Merge branch 'viewport' into docking

# Conflicts:
#	imgui.cpp

docs/TODO.txt

@@ -74,6 +74,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - input text: display bug when clicking a drag/slider after an input text in a different window has all-selected text (order dependent). actually a very old bug but no one appears to have noticed it.
  - input text: allow centering/positioning text so that ctrl+clicking Drag or Slider keeps the textual value at the same pixel position.
  - input text: what's the easiest way to implement a nice IP/Mac address input editor?
+ - input text: Global callback system so user can plug in an expression evaluator easily.
  - input text multi-line: don't directly call AddText() which does an unnecessary vertex reserve for character count prior to clipping. and/or more line-based clipping to AddText(). and/or reorganize TextUnformatted/RenderText for more efficiency for large text (e.g TextUnformatted could clip and log separately, etc).
  - input text multi-line: support for cut/paste without selection (cut/paste the current line)
  - input text multi-line: line numbers? status bar? (follow up on #200)
@@ -278,8 +279,11 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - font: add support for kerning, probably optional. A) perhaps default to (32..128)^2 matrix ~ 9K entries = 36KB, then hash for non-ascii?. B) or sparse lookup into per-char list?
  - font: add a simpler CalcTextSizeA() api? current one ok but not welcome if user needs to call it directly (without going through ImGui::CalcTextSize)
  - font: fix AddRemapChar() to work before font has been built.
- - font: (api breaking) removed "TTF" from symbol names. also because it now supports OTF.
+ - font: (api breaking) remove "TTF" from symbol names. also because it now supports OTF.
+ - font/opt: Considering storing standalone AdvanceX table as 16-bit fixed point integer?
+ - font/opt: Glyph currently 40 bytes (2+9*4). Consider storing UV as 16 bits integer? (->32 bytes). X0/Y0/X1/Y1 as 16 fixed-point integers? Or X0/Y0 as float and X1/Y1 as fixed8_8?
 
+ - nav: NavScrollToBringItemIntoView() with item bigger than view should focus top-right? Repro: using Nav in "About Window"
  - nav: wrap around logic to allow e.g. grid based layout (pressing NavRight on the right-most element would go to the next row, etc.). see internal's NavMoveRequestTryWrapping().
  - nav: patterns to make it possible for arrows key to update selection
  - nav: restore/find nearest navid when current one disappear (e.g. pressed a button that disappear, or perhaps auto restoring when current button change name)
@@ -291,8 +295,10 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - nav: NavFlattened: init request doesn't select items that are part of a NavFlattened child
  - nav: NavFlattened: cannot access menu-bar of a flattened child window with Alt/menu key (not a very common use case..).
  - nav: Left within a tree node block as a fallback (ImGuiTreeNodeFlags_NavLeftJumpsBackHere by default?)
- - nav: menus: pressing left-right on a vertically clipped menu bar tends to jump to the collapse/close buttons.
+ - nav/menus: pressing left-right on a vertically clipped menu bar tends to jump to the collapse/close buttons.
- - nav: menus: allow pressing Menu to leave a sub-menu.
+ - nav/menus: allow pressing Menu to leave a sub-menu.
+ - nav/menus: a way to access the main menu bar with Alt? (currently needs CTRL+TAB)
+ - nav/menus: when using the main menu bar, even though we restore focus after, the underlying window loses its title bar highlight during menu manipulation. could we prevent it?
  - nav: simulate right-click or context activation? (SHIFT+F10)
  - nav: tabs should go through most/all widgets (in submission order?).
  - nav: when CTRL-Tab/windowing is active, the HoveredWindow detection doesn't take account of the window display re-ordering.

