyRef(curr_cmd, draw_list._CmdHeader) -- Copy ClipRect, TexRef, VtxOffset
+    elseif not ImDrawCmd_HeaderCompare(curr_cmd, draw_list._CmdHeader) then
+        draw_list:AddDrawCmd()
+    end
+end
+
+--- @param count int
+function MT.ImDrawList:ChannelsSplit(count) self._Splitter:Split(self, count) end
+function MT.ImDrawList:ChannelsMerge() self._Splitter:Merge(self) end
+--- @param n int # 0-based
+function MT.ImDrawList:ChannelsSetCurrent(n) self._Splitter:SetCurrentChannel(self, n) end
+
 --- @param points       ImVec2[]
 --- @param points_count int
 --- @param col          ImU32
@@ -3912,6 +4108,27 @@ function MT.ImDrawList:AddTriangle(p1, p2, p3, col, thickness)
     self:PathStroke(col, thickness, ImDrawFlags.Closed)
 end
 
+function MT.ImDrawList:AddQuad(p1, p2, p3, p4, col, thickness)
+    if thickness == nil then thickness = 1.0 end
+    if bit32.band(col, IM_COL32_A_MASK) == 0 then return end
+
+    self:PathLineTo(p1)
+    self:PathLineTo(p2)
+    self:PathLineTo(p3)
+    self:PathLineTo(p4)
+    self:PathStroke(col, thickness, ImDrawFlags.Closed)
+end
+
+function MT.ImDrawList:AddQuadFilled(p1, p2, p3, p4, col)
+    if bit32.band(col, IM_COL32_A_MASK) == 0 then return end
+
+    self:PathLineTo(p1)
+    self:PathLineTo(p2)
+    self:PathLineTo(p3)
+    self:PathLineTo(p4)
+    self:PathFillConvex(col)
+end
+
 function MT.ImDrawList:AddTriangleFilled(p1, p2, p3, col)
     if bit32.band(col, IM_COL32_A_MASK) == 0 then return end
 

imgui/imgui_h.lua

@@ -513,7 +513,9 @@ function ImDrawChannel() return { _CmdBuffer = ImVector(), _IdxBuffer = ImVector
 
 --- @return ImDrawListSplitter
 --- @nodiscard
-function ImDrawListSplitter() return { _Current = 0, _Count = 0, _Channels = ImVector() } end
+MT.ImDrawListSplitter = {} -- methods in imgui_draw.lua
+MT.ImDrawListSplitter.__index = MT.ImDrawListSplitter
+function ImDrawListSplitter() return setmetatable({ _Current = 0, _Count = 0, _Channels = ImVector() }, MT.ImDrawListSplitter) end
 
 --- @class ImDrawList
 --- @field CmdBuffer         ImVector<ImDrawCmd>
@@ -1000,6 +1002,7 @@ ImGuiConfigFlags = {
     NoMouse             = bitLShift(1, 4),
     NoMouseCursorChange = bitLShift(1, 5),
     NoKeyboard          = bitLShift(1, 6),
+    DockingEnable       = bitLShift(1, 7),
     ViewportsEnable     = bitLShift(1, 10),
     IsSRGB              = bitLShift(1, 20),
     IsTouchScreen       = bitLShift(1, 21)
@@ -1054,7 +1057,25 @@ function ImGuiIO()
         ConfigWindowsResizeFromEdges = true,
 
         ConfigDebugIniSettings = false,
+        ConfigWindowsCopyContentsWithCtrlC = false,
+        ConfigWindowsMoveFromTitleBarOnly = false,
+        ConfigErrorRecovery = true,
+        ConfigErrorRecoveryEnableAssert = true,
+        ConfigErrorRecoveryEnableDebugLog = true,
+        ConfigErrorRecoveryEnableTooltip = true,
+        ConfigDebugHighlightIdConflicts = false,
+        ConfigDebugHighlightIdConflictsShowItemPicker = true,
 
+        IniFilename = "imgui.ini", -- Roblox: no disk access, only used as a flag (nil disables .ini handling)
+        IniSavingRate = 5.0,
+        LogFilename = "imgui_log.txt",
+        WantSaveIniSettings = false,
+
+        ConfigDockingNoSplit = false,
+        ConfigDockingNoDockingOver = false,
+        ConfigDockingWithShift = false,
+        ConfigDockingAlwaysTabBar = false,
+        ConfigDockingTransparentPayload = false,
         ConfigViewportsNoAutoMerge = false,
         ConfigViewportsNoTaskBarIcon = false,
         ConfigViewportsNoDecoration = true,
@@ -1084,6 +1105,7 @@ function ImGuiIO()
         MouseDoubleClicked = {[0] = false, [1] = false, [2] = false},
 
         MouseDoubleClickTime    = 0.30,
+        MouseSingleClickDelay   = 0.50,
         MouseDoubleClickMaxDist = 6.0,
         MouseDragThreshold      = 6.0,
         KeyRepeatDelay          = 0.275,
@@ -1546,6 +1568,7 @@ ImGuiHoveredFlags = {
     RootWindow                   = bitLShift(1, 1),
     AnyWindow                    = bitLShift(1, 2),
     NoPopupHierarchy             = bitLShift(1, 3),
+    DockHierarchy                = bitLShift(1, 4),
     AllowWhenBlockedByPopup      = bitLShift(1, 5),
     AllowWhenBlockedByActiveItem = bitLShift(1, 7),
     AllowWhenOverlappedByItem    = bitLShift(1, 8),
@@ -1560,11 +1583,22 @@ ImGuiHoveredFlags = {
     NoSharedDelay                = bitLShift(1, 17)
 }
 
+--- @enum ImGuiFocusedFlags
+ImGuiFocusedFlags = {
+    None             = 0,
+    ChildWindows     = bitLShift(1, 0), -- Return true if any children of the window is focused
+    RootWindow       = bitLShift(1, 1), -- Test from root window (top most parent of the current hierarchy)
+    AnyWindow        = bitLShift(1, 2), -- Return true if any window is focused
+    NoPopupHierarchy = bitLShift(1, 3), -- Do not consider popup hierarchy
+    DockHierarchy    = bitLShift(1, 4), -- Consider docking hierarchy
+}
+ImGuiFocusedFlags.RootAndChildWindows = bitOr(ImGuiFocusedFlags.RootWindow, ImGuiFocusedFlags.ChildWindows)
+
 ImGuiHoveredFlags.AllowWhenOverlapped = bitOr(ImGuiHoveredFlags.AllowWhenOverlappedByItem, ImGuiHoveredFlags.AllowWhenOverlappedByWindow)
 ImGuiHoveredFlags.RectOnly            = bitOr(ImGuiHoveredFlags.AllowWhenBlockedByPopup, ImGuiHoveredFlags.AllowWhenBlockedByActiveItem, ImGuiHoveredFlags.AllowWhenOverlapped)
 ImGuiHoveredFlags.RootAndChildWindows = bitOr(ImGuiHoveredFlags.RootWindow, ImGuiHoveredFlags.ChildWindows)
 ImGuiHoveredFlags.DelayMask_ = bitOr(ImGuiHoveredFlags.DelayNone, ImGuiHoveredFlags.DelayShort, ImGuiHoveredFlags.DelayNormal, ImGuiHoveredFlags.NoSharedDelay)
-ImGuiHoveredFlags.AllowedMaskForIsWindowHovered = bitOr(ImGuiHoveredFlags.ChildWindows, ImGuiHoveredFlags.RootWindow, ImGuiHoveredFlags.AnyWindow, ImGuiHoveredFlags.NoPopupHierarchy, ImGuiHoveredFlags.AllowWhenBlockedByPopup, ImGuiHoveredFlags.AllowWhenBlockedByActiveItem, ImGuiHoveredFlags.ForTooltip, ImGuiHoveredFlags.Stationary)
+ImGuiHoveredFlags.AllowedMaskForIsWindowHovered = bitOr(ImGuiHoveredFlags.ChildWindows, ImGuiHoveredFlags.RootWindow, ImGuiHoveredFlags.AnyWindow, ImGuiHoveredFlags.NoPopupHierarchy, ImGuiHoveredFlags.DockHierarchy, ImGuiHoveredFlags.AllowWhenBlockedByPopup, ImGuiHoveredFlags.AllowWhenBlockedByActiveItem, ImGuiHoveredFlags.ForTooltip, ImGuiHoveredFlags.Stationary)
 ImGuiHoveredFlags.AllowedMaskForIsItemHovered = bitOr(ImGuiHoveredFlags.AllowWhenBlockedByPopup, ImGuiHoveredFlags.AllowWhenBlockedByActiveItem, ImGuiHoveredFlags.AllowWhenOverlapped, ImGuiHoveredFlags.AllowWhenDisabled, ImGuiHoveredFlags.NoNavOverride, ImGuiHoveredFlags.ForTooltip, ImGuiHoveredFlags.Stationary, ImGuiHoveredFlags.DelayMask_)
 
 --- @enum ImGuiKey
@@ -1683,26 +1717,28 @@ ImGuiCol = {
     TabDimmed                 = 39,
     TabDimmedSelected         = 40,
     TabDimmedSelectedOverline = 41,
-    PlotLines                 = 42,
+    DockingPreview            = 42,
-    PlotLinesHovered          = 43,
+    DockingEmptyBg            = 43,
-    PlotHistogram             = 44,
+    PlotLines                 = 44,
-    PlotHistogramHovered      = 45,
+    PlotLinesHovered          = 45,
-    TableHeaderBg             = 46,
+    PlotHistogram             = 46,
-    TableBorderStrong         = 47,
+    PlotHistogramHovered      = 47,
-    TableBorderLight          = 48,
+    TableHeaderBg             = 48,
-    TableRowBg                = 49,
+    TableBorderStrong         = 49,
-    TableRowBgAlt             = 50,
+    TableBorderLight          = 50,
-    TextLink                  = 51,
+    TableRowBg                = 51,
-    TextSelectedBg            = 52,
+    TableRowBgAlt             = 52,
-    TreeLines                 = 53,
+    TextLink                  = 53,
-    DragDropTarget            = 54,
+    TextSelectedBg            = 54,
-    DragDropTargetBg          = 55,
+    TreeLines                 = 55,
-    UnsavedMarker             = 56,
+    DragDropTarget            = 56,
-    NavCursor                 = 57,
+    DragDropTargetBg          = 57,
-    NavWindowingHighlight     = 58,
+    UnsavedMarker             = 58,
-    NavWindowingDimBg         = 59,
+    NavCursor                 = 59,
-    ModalWindowDimBg          = 60,
+    NavWindowingHighlight     = 60,
-    COUNT                     = 61
+    NavWindowingDimBg         = 61,
+    ModalWindowDimBg          = 62,
+    COUNT = 63
 }
 
