Draw list 1.93 strokes: _AddPolyline ported (texture AA lines, joins/miter/bevel, CapSquare, AALineEnds, Stroke Inside/Center/CenterBiased/Outside/Legacy), AddConvexPolyFilled AAFill, all primitives with 1.93 signatures/flags, PathRect/PathArcTo 1.93, baked line textures; Custom Rendering demo flags UI restored. check_all: t_pixels incremental==full redraw, headless screenshot (tools/test/shot.py)

build/ImGui.linemap.json

@@ -1 +1 @@
-[[46, "imgui.lua"], [21461, "imgui_demo.lua"], [33299, "imgui_draw.lua"], [39279, "imgui_h.lua"], [42185, "imgui_impl_roblox.lua"], [43833, "imgui_impl_roblox_fonts.lua"], [50236, "imgui_internal.lua"], [53945, "imgui_tables.lua"], [59004, "imgui_widgets.lua"], [70993, "imstb_rectpack.lua"], [71657, "imstb_textedit.lua"], [73199, "imstb_truetype.lua"], [75987, "imstd_minstdio.lua"]]
+[[46, "imgui.lua"], [21461, "imgui_demo.lua"], [33313, "imgui_draw.lua"], [40456, "imgui_h.lua"], [43362, "imgui_impl_roblox.lua"], [45010, "imgui_impl_roblox_fonts.lua"], [51413, "imgui_internal.lua"], [55122, "imgui_tables.lua"], [60181, "imgui_widgets.lua"], [72170, "imstb_rectpack.lua"], [72834, "imstb_textedit.lua"], [74376, "imstb_truetype.lua"], [77164, "imstd_minstdio.lua"]]

build/imgui_love.linemap.json

@@ -1 +1 @@
-[[183, "imgui.lua"], [21598, "imgui_demo.lua"], [33436, "imgui_draw.lua"], [39416, "imgui_h.lua"], [42322, "imgui_impl_love.lua"], [42862, "imgui_internal.lua"], [46571, "imgui_tables.lua"], [51630, "imgui_widgets.lua"], [63619, "imstb_rectpack.lua"], [64283, "imstb_textedit.lua"], [65825, "imstb_truetype.lua"], [68613, "imstd_minstdio.lua"]]
+[[183, "imgui.lua"], [21598, "imgui_demo.lua"], [33450, "imgui_draw.lua"], [40593, "imgui_h.lua"], [43499, "imgui_impl_love.lua"], [44039, "imgui_internal.lua"], [47748, "imgui_tables.lua"], [52807, "imgui_widgets.lua"], [64796, "imstb_rectpack.lua"], [65460, "imstb_textedit.lua"], [67002, "imstb_truetype.lua"], [69790, "imstd_minstdio.lua"]]

docs/PORTING.md

@@ -65,5 +65,5 @@ there, but keep this port's existing data structures and conventions. Read the s
 
 - **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
+- Draw calls taking both thickness and flags use upstream's 1.92.8+ order: thickness BEFORE flags, e.g. `AddRect(min, max, col, rounding, thickness, flags)`, `PathStroke(col, thickness, flags)`, `AddPolyline(points, count, col, thickness, flags)`.
 - 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.

imgui_demo.lua

@@ -10413,6 +10413,9 @@ S.ShowExampleAppCustomRendering = {
     curve_segments_override_v = 8,
     colf_stroke = ImVec4(1.000, 0.384, 0.169, 1.000),
     colf_fill = ImVec4(0.416, 0.378, 0.420, 1.000),
+    prim_stroke_flags = ImDrawFlags.None,
+    prim_other_flags = ImDrawFlags.AALineEnds,
+    scope_flags = nil, -- First init copy current state (see below).
     -- Canvas
     points = ImVector(),
     scrolling = ImVec2(0.0, 0.0),
@@ -10496,25 +10499,35 @@ function ShowExampleAppCustomRendering(p_open)
             ImGui.ColorEdit4("Stroke Color", s.colf_stroke)
             ImGui.ColorEdit4("Fill Color", s.colf_fill)
 