examples/imgui_impl_glfw.cpp

@@ -141,7 +141,7 @@ static bool ImGui_ImplGlfw_Init(GLFWwindow* window, bool install_callbacks, Glfw
     io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;         // We can honor GetMouseCursor() values (optional)
     io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
     io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;    // We can create multi-viewports on the Platform side (optional)
-#if GLFW_HAS_GLFW_HOVERED
+#if GLFW_HAS_GLFW_HOVERED && defined(_WIN32)
     io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport; // We can set io.MouseHoveredViewport correctly (optional, not easy)
 #endif
     io.BackendPlatformName = "imgui_impl_glfw";
@@ -264,14 +264,32 @@ static void ImGui_ImplGlfw_UpdateMousePosAndButtons()
             {
                 double mouse_x, mouse_y;
                 glfwGetCursorPos(window, &mouse_x, &mouse_y);
-                io.MousePos = ImVec2((float)mouse_x + viewport->Pos.x, (float)mouse_y + viewport->Pos.y);
+                if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
+                {
+                    // Multi-viewport mode: mouse position in OS absolute coordinates (io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor)
+                    int window_x, window_y;
+                    glfwGetWindowPos(window, &window_x, &window_y);
+                    io.MousePos = ImVec2((float)mouse_x + window_x, (float)mouse_y + window_y);
+                }
+                else
+                {
+                    // Single viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
+                    io.MousePos = ImVec2((float)mouse_x, (float)mouse_y);
+                }
             }
             for (int i = 0; i < IM_ARRAYSIZE(io.MouseDown); i++)
                 io.MouseDown[i] |= glfwGetMouseButton(window, i) != 0;
         }
 
-#if GLFW_HAS_GLFW_HOVERED
+        // (Optional) When using multiple viewports: set io.MouseHoveredViewport to the viewport the OS mouse cursor is hovering.
-        io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport;
+        // Important: this information is not easy to provide and many high-level windowing library won't be able to provide it correctly, because
+        // - This is _ignoring_ viewports with the ImGuiViewportFlags_NoInputs flag (pass-through windows).
+        // - This is _regardless_ of whether another viewport is focused or being dragged from.
+        // If ImGuiBackendFlags_HasMouseHoveredViewport is not set by the back-end, imgui will ignore this field and infer the information by relying on the
+        // rectangles and last focused time of every viewports it knows about. It will be unaware of other windows that may be sitting between or over your windows.
+        // [GLFW] FIXME: This is currently only correct on Win32. See what we do below with the WM_NCHITTEST, missing an equivalent for other systems.
+        // See https://github.com/glfw/glfw/issues/1236 if you want to help in making this a GLFW feature.
+#if GLFW_HAS_GLFW_HOVERED && defined(_WIN32)
         if (glfwGetWindowAttrib(window, GLFW_HOVERED) && !(viewport->Flags & ImGuiViewportFlags_NoInputs))
             io.MouseHoveredViewport = viewport->ID;
 #endif

examples/imgui_impl_sdl.cpp

@@ -264,16 +264,20 @@ static void ImGui_ImplSDL2_UpdateMousePosAndButtons()
     SDL_Window* focused_window = SDL_GetKeyboardFocus();
     if (focused_window)
     {
-        // SDL_GetMouseState() gives mouse position seemingly based on the last window entered/focused(?)
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
-        // The creation of new windows at runtime and SDL_CaptureMouse both seems to severely mess up with that, so we retrieve that position globally.
+        {
-        int wx, wy;
+            // Multi-viewport mode: mouse position in OS absolute coordinates (io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor)
-        SDL_GetWindowPosition(focused_window, &wx, &wy);
             SDL_GetGlobalMouseState(&mx, &my);
-        mx -= wx;
+            if (ImGui::FindViewportByPlatformHandle((void*)focused_window) != NULL)
-        my -= wy;
+                io.MousePos = ImVec2((float)mx, (float)my);
+        }
+        else
+        {
+            // Single viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window)
+            if (focused_window == g_Window)
+                io.MousePos = ImVec2((float)mx, (float)my);
+        }
     }
-    if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle((void*)focused_window))
-        io.MousePos = ImVec2(viewport->Pos.x + (float)mx, viewport->Pos.y + (float)my);
 
     // We already retrieve global mouse position, SDL_CaptureMouse() also let the OS know e.g. that our imgui drag outside the SDL window boundaries shouldn't trigger the OS window resize cursor
     // The function is only supported from SDL 2.0.4 (released Jan 2016)

examples/imgui_impl_win32.cpp

@@ -135,21 +135,14 @@ static bool ImGui_ImplWin32_UpdateMouseCursor()
     return true;
 }
 