 --- @enum ImGuiBackendFlags
@@ -1992,8 +2028,124 @@ ImGuiTreeNodeFlags.DrawLinesMask_ = bitOr(ImGuiTreeNodeFlags.DrawLinesNone, ImGu
 --- @enum ImGuiTableFlags
 ImGuiTableFlags =
 {
-    None = 0,
+    None                       = 0,
+    Resizable                  = bitLShift(1, 0),
+    Reorderable                = bitLShift(1, 1),
+    Hideable                   = bitLShift(1, 2),
+    Sortable                   = bitLShift(1, 3),
+    NoSavedSettings            = bitLShift(1, 4),
+    ContextMenuInBody          = bitLShift(1, 5),
+    RowBg                      = bitLShift(1, 6),
+    BordersInnerH              = bitLShift(1, 7),
+    BordersOuterH              = bitLShift(1, 8),
+    BordersInnerV              = bitLShift(1, 9),
+    BordersOuterV              = bitLShift(1, 10),
+    NoBordersInBody            = bitLShift(1, 11),
+    NoBordersInBodyUntilResize = bitLShift(1, 12),
+    SizingFixedFit             = bitLShift(1, 13),
+    SizingFixedSame            = bitLShift(2, 13),
+    SizingStretchProp          = bitLShift(3, 13),
+    SizingStretchSame          = bitLShift(4, 13),
+    NoHostExtendX              = bitLShift(1, 16),
+    NoHostExtendY              = bitLShift(1, 17),
+    NoKeepColumnsVisible       = bitLShift(1, 18),
+    PreciseWidths              = bitLShift(1, 19),
+    NoClip                     = bitLShift(1, 20),
+    PadOuterX                  = bitLShift(1, 21),
+    NoPadOuterX                = bitLShift(1, 22),
+    NoPadInnerX                = bitLShift(1, 23),
+    ScrollX                    = bitLShift(1, 24),
+    ScrollY                    = bitLShift(1, 25),
+    SortMulti                  = bitLShift(1, 26),
+    SortTristate               = bitLShift(1, 27),
+    HighlightHoveredColumn     = bitLShift(1, 28),
 }
+ImGuiTableFlags.BordersH     = bitOr(ImGuiTableFlags.BordersInnerH, ImGuiTableFlags.BordersOuterH)
+ImGuiTableFlags.BordersV     = bitOr(ImGuiTableFlags.BordersInnerV, ImGuiTableFlags.BordersOuterV)
+ImGuiTableFlags.BordersInner = bitOr(ImGuiTableFlags.BordersInnerV, ImGuiTableFlags.BordersInnerH)
+ImGuiTableFlags.BordersOuter = bitOr(ImGuiTableFlags.BordersOuterV, ImGuiTableFlags.BordersOuterH)
+ImGuiTableFlags.Borders      = bitOr(ImGuiTableFlags.BordersInner, ImGuiTableFlags.BordersOuter)
+ImGuiTableFlags.SizingMask_  = bitOr(ImGuiTableFlags.SizingFixedFit, ImGuiTableFlags.SizingFixedSame, ImGuiTableFlags.SizingStretchProp, ImGuiTableFlags.SizingStretchSame)
 
+--- @enum ImGuiTableColumnFlags
+ImGuiTableColumnFlags =
+{
+    None                 = 0,
+    Disabled             = bitLShift(1, 0),
+    DefaultHide          = bitLShift(1, 1),
+    DefaultSort          = bitLShift(1, 2),
+    WidthStretch         = bitLShift(1, 3),
+    WidthFixed           = bitLShift(1, 4),
+    NoResize             = bitLShift(1, 5),
+    NoReorder            = bitLShift(1, 6),
+    NoHide               = bitLShift(1, 7),
+    NoClip               = bitLShift(1, 8),
+    NoSort               = bitLShift(1, 9),
+    NoSortAscending      = bitLShift(1, 10),
+    NoSortDescending     = bitLShift(1, 11),
+    NoHeaderLabel        = bitLShift(1, 12),
+    NoHeaderWidth        = bitLShift(1, 13),
+    PreferSortAscending  = bitLShift(1, 14),
+    PreferSortDescending = bitLShift(1, 15),
+    IndentEnable         = bitLShift(1, 16),
+    IndentDisable        = bitLShift(1, 17),
+    AngledHeader         = bitLShift(1, 18),
+
+    IsEnabled            = bitLShift(1, 24),
+    IsVisible            = bitLShift(1, 25),
+    IsSorted             = bitLShift(1, 26),
+    IsHovered            = bitLShift(1, 27),
+
+    NoDirectResize_      = bitLShift(1, 30),
+}
+ImGuiTableColumnFlags.WidthMask_  = bitOr(ImGuiTableColumnFlags.WidthStretch, ImGuiTableColumnFlags.WidthFixed)
+ImGuiTableColumnFlags.IndentMask_ = bitOr(ImGuiTableColumnFlags.IndentEnable, ImGuiTableColumnFlags.IndentDisable)
+ImGuiTableColumnFlags.StatusMask_ = bitOr(ImGuiTableColumnFlags.IsEnabled, ImGuiTableColumnFlags.IsVisible, ImGuiTableColumnFlags.IsSorted, ImGuiTableColumnFlags.IsHovered)
+
+--- @enum ImGuiTableRowFlags
+ImGuiTableRowFlags = { None = 0, Headers = bitLShift(1, 0) }
+
+--- @enum ImGuiTableBgTarget
+ImGuiTableBgTarget = { None = 0, RowBg0 = 1, RowBg1 = 2, CellBg = 3 }
+
+--- @enum ImGuiSortDirection
+ImGuiSortDirection = { None = 0, Ascending = 1, Descending = 2 }
+
+
+
+--- @class ImGuiPayload
+--- Drag and drop payload. `Data` is any Lua value (C++ stores raw bytes); `DataSize` kept for API parity.
+local IM_PAYLOAD = {}
+IM_PAYLOAD.__index = IM_PAYLOAD
+function IM_PAYLOAD:Clear() ImGuiPayload_Clear(self) end
+function IM_PAYLOAD:IsDataType(t) return ImGuiPayload_IsDataType(self, t) end
+function IM_PAYLOAD:IsPreview() return self.Preview end
+function IM_PAYLOAD:IsDelivery() return self.Delivery end
+function ImGuiPayload()
+    return setmetatable({ Data = nil, DataSize = 0, SourceId = 0, SourceParentId = 0, DataFrameCount = -1, DataType = "", Preview = false, Delivery = false }, IM_PAYLOAD)
+end
+function ImGuiPayload_Clear(p) p.SourceId = 0; p.SourceParentId = 0; p.Data = nil; p.DataSize = 0; p.DataType = ""; p.DataFrameCount = -1; p.Preview = false; p.Delivery = false end
+function ImGuiPayload_IsDataType(p, t) return p.DataFrameCount ~= -1 and p.DataType == t end
+function ImGuiPayload_IsPreview(p) return p.Preview end
+function ImGuiPayload_IsDelivery(p) return p.Delivery end
+
+--- @class ImGuiTextBuffer  # string builder: Buf is a list of string chunks
+local ImGuiTextBufferMT = {}
+ImGuiTextBufferMT.__index = ImGuiTextBufferMT
+function ImGuiTextBuffer() return setmetatable({ Buf = {} }, ImGuiTextBufferMT) end
+function ImGuiTextBufferMT:clear() self.Buf = {} end
+function ImGuiTextBufferMT:empty() return #self.Buf == 0 end
+function ImGuiTextBufferMT:append(str) self.Buf[#self.Buf + 1] = str end
+function ImGuiTextBufferMT:appendf(fmt, ...) self.Buf[#self.Buf + 1] = string.format(fmt, ...) end
+function ImGuiTextBufferMT:c_str() return table.concat(self.Buf) end
+function ImGuiTextBufferMT:size() return #self:c_str() end
+
+--- @class ImGuiSettingsHandler
+--- Fns take (ctx, handler, ...) like upstream. ReadOpenFn(ctx, handler, name) returns entry; ReadLineFn(ctx, handler, entry, line);
+--- WriteAllFn(ctx, handler, buf: ImGuiTextBuffer)
+function ImGuiSettingsHandler()
+    return { TypeName = nil, TypeHash = 0, ClearAllFn = nil, ReadInitFn = nil, ReadOpenFn = nil, ReadLineFn = nil,
+             ApplyAllFn = nil, WriteAllFn = nil, CleanupFn = nil, UserData = nil }
+end
 
 return true -- [Roblox] ModuleScripts must return exactly one value

imgui/imgui_internal.lua

@@ -33,6 +33,44 @@ function ImGui._ByteArrayToString(buf, buf_begin, buf_end)
     return table.concat(str)
 end
 