-            -- [Port] ImDrawFlags_StrokeInside/StrokeCenter/StrokeCenterBiased/StrokeOutside/StrokeLegacy, AAFill/AALines/AALineEnds,
-            -- [Port] JoinMiter/CapSquare, AllowInPushScope_ and ImDrawList::PushDrawFlag()/PopDrawFlag() don't exist in this port
-            -- [Port] (1.92 stroker): prim_stroke_flags/prim_other_flags/scope_flags and their widgets are not ported, flags = None.
             ImGui.SeparatorText("Per primitive flags (AddXXX functions)")
-            ImGui.TextDisabled("(not supported by this port)") -- [Port]
+            _, s.prim_stroke_flags = ImGui.RadioButton("Default", s.prim_stroke_flags, ImDrawFlags.None); ImGui.SameLine()
+            _, s.prim_stroke_flags = ImGui.RadioButton("Inside", s.prim_stroke_flags, ImDrawFlags.StrokeInside); ImGui.SameLine()
+            _, s.prim_stroke_flags = ImGui.RadioButton("Center", s.prim_stroke_flags, ImDrawFlags.StrokeCenter); ImGui.SameLine()
+            _, s.prim_stroke_flags = ImGui.RadioButton("CenterBiased", s.prim_stroke_flags, ImDrawFlags.StrokeCenterBiased); ImGui.SameLine()
+            _, s.prim_stroke_flags = ImGui.RadioButton("Outside", s.prim_stroke_flags, ImDrawFlags.StrokeOutside); ImGui.SameLine()
+            _, s.prim_stroke_flags = ImGui.RadioButton("Legacy", s.prim_stroke_flags, ImDrawFlags.StrokeLegacy)
+            _, s.prim_other_flags = ImGui.CheckboxFlags("AAFill", s.prim_other_flags, ImDrawFlags.AAFill); ImGui.SameLine() -- Note: Only for functions taking flags.
+            _, s.prim_other_flags = ImGui.CheckboxFlags("AALines", s.prim_other_flags, ImDrawFlags.AALines); ImGui.SameLine() -- Note: Only for functions taking flags.
+            _, s.prim_other_flags = ImGui.CheckboxFlags("AALineEnds", s.prim_other_flags, ImDrawFlags.AALineEnds); ImGui.SameLine()
+            _, s.prim_other_flags = ImGui.CheckboxFlags("JoinMiter", s.prim_other_flags, ImDrawFlags.JoinMiter); ImGui.SameLine()
+            _, s.prim_other_flags = ImGui.CheckboxFlags("CapSquare", s.prim_other_flags, ImDrawFlags.CapSquare)
             --ImGui.CheckboxFlags("UseTexForRoundCorners", &prim_other_flags, ImDrawFlags_UseTexForRoundCorners);
 
+            if s.scope_flags == nil then s.scope_flags = bit32.band(draw_list.Flags, ImDrawFlags.AllowInPushScope_) end -- First init copy current state.
             ImGui.SeparatorText("Current ImDrawList flags (e.g. PushDrawFlag function)")
             ImGui.PushID("ScopeFlags")
-            ImGui.TextDisabled("(not supported by this port)") -- [Port]
+            _, s.scope_flags = ImGui.CheckboxFlags("AAFill", s.scope_flags, ImDrawFlags.AAFill); ImGui.SameLine()
+            _, s.scope_flags = ImGui.CheckboxFlags("AALines", s.scope_flags, ImDrawFlags.AALines); ImGui.SameLine()
+            _, s.scope_flags = ImGui.CheckboxFlags("AALineEnds", s.scope_flags, ImDrawFlags.AALineEnds); ImGui.SameLine()
+            _, s.scope_flags = ImGui.CheckboxFlags("StrokeLegacy", s.scope_flags, ImDrawFlags.StrokeLegacy)
             --ImGui.CheckboxFlags("UseTexForRoundCorners", &scope_flags, ImDrawFlags_UseTexForRoundCorners);
             ImGui.PopID()
             ImGui.Spacing()
 
-            -- [Port] draw_list->PushDrawFlag(ImDrawFlags_AllowInPushScope_, false); // Reset all existing (very unusual: done for this demo)
+            draw_list:PushDrawFlag(ImDrawFlags.AllowInPushScope_, false) -- Reset all existing (very unusual: done for this demo)
-            -- [Port] draw_list->PushDrawFlag(scope_flags, true);
+            draw_list:PushDrawFlag(s.scope_flags, true)
-            local flags = ImDrawFlags.None -- [Port] prim_stroke_flags | prim_other_flags
+            local flags = bit32.bor(s.prim_stroke_flags, s.prim_other_flags)
 