-// This code supports multiple OS Windows mapped into different ImGui viewports, 
+// This code supports multi-viewports (multiple OS Windows mapped into different Dear ImGui viewports)
-// Because of that, it is a little more complicated than your typical single-viewport binding code.
+// Because of that, it is a little more complicated than your typical single-viewport binding code!
-// A) In Single-viewport mode imgui needs:
-//   - io.MousePos ............... mouse position, in client window coordinates (what you'd get from GetCursorPos+ScreenToClient() or from WM_MOUSEMOVE) 
-//                                 io.MousePos is (0,0) when the mouse is on the upper-left corner of the application window.
-// B) In Multi-viewport mode imgui needs: (when ImGuiConfigFlags_ViewportsEnable is set)
-//   - io.MousePos ............... mouse position, in OS absolute coordinates (what you'd get from GetCursorPos(), or from WM_MOUSEMOVE+viewport->Pos). 
-//                                 io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor.
-//   - io.MouseHoveredViewport ... [optional] viewport which mouse is hovering, with _VERY_ specific and strict conditions (Read comments next to io.MouseHoveredViewport. This is _NOT_ easy to provide in many high-level engine because of how we use the ImGuiViewportFlags_NoInputs flag)
 static void ImGui_ImplWin32_UpdateMousePos()
 {
     ImGuiIO& io = ImGui::GetIO();
 
     // Set OS mouse position if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
-    // (When multi-viewports are enabled, all imgui positions are same as OS positions.)
+    // (When multi-viewports are enabled, all imgui positions are same as OS positions)
     if (io.WantSetMousePos)
     {
         POINT pos = { (int)io.MousePos.x, (int)io.MousePos.y };
@@ -161,21 +154,39 @@ static void ImGui_ImplWin32_UpdateMousePos()
     io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
     io.MouseHoveredViewport = 0;
 
-    // Set mouse position and viewport
+    // Set imgui mouse position
-    // (Note that ScreenToClient() and adding +viewport->Pos are mutually cancelling each others when we have multi-viewport enabled. In single-viewport mode, viewport->Pos will be zero)
+    POINT mouse_screen_pos;
-    POINT pos;
+    if (!::GetCursorPos(&mouse_screen_pos))
-    if (!::GetCursorPos(&pos))
         return;
     if (HWND focused_hwnd = ::GetActiveWindow())
-        if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle((void*)focused_hwnd))
     {
-            POINT client_pos = pos;
+        if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
-            ::ScreenToClient(focused_hwnd, &client_pos);
+        {
-            io.MousePos = ImVec2(viewport->Pos.x + (float)client_pos.x, viewport->Pos.y + (float)client_pos.y);
+            // Multi-viewport mode: mouse position in OS absolute coordinates (io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor)
+            // This is the position you can get with GetCursorPos(). In theory adding viewport->Pos is also the reverse operation of doing ScreenToClient().
+            if (ImGui::FindViewportByPlatformHandle((void*)focused_hwnd) != NULL)
+                io.MousePos = ImVec2((float)mouse_screen_pos.x, (float)mouse_screen_pos.y);
+        }
+        else
+        {
+            // Single viewport mode: mouse position in client window coordinates (io.MousePos is (0,0) when the mouse is on the upper-left corner of the app window.)
+            // This is the position you can get with GetCursorPos() + ScreenToClient() or from WM_MOUSEMOVE.
+            if (focused_hwnd == g_hWnd)
+            {
+                POINT mouse_client_pos = mouse_screen_pos;
+                ::ScreenToClient(focused_hwnd, &mouse_client_pos);
+                io.MousePos = ImVec2((float)mouse_client_pos.x, (float)mouse_client_pos.y);
+            }
+        }
     }
 
-    // Our back-end can tell which window is under the mouse cursor (not every back-end can), so pass that info to imgui
+    // (Optional) When using multiple viewports: set io.MouseHoveredViewport to the viewport the OS mouse cursor is hovering.
-    if (HWND hovered_hwnd = ::WindowFromPoint(pos))
+    // Important: this information is not easy to provide and many high-level windowing library won't be able to provide it correctly, because
+    // - This is _ignoring_ viewports with the ImGuiViewportFlags_NoInputs flag (pass-through windows).
+    // - This is _regardless_ of whether another viewport is focused or being dragged from.
+    // If ImGuiBackendFlags_HasMouseHoveredViewport is not set by the back-end, imgui will ignore this field and infer the information by relying on the
+    // rectangles and last focused time of every viewports it knows about. It will be unaware of other windows that may be sitting between or over your windows.
+    if (HWND hovered_hwnd = ::WindowFromPoint(mouse_screen_pos))
         if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle((void*)hovered_hwnd))
             io.MouseHoveredViewport = viewport->ID;
 }

imgui.cpp

@@ -2544,7 +2544,7 @@ void ImGui::SetFocusID(ImGuiID id, ImGuiWindow* window)
     IM_ASSERT(id != 0);
 