+
+--- ImPool<T>: pool of objects keyed by ID. Public indices are 0-based like upstream (Buf is stored 1-based).
+--- `ctor` creates a new element. Removed slots are recycled via FreeIdx (-1 = none; free slots chain through `_NextFree`).
+local IM_POOL = {}
+IM_POOL.__index = IM_POOL
+function ImPool(ctor) return setmetatable({ Buf = {}, Map = {}, FreeIdx = 0, AliveCount = 0, BufSize = 0, _Ctor = ctor }, IM_POOL) end
+function IM_POOL:GetByKey(key) local i = self.Map[key]; return i and self.Buf[i + 1] or nil end
+function IM_POOL:GetByIndex(n) return self.Buf[n + 1] end
+function IM_POOL:GetIndex(p) return p._PoolIdx end
+function IM_POOL:Contains(p) return p ~= nil and self.Buf[(p._PoolIdx or -1) + 1] == p end
+function IM_POOL:GetMapSize() return self.BufSize end
+function IM_POOL:Clear() self.Buf = {}; self.Map = {}; self.FreeIdx = 0; self.AliveCount = 0; self.BufSize = 0 end
+function IM_POOL:Add()
+    local idx
+    if self._Free and #self._Free > 0 then idx = table.remove(self._Free) else idx = self.BufSize; self.BufSize = self.BufSize + 1 end
+    local p = self._Ctor and self._Ctor() or {}
+    p._PoolIdx = idx
+    self.Buf[idx + 1] = p
+    self.AliveCount = self.AliveCount + 1
+    return p
+end
+function IM_POOL:GetOrAddByKey(key)
+    local i = self.Map[key]
+    if i then return self.Buf[i + 1] end
+    local p = self:Add(); self.Map[key] = p._PoolIdx; return p
+end
+function IM_POOL:Remove(key, p)
+    if type(key) == "table" then p = key; key = nil end
+    if key == nil then for k, i in pairs(self.Map) do if i == p._PoolIdx then key = k break end end end
+    if key ~= nil then self.Map[key] = nil end
+    self.Buf[p._PoolIdx + 1] = false
+    self._Free = self._Free or {}
+    table.insert(self._Free, p._PoolIdx)
+    self.AliveCount = self.AliveCount - 1
+end
+function IM_POOL:Reserve(n) end
+-- NOTE: removed slots hold `false`; iterate with `for i = 0, pool:GetMapSize() - 1 do local t = pool:GetByIndex(i) if t then ... end end`
+
 --- @type ImGuiContext?
 local GImGui
 
@@ -1162,6 +1200,15 @@ function ImGuiNextWindowData()
         ScrollVal            = ImVec2(),
         WindowFlags          = nil,
         ChildFlags           = nil,
+        WindowFlagsSet       = 0,
+        WindowFlagsClear     = 0,
+        ChildFlagsSet        = 0,
+        ChildFlagsClear      = 0,
+        ViewportId           = 0,
+        DockId               = 0,
+        DockCond             = 0,
+        PosUndock            = false,
+        WindowClass          = nil,
         CollapsedVal         = nil,
         SizeConstraintRect   = nil,
         SizeCallback         = nil,
@@ -1293,6 +1340,7 @@ function ImGuiStyle()
         PopupBorderSize = 1.0,
 
         DockingSeparatorSize = 2.0,
+        DockingNodeHasCloseButton = true,
         MouseCursorScale = 1.0,
 
         ItemSpacing = ImVec2(8, 4),
@@ -1655,6 +1703,91 @@ end
 --- @field DebugAllocInfo                     ImGuiDebugAllocInfo
 --- @field TempBuffer                         ImVector<char>
 
+----------------------------------------------------------------
+-- [SECTION] Tab bar, Tab item support (public flags from imgui.h + private extensions)
+----------------------------------------------------------------
+
+--- @enum ImGuiTabBarFlags
+ImGuiTabBarFlags = {
+    None                         = 0,
+    Reorderable                  = bitLShift(1, 0),
+    AutoSelectNewTabs            = bitLShift(1, 1),
+    TabListPopupButton           = bitLShift(1, 2),
+    NoCloseWithMiddleMouseButton = bitLShift(1, 3),
+    NoTabListScrollingButtons    = bitLShift(1, 4),
+    NoTooltip                    = bitLShift(1, 5),
+    DrawSelectedOverline         = bitLShift(1, 6),
+    FittingPolicyMixed           = bitLShift(1, 7),
+    FittingPolicyShrink          = bitLShift(1, 8),
+    FittingPolicyScroll          = bitLShift(1, 9),
+    -- Private
+    DockNode                     = bitLShift(1, 20),
+    IsFocused                    = bitLShift(1, 21),
+    SaveSettings                 = bitLShift(1, 22),
+}
+ImGuiTabBarFlags.FittingPolicyMask_       = bitOr(ImGuiTabBarFlags.FittingPolicyMixed, ImGuiTabBarFlags.FittingPolicyShrink, ImGuiTabBarFlags.FittingPolicyScroll)
+ImGuiTabBarFlags.FittingPolicyDefault_    = ImGuiTabBarFlags.FittingPolicyMixed
+ImGuiTabBarFlags.FittingPolicyResizeDown  = ImGuiTabBarFlags.FittingPolicyShrink
+
+--- @enum ImGuiTabItemFlags
+ImGuiTabItemFlags = {
+    None                         = 0,
+    UnsavedDocument              = bitLShift(1, 0),
+    SetSelected                  = bitLShift(1, 1),
+    NoCloseWithMiddleMouseButton = bitLShift(1, 2),
+    NoPushId                     = bitLShift(1, 3),
+    NoTooltip                    = bitLShift(1, 4),
+    NoReorder                    = bitLShift(1, 5),
+    Leading                      = bitLShift(1, 6),
+    Trailing                     = bitLShift(1, 7),
+    NoAssumedClosure             = bitLShift(1, 8),
+    -- Private
+    NoCloseButton                = bitLShift(1, 20),
+    Button                       = bitLShift(1, 21),
+    Invisible                    = bitLShift(1, 22),
+    Unsorted                     = bitLShift(1, 23),
+}
+ImGuiTabItemFlags.SectionMask_ = bitOr(ImGuiTabItemFlags.Leading, ImGuiTabItemFlags.Trailing)
+
+-- Storage for one active tab item. In this port the label is stored in `Name` (C++ uses NameOffset into TabBar.TabsNames)
+--- @class ImGuiTabItem
+--- @return ImGuiTabItem
+function ImGuiTabItem()
+    return {
+        ID = 0, Flags = 0, Window = nil,
+        LastFrameVisible = -1, LastFrameSelected = -1,
+        Offset = 0.0, Width = 0.0, ContentWidth = 0.0, RequestedWidth = -1.0,
+        NameOffset = -1, Name = nil,
+        BeginOrder = -1,        -- 0-based
+        IndexDuringLayout = -1, -- 0-based
+        WantClose = false,
+    }
+end
+
+-- Storage for a tab bar. Tabs: ImVector of ImGuiTabItem tables (references; "pointers" stay valid across reorders)
+--- @class ImGuiTabBar
+--- @return ImGuiTabBar
+function ImGuiTabBar()
+    return {
+        Window = nil, Tabs = ImVector(), Flags = 0, ID = 0,
+        SelectedTabId = 0, NextSelectedTabId = 0, NextScrollToTabId = 0, VisibleTabId = 0,
+        CurrFrameVisible = -1, PrevFrameVisible = -1,
+        BarRect = ImRect(), BarRectPrevWidth = 0.0,
+        CurrTabsContentsHeight = 0.0, PrevTabsContentsHeight = 0.0,
+        WidthAllTabs = 0.0, WidthAllTabsIdeal = 0.0,
+        ScrollingAnim = 0.0, ScrollingTarget = 0.0, ScrollingTargetDistToVisibility = 0.0, ScrollingSpeed = 0.0,
+        ScrollingRectMinX = 0.0, ScrollingRectMaxX = 0.0, SeparatorMinX = 0.0, SeparatorMaxX = 0.0,
+        ReorderRequestTabId = 0, ReorderRequestOffset = 0, BeginCount = 0,
+        WantLayout = false, VisibleTabWasSubmitted = false, TabsAddedNew = false, ScrollButtonEnabled = false,
+        TabsActiveCount = 0,
+        LastTabItemIdx = -1, -- 0-based
+        ItemSpacingY = 0.0, FramePadding = ImVec2(), BackupCursorPos = ImVec2(),
+    }
+end
+
+--- @class ImGuiShrinkWidthItem
+function ImGuiShrinkWidthItem() return { Index = 0, Width = 0.0, InitialWidth = 0.0 } end
+
 --- @param shared_font_atlas? ImFontAtlas
 --- @return ImGuiContext
 --- @nodiscard
@@ -1881,6 +2014,15 @@ function ImGuiContext(shared_font_atlas) -- TODO: tidy up / complete this struct
 
         ComboPreviewData = ImGuiComboPreviewData(),
 
+        CurrentTabBar = nil,
+        TabBars = ImPool(ImGuiTabBar),   -- ImPool<ImGuiTabBar>
+        -- Docking
+        DockContext = ImGuiDockContext(),
+        DockNodeWindowMenuHandler = nil,
+        DebugHoveredDockNode = nil,
+        CurrentTabBarStack = ImVector(), -- holds ImGuiTabBar references directly (no ImGuiPtrOrIndex needed in Lua)
+        ShrinkWidthBuffer = ImVector(),  -- ImGuiShrinkWidthItem
+
         WindowResizeBorderExpectedRect = ImRect(),
         WindowResizeRelativeMode = false,
 
@@ -1914,16 +2056,61 @@ function ImGuiContext(shared_font_atlas) -- TODO: tidy up / complete this struct
         UserTextures = ImVector(),
 
         -- Settings
+        SettingsLoaded = false,
+        SettingsDirtyTimer = 0.0,
+        SettingsIniData = "",          -- In memory .ini settings (string)
+        SettingsHandlers = ImVector(), -- List of .ini settings handlers
         SettingsWindows = ImVector(),
+        SettingsTables = ImVector(),
+
+        -- Hooks
+        Hooks = ImVector(),
+        HookIdNext = 0,
 
