docking: runs end to end (dock/undock by drag, builder, ini round trip), test scripts

build/ImGui.linemap.json

@@ -1 +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"]]
+[[13, "imgui.lua"], [12966, "imgui_demo.lua"], [13859, "imgui_demo_2.lua"], [16747, "imgui_docking.lua"], [19875, "imgui_dragdrop.lua"], [20167, "imgui_draw.lua"], [25162, "imgui_h.lua"], [27316, "imgui_impl_roblox.lua"], [28072, "imgui_impl_roblox_fonts.lua"], [28850, "imgui_internal.lua"], [31999, "imgui_tables.lua"], [32046, "imgui_tabs.lua"], [33213, "imgui_widgets.lua"], [41303, "imstb_rectpack.lua"], [41749, "imstb_textedit.lua"], [42990, "imstb_truetype.lua"], [45458, "imstd_minstdio.lua"]]

build/ImGui.luau

@@ -1010,8 +1010,8 @@ local function ApplyWindowSettings(window, settings)
             window.AutoFitFramesX = 0; window.AutoFitFramesY = 0
         end
         window.Collapsed = settings.Collapsed
-        -- window.DockId = settings.DockId
+        window.DockId = settings.DockId or 0
-        -- window.DockOrder = settings.DockOrder
+        window.DockOrder = settings.DockOrder or -1
         SetWindowConditionAllowFlags(window, ImGuiCond.FirstUseEver, false)
     end
 
@@ -1042,7 +1042,7 @@ local function InitOrLoadWindowSettings(window, settings)
     window.SetWindowPosAllowFlags = bit32.bor(ImGuiCond.Always, ImGuiCond.Once, ImGuiCond.FirstUseEver, ImGuiCond.Appearing)
     window.SetWindowSizeAllowFlags = window.SetWindowPosAllowFlags
     window.SetWindowCollapsedAllowFlags = window.SetWindowPosAllowFlags
-    -- window.SetWindowDockAllowFlags = window.SetWindowPosAllowFlags
+    window.SetWindowDockAllowFlags = window.SetWindowPosAllowFlags
     ApplyWindowSettings(window, settings)
     if settings ~= nil then
         -- TODO: settings.LastUsedDate = g.SessionDate
@@ -5117,7 +5117,7 @@ local function RenderWindowOuterBorders(window)
         RenderWindowOuterSingleBorder(window, border_n, border_col_resizing, ImMax(2.0, window.WindowBorderSize))
     end
 
-    if g.Style.FrameBorderSize > 0 and (bit32.band(window.Flags, ImGuiWindowFlags.NoTitleBar) == 0) then
+    if g.Style.FrameBorderSize > 0 and (bit32.band(window.Flags, ImGuiWindowFlags.NoTitleBar) == 0) and not window.DockIsActive then
         local y = window.Pos.y + window.TitleBarHeight - 1
         window.DrawList:AddLineH(window.Pos.x + border_size * 0.5, window.Pos.x + window.Size.x - border_size * 0.5, y, border_col, g.Style.FrameBorderSize)
     end
@@ -5162,11 +5162,19 @@ local function RenderWindowDecorations(window, title_bar_rect, title_bar_is_high
 
             if bit32.band(bg_col, IM_COL32_A_MASK) ~= 0 then
                 local bg_rect = ImRect(window.Pos + ImVec2(0, window.TitleBarHeight), window.Pos + window.Size)
-                local bg_rounding_flags = (bit32.band(flags, ImGuiWindowFlags.NoTitleBar) ~= 0) and ImDrawFlags.RoundCornersAll or ImDrawFlags.RoundCornersBottom
+                local bg_rounding_flags
-                local bg_draw_list = window.DrawList
+                if window.DockIsActive then
+                    bg_rounding_flags = ImGui.CalcRoundingFlagsForRectInRect(bg_rect, window.DockNode.HostWindow:Rect(), 0.0)
+                else
+                    bg_rounding_flags = (bit32.band(flags, ImGuiWindowFlags.NoTitleBar) ~= 0) and ImDrawFlags.RoundCornersAll or ImDrawFlags.RoundCornersBottom
+                end
+                local bg_draw_list = window.DockIsActive and window.DockNode.HostWindow.DrawList or window.DrawList
+                if window.DockIsActive then bg_draw_list:ChannelsSetCurrent(0) end
                 bg_draw_list:AddRectFilled(bg_rect.Min, bg_rect.Max, bg_col, window_rounding, bg_rounding_flags)
+                if window.DockIsActive then bg_draw_list:ChannelsSetCurrent(1) end
             end
         end
+        if window.DockIsActive then window.DockNode.IsBgDrawnThisFrame = true end
 
         -- Title bar
         if bit32.band(flags, ImGuiWindowFlags.NoTitleBar) == 0 and not window.DockIsActive then
@@ -5184,6 +5192,25 @@ local function RenderWindowDecorations(window, title_bar_rect, title_bar_is_high
             end
         end
 
+        -- Docking: Unhide tab bar (small triangle in the corner), drag from small triangle to quickly undock
+        local node = window.DockNode
+        if window.DockIsActive and node:IsHiddenTabBar() and not node:IsNoTabBar() then
+            local unhide_sz_draw = ImTrunc(g.FontSize * 0.70)
+            local unhide_sz_hit = ImTrunc(g.FontSize * 0.55)
+            local p = node.Pos
+            local r = ImRect(p, p + ImVec2(unhide_sz_hit, unhide_sz_hit))
+            local unhide_id = window:GetID("#UNHIDE")
+            ImGui.KeepAliveID(unhide_id)
+            local pressed, hovered, held = ImGui.ButtonBehavior(r, unhide_id, ImGuiButtonFlags.FlattenChildren)
+            if pressed then
+                node.WantHiddenTabBarToggle = true
+            elseif held and ImGui.IsMouseDragging(0) then
+                ImGui.StartMouseMovingWindowOrNode(window, node, true)
+            end
+            local col = ImGui.GetColorU32(((held and hovered) or (node.IsFocused and not hovered)) and ImGuiCol.ButtonActive or (hovered and ImGuiCol.ButtonHovered or ImGuiCol.Button))
+            window.DrawList:AddTriangleFilled(p, p + ImVec2(unhide_sz_draw, 0.0), p + ImVec2(0.0, unhide_sz_draw), col)
+        end
+
         if window.ScrollbarX then
             ImGui.Scrollbar(ImGuiAxis.X)
         end
@@ -5212,13 +5239,14 @@ local function RenderWindowDecorations(window, title_bar_rect, title_bar_is_high
             end
         end
 
-        if handle_borders_and_resize_grips then
+        if handle_borders_and_resize_grips and not window.DockNodeAsHost then
             RenderWindowOuterBorders(window)
         end
     end
 
     window.DC.NavLayerCurrent = ImGuiNavLayer.Main
 end
+ImGui.RenderWindowOuterBorders = RenderWindowOuterBorders
 