-            -- [Port] In this port AddNgon/AddCircle/AddEllipse/AddTriangle/AddLine*/AddBezier*/PathFillConvex take no flags argument (dropped below).
             local sz = s.sz
             local start_pos = ImGui.GetCursorScreenPos()
             local pi = 3.141592
@@ -10582,7 +10595,7 @@ function ShowExampleAppCustomRendering(p_open)
                     for n = 0, 4 - 1 do
                         draw_list:PathLineTo(ImVec2(x + half_sz + rotating_square[n + 1].x, y + half_sz + rotating_square[n + 1].y))
                     end
-                    draw_list:PathFillConvex(col) -- [Port] no flags argument
+                    draw_list:PathFillConvex(col, flags)
                     x = x + step
 
                     -- Path
@@ -10609,14 +10622,14 @@ function ShowExampleAppCustomRendering(p_open)
                     -- First row uses a thickness of 1.0f, second row uses the configurable thickness
                     local col = ImColor(s.colf_stroke):U32()
                     local th = (row == 0) and 1.0 or thickness
-                    draw_list:AddNgon(ImVec2(x + half_sz, y + half_sz), half_sz, col, s.ngon_segments, th);                 x = x + step  -- N-gon
+                    draw_list:AddNgon(ImVec2(x + half_sz, y + half_sz), half_sz, col, s.ngon_segments, th, flags);                 x = x + step  -- N-gon
-                    draw_list:AddCircle(ImVec2(x + half_sz, y + half_sz), half_sz, col, circle_segments, th);               x = x + step  -- Circle
+                    draw_list:AddCircle(ImVec2(x + half_sz, y + half_sz), half_sz, col, circle_segments, th, flags);               x = x + step  -- Circle
-                    draw_list:AddEllipse(ImVec2(x + half_sz, y + half_sz), ImVec2(half_sz, sz * 0.3), col, -0.3, circle_segments, th); x = x + step  -- Ellipse
+                    draw_list:AddEllipse(ImVec2(x + half_sz, y + half_sz), ImVec2(half_sz, sz * 0.3), col, -0.3, circle_segments, th, flags); x = x + step  -- Ellipse
                     draw_list:AddRect(ImVec2(x, y), ImVec2(x + sz, y + sz), col, 0.0, th, flags);                           x = x + step  -- Square
                     draw_list:AddRect(ImVec2(x, y), ImVec2(x + sz, y + sz), col, rounding, th, flags);                      x = x + step  -- Square with all rounded corners
                     draw_list:AddRect(ImVec2(x, y), ImVec2(x + sz, y + sz), col, rounding, th, bit32.bor(flags, corners_tl_br)); x = x + step  -- Square with two rounded corners
-                    draw_list:AddTriangle(ImVec2(x + sz * 0.5, y), ImVec2(x + sz, y + sz), ImVec2(x, y + sz), col, th);     x = x + step  -- Triangle
+                    draw_list:AddTriangle(ImVec2(x + sz * 0.5, y), ImVec2(x + sz, y + sz), ImVec2(x, y + sz), col, th, flags); x = x + step  -- Triangle
-                    draw_list:AddTriangle(ImVec2(x + sz * 0.2, y), ImVec2(x + sz * 0.4, y + sz), ImVec2(x, y + sz), col, th); x = x + step - math.floor(sz * 0.6) -- Thin triangle
+                    draw_list:AddTriangle(ImVec2(x + sz * 0.2, y), ImVec2(x + sz * 0.4, y + sz), ImVec2(x, y + sz), col, th, flags); x = x + step - math.floor(sz * 0.6) -- Thin triangle
 
                     -- Concave shape: U
                     for _, p in ipairs(concave_shape) do
@@ -10634,15 +10647,15 @@ function ShowExampleAppCustomRendering(p_open)
 