         -- Drag and Drop
         DragDropActive = false,
         DragDropWithinSource = false,
         DragDropWithinTarget = false,
         DragDropSourceFlags = 0,
+        DragDropSourceFrameCount = -1,
+        DragDropMouseButton = -1,
+        DragDropPayload = ImGuiPayload(),
+        DragDropTargetRect = ImRect(),
+        DragDropTargetClipRect = ImRect(),
+        DragDropTargetId = 0,
+        DragDropTargetFullViewport = 0,
+        DragDropAcceptFlagsCurr = 0, DragDropAcceptFlagsPrev = 0,
+        DragDropAcceptIdCurrRectSurface = 0.0,
+        DragDropAcceptFrameCount = -1,
+        DragDropHoldJustPressedId = 0,
 
         DragDropAcceptIdPrev = 0, DragDropAcceptIdCurr = 0,
 
+        -- Clipper
+        ClipperTempDataStacked = 0,
+        ClipperTempData = ImVector(),
+
+        -- Logging
+        LogEnabled = false,
+        LogLineFirstItem = false,
+        LogFlags = 0,
+        LogWindow = nil,
+        LogFile = nil,
+        LogBuffer = ImGuiTextBuffer(),
+        LogNextPrefix = nil, LogNextSuffix = nil,
+        LogLinePosY = FLT_MAX,
+        LogDepthRef = 0,
+        LogDepthToExpand = 2, LogDepthToExpandDefault = 2,
+
+        -- Error handling
+        ErrorCallback = nil, ErrorCallbackUserData = nil,
+        ErrorTooltipLockedPos = ImVec2(),
+        ErrorFirst = true,
+        ErrorCountCurrentFrame = 0,
+        StackSizesInNewFrame = nil,
+        ContextName = "",
+        DebugBreakInWindow = 0,
+
         LocalizationTable = {},
 
         DebugLogFlags = bitOr(ImGuiDebugLogFlags.EventError, ImGuiDebugLogFlags.OutputToTTY),
@@ -1942,6 +2129,16 @@ function ImGuiContext(shared_font_atlas) -- TODO: tidy up / complete this struct
         WantCaptureKeyboardNextFrame = -1,
         WantTextInputNextFrame = -1,
         TempBuffer = ImVector(),
+
+        -- Tables (imgui_tables.lua)
+        CurrentTable = nil,
+        DebugBreakInTable = 0,
+        TablesTempDataStacked = 0,
+        TablesTempData = ImVector(),
+        Tables = ImPool(),                 -- ImPool<ImGuiTable>, 0-based indices (imgui_tables.lua)
+        TablesLastTimeActive = ImVector(), -- [table_idx + 1] = float
+        DrawChannelsTempMergeBuffer = ImVector(),
+        SettingsTables = ImVector(),       -- ImChunkStream<ImGuiTableSettings>: plain vector, SettingsOffset = 1-based index
     }
 
     for i = 0, 59 do this.FramerateSecPerFrame[i] = 0 end
@@ -1989,6 +2186,12 @@ function ImGuiWindowSettings()
         WantApply    = false,
         WantDelete   = false,
         Name         = "",
+        ViewportId   = 0,
+        ViewportPos  = ImVec2(0, 0),
+        DockId       = 0,
+        DockOrder    = -1,
+        ClassId      = 0,
+        LastUsedDate = 0,
     }, IMGUI_WINDOW_SETTINGS)
 end
 
@@ -2049,6 +2252,8 @@ end
 --- @nodiscard
 local function ImGuiWindowTempData()
     return {
+        DockTabItemStatusFlags = 0,
+        DockTabItemRect = ImRect(),
         CursorPos         = ImVec2(),
         CursorPosPrevLine = ImVec2(),
         CursorStartPos    = ImVec2(),
@@ -2082,6 +2287,8 @@ local function ImGuiWindowTempData()
         TreeRecordsClippedNodesY2Mask = nil,
 
         ChildWindows = ImVector(),
+        CurrentTableIdx = -1,  -- 0-based index into g.Tables, -1 if none
+        CurrentColumns = nil,  -- ImGuiOldColumns (legacy Columns API)
         StateStorage = nil,
 
         LayoutType = nil
@@ -2274,6 +2481,7 @@ function ImGuiWindow(ctx, name)
         LastTimeActive = -1.0,
 
         StateStorage = {},
+        ColumnsStorage = ImVector(), -- ImVector<ImGuiOldColumns>
 
         WriteAccessed = false,
 
@@ -2297,6 +2505,21 @@ function ImGuiWindow(ctx, name)
     this.ID = ImHashStr(name)
     this.IDStack:push_back(this.ID)
     this.MoveId = this:GetID("#MOVE")
+    this.TabId = this:GetID("#TAB")
+    -- Docking
+    this.ChildId = this.ChildId or 0
+    this.SetWindowDockAllowFlags = 0
+    this.ParentWindowForFocusRoute = nil
+    this.DockIsActive = false
+    this.DockNodeIsVisible = false
+    this.DockTabIsVisible = false
+    this.DockTabWantClose = false
+    this.DockOrder = -1
+    this.DockStyle = { Colors = {} }
+    for i = 0, 8 do this.DockStyle.Colors[i] = 0 end
+    this.DockNode = nil
+    this.DockNodeAsHost = nil
+    this.DockId = 0
 
     return this
 end

imgui/imgui_widgets.lua

@@ -301,6 +301,28 @@ function ImGui.BulletText(fmt, ...)
     ImGui.RenderText(bb.Min + ImVec2(g.FontSize + style.FramePadding.x * 2, 0.0), text, 1, text_end, false)
 end
 
+-- va_list variants: identical to the varargs versions in Lua
+ImGui.TextColoredV = ImGui.TextColored
+ImGui.TextDisabledV = ImGui.TextDisabled
+ImGui.TextWrappedV = ImGui.TextWrapped
+ImGui.TextAlignedV = ImGui.TextAligned
+ImGui.LabelTextV = ImGui.LabelText
+ImGui.BulletTextV = ImGui.BulletText
+
+-- Value(prefix, b) / Value(prefix, int) / Value(prefix, float, float_format)
+-- Lua can't tell int from float: integers without float_format print as %d, otherwise %.3f
+function ImGui.Value(prefix, v, float_format)
+    if type(v) == "boolean" then
+        ImGui.Text("%s: %s", prefix, v and "true" or "false")
+    elseif float_format then
+        ImGui.Text("%s: " .. float_format, prefix, v)
+    elseif math.floor(v) == v then
+        ImGui.Text("%s: %d", prefix, v)
+    else
+        ImGui.Text("%s: %.3f", prefix, v)
+    end
+end
+
 ----------------------------------------------------------------
 -- [SECTION] MAIN: BUTTONS, SCROLLBARS, ...
 ----------------------------------------------------------------
@@ -1198,6 +1220,7 @@ function ImGui.CheckboxFlags(label, flags, flags_value)
 
     return pressed, flags
 end
+ImGui.CheckboxFlagsT = ImGui.CheckboxFlags
 
 --- @param label  string
 --- @param active bool
@@ -2625,6 +2648,26 @@ function ImGui.InputFloat3(label, v, format, flags)
     return ImGui.InputScalarN(label, ImGuiDataType.Float, v, 3, nil, nil, format, flags)
 end
 
+function ImGui.InputFloat2(label, v, format, flags)
+    return ImGui.InputScalarN(label, ImGuiDataType.Float, v, 2, nil, nil, format or "%.3f", flags)
+end
+
+function ImGui.InputFloat4(label, v, format, flags)
+    return ImGui.InputScalarN(label, ImGuiDataType.Float, v, 4, nil, nil, format or "%.3f", flags)
+end
+
+function ImGui.InputInt2(label, v, flags)
+    return ImGui.InputScalarN(label, ImGuiDataType.S32, v, 2, nil, nil, "%d", flags)
+end
+
+function ImGui.InputInt3(label, v, flags)
+    return ImGui.InputScalarN(label, ImGuiDataType.S32, v, 3, nil, nil, "%d", flags)
+end
+
+function ImGui.InputInt4(label, v, flags)
+    return ImGui.InputScalarN(label, ImGuiDataType.S32, v, 4, nil, nil, "%d", flags)
+end
+
 --- @param label      string
 --- @param v          int
 --- @param step?      int
@@ -3041,6 +3084,112 @@ function ImGui.DragInt(label, v, v_speed, v_min, v_max, format, flags)
     return ImGui.DragScalar(label, ImGuiDataType.S32, v, v_speed, v_min, v_max, format, flags)
 end
 