 --- @param window         ImGuiWindow
 --- @param title_bar_rect ImRect
@@ -6068,6 +6096,11 @@ end
 --- @param popup_flags ImGuiPopupFlags
 function ImGui.IsPopupOpen(id, popup_flags)
     local g = GImGui
+    if popup_flags == nil then popup_flags = 0 end
+    if type(id) == "string" then
+        -- str_id overload: with AnyPopupId the id must be 0, otherwise it is hashed with the current window's ID stack
+        id = (bit32.band(popup_flags, ImGuiPopupFlags.AnyPopupId) ~= 0) and 0 or g.CurrentWindow:GetID(id)
+    end
 
     if bit32.band(popup_flags, ImGuiPopupFlags.AnyPopupId) ~= 0 then
         -- Return true if any popup is open at the current BeginPopup() level of the popup stack
@@ -7986,7 +8019,9 @@ local function AddWindowToDrawData(window, layer)
     local g = GImGui
     local viewport = window.Viewport
     g.IO.MetricsRenderWindows = g.IO.MetricsRenderWindows + 1
-    -- TODO: splitter
+    if window.DrawList._Splitter._Count > 1 then
+        window.DrawList:ChannelsMerge() -- Merge if user forgot to merge back. Also required for DockNodeHost windows.
+    end
     ImGui.AddDrawListToDrawDataEx(viewport.DrawDataP, viewport.DrawDataBuilder.Layers[layer], window.DrawList)
     for _, child in window.DC.ChildWindows:iter() do
         if (ImGui.IsWindowActiveAndVisible(child)) then -- Clipped children may have been marked not active
@@ -17305,6 +17340,7 @@ local function FixLargeWindowsWhenUndocking(size, ref_viewport)
 end
 
 function ImGui.DockContextProcessUndockWindow(ctx, window, clear_persistent_docking_ref)
+    if clear_persistent_docking_ref == nil then clear_persistent_docking_ref = true end -- C++ default argument
     if window.DockNode then
         ImGui.DockNodeRemoveWindow(window.DockNode, window, clear_persistent_docking_ref and 0 or window.DockId)
     else
@@ -18291,7 +18327,7 @@ function ImGui.DockNodeCalcSplitRects(pos_old, size_old, pos_new, size_new, dir,
     local g = ImGui.GetCurrentContext()
     local dock_spacing = g.Style.ItemInnerSpacing.x
     local axis = (dir == ImGuiDir.Left or dir == ImGuiDir.Right) and ImGuiAxis.X or ImGuiAxis.Y
-    local a, o = axis + 1, bit32.bxor(axis, 1) + 1
+    local a, o = axis, 3 - axis -- the port's ImGuiAxis is 1-based (X=1,Y=2): it is directly the ImVec2 index
     pos_new[o] = pos_old[o]
     size_new[o] = size_old[o]
 
@@ -18435,7 +18471,7 @@ function ImGui.DockNodePreviewDockSetup(host_window, host_node, payload_window,
         local size_new, size_old = ImVec2(0, 0), ImVec2(data.FutureNode.Size.x, data.FutureNode.Size.y)
         ImGui.DockNodeCalcSplitRects(pos_old, size_old, pos_new, size_new, split_dir, payload_window.Size)
 
-        local split_ratio = ImSaturate(size_new[split_axis + 1] / data.FutureNode.Size[split_axis + 1])
+        local split_ratio = ImSaturate(size_new[split_axis] / data.FutureNode.Size[split_axis])
         data.FutureNode.Pos = pos_new
         data.FutureNode.Size = size_new
         data.SplitRatio = (split_dir == ImGuiDir.Right or split_dir == ImGuiDir.Down) and (1.0 - split_ratio) or split_ratio
@@ -18523,7 +18559,7 @@ function ImGui.DockNodePreviewDockRender(host_window, host_node, root_payload, d
                 local cc = draw_r_in:GetCenter()
                 local center = ImVec2(math.floor(cc.x), math.floor(cc.y))
                 dl:AddRectFilled(draw_r.Min, draw_r.Max, overlay_col, overlay_rounding)
-                dl:AddRect(draw_r_in.Min, draw_r_in.Max, overlay_col_lines, overlay_rounding, 0, thickness)
+                dl:AddRect(draw_r_in.Min, draw_r_in.Max, overlay_col_lines, overlay_rounding, thickness)
                 if dir == ImGuiDir.Left or dir == ImGuiDir.Right then
                     dl:AddLineV(center.x, draw_r_in.Min.y, draw_r_in.Max.y, overlay_col_lines, thickness)
                 end
@@ -18562,7 +18598,7 @@ function ImGui.DockNodeTreeSplit(ctx, parent_node, split_axis, split_inheritor_c
     parent_node.AuthorityForPos = ImGuiDataAuthority.DockNode
     parent_node.AuthorityForSize = ImGuiDataAuthority.DockNode
 
-    local a = split_axis + 1
+    local a = split_axis
     local size_avail = parent_node.Size[a] - g.Style.DockingSeparatorSize
     size_avail = ImMax(size_avail, g.Style.WindowMinSize[a] * 2.0)
     IM_ASSERT(size_avail > 0.0)
@@ -18648,7 +18684,7 @@ function ImGui.DockNodeTreeUpdatePosSize(node, pos, size, only_write_to_single_n
 
     if child_0_is_or_will_be_visible and child_1_is_or_will_be_visible then
         local spacing = g.Style.DockingSeparatorSize
-        local a = node.SplitAxis + 1
+        local a = node.SplitAxis
         local size_avail = ImMax(size[a] - spacing, 0.0)
 
         local size_min_each = ImTrunc(ImMin(size_avail, g.Style.WindowMinSize[a] * 2.0) * 0.5)
@@ -18717,7 +18753,7 @@ function ImGui.DockNodeTreeUpdateSplitter(node)
     if child_0.IsVisible and child_1.IsVisible then
         local axis = node.SplitAxis
         IM_ASSERT(axis ~= ImGuiAxis.None)
-        local a, o = axis + 1, bit32.bxor(axis, 1) + 1
+        local a, o = axis, 3 - axis -- the port's ImGuiAxis is 1-based (X=1,Y=2): it is directly the ImVec2 index
         local bb = ImRect(ImVec2(child_0.Pos.x, child_0.Pos.y), ImVec2(child_1.Pos.x, child_1.Pos.y))
         bb.Min[a] = bb.Min[a] + child_0.Size[a]
         bb.Max[o] = bb.Max[o] + child_1.Size[o]
@@ -19808,7 +19844,7 @@ function ImGui.SplitterBehavior(bb, id, axis, size1, size2, min_size1, min_size2
     local bb_render = ImRect(bb.Min, bb.Max)
     if held then
         local d = g.IO.MousePos - g.ActiveIdClickOffset - bb_interact.Min
-        local mouse_delta = d[axis + 1]
+        local mouse_delta = d[axis]
 
         local size_1_maximum_delta = ImMax(0.0, size1 - min_size1)
         local size_2_maximum_delta = ImMax(0.0, size2 - min_size2)
@@ -20104,7 +20140,7 @@ 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)
+    draw_list:AddRect(bb.Min, bb.Max, ImGui.GetColorU32(ImGuiCol.DragDropTarget), rounding, g.Style.DragDropTargetBorderSize)
 end
 
 --- @return ImGuiPayload?
@@ -23622,7 +23658,8 @@ function MT.ImDrawListSplitter:SetCurrentChannel(draw_list, idx)
     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]
+    local curr_cmd = nil
+    if draw_list.CmdBuffer.Size > 0 then curr_cmd = draw_list.CmdBuffer.Data[draw_list.CmdBuffer.Size] end
     if curr_cmd == nil then
         draw_list:AddDrawCmd()
     elseif curr_cmd.ElemCount == 0 then
@@ -25099,6 +25136,25 @@ function ImGui.RenderColorRectWithAlphaCheckerboard(draw_list, p_min, p_max, col
 end
 