                     -- Horizontal/Vertical/Diagonal lines
                     local off = math.floor(sz * 0.4)
-                    draw_list:AddLineH(x, x + sz, y, col, th)
+                    draw_list:AddLineH(x, x + sz, y, col, th, flags)
-                    draw_list:AddLine(ImVec2(x, y + off), ImVec2(x + sz, y + off), col, th)
+                    draw_list:AddLine(ImVec2(x, y + off), ImVec2(x + sz, y + off), col, th, flags)
                     x = x + step
-                    draw_list:AddLineV(x, y, y + sz, col, th)
+                    draw_list:AddLineV(x, y, y + sz, col, th, flags)
-                    draw_list:AddLine(ImVec2(x + off, y + sz), ImVec2(x + off, y), col, th)
+                    draw_list:AddLine(ImVec2(x + off, y + sz), ImVec2(x + off, y), col, th, flags)
                     x = x + step - math.floor(half_sz)
                     if not (draw_fill and draw_strokes) then -- -V560
-                        draw_list:AddLine(ImVec2(x, y), ImVec2(x + half_sz, y + sz), col, th)
+                        draw_list:AddLine(ImVec2(x, y), ImVec2(x + half_sz, y + sz), col, th, flags)
-                        draw_list:AddLine(ImVec2(x, y + sz), ImVec2(x + half_sz, y), col, th)
+                        draw_list:AddLine(ImVec2(x, y + sz), ImVec2(x + half_sz, y), col, th, flags)
                     end
                     x = x + step - math.floor(half_sz)
 
@@ -10661,12 +10674,12 @@ function ShowExampleAppCustomRendering(p_open)
                     x = x + step
 
                     -- Quadratic Bezier Curve (3 control points)
-                    draw_list:AddBezierQuadratic(ImVec2(x + cp3[1].x, y + cp3[1].y), ImVec2(x + cp3[2].x, y + cp3[2].y), ImVec2(x + cp3[3].x, y + cp3[3].y), col, th, curve_segments)
+                    draw_list:AddBezierQuadratic(ImVec2(x + cp3[1].x, y + cp3[1].y), ImVec2(x + cp3[2].x, y + cp3[2].y), ImVec2(x + cp3[3].x, y + cp3[3].y), col, th, curve_segments, flags)
                     x = x + step
 
                     -- Cubic Bezier Curve (4 control points)
                     if not (draw_fill and draw_strokes) then -- -V560
-                        draw_list:AddBezierCubic(ImVec2(x + cp4[1].x, y + cp4[1].y), ImVec2(x + cp4[2].x, y + cp4[2].y), ImVec2(x + cp4[3].x, y + cp4[3].y), ImVec2(x + cp4[4].x, y + cp4[4].y), col, th, curve_segments)
+                        draw_list:AddBezierCubic(ImVec2(x + cp4[1].x, y + cp4[1].y), ImVec2(x + cp4[2].x, y + cp4[2].y), ImVec2(x + cp4[3].x, y + cp4[3].y), ImVec2(x + cp4[4].x, y + cp4[4].y), col, th, curve_segments, flags)
                         x = x + step
                     end
                 end
@@ -10674,7 +10687,8 @@ function ShowExampleAppCustomRendering(p_open)
             end
 
             ImGui.Dummy(ImVec2(step * 15.5, step * 4.0))
-            -- [Port] draw_list->PopDrawFlag(); x2
+            draw_list:PopDrawFlag()
+            draw_list:PopDrawFlag()
 
             ImGui.Text("ImDrawList Vector Rendering Reference:")
             ImGui.TextLinkOpenURL("https://github.com/ocornut/imgui/wiki/Draw-List")

tools/test/check_all.sh

@@ -32,6 +32,8 @@ CHECKS=(
 "libhash|LIBHASH|NO_DEMO=1 $R --main tools/test/scripts/t_libhash.luau --frames 120"
 "demo_open|DRAWHASH|$R --main tools/test/scripts/t_drawhash.luau --frames 150 --open"
 "demo_random|^|python3 tools/test/run.py --roblox --timeout 600 --frames 400 --open"
+"pixels|PIXELS SAME|a=\$($R --main tools/test/scripts/t_pixels.luau --frames 600 | grep -P '^PIX\t'); b=\$(RUN_FLAGS=ARG_FORCE=true $R --main tools/test/scripts/t_pixels.luau --frames 600 | grep -P '^PIX\t'); [ -n \"\$a\" ] && [ \"\$a\" = \"\$b\" ] && echo PIXELS SAME"
+"shot|wrote|python3 tools/test/shot.py /tmp/imgui_shot.png --app"
 "love|DRAWHASH|python3 tools/bundle.py --target love >/dev/null && luajit tools/test/love/t_drawhash.lua 60 Widgets,Basic && luajit tools/test/love/t_examples.lua"
 )
 