+-- `v` is mutated in place (1-based), returns value_changed
+function ImGui.DragScalarN(label, data_type, v, components, v_speed, v_min, v_max, format, flags)
+    if v_speed == nil then v_speed = 1.0 end
+    if flags == nil then flags = 0 end
+
+    local window = ImGui.GetCurrentWindow()
+    if window.SkipItems then
+        return false
+    end
+
+    local g = GImGui
+    local value_changed = false
+    ImGui.BeginGroup()
+    ImGui.PushID(label)
+    ImGui.PushMultiItemsWidths(components, ImGui.CalcItemWidth())
+    for i = 1, components do
+        ImGui.PushID(i - 1)
+        if i > 1 then
+            ImGui.SameLine(0, g.Style.ItemInnerSpacing.x)
+        end
+        if bit32.band(flags, ImGuiSliderFlags.ColorMarkers) ~= 0 then
+            ImGui.SetNextItemColorMarker(GDefaultRgbaColorMarkers[i])
+        end
+        local changed
+        v[i], changed = ImGui.DragScalar("", data_type, v[i], v_speed, v_min, v_max, format, flags)
+        value_changed = value_changed or changed
+        ImGui.PopID()
+        ImGui.PopItemWidth()
+    end
+    ImGui.PopID()
+
+    local label_end = ImGui.FindRenderedTextEnd(label)
+    if label_end > 1 then
+        ImGui.SameLine(0, g.Style.ItemInnerSpacing.x)
+        ImGui.TextEx(label, label_end)
+    end
+
+    ImGui.EndGroup()
+    return value_changed
+end
+
+local function DragFloatN(n)
+    return function(label, v, v_speed, v_min, v_max, format, flags)
+        return ImGui.DragScalarN(label, ImGuiDataType.Float, v, n, v_speed or 1.0, v_min or 0.0, v_max or 0.0, format or "%.3f", flags or 0)
+    end
+end
+local function DragIntN(n)
+    return function(label, v, v_speed, v_min, v_max, format, flags)
+        return ImGui.DragScalarN(label, ImGuiDataType.S32, v, n, v_speed or 1.0, v_min or 0, v_max or 0, format or "%d", flags or 0)
+    end
+end
+ImGui.DragFloat2 = DragFloatN(2)
+ImGui.DragFloat3 = DragFloatN(3)
+ImGui.DragFloat4 = DragFloatN(4)
+ImGui.DragInt2 = DragIntN(2)
+ImGui.DragInt3 = DragIntN(3)
+ImGui.DragInt4 = DragIntN(4)
+
+-- NB: You likely want to specify the ImGuiSliderFlags_AlwaysClamp when using this.
+--- @return float v_current_min
+--- @return float v_current_max
+--- @return bool  value_changed
+local function DragRange2(data_type, label, v_current_min, v_current_max, v_speed, v_min, v_max, format, format_max, flags)
+    local window = ImGui.GetCurrentWindow()
+    if window.SkipItems then
+        return v_current_min, v_current_max, false
+    end
+
+    local g = GImGui
+    local lo = (data_type == ImGuiDataType.Float) and -FLT_MAX or INT_MIN
+    local hi = (data_type == ImGuiDataType.Float) and FLT_MAX or INT_MAX
+    ImGui.PushID(label)
+    ImGui.BeginGroup()
+    ImGui.PushMultiItemsWidths(2, ImGui.CalcItemWidth())
+
+    local min_min = (v_min >= v_max) and lo or v_min
+    local min_max = (v_min >= v_max) and v_current_max or ImMin(v_max, v_current_max)
+    local min_flags = bit32.bor(flags, (min_min == min_max) and ImGuiSliderFlags.ReadOnly or 0)
+    local value_changed, changed
+    v_current_min, value_changed = ImGui.DragScalar("##min", data_type, v_current_min, v_speed, min_min, min_max, format, min_flags)
+    ImGui.PopItemWidth()
+    ImGui.SameLine(0, g.Style.ItemInnerSpacing.x)
+
+    local max_min = (v_min >= v_max) and v_current_min or ImMax(v_min, v_current_min)
+    local max_max = (v_min >= v_max) and hi or v_max
+    local max_flags = bit32.bor(flags, (max_min == max_max) and ImGuiSliderFlags.ReadOnly or 0)
+    v_current_max, changed = ImGui.DragScalar("##max", data_type, v_current_max, v_speed, max_min, max_max, format_max or format, max_flags)
+    value_changed = value_changed or changed
+    ImGui.PopItemWidth()
+    ImGui.SameLine(0, g.Style.ItemInnerSpacing.x)
+
+    ImGui.TextEx(label, ImGui.FindRenderedTextEnd(label))
+    ImGui.EndGroup()
+    ImGui.PopID()
+
+    return v_current_min, v_current_max, value_changed
+end
+
+function ImGui.DragFloatRange2(label, v_current_min, v_current_max, v_speed, v_min, v_max, format, format_max, flags)
+    return DragRange2(ImGuiDataType.Float, label, v_current_min, v_current_max, v_speed or 1.0, v_min or 0.0, v_max or 0.0, format or "%.3f", format_max, flags or 0)
+end
+
+function ImGui.DragIntRange2(label, v_current_min, v_current_max, v_speed, v_min, v_max, format, format_max, flags)
+    return DragRange2(ImGuiDataType.S32, label, v_current_min, v_current_max, v_speed or 1.0, v_min or 0, v_max or 0, format or "%d", format_max, flags or 0)
+end
+
 ----------------------------------------------------------------
 -- [SECTION] SLIDERXXX
 ----------------------------------------------------------------
@@ -3651,6 +3800,18 @@ function ImGui.SliderInt(label, v, v_min, v_max, format, flags)
     return ImGui.SliderScalar(label, ImGuiDataType.S32, v, v_min, v_max, format, flags)
 end
 
+function ImGui.SliderInt2(label, v, v_min, v_max, format, flags)
+    return ImGui.SliderScalarN(label, ImGuiDataType.S32, v, 2, v_min, v_max, format or "%d", flags)
+end
+
+function ImGui.SliderInt3(label, v, v_min, v_max, format, flags)
+    return ImGui.SliderScalarN(label, ImGuiDataType.S32, v, 3, v_min, v_max, format or "%d", flags)
+end
+
+function ImGui.SliderInt4(label, v, v_min, v_max, format, flags)
+    return ImGui.SliderScalarN(label, ImGuiDataType.S32, v, 4, v_min, v_max, format or "%d", flags)
+end
+
 --- @param label     string
 --- @param size      ImVec2
 --- @param data_type ImGuiDataType
@@ -3764,6 +3925,11 @@ function ImGui.InputText(label, buf, buf_size, flags, callback, user_data)
     return ImGui.InputTextEx(label, nil, buf, buf_size, ImVec2(0, 0), flags, callback, user_data)
 end
 
+--- @param size? ImVec2
+function ImGui.InputTextMultiline(label, buf, buf_size, size, flags, callback, user_data)
+    return ImGui.InputTextEx(label, nil, buf, buf_size, size or ImVec2(0, 0), bit32.bor(flags or 0, ImGuiInputTextFlags.Multiline), callback, user_data)
+end
+
 ImStb = {}
 
 --- @module "imstb_textedit"
@@ -5811,6 +5977,27 @@ function ImGui.ColorEdit3(label, col, flags)
     return ImGui.ColorEdit4(label, col, bit32.bor(flags, ImGuiColorEditFlags.NoAlpha))
 end
 
+-- `col` mutated in place, returns value_changed
+function ImGui.ColorPicker3(label, col, flags)
+    local col4 = { col[1], col[2], col[3], 1.0 }
+    if not ImGui.ColorPicker4(label, col4, bit32.bor(flags or 0, ImGuiColorEditFlags.NoAlpha)) then
+        return false
+    end
+    col[1] = col4[1]; col[2] = col4[2]; col[3] = col4[3]
+    return true
+end
+
+function ImGui.SetColorEditOptions(flags)
+    local g = GImGui
+    local def = ImGuiColorEditFlags.DefaultOptions_
+    for _, mask in ipairs({ ImGuiColorEditFlags.DisplayMask_, ImGuiColorEditFlags.DataTypeMask_, ImGuiColorEditFlags.PickerMask_, ImGuiColorEditFlags.InputMask_ }) do
+        if bit32.band(flags, mask) == 0 then
+            flags = bit32.bor(flags, bit32.band(def, mask))
+        end
+    end
+    g.IO.ConfigColorEditFlags = flags
+end
+
 -- Helper for ColorPicker4()
 --- @param draw_list ImDrawList
 --- @param pos       ImVec2

tools/bundle.py

@@ -13,7 +13,7 @@ for dp, _, fn in os.walk(SRC):
         if f.endswith(".lua"):
             FILES[f] = open(os.path.join(dp, f)).read()
 
-ENTRY = ["imgui.lua", "imgui_impl_roblox.lua", "imgui_demo.lua"]  # run order
+ENTRY = ["imgui.lua", "imgui_impl_roblox.lua"] + sorted(f for f in FILES if f.startswith("imgui_demo"))  # run order
 
 names = set()
 for src in FILES.values():
@@ -27,8 +27,10 @@ out = ["--!native", "--!optimize 2", "-- GENERATED by tools/bundle.py from imgui
        "    if r == nil then r = __FILES[name](); if r == nil then r = true end; __LOADED[name] = r end",
        "    return r",
        "end", ""]
+linemap = []  # (first bundle line, file) for error -> source mapping (tools/test/run.py)
 for name, src in sorted(FILES.items()):
     out.append("__FILES[%r] = function()" % name)
+    linemap.append((sum(x.count("\n") + 1 for x in out) + 1, name))
     out.append(src.rstrip("\n"))
     out.append("end")
     out.append("")
@@ -40,6 +42,10 @@ for n in sorted(names):
     out.append("    %s = %s," % (n, n))
 out.append("}")
 
-os.makedirs(os.path.join(ROOT, "build"), exist_ok=True)
+import sys
-open(os.path.join(ROOT, "build", "ImGui.luau"), "w").write("\n".join(out) + "\n")
+OUT = sys.argv[1] if len(sys.argv) > 1 else os.path.join(ROOT, "build")
+os.makedirs(OUT, exist_ok=True)
+open(os.path.join(OUT, "ImGui.luau"), "w").write("\n".join(out) + "\n")
+import json
+json.dump(linemap, open(os.path.join(OUT, "ImGui.linemap.json"), "w"))
 print("wrote build/ImGui.luau (%d files, %d exports)" % (len(FILES), len(names)))