     // Assume that SetFocusID() is called in the context where its NavLayer is the current layer, which is the case everywhere we call it.
-    const int nav_layer = window->DC.NavLayerCurrent;
+    const ImGuiNavLayer nav_layer = window->DC.NavLayerCurrent;
     if (g.NavWindow != window)
         g.NavInitRequest = false;
     g.NavId = id;
@@ -4511,14 +4511,14 @@ static void CheckStacksSize(ImGuiWindow* window, bool write)
 {
     // NOT checking: DC.ItemWidth, DC.AllowKeyboardFocus, DC.ButtonRepeat, DC.TextWrapPos (per window) to allow user to conveniently push once and not pop (they are cleared on Begin)
     ImGuiContext& g = *GImGui;
-    int* p_backup = &window->DC.StackSizesBackup[0];
+    short* p_backup = &window->DC.StackSizesBackup[0];
-    { int current = window->IDStack.Size;       if (write) *p_backup = current; else IM_ASSERT(*p_backup == current && "PushID/PopID or TreeNode/TreePop Mismatch!");   p_backup++; }    // Too few or too many PopID()/TreePop()
+    { int current = window->IDStack.Size;       if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup == current && "PushID/PopID or TreeNode/TreePop Mismatch!");   p_backup++; }    // Too few or too many PopID()/TreePop()
-    { int current = window->DC.GroupStack.Size; if (write) *p_backup = current; else IM_ASSERT(*p_backup == current && "BeginGroup/EndGroup Mismatch!");                p_backup++; }    // Too few or too many EndGroup()
+    { int current = window->DC.GroupStack.Size; if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup == current && "BeginGroup/EndGroup Mismatch!");                p_backup++; }    // Too few or too many EndGroup()
-    { int current = g.CurrentPopupStack.Size;   if (write) *p_backup = current; else IM_ASSERT(*p_backup == current && "BeginMenu/EndMenu or BeginPopup/EndPopup Mismatch"); p_backup++;}// Too few or too many EndMenu()/EndPopup()
+    { int current = g.CurrentPopupStack.Size;   if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup == current && "BeginMenu/EndMenu or BeginPopup/EndPopup Mismatch"); p_backup++;}// Too few or too many EndMenu()/EndPopup()
     // For color, style and font stacks there is an incentive to use Push/Begin/Pop/.../End patterns, so we relax our checks a little to allow them.
-    { int current = g.ColorModifiers.Size;      if (write) *p_backup = current; else IM_ASSERT(*p_backup >= current && "PushStyleColor/PopStyleColor Mismatch!");       p_backup++; }    // Too few or too many PopStyleColor()
+    { int current = g.ColorModifiers.Size;      if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup >= current && "PushStyleColor/PopStyleColor Mismatch!");       p_backup++; }    // Too few or too many PopStyleColor()
-    { int current = g.StyleModifiers.Size;      if (write) *p_backup = current; else IM_ASSERT(*p_backup >= current && "PushStyleVar/PopStyleVar Mismatch!");           p_backup++; }    // Too few or too many PopStyleVar()
+    { int current = g.StyleModifiers.Size;      if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup >= current && "PushStyleVar/PopStyleVar Mismatch!");           p_backup++; }    // Too few or too many PopStyleVar()
-    { int current = g.FontStack.Size;           if (write) *p_backup = current; else IM_ASSERT(*p_backup >= current && "PushFont/PopFont Mismatch!");                   p_backup++; }    // Too few or too many PopFont()
+    { int current = g.FontStack.Size;           if (write) *p_backup = (short)current; else IM_ASSERT(*p_backup >= current && "PushFont/PopFont Mismatch!");                   p_backup++; }    // Too few or too many PopFont()
     IM_ASSERT(p_backup == window->DC.StackSizesBackup + IM_ARRAYSIZE(window->DC.StackSizesBackup));
 }
 