 
+
+function ImGui.RenderRectFilledWithHole(draw_list, outer, inner, col, rounding)
+    local fill_L = inner.Min.x > outer.Min.x
+    local fill_R = inner.Max.x < outer.Max.x
+    local fill_U = inner.Min.y > outer.Min.y
+    local fill_D = inner.Max.y < outer.Max.y
+    local D = ImDrawFlags
+    local bor = bit32.bor
+    local function f(c, v) return c and 0 or v end
+    if fill_L then draw_list:AddRectFilled(ImVec2(outer.Min.x, inner.Min.y), ImVec2(inner.Min.x, inner.Max.y), col, rounding, bor(D.RoundCornersNone, f(fill_U, D.RoundCornersTopLeft), f(fill_D, D.RoundCornersBottomLeft))) end
+    if fill_R then draw_list:AddRectFilled(ImVec2(inner.Max.x, inner.Min.y), ImVec2(outer.Max.x, inner.Max.y), col, rounding, bor(D.RoundCornersNone, f(fill_U, D.RoundCornersTopRight), f(fill_D, D.RoundCornersBottomRight))) end
+    if fill_U then draw_list:AddRectFilled(ImVec2(inner.Min.x, outer.Min.y), ImVec2(inner.Max.x, inner.Min.y), col, rounding, bor(D.RoundCornersNone, f(fill_L, D.RoundCornersTopLeft), f(fill_R, D.RoundCornersTopRight))) end
+    if fill_D then draw_list:AddRectFilled(ImVec2(inner.Min.x, inner.Max.y), ImVec2(inner.Max.x, outer.Max.y), col, rounding, bor(D.RoundCornersNone, f(fill_L, D.RoundCornersBottomLeft), f(fill_R, D.RoundCornersBottomRight))) end
+    if fill_L and fill_U then draw_list:AddRectFilled(ImVec2(outer.Min.x, outer.Min.y), ImVec2(inner.Min.x, inner.Min.y), col, rounding, D.RoundCornersTopLeft) end
+    if fill_R and fill_U then draw_list:AddRectFilled(ImVec2(inner.Max.x, outer.Min.y), ImVec2(outer.Max.x, inner.Min.y), col, rounding, D.RoundCornersTopRight) end
+    if fill_L and fill_D then draw_list:AddRectFilled(ImVec2(outer.Min.x, inner.Max.y), ImVec2(inner.Min.x, outer.Max.y), col, rounding, D.RoundCornersBottomLeft) end
+    if fill_R and fill_D then draw_list:AddRectFilled(ImVec2(inner.Max.x, inner.Max.y), ImVec2(outer.Max.x, outer.Max.y), col, rounding, D.RoundCornersBottomRight) end
+end
+
 return true -- [Roblox] ModuleScripts must return exactly one value
 end
 
@@ -32207,7 +32263,7 @@ function ImGui.EndTabBar()
     end
 
     g.CurrentTabBarStack:pop_back()
-    g.CurrentTabBar = (g.CurrentTabBarStack.Size == 0) and nil or g.CurrentTabBarStack.Data[g.CurrentTabBarStack.Size]
+    if g.CurrentTabBarStack.Size == 0 then g.CurrentTabBar = nil else g.CurrentTabBar = g.CurrentTabBarStack.Data[g.CurrentTabBarStack.Size] end
 end
 
 function ImGui.TabBarLayout(tab_bar)

imgui/imgui.lua

@@ -998,8 +998,8 @@ local function ApplyWindowSettings(window, settings)
             window.AutoFitFramesX = 0; window.AutoFitFramesY = 0
         end
         window.Collapsed = settings.Collapsed
-        -- window.DockId = settings.DockId
+        window.DockId = settings.DockId or 0
-        -- window.DockOrder = settings.DockOrder
+        window.DockOrder = settings.DockOrder or -1
         SetWindowConditionAllowFlags(window, ImGuiCond.FirstUseEver, false)
     end
 
@@ -1030,7 +1030,7 @@ local function InitOrLoadWindowSettings(window, settings)
     window.SetWindowPosAllowFlags = bit32.bor(ImGuiCond.Always, ImGuiCond.Once, ImGuiCond.FirstUseEver, ImGuiCond.Appearing)
     window.SetWindowSizeAllowFlags = window.SetWindowPosAllowFlags
     window.SetWindowCollapsedAllowFlags = window.SetWindowPosAllowFlags
-    -- window.SetWindowDockAllowFlags = window.SetWindowPosAllowFlags
+    window.SetWindowDockAllowFlags = window.SetWindowPosAllowFlags
     ApplyWindowSettings(window, settings)
     if settings ~= nil then
         -- TODO: settings.LastUsedDate = g.SessionDate
@@ -5105,7 +5105,7 @@ local function RenderWindowOuterBorders(window)
         RenderWindowOuterSingleBorder(window, border_n, border_col_resizing, ImMax(2.0, window.WindowBorderSize))
     end
 
-    if g.Style.FrameBorderSize > 0 and (bit32.band(window.Flags, ImGuiWindowFlags.NoTitleBar) == 0) then
+    if g.Style.FrameBorderSize > 0 and (bit32.band(window.Flags, ImGuiWindowFlags.NoTitleBar) == 0) and not window.DockIsActive then
         local y = window.Pos.y + window.TitleBarHeight - 1
         window.DrawList:AddLineH(window.Pos.x + border_size * 0.5, window.Pos.x + window.Size.x - border_size * 0.5, y, border_col, g.Style.FrameBorderSize)
     end
@@ -5150,11 +5150,19 @@ local function RenderWindowDecorations(window, title_bar_rect, title_bar_is_high
 
             if bit32.band(bg_col, IM_COL32_A_MASK) ~= 0 then
                 local bg_rect = ImRect(window.Pos + ImVec2(0, window.TitleBarHeight), window.Pos + window.Size)
-                local bg_rounding_flags = (bit32.band(flags, ImGuiWindowFlags.NoTitleBar) ~= 0) and ImDrawFlags.RoundCornersAll or ImDrawFlags.RoundCornersBottom
+                local bg_rounding_flags
-                local bg_draw_list = window.DrawList
+                if window.DockIsActive then
+                    bg_rounding_flags = ImGui.CalcRoundingFlagsForRectInRect(bg_rect, window.DockNode.HostWindow:Rect(), 0.0)
+                else
+                    bg_rounding_flags = (bit32.band(flags, ImGuiWindowFlags.NoTitleBar) ~= 0) and ImDrawFlags.RoundCornersAll or ImDrawFlags.RoundCornersBottom
+                end
+                local bg_draw_list = window.DockIsActive and window.DockNode.HostWindow.DrawList or window.DrawList
+                if window.DockIsActive then bg_draw_list:ChannelsSetCurrent(0) end
                 bg_draw_list:AddRectFilled(bg_rect.Min, bg_rect.Max, bg_col, window_rounding, bg_rounding_flags)
+                if window.DockIsActive then bg_draw_list:ChannelsSetCurrent(1) end
             end
         end
+        if window.DockIsActive then window.DockNode.IsBgDrawnThisFrame = true end
 
         -- Title bar
         if bit32.band(flags, ImGuiWindowFlags.NoTitleBar) == 0 and not window.DockIsActive then
@@ -5172,6 +5180,25 @@ local function RenderWindowDecorations(window, title_bar_rect, title_bar_is_high
             end
         end
 