tools/test/PORTING.md

@@ -0,0 +1,54 @@
+# Porting rules (Dear ImGui docking branch -> this Lua/Luau port)
+
+Upstream reference: `tools/test/upstream/*.cpp|h` (ocornut/imgui `docking` branch, 1.93 WIP). Port semantics 1:1 from
+there, but keep this port's existing data structures and conventions. Read the surrounding existing Lua code first.
+
+## Runtime
+- Target is **Luau (Roblox)** only. All files are concatenated into one ModuleScript by `tools/bundle.py`; every
+  file shares one global namespace. Globals defined by one file are visible to the others at call time.
+- Each `imgui/*.lua` file is a function body in the bundle. New files must be loaded with `IM_INCLUDE"file.lua"`
+  from an existing file (files named `imgui_demo*.lua` are loaded automatically, after `imgui.lua`).
+- No `goto`, no `::labels::`, no `setfenv/getfenv`, no LuaJIT `bit`/`ffi`. Use `bit32`. For `continue` use
+  `repeat ... until true` with `break`, and an explicit flag when the loop itself must break out of the wrapper.
+- Luau has a limit of 200 locals per function and 255 upvalues; split huge functions (like demo sections) into
+  several local/global functions.
+
+## Conventions (follow what the port already does)
+- `ImVector`: 1-based `.Data`, `.Size`, methods `push_back/pop_back/resize/back/iter/erase/...` (imgui_h.lua).
+  Indices that C++ stores as 0-based *values* (e.g. column index, tab order) stay 0-based unless the surrounding
+  port code already shifted them; document `-- 0-based` / `-- 1-based` next to anything ambiguous.
+- `ImVec2(x, y)` stores `[1],[2]` with `.x/.y` aliases (metatable). Arithmetic operators exist. Prefer
+  `ImVec2_Copy(dst, src)` / `ImVec2_CopyV(dst, x, y)` when C++ assigns into an existing struct field.
+  `ImVec4`, `ImRect` (`.Min/.Max`) likewise.
+- Structs: constructor function `ImGuiFoo()` returning a table, methods on `MT.ImGuiFoo` with
+  `MT.ImGuiFoo.__index = MT.ImGuiFoo`. `local MT = ImGui.GetMetatables()`.
+- Flags/enums: tables like `ImGuiTableFlags.Resizable`; combine with `bit32.bor`, test with `bit32.band(...) ~= 0`.
+- Context: `local g = GImGui` (each file has its own local `GImGui` kept in sync; follow how the file you are in
+  does it). New fields on `ImGuiContext`/`ImGuiWindow`: add them to the constructor in imgui_internal.lua.
+- Strings: Lua strings + 1-based byte positions; `text_end` is exclusive. Editable text buffers are `char[]`
+  (byte tables), like `ImGui.InputText(label, buf, buf_size)`.
+- **Output parameters** (C++ `bool* p_open`, `float* v`, `int* current_item`...) become return values:
+  - bool-like widgets: `return pressed, new_v`  (Checkbox, RadioButton, Selectable, MenuItem, CheckboxFlags)
+  - scalar widgets: `return new_v, changed`  (Slider*/Drag*/Input* scalar, SliderAngle, Combo -> `new_idx, changed`)
+  - multi-component (`float v[3]`, ImVec4 colors, `char[]` buffers): table mutated in place, return `changed`
+  - `Begin(name, p_open)` style: `return open, visible` / follow existing `ImGui.Begin`.
+  When an existing similar function already exists, copy its convention exactly.
+- `static` locals in C++ become file-level upvalue tables / fields (demo uses a `static` table per section).
+- `IM_ASSERT(cond, msg)` exists. `IM_COL32(r,g,b,a)`, `ImMax/ImMin/ImClamp/ImLerp/ImFloor/ImTrunc` etc. exist.
+- Keep function names identical to upstream (`ImGui.TableNextRow`, `ImGui.TabBarLayout`, ...). Internal helpers
+  that are `static` in C++ become `local function` in the file.
+- Roblox can't do: OS clipboard (internal only), files/URLs (VFS `ImStd.ImFileLoadToMemory` only), multi-viewports,
+  gamepad. Port the code paths anyway where cheap; demo shows "(not supported on Roblox)" text instead of
+  widgets that cannot work.
+
+## Testing
+- `python3 tools/test/run.py` — runs main.client.luau 400 frames with scripted random input (mouse, clicks,
+  keys, typing). Errors print with `imgui/<file>.lua:<line>` mapped stack traces.
+- `--open` forces every CollapsingHeader/TreeNode open (exercises the whole demo). `--big` makes the demo
+  window 900x1000. `--png out.png` writes a screenshot (Read the PNG to look at it). `--check` asserts the
+  incremental renderer is pixel identical to a full redraw. `--main file.luau` runs your own test LocalScript
+  (copy main.client.luau as a template: `local G = require(ReplicatedStorage:WaitForChild("ImGui"))`, all
+  library globals are fields of `G`).
+- `python3 tools/test/missing.py [tables|widgets|imgui.cpp]` lists upstream functions not yet ported.
+- Several people edit the repo concurrently. Keep every file syntactically valid after each edit. If a run fails
+  because of an error in a file you don't own, wait a minute and retry instead of editing it.

tools/test/missing.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python3
+"""Lists upstream ImGui:: functions (tools/test/upstream/*.cpp, docking branch) that the Lua port doesn't define.
+  python3 tools/test/missing.py              # summary per upstream file
+  python3 tools/test/missing.py tables       # names missing from imgui_tables.cpp
+"""
+import os, re, sys
+HERE = os.path.dirname(os.path.abspath(__file__))
+ROOT = os.path.dirname(os.path.dirname(HERE))
+port = set()
+for f in os.listdir(os.path.join(ROOT, "imgui")):
+    if f.endswith(".lua"):
+        port.update(re.findall(r"function ImGui[.:](\w+)", open(os.path.join(ROOT, "imgui", f)).read()))
+filt = sys.argv[1] if len(sys.argv) > 1 else None
+for f in sorted(os.listdir(os.path.join(HERE, "upstream"))):
+    if not f.endswith(".cpp") or f == "imgui_demo.cpp": continue
+    if filt and filt not in f: continue
+    src = open(os.path.join(HERE, "upstream", f)).read()
+    names = sorted(set(re.findall(r"^[\w:<>*& ]+?\bImGui::(\w+)\(", src, re.M)))
+    miss = [n for n in names if n not in port]
+    print("%-20s %4d/%4d ported, missing %d" % (f, len(names) - len(miss), len(names), len(miss)))
+    if filt: print("  " + "\n  ".join(miss))