tools/test/love/run.sh

@@ -4,4 +4,4 @@ set -e
 cd "$(dirname "$0")/../../.."
 python3 tools/bundle.py --target love >/dev/null
 nix-shell -p luajit --run "luajit tools/test/love/t_drawhash.lua 150 Widgets,Basic && luajit tools/test/love/t_drawhash.lua 150 all && luajit tools/test/love/t_examples.lua"
-echo "expected (Luau, tools/test/scripts/t_drawhash.luau): 855922436 / 1889516030"
+echo "expected (Luau, tools/test/scripts/t_drawhash.luau): 2057580240 / 2004376225"

tools/test/scripts/t_shot.luau

@@ -0,0 +1,138 @@
+-- Screenshot of a fixed scene (t_libhash's widgets + primitives, optionally the Custom Rendering example):
+-- composites the ScreenGui like t_composite and prints "ROW y hex". tools/test/shot.py turns it into a PNG.
+-- RUN_FLAGS: ARG_APP=true also opens ShowExampleAppCustomRendering (needs the demo).
+local G = require(game:GetService("ReplicatedStorage"):WaitForChild("ImGui"))
+local ImGui, ImVec2, ImVec4 = G.ImGui, G.ImVec2, G.ImVec4
+ImGui.CreateContext(); G.ImGui_ImplRoblox.Init(); G.ImGui_ImplRoblox.SetRenderRate(0)
+local io = ImGui.GetIO()
+local W, H = 1280, 760
+local frame = 0
+local st = { b = false, f = 0.25, i = 42, c = ImVec4(0.2, 0.7, 0.4, 1.0), buf = ImGui.NewTextBuffer("hello", 64), r = 0, tab = 0, combo = 1, list = 2 }
+local plot = {}
+for i = 1, 40 do plot[i] = math.sin(i * 0.3) end
+local poly = { ImVec2(0, 0), ImVec2(60, 10), ImVec2(30, 30), ImVec2(70, 60), ImVec2(0, 50) }
+
+local function composite(gui)
+    local screen = buffer.create(W * H * 3)
+    local function walk(inst, ox, oy, kx0, ky0, kx1, ky1)
+        local kids = inst:GetChildren()
+        table.sort(kids, function(a, b) return (a.ZIndex or 1) < (b.ZIndex or 1) end) -- table.sort isn't stable, but siblings with equal ZIndex never overlap here
+        for _, c in ipairs(kids) do
+            if c.Visible ~= false then
+                local x, y = ox + (c.Position and c.Position.X or 0), oy + (c.Position and c.Position.Y or 0)
+                local cx0, cy0, cx1, cy1 = kx0, ky0, kx1, ky1
+                if c.ClipsDescendants then
+                    cx0, cy0 = math.max(cx0, x), math.max(cy0, y)
+                    cx1, cy1 = math.min(cx1, x + c.Size.X), math.min(cy1, y + c.Size.Y)
+                end
+                if c.ClassName == "ImageLabel" then
+                    local img = c.ImageContent.Object
+                    local px, sz = img.Pixels, img.Size.X
+                    for ty = 0, sz - 1 do
+                        local sy = y + ty
+                        if sy >= ky0 and sy < ky1 then
+                            for tx = 0, sz - 1 do
+                                local sx = x + tx
+                                if sx >= kx0 and sx < kx1 then
+                                    local o = (ty * sz + tx) * 4
+                                    local a = buffer.readu8(px, o + 3)
+                                    if a > 0 then
+                                        local d = (sy * W + sx) * 3
+                                        local fa = a / 255
+                                        for ch = 0, 2 do
+                                            local v = buffer.readu8(px, o + ch) * fa + buffer.readu8(screen, d + ch) * (1 - fa)
+                                            buffer.writeu8(screen, d + ch, math.floor(v + 0.5))
+                                        end
+                                    end
+                                end
+                            end
+                        end
+                    end
+                end
+                walk(c, x, y, cx0, cy0, cx1, cy1)
+            end
+        end
+    end
+    walk(gui, 0, 0, 0, 0, W, H)
+    return screen
+end
+
+game:GetService("RunService").Stepped:Connect(function()
+    frame += 1
+    G.ImGui_ImplRoblox.NewFrame()
+    io.DeltaTime = 1 / 60
+    ImGui.NewFrame()
+    ImGui.SetNextWindowPos(ImVec2(10, 10), G.ImGuiCond.Always); ImGui.SetNextWindowSize(ImVec2(320, 560), G.ImGuiCond.Always)
+    ImGui.Begin("Widgets")
+    ImGui.Text("Text %d", 123); ImGui.TextColored(ImVec4(1, 0.5, 0, 1), "Colored"); ImGui.TextWrapped("Wrapped text that is long enough to wrap around the window edge at least once.")
+    ImGui.Button("Button"); ImGui.SameLine(); ImGui.SmallButton("Small"); ImGui.SameLine(); ImGui.ArrowButton("##a", G.ImGuiDir.Left)
+    st.b = ImGui.Checkbox("Checkbox", st.b)