+        -- Docking: Unhide tab bar (small triangle in the corner), drag from small triangle to quickly undock
+        local node = window.DockNode
+        if window.DockIsActive and node:IsHiddenTabBar() and not node:IsNoTabBar() then
+            local unhide_sz_draw = ImTrunc(g.FontSize * 0.70)
+            local unhide_sz_hit = ImTrunc(g.FontSize * 0.55)
+            local p = node.Pos
+            local r = ImRect(p, p + ImVec2(unhide_sz_hit, unhide_sz_hit))
+            local unhide_id = window:GetID("#UNHIDE")
+            ImGui.KeepAliveID(unhide_id)
+            local pressed, hovered, held = ImGui.ButtonBehavior(r, unhide_id, ImGuiButtonFlags.FlattenChildren)
+            if pressed then
+                node.WantHiddenTabBarToggle = true
+            elseif held and ImGui.IsMouseDragging(0) then
+                ImGui.StartMouseMovingWindowOrNode(window, node, true)
+            end
+            local col = ImGui.GetColorU32(((held and hovered) or (node.IsFocused and not hovered)) and ImGuiCol.ButtonActive or (hovered and ImGuiCol.ButtonHovered or ImGuiCol.Button))
+            window.DrawList:AddTriangleFilled(p, p + ImVec2(unhide_sz_draw, 0.0), p + ImVec2(0.0, unhide_sz_draw), col)
+        end
+
         if window.ScrollbarX then
             ImGui.Scrollbar(ImGuiAxis.X)
         end
@@ -5200,13 +5227,14 @@ local function RenderWindowDecorations(window, title_bar_rect, title_bar_is_high
             end
         end
 
-        if handle_borders_and_resize_grips then
+        if handle_borders_and_resize_grips and not window.DockNodeAsHost then
             RenderWindowOuterBorders(window)
         end
     end
 
     window.DC.NavLayerCurrent = ImGuiNavLayer.Main
 end
+ImGui.RenderWindowOuterBorders = RenderWindowOuterBorders
 
 --- @param window         ImGuiWindow
 --- @param title_bar_rect ImRect
@@ -6056,6 +6084,11 @@ end
 --- @param popup_flags ImGuiPopupFlags
 function ImGui.IsPopupOpen(id, popup_flags)
     local g = GImGui
+    if popup_flags == nil then popup_flags = 0 end
+    if type(id) == "string" then
+        -- str_id overload: with AnyPopupId the id must be 0, otherwise it is hashed with the current window's ID stack
+        id = (bit32.band(popup_flags, ImGuiPopupFlags.AnyPopupId) ~= 0) and 0 or g.CurrentWindow:GetID(id)
+    end
 
     if bit32.band(popup_flags, ImGuiPopupFlags.AnyPopupId) ~= 0 then
         -- Return true if any popup is open at the current BeginPopup() level of the popup stack
@@ -7974,7 +8007,9 @@ local function AddWindowToDrawData(window, layer)
     local g = GImGui
     local viewport = window.Viewport
     g.IO.MetricsRenderWindows = g.IO.MetricsRenderWindows + 1
-    -- TODO: splitter
+    if window.DrawList._Splitter._Count > 1 then
+        window.DrawList:ChannelsMerge() -- Merge if user forgot to merge back. Also required for DockNodeHost windows.
+    end
     ImGui.AddDrawListToDrawDataEx(viewport.DrawDataP, viewport.DrawDataBuilder.Layers[layer], window.DrawList)
     for _, child in window.DC.ChildWindows:iter() do
         if (ImGui.IsWindowActiveAndVisible(child)) then -- Clipped children may have been marked not active

imgui/imgui_docking.lua

@@ -594,6 +594,7 @@ local function FixLargeWindowsWhenUndocking(size, ref_viewport)
 end
 
 function ImGui.DockContextProcessUndockWindow(ctx, window, clear_persistent_docking_ref)
+    if clear_persistent_docking_ref == nil then clear_persistent_docking_ref = true end -- C++ default argument
     if window.DockNode then
         ImGui.DockNodeRemoveWindow(window.DockNode, window, clear_persistent_docking_ref and 0 or window.DockId)
     else
@@ -1580,7 +1581,7 @@ function ImGui.DockNodeCalcSplitRects(pos_old, size_old, pos_new, size_new, dir,
     local g = ImGui.GetCurrentContext()
     local dock_spacing = g.Style.ItemInnerSpacing.x
     local axis = (dir == ImGuiDir.Left or dir == ImGuiDir.Right) and ImGuiAxis.X or ImGuiAxis.Y
-    local a, o = axis + 1, bit32.bxor(axis, 1) + 1
+    local a, o = axis, 3 - axis -- the port's ImGuiAxis is 1-based (X=1,Y=2): it is directly the ImVec2 index
     pos_new[o] = pos_old[o]
     size_new[o] = size_old[o]
 
@@ -1724,7 +1725,7 @@ function ImGui.DockNodePreviewDockSetup(host_window, host_node, payload_window,
         local size_new, size_old = ImVec2(0, 0), ImVec2(data.FutureNode.Size.x, data.FutureNode.Size.y)
         ImGui.DockNodeCalcSplitRects(pos_old, size_old, pos_new, size_new, split_dir, payload_window.Size)
 
-        local split_ratio = ImSaturate(size_new[split_axis + 1] / data.FutureNode.Size[split_axis + 1])
+        local split_ratio = ImSaturate(size_new[split_axis] / data.FutureNode.Size[split_axis])
         data.FutureNode.Pos = pos_new
         data.FutureNode.Size = size_new
         data.SplitRatio = (split_dir == ImGuiDir.Right or split_dir == ImGuiDir.Down) and (1.0 - split_ratio) or split_ratio
@@ -1812,7 +1813,7 @@ function ImGui.DockNodePreviewDockRender(host_window, host_node, root_payload, d
                 local cc = draw_r_in:GetCenter()
                 local center = ImVec2(math.floor(cc.x), math.floor(cc.y))
                 dl:AddRectFilled(draw_r.Min, draw_r.Max, overlay_col, overlay_rounding)
-                dl:AddRect(draw_r_in.Min, draw_r_in.Max, overlay_col_lines, overlay_rounding, 0, thickness)
+                dl:AddRect(draw_r_in.Min, draw_r_in.Max, overlay_col_lines, overlay_rounding, thickness)
                 if dir == ImGuiDir.Left or dir == ImGuiDir.Right then
                     dl:AddLineV(center.x, draw_r_in.Min.y, draw_r_in.Max.y, overlay_col_lines, thickness)
                 end
@@ -1851,7 +1852,7 @@ function ImGui.DockNodeTreeSplit(ctx, parent_node, split_axis, split_inheritor_c
     parent_node.AuthorityForPos = ImGuiDataAuthority.DockNode
     parent_node.AuthorityForSize = ImGuiDataAuthority.DockNode
 