tools/test/roblox_mock.luau

@@ -0,0 +1,245 @@
+-- Minimal Roblox mock for running the imgui Roblox backend + the real CanvasDraw module in the Luau CLI.
+local realG = {} -- (no getfenv: it would mark the global env unsafe and deoptimize everything)
+FAKE_TIME = 0
+local SCREEN_W, SCREEN_H = 1920, 1080
+local NFRAMES = tonumber(ARG_FRAMES) or 400
+local FORCE = ARG_FORCE == true
+local DUMP_FRAMES = { [60] = true, [200] = true, [NFRAMES] = true }
+
+local function Signal()
+    local s = { conns = {} }
+    function s:Connect(fn)
+        local c = { fn = fn, Connected = true }
+        function c:Disconnect() c.Connected = false end
+        table.insert(s.conns, c)
+        return c
+    end
+    function s:Fire(...) for _, c in ipairs(s.conns) do if c.Connected then c.fn(...) end end end
+    return s
+end
+
+local V2 = {}
+V2.__index = V2
+local function v2(x, y) return setmetatable({ X = x or 0, Y = y or 0 }, V2) end
+V2.__add = function(a, b) return v2(a.X + b.X, a.Y + b.Y) end
+V2.__sub = function(a, b) return v2(a.X - b.X, a.Y - b.Y) end
+V2.__mul = function(a, b) if type(b) == "number" then return v2(a.X * b, a.Y * b) end return v2(a.X * b.X, a.Y * b.Y) end
+V2.__div = function(a, b) if type(b) == "number" then return v2(a.X / b, a.Y / b) end return v2(a.X / b.X, a.Y / b.Y) end
+V2.__eq = function(a, b) return a.X == b.X and a.Y == b.Y end
+local Vector2 = { new = v2, zero = v2(0, 0), one = v2(1, 1) }
+
+-- Enums: KeyCode values as in Roblox; unknown KeyCode names error (catches typos in the backend)
+local KEYCODES = {
+    Unknown = 0, Backspace = 8, Tab = 9, Return = 13, Escape = 27, Space = 32, Quote = 39, Comma = 44, Minus = 45, Period = 46, Slash = 47,
+    Semicolon = 59, Equals = 61, LeftBracket = 91, BackSlash = 92, RightBracket = 93, Backquote = 96, Delete = 127,
+    KeypadPeriod = 266, KeypadDivide = 267, KeypadMultiply = 268, KeypadMinus = 269, KeypadPlus = 270, KeypadEnter = 271, KeypadEquals = 272,
+    Up = 273, Down = 274, Right = 275, Left = 276, Insert = 277, Home = 278, End = 279, PageUp = 280, PageDown = 281,
+    CapsLock = 301, RightShift = 303, LeftShift = 304, RightControl = 305, LeftControl = 306, RightAlt = 307, LeftAlt = 308,
+    LeftSuper = 311, RightSuper = 312,
+}
+local digits = { "Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine" }
+for i = 0, 9 do KEYCODES[digits[i + 1]] = 48 + i; KEYCODES["Keypad" .. digits[i + 1]] = 256 + i end
+for i = 0, 25 do KEYCODES[string.char(65 + i)] = 97 + i end
+for i = 1, 15 do KEYCODES["F" .. i] = 281 + i end
+
+local Enum = setmetatable({}, { __index = function(t, enum_name)
+    local e = setmetatable({}, { __index = function(e, item)
+        local value = 0
+        if enum_name == "KeyCode" then value = KEYCODES[item]; assert(value, "invalid KeyCode " .. item) end
+        local it = { Name = item, Value = value, EnumType = enum_name }
+        rawset(e, item, it)
+        return it
+    end })
+    rawset(t, enum_name, e)
+    return e
+end })
+
+-- Instances
+local InstMethods = {}
+local InstMT = {}
+InstMT.__index = function(t, k)
+    if k == "Parent" then return rawget(t, "_parent") end
+    local m = InstMethods[k]; if m then return m end
+    for _, c in ipairs(rawget(t, "_children")) do if c.Name == k then return c end end
+    return nil
+end
+InstMT.__newindex = function(t, k, v)
+    if k == "Parent" then
+        local old = rawget(t, "_parent")
+        if old then local ch = rawget(old, "_children"); for i, c in ipairs(ch) do if c == t then table.remove(ch, i) break end end end
+        rawset(t, "_parent", v)
+        if v then table.insert(rawget(v, "_children"), t) end
+    else
+        rawset(t, k, v)
+    end
+end
+local function newInst(class, name, parent)
+    local o = setmetatable({ ClassName = class, Name = name or class, _children = {} }, InstMT)
+    if class == "ScreenGui" or class == "Frame" or class == "ImageLabel" then o.AbsoluteSize = v2(SCREEN_W, SCREEN_H) end
+    o.Visible = true
+    if class == "BindableEvent" then local sig = Signal(); rawset(o, "Event", sig); rawset(o, "Fire", function(_, ...) sig:Fire(...) end) end
+    if parent then o.Parent = parent end
+    return o
+end
+function InstMethods:FindFirstChild(name, recursive)
+    for _, c in ipairs(rawget(self, "_children")) do if c.Name == name then return c end end
+    if recursive then for _, c in ipairs(rawget(self, "_children")) do local r = c:FindFirstChild(name, true); if r then return r end end end
+    return nil
+end
+function InstMethods:WaitForChild(name) return assert(self:FindFirstChild(name), "WaitForChild would hang: " .. name) end
+function InstMethods:FindFirstChildOfClass(class) for _, c in ipairs(rawget(self, "_children")) do if c.ClassName == class then return c end end end
+function InstMethods:GetChildren() return table.clone(rawget(self, "_children")) end
+function InstMethods:IsA(class)
+    if class == "GuiObject" then return self.ClassName == "Frame" or self.ClassName == "ImageLabel" end
+    return self.ClassName == class
+end
+function InstMethods:Destroy() self.Parent = nil end
+
+-- Services
+local mouse = v2(0, 0)
+local keys_down = {}
+local UIS = {
+    InputBegan = Signal(), InputEnded = Signal(), InputChanged = Signal(), WindowFocused = Signal(), WindowFocusReleased = Signal(),
+}
+function UIS:GetMouseLocation() return mouse end
+function UIS:IsKeyDown(kc) return keys_down[kc] == true end
+
+local RunService = { Heartbeat = Signal(), Stepped = Signal(), PreAnimation = Signal(), RenderStepped = Signal() }
+local last_pixels -- last buffer written to an EditableImage
+local AssetService = {}
+function AssetService:CreateEditableImage(opts)
+    local img = { Size = opts.Size, Pixels = buffer.create(opts.Size.X * opts.Size.Y * 4) }
+    UPLOADS = 0
+    function img:WritePixelsBuffer(origin, size, buf) buffer.copy(img.Pixels, 0, buf); _G_UPLOADS = (_G_UPLOADS or 0) + 1 end
+    function img:Destroy() end
+    return img
+end
+local ReplicatedStorage = newInst("ReplicatedStorage")
+local PlayerGui = newInst("PlayerGui")
+local LocalPlayer = newInst("Player"); PlayerGui.Parent = LocalPlayer
+local services = {
+    UserInputService = UIS, RunService = RunService, AssetService = AssetService, ReplicatedStorage = ReplicatedStorage,
+    Players = { LocalPlayer = LocalPlayer }, HttpService = {}, GuiService = { GetGuiInset = function() return v2(0, 0), v2(0, 0) end },
+}
+local game = {}
+function game:GetService(name) services[name] = services[name] or {}; return services[name] end
+
+local fakeG = {} -- Roblox's shared _G
+local cache = {}
+local ROBLOX
+local function makeEnv(inst) return setmetatable({ script = inst }, { __index = ROBLOX }) end
+local GLOBAL_NAMES = { "game", "workspace", "Instance", "Enum", "Vector2", "Vector3", "UDim2", "Color3", "Content", "warn", "require", "script", "os" }
+-- Load like Roblox does but WITHOUT setfenv (which would disable Luau optimizations): Roblox globals become chunk locals.
+local function loadAsScript(src_name, inst)
+    local fn = SOURCE_FNS[src_name]
+    local vals = {}
+    for i, n in ipairs(GLOBAL_NAMES) do vals[i] = (n == "script") and inst or ROBLOX[n] end
+    return function() return fn(table.unpack(vals, 1, #GLOBAL_NAMES)) end
+end
+local function rbxrequire(inst)
+    assert(type(inst) == "table" and inst.ClassName == "ModuleScript", "require() expects a ModuleScript")
+    if cache[inst] then return cache[inst].v end
+    local r = table.pack(loadAsScript(rawget(inst, "_src"), inst)())
+    assert(r.n == 1, "Module code did not return exactly one value")
+    cache[inst] = { v = r[1] }
+    return r[1]
+end
+
+ROBLOX = setmetatable({
+    game = game, workspace = { CurrentCamera = { ViewportSize = v2(SCREEN_W, SCREEN_H) } }, require = rbxrequire, _G = fakeG,
+    Instance = { new = function(class) return newInst(class) end },
+    Enum = Enum, Vector2 = Vector2,
+    Vector3 = { new = function(x, y, z) return { X = x, Y = y, Z = z } end },
+    UDim2 = { new = function(...) return { ... } end, fromScale = function(...) return { ... } end, fromOffset = function(x, y) return { X = x, Y = y } end },
+    Color3 = { new = function(r, g, b) return { R = r or 0, G = g or 0, B = b or 0 } end },
+    Content = { fromObject = function(o) return { Object = o } end },
+    warn = function(...) print("WARN", ...) end,
+    os = { clock = function() return FAKE_TIME end, time = os.time },
+}, { __index = realG })
+
+local mod = newInst("ModuleScript", "ImGui", ReplicatedStorage); rawset(mod, "_src", "ImGui.luau")
+-- Run main.lua as a LocalScript
+local main = loadAsScript("main.client.luau", newInst("LocalScript", "main"))
+main()
+local G = cache[mod].v
+local render_time = 0
+local realDemo = G.ImGui.ShowDemoWindow
+local realCH = G.ImGui.CollapsingHeader
+G.ImGui.CollapsingHeader = function(...)
+    if ARG_OPEN then G.ImGui.SetNextItemOpen(true, G.ImGuiCond.Always) end
+    return realCH(...)
+end
+local realTN = G.ImGui.TreeNode
+G.ImGui.TreeNode = function(...)
+    if ARG_OPEN then G.ImGui.SetNextItemOpen(true, G.ImGuiCond.Always) end
+    return realTN(...)
+end
+G.ImGui.ShowDemoWindow = function(...)
+    if ARG_BIG then G.ImGui.SetNextWindowSize(G.ImVec2(900, 1000), G.ImGuiCond.Always) end
+    return realDemo(...)
+end
+local realRender = G.ImGui_ImplRoblox.RenderDrawData
+G.ImGui_ImplRoblox.RenderDrawData = function(dd)
+    if FORCE then G.ImGui.GetIO().BackendPlatformUserData.ForceRedraw = true end
+    local t0 = os.clock(); realRender(dd); render_time = render_time + os.clock() - t0
+end
+
+-- Drive frames with scripted (deterministic) input
+local seed = 12345
+local function rnd(n) seed = (seed * 1103515245 + 12345) % 2147483648; return seed % n end
+local function input(t, kc, pos) return { UserInputType = Enum.UserInputType[t], KeyCode = Enum.KeyCode[kc or "Unknown"], Position = pos or { X = 0, Y = 0, Z = 0 } } end
+local held = false
+local typing = { "H", "E", "L", "L", "O", "Space", "One", "Two", "Minus", "Backspace", "Left", "Return" }
+local hex = {}
+for i = 0, 255 do hex[i] = string.format("%02x", i) end
+
+local total = 0
+for frame = 1, NFRAMES do
+    local r = rnd(100)
+    if r < 40 then
+        mouse = v2(math.clamp(mouse.X + rnd(81) - 40, 0, SCREEN_W - 1), math.clamp(mouse.Y + rnd(81) - 40, 0, SCREEN_H - 1))
+    elseif r < 55 then
+        held = not held
+        if held then UIS.InputBegan:Fire(input("MouseButton1"), false) else UIS.InputEnded:Fire(input("MouseButton1"), false) end
+    elseif r < 60 then
+        UIS.InputChanged:Fire(input("MouseWheel", nil, { X = 0, Y = 0, Z = rnd(3) - 1 }), false)
+    elseif r < 75 then
+        local k = typing[rnd(#typing) + 1]
+        local shift = rnd(4) == 0
+        if shift then keys_down[Enum.KeyCode.LeftShift] = true; UIS.InputBegan:Fire(input("Keyboard", "LeftShift"), false) end
+        UIS.InputBegan:Fire(input("Keyboard", k), false)
+        UIS.InputEnded:Fire(input("Keyboard", k), false)
+        if shift then keys_down[Enum.KeyCode.LeftShift] = nil; UIS.InputEnded:Fire(input("Keyboard", "LeftShift"), false) end
+    elseif r < 90 then
+        mouse = v2(rnd(700), rnd(500))
+    end
+
+    FAKE_TIME = frame / 60
+    local t0 = os.clock()
+    RunService.Stepped:Fire(frame / 60, 1 / 60)
+    local dt = os.clock() - t0
+    if frame > 10 then total = total + dt end
+
+    if frame == 10 then render_time = 0; _G_UPLOADS = 0 end
+    if DUMP_FRAMES[frame] and ARG_DUMP then
+        local W, H = SCREEN_W, SCREEN_H
+        local screen = buffer.create(W * H * 4)
+        local gui = PlayerGui:FindFirstChild("ImGui")
+        for _, label in ipairs(gui:GetChildren()) do
+            if label.Visible then
+                local img, px, py = label.ImageContent.Object, label.Position.X, label.Position.Y
+                local tw, th = img.Size.X, img.Size.Y
+                for y = 0, th - 1 do
+                    if py + y < H then
+                        local n = math.min(tw, W - px)
+                        buffer.copy(screen, ((py + y) * W + px) * 4, img.Pixels, y * tw * 4, n * 4)
+                    end
+                end
+            end
+        end
+        local parts = {}
+        for i = 0, W * H * 4 - 1 do parts[#parts + 1] = hex[buffer.readu8(screen, i)] end
+        print(string.format("IMG %d %d %d %s", frame, W, H, table.concat(parts)))
+    end
+end
+print(string.format("avg frame total %.2f ms, of which render %.2f ms, uploads/frame %.2f", total / (NFRAMES - 10) * 1000, render_time / (NFRAMES - 10) * 1000, _G_UPLOADS / (NFRAMES - 10)))