@@ -4972,7 +4972,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window->Flags = (ImGuiWindowFlags)flags;
         window->LastFrameActive = current_frame;
         window->BeginOrderWithinParent = 0;
-        window->BeginOrderWithinContext = g.WindowsActiveCount++;
+        window->BeginOrderWithinContext = (short)(g.WindowsActiveCount++);
     }
     else
     {
@@ -5213,7 +5213,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         // Position child window
         if (flags & ImGuiWindowFlags_ChildWindow)
         {
-            window->BeginOrderWithinParent = parent_window->DC.ChildWindows.Size;
+            window->BeginOrderWithinParent = (short)parent_window->DC.ChildWindows.Size;
             parent_window->DC.ChildWindows.push_back(window);
             if (!(flags & ImGuiWindowFlags_Popup) && !window_pos_set_by_api && !window_is_child_tooltip)
                 window->Pos = parent_window->DC.CursorPos;
@@ -5496,7 +5496,7 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         window->DC.CurrentLineSize = window->DC.PrevLineSize = ImVec2(0.0f, 0.0f);
         window->DC.CurrentLineTextBaseOffset = window->DC.PrevLineTextBaseOffset = 0.0f;
         window->DC.NavHideHighlightOneFrame = false;
-        window->DC.NavHasScroll = (GetScrollMaxY() > 0.0f);
+        window->DC.NavHasScroll = (GetWindowScrollMaxY(window) > 0.0f);
         window->DC.NavLayerActiveMask = window->DC.NavLayerActiveMaskNext;
         window->DC.NavLayerActiveMaskNext = 0x00;
         window->DC.MenuBarAppending = false;
@@ -5552,8 +5552,8 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
             // Close & collapse button are on layer 1 (same as menus) and don't default focus
             const ImGuiItemFlags item_flags_backup = window->DC.ItemFlags;
             window->DC.ItemFlags |= ImGuiItemFlags_NoNavDefaultFocus;
-            window->DC.NavLayerCurrent++;
+            window->DC.NavLayerCurrent = ImGuiNavLayer_Menu;
-            window->DC.NavLayerCurrentMask <<= 1;
+            window->DC.NavLayerCurrentMask = (1 << ImGuiNavLayer_Menu);
 
             // Collapse button
             if (!(flags & ImGuiWindowFlags_NoCollapse))
@@ -5568,8 +5568,8 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
                     *p_open = false;
             }
 
-            window->DC.NavLayerCurrent--;
+            window->DC.NavLayerCurrent = ImGuiNavLayer_Main;
-            window->DC.NavLayerCurrentMask >>= 1;
+            window->DC.NavLayerCurrentMask = (1 << ImGuiNavLayer_Main);
             window->DC.ItemFlags = item_flags_backup;
 
             // Title bar text (with: horizontal alignment, avoiding collapse/close button, optional "unsaved document" marker)
@@ -5807,7 +5807,7 @@ void ImGui::FocusWindow(ImGuiWindow* window)
         g.NavInitRequest = false;
         g.NavId = window ? window->NavLastIds[0] : 0; // Restore NavId
         g.NavIdIsAlive = false;
-        g.NavLayer = 0;
+        g.NavLayer = ImGuiNavLayer_Main;
         //IMGUI_DEBUG_LOG("FocusWindow(\"%s\")\n", window ? window->Name : NULL);
     }
 
@@ -8386,7 +8386,7 @@ static ImGuiWindow* ImGui::NavRestoreLastChildNavWindow(ImGuiWindow* window)
     return window->NavLastChildNavWindow ? window->NavLastChildNavWindow : window;
 }
 
-static void NavRestoreLayer(int layer)
+static void NavRestoreLayer(ImGuiNavLayer layer)
 {
     ImGuiContext& g = *GImGui;
     g.NavLayer = layer;
@@ -8643,7 +8643,7 @@ static void ImGui::NavUpdate()
         else if (g.NavLayer != 0)
         {
             // Leave the "menu" layer
-            NavRestoreLayer(0);
+            NavRestoreLayer(ImGuiNavLayer_Main);
         }
         else
         {
@@ -9028,8 +9028,8 @@ static void ImGui::NavUpdateWindowing()
             NavInitWindow(apply_focus_window, false);
 
         // If the window only has a menu layer, select it directly
-        if (apply_focus_window->DC.NavLayerActiveMask == (1 << 1))
+        if (apply_focus_window->DC.NavLayerActiveMask == (1 << ImGuiNavLayer_Menu))
-            g.NavLayer = 1;
+            g.NavLayer = ImGuiNavLayer_Menu;
 
         // Request OS level focus
         if (apply_focus_window->Viewport != previous_viewport && g.PlatformIO.Platform_SetWindowFocus)
@@ -9058,10 +9058,10 @@ static void ImGui::NavUpdateWindowing()
         g.NavDisableMouseHover = true;
 