+    st.r = ImGui.RadioButton("R0", st.r, 0); ImGui.SameLine(); st.r = ImGui.RadioButton("R1", st.r, 1)
+    st.f = ImGui.SliderFloat("Slider", st.f, 0, 1); st.i = ImGui.DragInt("Drag", st.i, 1, 0, 100)
+    ImGui.InputText("Input", st.buf, 64)
+    ImGui.ColorEdit4("Color", st.c)
+    st.combo = ImGui.Combo("Combo", st.combo, { "AAA", "BBB", "CCC" })
+    st.list = ImGui.ListBox("List", st.list, { "one", "two", "three", "four" }, 4, 3)
+    ImGui.ProgressBar(0.4, ImVec2(-1, 0)); ImGui.ProgressBar(-1.0 * frame / 60, ImVec2(-1, 0), "busy")
+    ImGui.PlotLines("Lines", plot, nil, #plot); ImGui.PlotHistogram("Hist", plot, nil, #plot, 0, nil, -1, 1, ImVec2(0, 40))
+    ImGui.Bullet(); ImGui.Text("bullet"); ImGui.Separator(); ImGui.SeparatorText("Sep")
+    if ImGui.TreeNode("Tree") then ImGui.Text("inside"); ImGui.TreePop() end
+    ImGui.SetNextItemOpen(true, G.ImGuiCond.Once)
+    if ImGui.CollapsingHeader("Header") then
+        if ImGui.BeginTabBar("tabs") then
+            if ImGui.BeginTabItem("Tab A") then ImGui.Text("A"); ImGui.EndTabItem() end
+            if ImGui.BeginTabItem("Tab B") then ImGui.Text("B"); ImGui.EndTabItem() end
+            ImGui.EndTabBar()
+        end
+        if ImGui.BeginTable("t", 3, bit32.bor(G.ImGuiTableFlags.Borders, G.ImGuiTableFlags.RowBg, G.ImGuiTableFlags.Resizable)) then
+            ImGui.TableSetupColumn("One"); ImGui.TableSetupColumn("Two"); ImGui.TableSetupColumn("Three"); ImGui.TableHeadersRow()
+            for row = 0, 4 do ImGui.TableNextRow(); for col = 0, 2 do ImGui.TableSetColumnIndex(col); ImGui.Text("r%d c%d", row, col) end end
+            ImGui.EndTable()
+        end
+    end
+    ImGui.End()
+
+    ImGui.SetNextWindowPos(ImVec2(340, 10), G.ImGuiCond.Always); ImGui.SetNextWindowSize(ImVec2(300, 560), G.ImGuiCond.Always)
+    ImGui.Begin("Draw")
+    local dl, p = ImGui.GetWindowDrawList(), ImGui.GetCursorScreenPos()
+    local x, y, col = p.x + 4, p.y + 4, 0xFF40C0FF
+    for i, th in { 1.0, 2.5, 6.0 } do
+        local yy = y + (i - 1) * 70
+        dl:AddRect(ImVec2(x, yy), ImVec2(x + 50, yy + 50), col, 10.0, th)
+        dl:AddRectFilled(ImVec2(x + 60, yy), ImVec2(x + 110, yy + 50), col, 10.0, G.ImDrawFlags.RoundTopLeft or G.ImDrawFlags.RoundCornersTopLeft) -- RoundCornersTopLeft: pre-1.93 revs (hashes.sh)
+        dl:AddCircle(ImVec2(x + 145, yy + 25), 25, col, 0, th)
+        dl:AddNgon(ImVec2(x + 200, yy + 25), 25, col, 6, th)
+        dl:AddTriangle(ImVec2(x + 230, yy + 50), ImVec2(x + 255, yy), ImVec2(x + 280, yy + 50), col, th)
+        dl:AddLine(ImVec2(x, yy + 60), ImVec2(x + 280, yy + 55), col, th)
+    end
+    y += 210
+    dl:AddBezierCubic(ImVec2(x, y), ImVec2(x + 60, y - 30), ImVec2(x + 120, y + 60), ImVec2(x + 180, y), col, 3.0)
+    dl:AddBezierQuadratic(ImVec2(x, y + 30), ImVec2(x + 90, y - 10), ImVec2(x + 180, y + 30), col, 2.0)
+    dl:AddEllipse(ImVec2(x + 230, y + 15), ImVec2(40, 15), col, 0.5, 0, 2.0)
+    y += 50
+    local pts = {}
+    for i, v in poly do pts[i] = ImVec2(x + v.x, y + v.y) end
+    dl:AddConcavePolyFilled(pts, #pts, 0xFF8080FF)
+    for i, v in poly do pts[i] = ImVec2(x + 100 + v.x, y + v.y) end
+    dl:AddPolyline(pts, #pts, col, 4.0, G.ImDrawFlags.Closed)
+    for i, v in poly do pts[i] = ImVec2(x + 200 + v.x, y + v.y) end
+    dl:AddPolyline(pts, #pts, col, 1.0, 0)
+    y += 80
+    dl:AddRectFilledMultiColor(ImVec2(x, y), ImVec2(x + 100, y + 40), 0xFF0000FF, 0xFF00FF00, 0xFFFF0000, 0xFFFFFFFF)
+    dl:AddCircleFilled(ImVec2(x + 140, y + 20), 20, col)
+    dl:AddEllipseFilled(ImVec2(x + 210, y + 20), ImVec2(30, 15), col, 0.3)
+    dl:AddText(ImVec2(x, y + 50), 0xFFFFFFFF, "AddText")
+    ImGui.End()
+
+    if ARG_APP then ImGui.SetNextWindowPos(ImVec2(650, 10), G.ImGuiCond.Always); ImGui.SetNextWindowSize(ImVec2(620, 740), G.ImGuiCond.Always); G.ShowExampleAppCustomRendering(true) end
+    ImGui.Render()
+    G.ImGui_ImplRoblox.RenderDrawData(ImGui.GetDrawData())
+    if frame == ARG_FRAMES - 1 then
+        local screen = composite(game:GetService("Players").LocalPlayer.PlayerGui:FindFirstChild("ImGui"))
+        for y = 0, H - 1 do
+            local t = table.create(W * 3)
+            for i = 0, W * 3 - 1 do t[i + 1] = string.format("%02x", buffer.readu8(screen, y * W * 3 + i)) end
+            print("ROW", y, table.concat(t))
+        end
+    end
+end)