-    local a = split_axis + 1
+    local a = split_axis
     local size_avail = parent_node.Size[a] - g.Style.DockingSeparatorSize
     size_avail = ImMax(size_avail, g.Style.WindowMinSize[a] * 2.0)
     IM_ASSERT(size_avail > 0.0)
@@ -1937,7 +1938,7 @@ function ImGui.DockNodeTreeUpdatePosSize(node, pos, size, only_write_to_single_n
 
     if child_0_is_or_will_be_visible and child_1_is_or_will_be_visible then
         local spacing = g.Style.DockingSeparatorSize
-        local a = node.SplitAxis + 1
+        local a = node.SplitAxis
         local size_avail = ImMax(size[a] - spacing, 0.0)
 
         local size_min_each = ImTrunc(ImMin(size_avail, g.Style.WindowMinSize[a] * 2.0) * 0.5)
@@ -2006,7 +2007,7 @@ function ImGui.DockNodeTreeUpdateSplitter(node)
     if child_0.IsVisible and child_1.IsVisible then
         local axis = node.SplitAxis
         IM_ASSERT(axis ~= ImGuiAxis.None)
-        local a, o = axis + 1, bit32.bxor(axis, 1) + 1
+        local a, o = axis, 3 - axis -- the port's ImGuiAxis is 1-based (X=1,Y=2): it is directly the ImVec2 index
         local bb = ImRect(ImVec2(child_0.Pos.x, child_0.Pos.y), ImVec2(child_1.Pos.x, child_1.Pos.y))
         bb.Min[a] = bb.Min[a] + child_0.Size[a]
         bb.Max[o] = bb.Max[o] + child_1.Size[o]
@@ -3097,7 +3098,7 @@ function ImGui.SplitterBehavior(bb, id, axis, size1, size2, min_size1, min_size2
     local bb_render = ImRect(bb.Min, bb.Max)
     if held then
         local d = g.IO.MousePos - g.ActiveIdClickOffset - bb_interact.Min
-        local mouse_delta = d[axis + 1]
+        local mouse_delta = d[axis]
 
         local size_1_maximum_delta = ImMax(0.0, size1 - min_size1)
         local size_2_maximum_delta = ImMax(0.0, size2 - min_size2)

imgui/imgui_dragdrop.lua

@@ -266,7 +266,7 @@ 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)
+    draw_list:AddRect(bb.Min, bb.Max, ImGui.GetColorU32(ImGuiCol.DragDropTarget), rounding, g.Style.DragDropTargetBorderSize)
 end
 
 --- @return ImGuiPayload?

imgui/imgui_draw.lua

@@ -3492,7 +3492,8 @@ function MT.ImDrawListSplitter:SetCurrentChannel(draw_list, idx)
     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]
+    local curr_cmd = nil
+    if draw_list.CmdBuffer.Size > 0 then curr_cmd = draw_list.CmdBuffer.Data[draw_list.CmdBuffer.Size] end
     if curr_cmd == nil then
         draw_list:AddDrawCmd()
     elseif curr_cmd.ElemCount == 0 then
@@ -4969,4 +4970,23 @@ function ImGui.RenderColorRectWithAlphaCheckerboard(draw_list, p_min, p_max, col
 end
 
 
+
+function ImGui.RenderRectFilledWithHole(draw_list, outer, inner, col, rounding)
+    local fill_L = inner.Min.x > outer.Min.x
+    local fill_R = inner.Max.x < outer.Max.x
+    local fill_U = inner.Min.y > outer.Min.y
+    local fill_D = inner.Max.y < outer.Max.y
+    local D = ImDrawFlags
+    local bor = bit32.bor
+    local function f(c, v) return c and 0 or v end
+    if fill_L then draw_list:AddRectFilled(ImVec2(outer.Min.x, inner.Min.y), ImVec2(inner.Min.x, inner.Max.y), col, rounding, bor(D.RoundCornersNone, f(fill_U, D.RoundCornersTopLeft), f(fill_D, D.RoundCornersBottomLeft))) end
+    if fill_R then draw_list:AddRectFilled(ImVec2(inner.Max.x, inner.Min.y), ImVec2(outer.Max.x, inner.Max.y), col, rounding, bor(D.RoundCornersNone, f(fill_U, D.RoundCornersTopRight), f(fill_D, D.RoundCornersBottomRight))) end
+    if fill_U then draw_list:AddRectFilled(ImVec2(inner.Min.x, outer.Min.y), ImVec2(inner.Max.x, inner.Min.y), col, rounding, bor(D.RoundCornersNone, f(fill_L, D.RoundCornersTopLeft), f(fill_R, D.RoundCornersTopRight))) end
+    if fill_D then draw_list:AddRectFilled(ImVec2(inner.Min.x, inner.Max.y), ImVec2(inner.Max.x, outer.Max.y), col, rounding, bor(D.RoundCornersNone, f(fill_L, D.RoundCornersBottomLeft), f(fill_R, D.RoundCornersBottomRight))) end
+    if fill_L and fill_U then draw_list:AddRectFilled(ImVec2(outer.Min.x, outer.Min.y), ImVec2(inner.Min.x, inner.Min.y), col, rounding, D.RoundCornersTopLeft) end
+    if fill_R and fill_U then draw_list:AddRectFilled(ImVec2(inner.Max.x, outer.Min.y), ImVec2(outer.Max.x, inner.Min.y), col, rounding, D.RoundCornersTopRight) end
+    if fill_L and fill_D then draw_list:AddRectFilled(ImVec2(outer.Min.x, inner.Max.y), ImVec2(inner.Min.x, outer.Max.y), col, rounding, D.RoundCornersBottomLeft) end
+    if fill_R and fill_D then draw_list:AddRectFilled(ImVec2(inner.Max.x, inner.Max.y), ImVec2(outer.Max.x, outer.Max.y), col, rounding, D.RoundCornersBottomRight) end
+end
+
 return true -- [Roblox] ModuleScripts must return exactly one value

imgui/imgui_tabs.lua

@@ -218,7 +218,7 @@ function ImGui.EndTabBar()
     end
 
     g.CurrentTabBarStack:pop_back()
-    g.CurrentTabBar = (g.CurrentTabBarStack.Size == 0) and nil or g.CurrentTabBarStack.Data[g.CurrentTabBarStack.Size]
+    if g.CurrentTabBarStack.Size == 0 then g.CurrentTabBar = nil else g.CurrentTabBar = g.CurrentTabBarStack.Data[g.CurrentTabBarStack.Size] end
 end
 
 function ImGui.TabBarLayout(tab_bar)

main.client.luau

@@ -17,7 +17,7 @@ local counter = 0
 ImGui.CreateContext()
 
 local io = ImGui.GetIO()
-io.ConfigFlags = bit32.bor(io.ConfigFlags, ImGuiConfigFlags.NavEnableKeyboard)
+io.ConfigFlags = bit32.bor(io.ConfigFlags, ImGuiConfigFlags.NavEnableKeyboard, ImGuiConfigFlags.DockingEnable)
 
 local style = ImGui.GetStyle()
 style:ScaleAllSizes(main_scale)
@@ -29,6 +29,9 @@ RunService.Stepped:Connect(function()
     ImGui_ImplRoblox.NewFrame()
     ImGui.NewFrame()
 
+    -- Dockspace covering the whole screen; the centre stays transparent so the game shows through
+    ImGui.DockSpaceOverViewport(0, nil, G.ImGuiDockNodeFlags.PassthruCentralNode)
+
     if show_demo_window then
         ImGui.ShowDemoWindow()
     end

tools/test/PORTING.md

@@ -45,10 +45,14 @@ there, but keep this port's existing data structures and conventions. Read the s
 - `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.
+
+- **ImGuiAxis is 1-based in this port** (`None=0, X=1, Y=2`; upstream `None=-1, X=0, Y=1`). Use `v[axis]` to index an ImVec2 and `3 - axis` for the other axis. `ImGuiDir` keeps upstream values (`None=-1, Left=0, Right=1, Up=2, Down=3`).
+- Never write `cond and nil or x` in Lua: it always evaluates `x`. Use an `if`.
+- Port signature quirk: `AddRect(min, max, col, rounding, thickness, flags)` (thickness BEFORE flags; upstream has flags first). Check the port's signature before porting any draw call that takes both.\n
+- C++ default arguments (e.g. `bool x = true`) must be reproduced with `if x == nil then x = true end`; a missing Lua argument is nil/falsy.