         // When entering a regular menu bar with the Alt key, we always reinitialize the navigation ID. It however persist on docking tab tabs.
-        const int new_nav_layer = (g.NavWindow->DC.NavLayerActiveMask & (1 << 1)) ? (g.NavLayer ^ 1) : 0;
+        const ImGuiNavLayer new_nav_layer = (g.NavWindow->DC.NavLayerActiveMask & (1 << ImGuiNavLayer_Menu)) ? (ImGuiNavLayer)((int)g.NavLayer ^ 1) : ImGuiNavLayer_Main;
         const bool preserve_layer_1_nav_id = (new_nav_window->DockNodeAsHost != NULL);
-        if (new_nav_layer == 1 && !preserve_layer_1_nav_id)
+        if (new_nav_layer == ImGuiNavLayer_Menu && !preserve_layer_1_nav_id)
-            g.NavWindow->NavLastIds[1] = 0;
+            g.NavWindow->NavLastIds[ImGuiNavLayer_Menu] = 0;
         NavRestoreLayer(new_nav_layer);
     }
 }
@@ -11019,8 +11019,8 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
     if (!node->IsDockSpace)
     {
         host_window->SkipItems = false;
-        host_window->DC.NavLayerCurrent++;
+        host_window->DC.NavLayerCurrent = ImGuiNavLayer_Menu;
-        host_window->DC.NavLayerCurrentMask <<= 1;
+        host_window->DC.NavLayerCurrentMask = (1 << ImGuiNavLayer_Menu);
     }
 
     PushID(node->ID);
@@ -11209,8 +11209,8 @@ static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_w
     // Restore SkipItems flag
     if (!node->IsDockSpace)
     {
-        host_window->DC.NavLayerCurrent--;
+        host_window->DC.NavLayerCurrent = ImGuiNavLayer_Main;
-        host_window->DC.NavLayerCurrentMask >>= 1;
+        host_window->DC.NavLayerCurrentMask = (1 << ImGuiNavLayer_Main);
         host_window->SkipItems = backup_skip_item;
     }
 }

imgui.h

@@ -45,7 +45,7 @@ Index of this file:
 
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY00 then bounced up to XYY01 when release tagging happens)
-#define IMGUI_VERSION               "1.66b"
+#define IMGUI_VERSION               "1.67 WIP"
 #define IMGUI_VERSION_NUM           16602
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert))
 #define IMGUI_HAS_VIEWPORT          1 // Viewport WIP branch
@@ -1316,7 +1316,7 @@ struct ImGuiIO
     bool        MouseDown[5];                   // Mouse buttons: 0=left, 1=right, 2=middle + extras. ImGui itself mostly only uses left button (BeginPopupContext** are using right button). Others buttons allows us to track if the mouse is being used by your application + available to user as a convenience via IsMouse** API.
     float       MouseWheel;                     // Mouse wheel Vertical: 1 unit scrolls about 5 lines text.
     float       MouseWheelH;                    // Mouse wheel Horizontal. Most users don't have a mouse with an horizontal wheel, may not be filled by all back-ends.
-    ImGuiID     MouseHoveredViewport;           // (Optional) When using multiple viewports: viewport the OS mouse cursor is hovering _IGNORING_ viewports with the ImGuiViewportFlags_NoInputs flag, and _REGARDLESS_ of whether another viewport is focused. Set io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport if you can provide this info. If you don't imgui will use a decent heuristic instead.
+    ImGuiID     MouseHoveredViewport;           // (Optional) When using multiple viewports: viewport the OS mouse cursor is hovering _IGNORING_ viewports with the ImGuiViewportFlags_NoInputs flag, and _REGARDLESS_ of whether another viewport is focused. Set io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport if you can provide this info. If you don't imgui will infer the value using the rectangles and last focused time of the viewports it knows about (ignoring other OS windows).
     bool        KeyCtrl;                        // Keyboard modifier pressed: Control
     bool        KeyShift;                       // Keyboard modifier pressed: Shift
     bool        KeyAlt;                         // Keyboard modifier pressed: Alt

imgui_internal.h

@@ -408,13 +408,20 @@ enum ImGuiNavForward
     ImGuiNavForward_ForwardActive
 };
 
+enum ImGuiNavLayer
+{
+    ImGuiNavLayer_Main  = 0,    // Main scrolling layer
+    ImGuiNavLayer_Menu  = 1,    // Menu layer (access with Alt/ImGuiNavInput_Menu)
+    ImGuiNavLayer_COUNT
+};
+
 enum ImGuiPopupPositionPolicy
 {
     ImGuiPopupPositionPolicy_Default,
     ImGuiPopupPositionPolicy_ComboBox
 };
 