tools/test/shot.py

@@ -0,0 +1,14 @@
+#!/usr/bin/env python3
+"""Headless screenshot: tools/test/shot.py out.png [--app]  (runs scripts/t_shot.luau, writes a PNG; stdlib only)"""
+import os, subprocess, sys, struct, zlib
+HERE = os.path.dirname(os.path.abspath(__file__))
+env = dict(os.environ, FULL_OUTPUT="1", RUN_FLAGS="ARG_APP=true" if "--app" in sys.argv else "")
+out = subprocess.run([sys.executable, os.path.join(HERE, "run.py"), "--quiet", "--roblox", "--frames", "30", "--timeout", "600",
+                      "--main", os.path.join(HERE, "scripts", "t_shot.luau")], env=env, capture_output=True, text=True).stdout
+rows = {int(l.split()[1]): bytes.fromhex(l.split()[2]) for l in out.splitlines() if l.startswith("ROW")}
+assert rows, out[-2000:]
+w, h = len(rows[0]) // 3, len(rows)
+raw = b"".join(b"\0" + rows[y] for y in range(h))
+chunk = lambda t, d: struct.pack(">I", len(d)) + t + d + struct.pack(">I", zlib.crc32(t + d) & 0xffffffff)
+open(sys.argv[1], "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(raw, 6)) + chunk(b"IEND", b""))
+print("wrote", sys.argv[1], w, h)