tools/test/roblox_mock.luau

@@ -195,7 +195,7 @@ for i = 0, 255 do hex[i] = string.format("%02x", i) end
 
 local total = 0
 for frame = 1, NFRAMES do
-    local r = rnd(100)
+    local r = ARG_QUIET and 100 or 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
@@ -221,25 +221,5 @@ for frame = 1, NFRAMES do
     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

@@ -4,12 +4,9 @@
 
   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
+import argparse, os, shutil, subprocess, sys, tempfile
 TMP = tempfile.mkdtemp(prefix="imgui_test_")  # per process: parallel runs must not share files
 
 HERE = os.path.dirname(os.path.abspath(__file__))
@@ -34,7 +31,7 @@ def build_run(args, flags):
     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)
+    flags = "ARG_FRAMES=%d; ARG_BIG=%s; ARG_OPEN=%s; ARG_QUIET=%s; %s" % (args.frames, str(args.big).lower(), str(args.open).lower(), str(args.quiet).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:
@@ -56,57 +53,18 @@ def remap(text):
         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)
+    ap.add_argument("--quiet", action="store_true", help="no random input (scripted tests drive io themselves)")
     args = ap.parse_args()
 
-    if args.bench:
+    code, out = run(args, "")
-        for mode in ["", "ARG_FORCE=true"]:
+    print(out[-4000:])
-            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:

tools/test/scripts/t_dock.luau

@@ -0,0 +1,47 @@
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+local RunService = game:GetService("RunService")
+local G = require(ReplicatedStorage:WaitForChild("ImGui"))
+local ImGui, ImVec2 = G.ImGui, G.ImVec2
+ImGui.CreateContext()
+local io = ImGui.GetIO()
+io.ConfigFlags = bit32.bor(io.ConfigFlags, G.ImGuiConfigFlags.DockingEnable)
+G.ImGui_ImplRoblox.Init()
+local frame = 0
+local dockspace_id
+local winA, winB, winC
+RunService.Stepped:Connect(function()
+    frame += 1
+    G.ImGui_ImplRoblox.NewFrame()
+    ImGui.NewFrame()
+    dockspace_id = ImGui.DockSpaceOverViewport(0, nil, 0)
+    if frame == 2 then
+        ImGui.DockBuilderRemoveNode(dockspace_id)
+        ImGui.DockBuilderAddNode(dockspace_id, bit32.bor(G.ImGuiDockNodeFlags.DockSpace))
+        ImGui.DockBuilderSetNodeSize(dockspace_id, ImGui.GetMainViewport().Size)
+        local left, right = ImGui.DockBuilderSplitNode(dockspace_id, G.ImGuiDir.Left, 0.3)
+        ImGui.DockBuilderDockWindow("A", left)
+        ImGui.DockBuilderDockWindow("B", right)
+        ImGui.DockBuilderDockWindow("C", right)
+        ImGui.DockBuilderFinish(dockspace_id)
+        print("split", left, right)
+    end
+    for _, n in ipairs({"A", "B", "C"}) do
+        if ImGui.Begin(n) then ImGui.Text("window " .. n) end
+        ImGui.End()
+    end
+    if frame == 30 then
+        local g = ImGui.GetCurrentContext()
+        local a, b, c = ImGui.FindWindowByName("A"), ImGui.FindWindowByName("B"), ImGui.FindWindowByName("C")
+        print("A node", a.DockNode and a.DockNode.ID, "B node", b.DockNode and b.DockNode.ID, "C node", c.DockNode and c.DockNode.ID)
+        assert(a.DockNode ~= nil and b.DockNode ~= nil, "windows must be docked")
+        assert(a.DockNode ~= b.DockNode, "A and B in different nodes")
+        assert(b.DockNode == c.DockNode, "B and C share a node")
+        assert(b.DockNode.TabBar ~= nil and b.DockNode.TabBar.Tabs.Size == 2, "B/C tab bar with 2 tabs")
+        local ini = ImGui.SaveIniSettingsToMemory()
+        print(ini)
+        assert(ini:find("%[Docking%]%[Data%]"), "docking ini section")
+        print("DOCK OK")
+    end
+    ImGui.Render()
+    G.ImGui_ImplRoblox.RenderDrawData(ImGui.GetDrawData())
+end)

tools/test/scripts/t_dock_drag.luau

@@ -0,0 +1,69 @@
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+local RunService = game:GetService("RunService")
+local G = require(ReplicatedStorage:WaitForChild("ImGui"))
+local ImGui, ImVec2 = G.ImGui, G.ImVec2
+ImGui.CreateContext()
+local io = ImGui.GetIO()
+io.ConfigFlags = bit32.bor(io.ConfigFlags, G.ImGuiConfigFlags.DockingEnable)
+G.ImGui_ImplRoblox.Init()
+local frame = 0
+-- script: {frame, x, y, down}
+local function lerp(a, b, t) return a + (b - a) * t end
+local function script(f)
+    if f >= 50 then
+        -- tab of B inside the docked node: press on the tab, drag far downward to undock
+        if f < 52 then return 150, 108, false end
+        if f == 52 then return 150, 108, true end
+        if f <= 66 then local t = (f - 52) / 14 return lerp(150, 700, t), lerp(108, 600, t), true end
+        if f <= 70 then return 700, 600, true end
+        return 700, 600, false
+    end
+    if f < 6 then return 600, 108, false end
+    if f == 6 then return 600, 108, true end
+    if f <= 20 then local t = (f - 6) / 14 return lerp(600, 250, t), lerp(108, 190, t), true end
+    if f <= 26 then return 250, 190, true end
+    if f == 27 then return 250, 190, false end
+    return 250, 190, false
+end
+local last_down = false
+RunService.Stepped:Connect(function()
+    frame += 1
+    G.ImGui_ImplRoblox.NewFrame()
+    local x, y, down = script(frame)
+    io:AddMousePosEvent(x, y)
+    if down ~= last_down then io:AddMouseButtonEvent(0, down); last_down = down end
+    ImGui.NewFrame()
+    ImGui.SetNextWindowPos(ImVec2(100, 100), G.ImGuiCond.FirstUseEver)
+    ImGui.SetNextWindowSize(ImVec2(300, 200), G.ImGuiCond.FirstUseEver)
+    if ImGui.Begin("A") then ImGui.Text("window A") end
+    ImGui.End()
+    ImGui.SetNextWindowPos(ImVec2(500, 100), G.ImGuiCond.FirstUseEver)
+    ImGui.SetNextWindowSize(ImVec2(300, 200), G.ImGuiCond.FirstUseEver)
+    if ImGui.Begin("B") then ImGui.Text("window B") end
+    ImGui.End()
+    if frame == 28 or frame == 40 then
+        local a, b = ImGui.FindWindowByName("A"), ImGui.FindWindowByName("B")
+        local g = ImGui.GetCurrentContext()
+        print("frame", frame, "movingwindow", g.MovingWindow and g.MovingWindow.Name, "dragdrop", g.DragDropActive, "A.node", a.DockNode and a.DockNode.ID, "B.node", b.DockNode and b.DockNode.ID, "B.pos", b.Pos.x, b.Pos.y)
+    end
+    if frame == 45 then
+        local a, b = ImGui.FindWindowByName("A"), ImGui.FindWindowByName("B")
+        assert(a.DockNode ~= nil and a.DockNode == b.DockNode, "B must be docked into A's node")
+        assert(a.DockNode.Windows.Size == 2, "node has 2 windows")
+        print("DRAG DOCK OK")
+    end
+    if frame >= 60 and frame <= 90 and frame % 3 == 0 then local g = ImGui.GetCurrentContext(); local b = ImGui.FindWindowByName("B"); local tb = b.DockNode and b.DockNode.TabBar; print("f", frame, "Bnode", b.DockNode and b.DockNode.ID, "Bpos", b.Pos.x, b.Pos.y, "active", g.ActiveId, "hovered", g.HoveredId, "hovwin", g.HoveredWindow and g.HoveredWindow.Name, "tabid", b.TabId, "moving", g.MovingWindow and g.MovingWindow.Name, "dd", g.DragDropActive, "mouse", g.IO.MousePos.x, g.IO.MousePos.y, "down", g.IO.MouseDown[0], "drag", ImGui.IsMouseDragging(0)) end
+    if frame == 52 then
+        local b = ImGui.FindWindowByName("B")
+        local tb = b.DockNode.TabBar
+        for i = 1, tb.Tabs.Size do local t = tb.Tabs.Data[i]; print("tab", i, ImGui.TabBarGetTabName(tb, t), "offset", t.Offset, "width", t.Width, "bar", tb.BarRect.Min.x, tb.BarRect.Min.y, tb.BarRect.Max.x, tb.BarRect.Max.y) end
+    end
+    if frame == 90 then
+        local a, b = ImGui.FindWindowByName("A"), ImGui.FindWindowByName("B")
+        print("final", "A.node", a.DockNode and a.DockNode.ID, "B.node", b.DockNode and b.DockNode.ID, "B.pos", b.Pos.x, b.Pos.y)
+        assert(b.DockNode == nil or b.DockNode ~= a.DockNode, "B must be undocked from A")
+        print("UNDOCK OK")
+    end
+    ImGui.Render()
+    G.ImGui_ImplRoblox.RenderDrawData(ImGui.GetDrawData())
+end)