-// 1D vector (this odd construct is used to facilitate the transition between 1D and 2D and maintenance of some patches)
+// 1D vector (this odd construct is used to facilitate the transition between 1D and 2D, and the maintenance of some branches/patches)
 struct ImVec1
 {
     float   x;
@@ -892,7 +899,7 @@ struct ImGuiContext
     float                   NavWindowingTimer;
     float                   NavWindowingHighlightAlpha;
     bool                    NavWindowingToggleLayer;
-    int                     NavLayer;                           // Layer we are navigating on. For now the system is hard-coded for 0=main contents and 1=menu/title bar, may expose layers later.
+    ImGuiNavLayer           NavLayer;                           // Layer we are navigating on. For now the system is hard-coded for 0=main contents and 1=menu/title bar, may expose layers later.
     int                     NavIdTabCounter;                    // == NavWindow->DC.FocusIdxTabCounter at time of NavId processing
     bool                    NavIdIsAlive;                       // Nav widget has been seen this frame ~~ NavRefRectRel is valid
     bool                    NavMousePosDirty;                   // When set we will update mouse position if (io.ConfigFlags & ImGuiConfigFlags_NavEnableSetMousePos) if set (NB: this not enabled by default)
@@ -1038,7 +1045,7 @@ struct ImGuiContext
         NavWindowingTarget = NavWindowingTargetAnim = NavWindowingList = NULL;
         NavWindowingTimer = NavWindowingHighlightAlpha = 0.0f;
         NavWindowingToggleLayer = false;
-        NavLayer = 0;
+        NavLayer = ImGuiNavLayer_Main;
         NavIdTabCounter = INT_MAX;
         NavIdIsAlive = false;
         NavMousePosDirty = false;
@@ -1119,12 +1126,12 @@ struct IMGUI_API ImGuiWindowTempData
     ImGuiItemStatusFlags    LastItemStatusFlags;
     ImRect                  LastItemRect;           // Interaction rect
     ImRect                  LastItemDisplayRect;    // End-user display rect (only valid if LastItemStatusFlags & ImGuiItemStatusFlags_HasDisplayRect)
-    bool                    NavHideHighlightOneFrame;
+    ImGuiNavLayer           NavLayerCurrent;        // Current layer, 0..31 (we currently only use 0..1)
-    bool                    NavHasScroll;           // Set when scrolling can be used (ScrollMax > 0.0f)
-    int                     NavLayerCurrent;        // Current layer, 0..31 (we currently only use 0..1)
     int                     NavLayerCurrentMask;    // = (1 << NavLayerCurrent) used by ItemAdd prior to clipping.
     int                     NavLayerActiveMask;     // Which layer have been written to (result from previous frame)
     int                     NavLayerActiveMaskNext; // Which layer have been written to (buffer for current frame)
+    bool                    NavHideHighlightOneFrame;
+    bool                    NavHasScroll;           // Set when scrolling can be used (ScrollMax > 0.0f)
     bool                    MenuBarAppending;       // FIXME: Remove this
     ImVec2                  MenuBarOffset;          // MenuBarOffset.x is sort of equivalent of a per-layer CursorPos.x, saved/restored as we switch to the menu bar. The only situation when MenuBarOffset.y is > 0 if when (SafeAreaPadding.y > FramePadding.y), often used on TVs.
     ImVector<ImGuiWindow*>  ChildWindows;
@@ -1140,7 +1147,7 @@ struct IMGUI_API ImGuiWindowTempData
     ImVector<float>         ItemWidthStack;
     ImVector<float>         TextWrapPosStack;
     ImVector<ImGuiGroupData>GroupStack;
-    int                     StackSizesBackup[6];    // Store size of various stacks for asserting
+    short                   StackSizesBackup[6];    // Store size of various stacks for asserting
 