tools/test/run.py

@@ -0,0 +1,115 @@
+#!/usr/bin/env python3
+"""Headless test harness: runs build/ImGui.luau + a main script in the Luau CLI against a mocked Roblox
+(roblox_mock.luau). Rebuilds the bundle first.
+
+  python3 tools/test/run.py                      # 400 frames of main.client.luau, scripted random input
+  python3 tools/test/run.py --open               # force every CollapsingHeader/TreeNode open (exercises whole demo)
+  python3 tools/test/run.py --big --open --bench # timing, best of 5
+  python3 tools/test/run.py --check              # incremental vs forced redraw must be pixel identical
+  python3 tools/test/run.py --png out.png        # screenshot of the last frame
+  python3 tools/test/run.py --main my_test.luau  # different LocalScript
+"""
+import argparse, os, shutil, subprocess, sys, zlib, struct, tempfile
+TMP = tempfile.mkdtemp(prefix="imgui_test_")  # per process: parallel runs must not share files
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+ROOT = os.path.dirname(os.path.dirname(HERE))
+LUAU = shutil.which("luau") or "/nix/store/2m2ja613nndihc8qm10f2rhq6znp1nh4-luau-0.734/bin/luau"
+G = "game, workspace, Instance, Enum, Vector2, Vector3, UDim2, Color3, Content, warn, require, script, os"
+
+def build_run(args, flags):
+    subprocess.run([sys.executable, os.path.join(ROOT, "tools", "bundle.py"), TMP], check=True, stdout=subprocess.DEVNULL)
+    out = ["--!native", "--!optimize 2", flags, "local SOURCE_FNS = {}"]
+    def add(key, path):
+        s = "\n".join(l for l in open(path).read().split("\n") if not l.startswith("--!"))
+        out.append("SOURCE_FNS[%r] = function(%s)\n%s\nend" % (key, G, s))
+    add("ImGui.luau", os.path.join(TMP, "ImGui.luau"))
+    add("main.client.luau", args.main)
+    out.append(open(os.path.join(HERE, "roblox_mock.luau")).read())
+    global OFFSET, LAST_LINE
+    LAST_LINE = open(os.path.join(TMP, "ImGui.luau")).read().count("\n")
+    OFFSET = 5  # lines before the ImGui function body in run.luau (flags/header lines + "function(...)" line)
+    path = os.path.join(TMP, "run.luau")
+    open(path, "w").write("\n".join(out))
+    return path
+
+def run(args, extra=""):
+    flags = "ARG_FRAMES=%d; ARG_BIG=%s; ARG_OPEN=%s; %s" % (args.frames, str(args.big).lower(), str(args.open).lower(), extra)
+    try:
+        p = subprocess.run([LUAU, "-O2", "--codegen", build_run(args, flags)], capture_output=True, text=True, timeout=args.timeout)
+    except subprocess.TimeoutExpired as e:
+        return 124, "TIMEOUT (infinite loop?)\n" + remap((e.stdout or b"").decode(errors="replace"))
+    return p.returncode, remap(p.stdout + p.stderr)
+
+def remap(text):
+    """run.luau:N -> imgui/<file>.lua:M"""
+    import json, re
+    lm = json.load(open(os.path.join(TMP, "ImGui.linemap.json")))
+    def sub(m):
+        n = int(m.group(1)) - OFFSET  # line inside build/ImGui.luau (minus its 2 stripped --! lines)
+        n += 2
+        best = None
+        if n > LAST_LINE: return "<harness>:%d" % n
+        for start, name in lm:
+            if start <= n: best = (start, name)
+        if not best: return m.group(0)
+        return "%s:%d" % (best[1], n - best[0] + 1)
+    return re.sub(r"\S*run\.luau:(\d+)", sub, text)
+
+def images(out):
+    return [l.split() for l in out.split("\n") if l.startswith("IMG ")]
+
+def write_png(img, path, crop=None):
+    _, fr, w, h, hx = img; w, h = int(w), int(h); px = bytes.fromhex(hx)
+    W, H = crop or (w, h)
+    raw = bytearray()
+    for y in range(H):
+        raw.append(0)
+        for x in range(W):
+            o = (y * w + x) * 4; r, g, b, a = px[o:o + 4]; k = a / 255
+            raw += bytes([int(r * k + 90 * (1 - k)), int(g * k + 90 * (1 - k)), int(b * k + 90 * (1 - k))])
+    def chunk(t, d): return struct.pack('>I', len(d)) + t + d + struct.pack('>I', zlib.crc32(t + d) & 0xffffffff)
+    open(path, 'wb').write(b'\x89PNG\r\n\x1a\n' + chunk(b'IHDR', struct.pack('>IIBBBBB', W, H, 8, 2, 0, 0, 0))
+                           + chunk(b'IDAT', zlib.compress(bytes(raw))) + chunk(b'IEND', b''))
+
+def main():
+    ap = argparse.ArgumentParser()
+    ap.add_argument("--frames", type=int, default=400)
+    ap.add_argument("--main", default=os.path.join(ROOT, "main.client.luau"))
+    ap.add_argument("--big", action="store_true", help="demo window forced to 900x1000")
+    ap.add_argument("--open", action="store_true", help="force all CollapsingHeader/TreeNode open")
+    ap.add_argument("--bench", action="store_true")
+    ap.add_argument("--check", action="store_true")
+    ap.add_argument("--png")
+    ap.add_argument("--crop", default="1100x1080")
+    ap.add_argument("--timeout", type=int, default=120)
+    args = ap.parse_args()
+
+    if args.bench:
+        for mode in ["", "ARG_FORCE=true"]:
+            best = None
+            for _ in range(5):
+                code, out = run(args, mode)
+                if code: print(out[-3000:]); sys.exit(1)
+                line = [l for l in out.split("\n") if l.startswith("avg frame")][-1]
+                if best is None or float(line.split()[3]) < float(best.split()[3]): best = line
+            print("%-12s %s" % (mode or "incremental", best))
+        return
+    if args.check:
+        code, a = run(args, "ARG_DUMP=true")
+        code2, b = run(args, "ARG_DUMP=true; ARG_FORCE=true")
+        if code or code2: print((a if code else b)[-3000:]); sys.exit(1)
+        ok = [x[4] for x in images(a)] == [x[4] for x in images(b)]
+        print("PIXELS-IDENTICAL" if ok else "PIXELS-DIFFER"); sys.exit(0 if ok else 1)
+
+    code, out = run(args, "ARG_DUMP=true" if args.png else "")
+    print("\n".join(l if not l.startswith("IMG ") else l[:40] + "..." for l in out.split("\n"))[-4000:])
+    if args.png and images(out):
+        write_png(images(out)[-1], args.png, tuple(map(int, args.crop.split("x"))))
+        print("wrote", args.png)
+    sys.exit(code)
+
+try:
+    main()
+finally:
+    shutil.rmtree(TMP, ignore_errors=True)

tools/test/undefined.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python3
+"""Static check: ImGui.X / ImGui:X / global ImFoo() calls in imgui/*.lua that nothing defines.
+  python3 tools/test/undefined.py
+"""
+import os, re, collections
+ROOT = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+SRC = os.path.join(ROOT, "imgui")
+files = {}
+for dp, _, fn in os.walk(SRC):
+    for f in fn:
+        if f.endswith(".lua"):
+            files[os.path.relpath(os.path.join(dp, f), SRC)] = open(os.path.join(dp, f)).read()
+
+def strip(s):  # drop comments and strings (roughly) so we don't report text
+    s = re.sub(r"--\[(=*)\[.*?\]\1\]", "", s, flags=re.S)
+    s = re.sub(r"\[(=*)\[.*?\]\1\]", '""', s, flags=re.S)
+    s = re.sub(r'"(\\.|[^"\\\n])*"', '""', s)
+    s = re.sub(r"'(\\.|[^'\\\n])*'", "''", s)
+    return re.sub(r"--[^\n]*", "", s)
+
+defined_imgui, defined_global, used = set(), set(), collections.defaultdict(list)
+for name, src in files.items():
+    s = strip(src)
+    defined_imgui.update(re.findall(r"function\s+ImGui[.:](\w+)", s))
+    defined_imgui.update(re.findall(r"\bImGui\.(\w+)\s*=[^=]", s))
+    defined_global.update(re.findall(r"^\s*function\s+([A-Za-z_]\w*)\s*\(", s, re.M))
+    defined_global.update(re.findall(r"^\s*([A-Za-z_]\w*)\s*=[^=]", s, re.M))
+    defined_global.update(re.findall(r"^\s*local\s+function\s+([A-Za-z_]\w*)", s, re.M))
+    defined_global.update(re.findall(r"^\s*local\s+([A-Za-z_][\w, ]*)", s, re.M) and
+                          [x.strip() for l in re.findall(r"^\s*local\s+([A-Za-z_][\w, ]*)", s, re.M) for x in l.split(",")])
+    for i, line in enumerate(s.split("\n"), 1):
+        for m in re.findall(r"\bImGui\.(\w+)\s*\(", line):
+            used[("ImGui." + m, m, True)].append("%s:%d" % (name, i))
+        for m in re.findall(r"(?<![.:\w])(Im[A-Z]\w*)\s*\(", line):
+            used[(m, m, False)].append("%s:%d" % (name, i))
+
+missing = [(k, v) for k, v in used.items() if (k[1] not in defined_imgui if k[2] else k[1] not in defined_global)]
+for (full, _, _), locs in sorted(missing):
+    print("%-45s %d uses, e.g. %s" % (full, len(locs), ", ".join(locs[:3])))
+print("total undefined:", len(missing))