tools/test/scripts/t_dock_fuzz2.luau

@@ -0,0 +1,80 @@
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+local RunService = game:GetService("RunService")
+local G = require(ReplicatedStorage:WaitForChild("ImGui"))
+local ImGui, ImVec2 = G.ImGui, G.ImVec2
+ImGui.CreateContext()
+local io = ImGui.GetIO()
+io.ConfigFlags = bit32.bor(io.ConfigFlags, G.ImGuiConfigFlags.DockingEnable)
+G.ImGui_ImplRoblox.Init()
+local frame = 0
+local seed = 7
+local function rnd(n) seed = (seed * 1103515245 + 12345) % 2147483648; return seed % n end
+local names = {"A", "B", "C", "D", "E"}
+local drag -- {fx,fy,tx,ty,start}
+local last_down = false
+local docks, undocks = 0, 0
+local function check_tree()
+    local g = ImGui.GetCurrentContext()
+    for id, node in pairs(g.DockContext.Nodes) do
+        assert(node.ID == id)
+        if node.ParentNode then
+            assert(node.ParentNode.ChildNodes[0] == node or node.ParentNode.ChildNodes[1] == node, "parent link")
+        end
+        for _, w in node.Windows:iter() do assert(w.DockNode == node or w.DockNode == nil, "window->node link") end
+        if node:IsSplitNode() then assert(node.ChildNodes[1] ~= nil and node.Windows.Size == 0, "split node has two children and no windows") end
+    end
+    for _, n in ipairs(names) do
+        local w = ImGui.FindWindowByName(n)
+        if w and w.DockNode then assert(w.DockNode.Windows:find_index(w) ~= nil, "node contains window") end
+    end
+end
+RunService.Stepped:Connect(function()
+    frame += 1
+    G.ImGui_ImplRoblox.NewFrame()
+    -- scripted drag
+    local x, y, down = (drag and drag.x or 5), (drag and drag.y or 5), false
+    if not drag and frame % 45 == 0 then
+        local w = ImGui.FindWindowByName(names[rnd(#names) + 1])
+        if w and w.Active then
+            local sx, sy
+            if w.DockNode and w.DockNode.TabBar and w.DockNode.TabBar.Tabs.Size > 0 and rnd(2) == 0 then
+                local tb = w.DockNode.TabBar; local t = tb.Tabs.Data[rnd(tb.Tabs.Size) + 1]
+                sx, sy = tb.BarRect.Min.x + t.Offset + 4, tb.BarRect.Min.y + 8
+            else sx, sy = w.Pos.x + 40, w.Pos.y + 8 end
+            local mode = rnd(3)
+            local tx, ty
+            if mode == 0 then local o = ImGui.FindWindowByName(names[rnd(#names) + 1]); tx, ty = o.Pos.x + o.Size.x * (0.1 + rnd(80) / 100), o.Pos.y + o.Size.y * (0.1 + rnd(80) / 100)
+            else tx, ty = 50 + rnd(1800), 50 + rnd(980) end
+            drag = { sx = sx, sy = sy, tx = tx, ty = ty, start = frame, x = sx, y = sy }
+            x, y = sx, sy
+        end
+    end
+    if drag then
+        local f = frame - drag.start
+        local t = math.min(f / 14, 1)
+        drag.x = drag.sx + (drag.tx - drag.sx) * t; drag.y = drag.sy + (drag.ty - drag.sy) * t
+        x, y = drag.x, drag.y
+        down = f >= 1 and f <= 24
+        if f > 26 then drag = nil end
+    end
+    io:AddMousePosEvent(x, y)
+    if down ~= last_down then io:AddMouseButtonEvent(0, down); last_down = down end
+    ImGui.NewFrame()
+    ImGui.DockSpaceOverViewport(0, nil, G.ImGuiDockNodeFlags.PassthruCentralNode)
+    for i, n in ipairs(names) do
+        ImGui.SetNextWindowPos(ImVec2(60 + i * 90, 60 + i * 50), G.ImGuiCond.FirstUseEver)
+        ImGui.SetNextWindowSize(ImVec2(260, 180), G.ImGuiCond.FirstUseEver)
+        if ImGui.Begin(n) then ImGui.Text("window " .. n) end
+        ImGui.End()
+    end
+    ImGui.Render()
+    G.ImGui_ImplRoblox.RenderDrawData(ImGui.GetDrawData())
+    if frame % 50 == 0 then check_tree() end
+    if frame % 1000 == 0 then
+        local nodes, docked = 0, 0
+        for _ in pairs(ImGui.GetCurrentContext().DockContext.Nodes) do nodes += 1 end
+        for _, n in ipairs(names) do local w = ImGui.FindWindowByName(n); if w and w.DockNode then docked += 1 end end
+        print("frame", frame, "nodes", nodes, "docked windows", docked)
+        local ini = ImGui.SaveIniSettingsToMemory()
+    end
+end)