     ImVec1                  Indent;                 // Indentation / start position from left of window (increased by TreePush/TreePop, etc.)
     ImVec1                  GroupOffset;
@@ -1158,11 +1165,11 @@ struct IMGUI_API ImGuiWindowTempData
         LastItemId = 0;
         LastItemStatusFlags = 0;
         LastItemRect = LastItemDisplayRect = ImRect();
+        NavLayerActiveMask = NavLayerActiveMaskNext = 0x00;
+        NavLayerCurrent = ImGuiNavLayer_Main;
+        NavLayerCurrentMask = (1 << ImGuiNavLayer_Main);
         NavHideHighlightOneFrame = false;
         NavHasScroll = false;
-        NavLayerActiveMask = NavLayerActiveMaskNext = 0x00;
-        NavLayerCurrent = 0;
-        NavLayerCurrentMask = 1 << 0;
         MenuBarAppending = false;
         MenuBarOffset = ImVec2(0.0f, 0.0f);
         StateStorage = NULL;
@@ -1215,9 +1222,9 @@ struct IMGUI_API ImGuiWindow
     bool                    Appearing;                          // Set during the frame where the window is appearing (or re-appearing)
     bool                    Hidden;                             // Do not display (== (HiddenFramesForResize > 0) ||
     bool                    HasCloseButton;                     // Set when the window has a close button (p_open != NULL)
-    int                     BeginCount;                         // Number of Begin() during the current frame (generally 0 or 1, 1+ if appending via multiple Begin/End pairs)
+    short                   BeginCount;                         // Number of Begin() during the current frame (generally 0 or 1, 1+ if appending via multiple Begin/End pairs)
-    int                     BeginOrderWithinParent;             // Order within immediate parent window, if we are a child window. Otherwise 0.
+    short                   BeginOrderWithinParent;             // Order within immediate parent window, if we are a child window. Otherwise 0.
-    int                     BeginOrderWithinContext;            // Order within entire imgui context. This is mostly used for debugging submission order related issues.
+    short                   BeginOrderWithinContext;            // Order within entire imgui context. This is mostly used for debugging submission order related issues.
     ImGuiID                 PopupId;                            // ID in the popup stack when this window is used as a popup/menu (because we use generic Name/ID for recycling)
     int                     AutoFitFramesX, AutoFitFramesY;
     bool                    AutoFitOnlyGrows;
@@ -1258,8 +1265,8 @@ struct IMGUI_API ImGuiWindow
     ImGuiWindow*            RootWindowForNav;                   // Point to ourself or first ancestor which doesn't have the NavFlattened flag.
 
     ImGuiWindow*            NavLastChildNavWindow;              // When going to the menu bar, we remember the child window we came from. (This could probably be made implicit if we kept g.Windows sorted by last focused including child window.)
-    ImGuiID                 NavLastIds[2];                      // Last known NavId for this window, per layer (0/1)
+    ImGuiID                 NavLastIds[ImGuiNavLayer_COUNT];    // Last known NavId for this window, per layer (0/1)
-    ImRect                  NavRectRel[2];                      // Reference rectangle, in window relative space
+    ImRect                  NavRectRel[ImGuiNavLayer_COUNT];    // Reference rectangle, in window relative space
 
     // Navigation / Focus
     // FIXME-NAV: Merge all this with the new Nav system, at least the request variables should be moved to ImGuiContext

imgui_widgets.cpp

@@ -5529,8 +5529,8 @@ bool ImGui::BeginMenuBar()
 
     window->DC.CursorPos = ImVec2(bar_rect.Min.x + window->DC.MenuBarOffset.x, bar_rect.Min.y + window->DC.MenuBarOffset.y);
     window->DC.LayoutType = ImGuiLayoutType_Horizontal;
-    window->DC.NavLayerCurrent++;
+    window->DC.NavLayerCurrent = ImGuiNavLayer_Menu;
-    window->DC.NavLayerCurrentMask <<= 1;
+    window->DC.NavLayerCurrentMask = (1 << ImGuiNavLayer_Menu);
     window->DC.MenuBarAppending = true;
     AlignTextToFramePadding();
     return true;
@@ -5556,7 +5556,7 @@ void ImGui::EndMenuBar()
             IM_ASSERT(window->DC.NavLayerActiveMaskNext & 0x02); // Sanity check
             FocusWindow(window);
             SetNavIDWithRectRel(window->NavLastIds[1], 1, window->NavRectRel[1]);
-            g.NavLayer = 1;
+            g.NavLayer = ImGuiNavLayer_Menu;
             g.NavDisableHighlight = true; // Hide highlight for the current frame so we don't see the intermediary selection.
             g.NavMoveRequestForward = ImGuiNavForward_ForwardQueued;
             NavMoveRequestCancel();
@@ -5571,8 +5571,8 @@ void ImGui::EndMenuBar()
     window->DC.GroupStack.back().AdvanceCursor = false;
     EndGroup(); // Restore position on layer 0
     window->DC.LayoutType = ImGuiLayoutType_Vertical;
-    window->DC.NavLayerCurrent--;
+    window->DC.NavLayerCurrent = ImGuiNavLayer_Main;
-    window->DC.NavLayerCurrentMask >>= 1;
+    window->DC.NavLayerCurrentMask = (1 << ImGuiNavLayer_Main);
     window->DC.MenuBarAppending = false;
 }