tools/test/scripts/t_dock_ini.luau

@@ -0,0 +1,61 @@
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+local RunService = game:GetService("RunService")
+local G = require(ReplicatedStorage:WaitForChild("ImGui"))
+local ImGui, ImVec2 = G.ImGui, G.ImVec2
+local function setup()
+    ImGui.CreateContext()
+    local io = ImGui.GetIO()
+    io.ConfigFlags = bit32.bor(io.ConfigFlags, G.ImGuiConfigFlags.DockingEnable)
+    G.ImGui_ImplRoblox.Init()
+end
+setup()
+local frame, phase, ini, base = 0, 1, nil, 0
+local function windows()
+    for _, n in ipairs({"A", "B", "C"}) do
+        if ImGui.Begin(n) then ImGui.Text("window " .. n) end
+        ImGui.End()
+    end
+end
+RunService.Stepped:Connect(function()
+    frame += 1
+    G.ImGui_ImplRoblox.NewFrame()
+    ImGui.NewFrame()
+    local id = ImGui.DockSpaceOverViewport(0, nil, 0)
+    local f = frame - base
+    if phase == 1 then
+        if f == 2 then
+            ImGui.DockBuilderRemoveNode(id)
+            ImGui.DockBuilderAddNode(id, G.ImGuiDockNodeFlags.DockSpace)
+            ImGui.DockBuilderSetNodeSize(id, ImGui.GetMainViewport().Size)
+            local l, r = ImGui.DockBuilderSplitNode(id, G.ImGuiDir.Left, 0.25)
+            local rt, rb = ImGui.DockBuilderSplitNode(r, G.ImGuiDir.Up, 0.6)
+            ImGui.DockBuilderDockWindow("A", l); ImGui.DockBuilderDockWindow("B", rt); ImGui.DockBuilderDockWindow("C", rb)
+            ImGui.DockBuilderFinish(id)
+        end
+        windows()
+        if f == 20 then
+            ini = ImGui.SaveIniSettingsToMemory()
+            print(ini:match("%[Docking%].*"))
+        end
+    else
+        windows()
+        if f == 20 then
+            local a, b, c = ImGui.FindWindowByName("A"), ImGui.FindWindowByName("B"), ImGui.FindWindowByName("C")
+            print("reloaded nodes", a.DockNode and a.DockNode.ID, b.DockNode and b.DockNode.ID, c.DockNode and c.DockNode.ID, "sizes", a.Size.x, b.Size.x, b.Size.y, c.Size.y)
+            assert(a.DockNode and b.DockNode and c.DockNode, "all docked after reload")
+            assert(a.DockNode ~= b.DockNode and b.DockNode ~= c.DockNode, "3 distinct nodes")
+            local ini2 = ImGui.SaveIniSettingsToMemory()
+            assert(ini2:match("%[Docking%].*") == ini:match("%[Docking%].*"), "docking ini identical after round trip")
+            print("INI ROUNDTRIP OK")
+        end
+    end
+    ImGui.Render()
+    G.ImGui_ImplRoblox.RenderDrawData(ImGui.GetDrawData())
+    if phase == 1 and f == 20 then
+        G.ImGui_ImplRoblox.Shutdown()
+        ImGui.DestroyContext()
+        setup()
+        ImGui.LoadIniSettingsFromMemory(ini)
+        phase, base = 2, frame
+    end
+end)

tools/test/scripts/t_modal.luau

@@ -0,0 +1,41 @@
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+local RunService = game:GetService("RunService")
+local G = require(ReplicatedStorage:WaitForChild("ImGui"))
+local ImGui, ImVec2 = G.ImGui, G.ImVec2
+ImGui.CreateContext()
+G.ImGui_ImplRoblox.Init()
+local frame = 0
+local logged = nil
+RunService.Stepped:Connect(function()
+    frame += 1
+    G.ImGui_ImplRoblox.NewFrame()
+    ImGui.NewFrame()
+    ImGui.SetNextWindowPos(ImVec2(20, 20), G.ImGuiCond.Always)
+    ImGui.SetNextWindowSize(ImVec2(400, 300), G.ImGuiCond.Always)
+    ImGui.Begin("Popups")
+    if frame == 3 then ImGui.OpenPopup("Delete?") end
+    if frame == 5 then ImGui.LogToClipboard() end
+    ImGui.Text("Some text to log")
+    if frame == 5 then ImGui.LogFinish(); logged = ImGui.GetClipboardText() end
+    ImGui.BeginChild("child", ImVec2(0, 100), G.ImGuiChildFlags.Borders)
+    for i = 1, 20 do ImGui.Text("child line " .. i) end
+    ImGui.EndChild()
+    if ImGui.BeginPopupContextWindow() then ImGui.Text("ctx"); ImGui.EndPopup() end
+    if ImGui.BeginPopupModal("Delete?", nil, G.ImGuiWindowFlags.AlwaysAutoResize) then
+        ImGui.Text("All those beautiful files will be deleted.\nThis operation cannot be undone!")
+        ImGui.Separator()
+        if ImGui.Button("OK", ImVec2(120, 0)) then ImGui.CloseCurrentPopup() end
+        ImGui.EndPopup()
+    end
+    ImGui.End()
+    ImGui.Render()
+    G.ImGui_ImplRoblox.RenderDrawData(ImGui.GetDrawData())
+    if frame == 6 then
+        print("LOG:", logged)
+        local ini = ImGui.SaveIniSettingsToMemory()
+        print("INI:", ini)
+        ImGui.LoadIniSettingsFromMemory(ini)
+        assert(ImGui.SaveIniSettingsToMemory() == ini, "ini round trip")
+        print("INI round trip ok")
+    end
+end)

tools/test/scripts/t_tabs.luau

@@ -0,0 +1,30 @@
+local ReplicatedStorage = game:GetService("ReplicatedStorage")
+local RunService = game:GetService("RunService")
+local G = require(ReplicatedStorage:WaitForChild("ImGui"))
+local ImGui, ImVec2 = G.ImGui, G.ImVec2
+ImGui.CreateContext()
+G.ImGui_ImplRoblox.Init()
+local opened = {true, true, true, true, true, true, true, true}
+local frame = 0
+RunService.Stepped:Connect(function()
+    frame += 1
+    G.ImGui_ImplRoblox.NewFrame()
+    ImGui.NewFrame()
+    ImGui.SetNextWindowPos(ImVec2(0, 0), G.ImGuiCond.Always)
+    ImGui.SetNextWindowSize(ImVec2(300, 300), G.ImGuiCond.Always)
+    ImGui.Begin("Tabs")
+    local flags = bit32.bor(G.ImGuiTabBarFlags.Reorderable, G.ImGuiTabBarFlags.TabListPopupButton, G.ImGuiTabBarFlags.FittingPolicyScroll, G.ImGuiTabBarFlags.AutoSelectNewTabs)
+    if ImGui.BeginTabBar("bar", flags) then
+        if ImGui.TabItemButton("+", G.ImGuiTabItemFlags.Trailing) then end
+        for i = 1, #opened do
+            local vis
+            vis, opened[i] = ImGui.BeginTabItem("Tab number " .. i, opened[i], (i == 3) and G.ImGuiTabItemFlags.UnsavedDocument or 0)
+            if vis then ImGui.Text("Contents of tab " .. i); ImGui.EndTabItem() end
+        end
+        ImGui.EndTabBar()
+    end
+    if frame == 50 then local tb = ImGui.GetCurrentContext().TabBars:GetByIndex(0); print("tabs", tb.Tabs.Size, "selected", tb.SelectedTabId ~= 0, "scrollbtn", tb.ScrollButtonEnabled) end
+    ImGui.End()
+    ImGui.Render()
+    G.ImGui_ImplRoblox.RenderDrawData(ImGui.GetDrawData())
+end)